Società Italiana di elettroencefalografia e neurofisiologia clinica

Società Italiana di elettroencefalografia e neurofisiologia clinica

36P Electroencephalography and clinical Neurophysiology, 1983, 56: 36P-53P Elsevier Scientific Publishers Ireland, Ltd. Society proceedings S O C I ...

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36P

Electroencephalography and clinical Neurophysiology, 1983, 56: 36P-53P Elsevier Scientific Publishers Ireland, Ltd.

Society proceedings S O C I E T Y , I T A L I A N A DI ELETI~OENCEFALOGRAFIA E N E U R O F I S I O L O G I A

CLINICA

Garda, May 28-30, 1981

Secretary: Prof. BRUNO BERGAMASCO c / o Clinica Neurologica, Via Cherasco 15, 10126 Turin (Italy) (Received for publication: May 9, 1983)

1. Visual evoked responses (VER) in normal and ~ cats: an analysis of cortical ~ - - R . Cheraelio, A. P a l l ~ n i , D. Giaretta, M. Famani, L. Zanotto and G. Testa (Padiua)

3. Penicillin epilepsy in the rabbit: some neurophyaiological

comments. -- It. ~

G. ~ t t o ,

A. Iton~tn~a, M.

Corica, P. De D ~ G. Di Stefano, M, Santoro, G. Troilo and R. Di P e r d ( M ~ n a )

Intracortical recording of VERs was performed in the cat (using a microelectrode pushed into the visual cortex from the surface to 2000 p,m by i00 pm steps) before and during generalized 'penicillin epilepsy. Flash stimuli were randomly delivered before penicillin and during the periods between bursts after penicillin, time-locked to the spike of the S-W bursts with a delay of 30 msec, so that the VER was recorded during the wave. Averaged cortical VERs were also analyzed by Current Source Density Analysis method. An early excitatory event, a large sink, was recognized at deep levels (1100-1400 pro) corresponding to a large surface positive wave of the VEP in the animals before penicillin; during the periods between bursts after penicillin, it was replaced by multiple sinks at different depths (500-600 /~m, 800-1 I00 pro, 1600 pro) followed at these same levels by large sources. During the wave of the S-W complex a single large deep sink was again noticed, whereas superficial layers seemed to be less active than during both normal recordings and those recorded between bursts. These results suggest that after penicillin there is a spread of excitation to adjacent layers whereas during the wave of the S-W complex the cortical excitability is decreased although cortical neurones are still able to respond in a quasi-normal fashion to specific excitatory afferents.

In cats parenteral penicillin is known to induce a generalized epileptic pattern similar to human 'petit mal' (Prince and Farrell 1969), whereas in rats and chicks it induces multifocal epilepsy. At present, however, there is only little data concerning the clinical and EEG effects of penicillin in rabbits. The aim of this study was to observe the epileptogenic effect of i.v. penicillin in rabbits. Electrocorticographic activity has been recorded before and after i.v. Na-Penicillin-G (l,100.0001.300,000/kg) in l0 chronically implanted rabbits. Two to 30 rain following the injection, all rabbits showed: (l) and increase in density, duration and amplitude of their basal spindle activity; (2) high amplitude spikes and polyspikes occurring in the spindle complex in 70~ of the rabbits; (3) isolated spikes in the remaining 30%. A convulsive electroclinical pattern was observed in 30~ of the whole group. A relationship between spindles and epileptiform activity has already been reported (Fenney et al. 1977). The prominent occurrence of penicillin spikes during spindle activity makes our experimental model a valid tool for further neurophysiological and neuropharmacologlcal studies concerning the interactions between spindles and epilepsy.

2. Carimmazepine brain uptake in the normal cat and in the cat rendered ~ by parenteral penicillin, - - F. Monaco, S. Plredda, S. Traccis, M. Frassetto and R. Mutani (Sassari)

4. EEG and behaviourai ~ induced by hypothalamic hormones in the ~ . Prelhmhlutry results concerning thyrotmphin-raleasing hormone and somatostatin. - - A. Tartara, P. Bo, M. Mat~elli, G. Murlaldo and F. Savoldi (Pavia)

Carbamazepine (CBZ) brain uptake was determined in norreal cats and in cats rendered epileptic by administration of 250,000 IU of penicillin/kg given parenterally. CBZ penetration in the brain was significantly different in the two groups (0.005 < P < 0.025). In normal cats brain/plasma ratio peaked at 15 rain (2.44), while in epileptic cats the peak occurred at 30 rain (0.7). CBZ uptake in the epileptic brain was delayed (peak at 60 rain). In both groups, a substantial binding of the drug to brain tissue occurred. In the absence of gliosis and/or focal scar tissue in our experimental model, it is suggested that CBZ is bound to the normal epileptic cortex in a manner different from that of healthy brain.

Preliminary results concerning the effects of thyrotrophinreleasing hormone (TRH) and somatostatin on the EEG and behaviour in the conscious rabbit are reported. The drugs were administered by means of a constant perfusion pump into the mesencephalic ventricle, being run through a cannula inserted according to Monnier and Hatt's technique. The following doses were used: TRH, 50 pg; somatostatin, 100-200 #g. The electrical activity of the motor, sensory-motor and visual cortex, Ammon's dorsal horn and medial nuclei of the thalamus have been evaluated. The rabbits were in a hammock and able to move to a limited extent.

0013-4649/83/$03.00 © 1983 Elsevier Scientific Publishers Ireland, Ltd.

ITALIAN EEG SOCIETY TRH produced a desynchronizing effect on cortical activity. It also induced peculiar stereotyped behaviour and an increase in colonic temperature of about I°C. Somatostatin induced synchronization of electrical cortical activity, no significant changes of behaviour and an increase in colonic temperature of 0.5°C. Our results partially agree with those reported in the literature and appear to emphasize the value of EEG methods in the study of central extrahypothalamic effects of these compounds. 5. Automatic analysis of the EEG during hyperbaric oxygen in patients with cerebral vascular insufficiency. - - C. Anne, G. Malta, P. Pola, R. Roselli, G.F. Rossi and A. Vignafi (Rome) The purpose of the present study was to develop a method capable of providing data which could be used to evaluate the reversibility of neuronal functional derangement following cerebral vascular insufficiency leading to stabilized stroke. This would allow selection of patients suitable for cerebral surgical revascularization (extra-intracranial arterial anastomosis). The method is based on the automatic elaboration (Digital MINC-II) of the electrocerebral activity recorded prior and during hyperbaric oxygen treatment (1.5 arm for 40 min). The power spectra of the different EEG bands was calculated. The results of the EEG analysis were then compared with those of the neurological examination and cerebral blood flow obtained before and after cerebral surgical revascularization. The results obtained in the first 15 patients so far studied indicate the reliability of the method employed. 6. Remarks on the preventive treatment of febrile convulsions. - - G. Capocchi, L. Girelli and P. D'Alessandro ( C i ~ di CasteHo and Perugla)

Since 1974, 152 children of under 3 years of age have been given prophylactic treatment after the first febrile convulsion, 132 were given dipropylacetate (DPA), 25 mg/kg, 3 times daily, and 20 were given phenobarbitone (PB) 4-5 mg/kg, in the evening oniy. All these children have been followed up until the age of 6 years. In the group of 54 children who have been treated regularly until the age of 6 years, 6 children (DPA, 4; PB, 2) have suffered relapses (11~). In the group of 51 children in whom treatment was interrupted after 1 or 2 years, 4 children have had relapses during the 3 years following the premature interruption of treatment. In the group of 47 children who stopped the prophylactic treatment after only a few months (6 because of vomiting) there have been 1-3 relapses in 15 children (32~) during the 3 years following the first febrile convulsion. It is concluded that: (1) DPA and PB, if taken regularly, prevent any form of relapse; (2) it is difficult to continue the preventive treatment with DPA (suspended prematurely in 95 out of 132 children); (3) relapses are not frequent in children who stop the treatment after 1 or 2 years; (4) side effects are rarely a cause for stopping treatment.

37P 7. Clinical and EEG study of acquired aphasia with epileptic seizures and EEG abnormalities. - - G. Capocehi and R. Urciuoll (Perugla and Foligno) A complete loss of language comprehension and production occurred in a right-handed girl of 3 years, a few days following 3 partial seizures with secondary generalization. During the following 4 years she has had short periods without seizures with an improvement in language and long periods with several seizures characterized by a complete regression in language. The seizures, more numerous during the night than during the day, have been of the following types: complex partial seizures with psychomotor or affective symptomatology, seizures with loss of contact and jerking of eyelids, seizures consisting of focal motor symptoms and automatisms, tonic-clonic seizures generalized from onset, and partial seizures with secondary generaliT~tion. The EEG showed interictal discharges of bilateral and often asynchronous foci, more frequent and obvious in the temporal regions, brief bursts of diffuse spikes and waves with eyelid jerks, long discharges of generalized spikes and waves during NREM deep. The results of routine neurological examinations were normal. Tests of intellectual function (non-verbal tests) showed her to be slightly below average. CAT and AERs were normal. 8. A peculiar form of reflex epilepsy: a case report. - - F. Cirignotta, L Gervasio, R. Medori, P. Giovanardi Rossi and E. Lugaresi (Bologna and Milan)

A 12-year-old child with a severe encephalopathy showed tonic seizures every time his napkins were changed. No seizures occurred on other occasions except during sleep. Polygraphic recordings, with TV control, showed that seizures always began when the trousers were hitched up after the change of napkins was finished. Several types of stimulation and simulation were ineffective, indicating that the factor triggering the seizure was related to the satisfaction and pleasure of dressing with the hitching up of the trousers as the final conclusive and gratifying act, without which the seizure did not occur. 9. H-reflex facilitation during generalized epileptic discharges without dinical symptoms. - - P. Ciripotta, P. Montagna, C,A. Tassinari and g. Lugaresi (Bologna)

Changes of H-reflex amplitude during generalized discharges of multiple spikes occurring in sleep were studied in 2 patients with Lennox-Gastaut syndrome. In both patients polygraphic studies included EEG, EOG, EKG, and EMG of deltoid, neck, chin, soleus and anterior tibial muscles. The H-reflex, evoked by stimulation of the posterior tibial nerve in the popliteal fossa, was automatically measured by means of a time-window and displayed on the polygraph. The discharges were clinically asymptomatic and no changes were present in the EMG and EKG. However, the H-reflex showed clear facilitation a short time after the onset of discharge and lasted a few seconds after the end of the discharge.

38P Such facilitation could be a non-specific sign related to arousal or the effect of a direct fa~litatory influence of the discharge on the spinal neurones. 10. ~ i c a t i o n of myoclonic ~ of the first three years o¢ I ~ e . - B. Dalla ~ G. C a p a v ~ V. Colamarla, M.B. Gatloni, F. De/ ZoCti, C. Drm,et, M. lhu'eau and J. Roger (Verona and M a r s e l l ~ France) An electroclinical analysis has been made in a group of 141 patients with repeated epileptic myoclonic seizures presenting from 0 to 3 years of age. The parameters considered were as follows: (1) family history of epilepsy or febrile convulsions; (2) previous history of patients; (3) age at which first seizure occurred; (4) symptomatology and frequency of fits; (5) early response to treatment; (6) polygraphic EEG patterns of interictal periods and attacks; (7) evolution of neurological development; (8) evolution of seizures; (9) evolution of EEG or polygraphic patterns. On the basis of these parameters the following electroclinical data were recognized: (l) early myoclonic epileptic encephalopathy; (2) West syndrome with typical pattern; (3) myoclonic epileptic status; (4) generalized myoclonic epilepsy of infancy; (5) benign myoclonic epilepsy. Classification appeared to be impossible for 45 of the patients. On the basis of these results the classification and the possibility of using the same parameters from the prognostic point of view in the unclassified cases are discussed. 11. Em'ly myodonic epileptic encephalopathy. - - B. Dalla B e r n a r d i ~ $. Bondavalli, V. Feyerman, O. Dulac, C. Dravet, M. i~,~,~a,~l a ~ J. Roger (Verona and Marseilles, France) An electroclinical longitudinal study has been made of 9 infants born after uneventful pregnancy and birth who had developed normally until the appearance of seizures. The first attacks were partial erratic myoclonic phenomena appearing between the second day and the second month of life. At the same time the babies became hypotonic and psychomotor development stopped completdy. Partial erratic seizures and tonic non-epileptic spasms appeared during the following months; at the same time muitifocal abnormalities and frequent suppression bursts during sleep were seen in the EEG. The children either died before the end of the second year of life or evidence of gross neurological damage was present. The absence of an expanding lesion or malformation and the resemblance with other dysmetabolic epileptic encephalopathies suggest that these electroclinical features are caused by an inborn error of metabolism. 12. Side.effects of anticonvulmnt dcugs: doee-dependem cardiac block induced by carl~vuN~ne. - - L. Durelli, R, Mutani, G. Seehi and N; ~ ($asmut and Turin) Since carbamazepine possesses a depressive effect on atrioventricular conduction and is used in patients with possible

SOCIETY PROCEEDINGS cardiac abnormalities (such as patients with dystrophia myotonica or elderly people), the observation of cardiological side-effects deserves considerable attention. In two brothers with dystrophia myotonica a double-blind study of carbamazepine treatment was initiated under careful electrocardiographic control and frequent determinations of blood levels of the drug. In both patients the occurrence of atrioventricular block of 1° type was noted and the atrioventricular conduction time was directly proportional to the blood level of carbamazepine. The cardiac block disappeared after discontinuation of the drug. Only a few clinical reports of cardiac effects of carbamazepine have thus far appeared and always when very high oral doses (800-1200 mg/day) have been used and in patients already affected with severe disturbances of atrioventricular conduction. Our report, concerning patients with possible but not clinically apparent conduction deficit, emphasizes the occurrence of a dose-dependent atrioventricular block at low blood levels of carbamazepine. These findings, together with the experimental data, suggest a direct effect of carbamazepine on the His-Purkinje system. Because carbamazepine diffuses widely, the need for careful electrocardiographic control, particularly in potentially cardiopathic patients, must be stressed. 13. A correlation stmly between EEG and i B y ~

eters. - - S. ~ G. Ptzzi ( ~

paramA. ~ , G. Nolle, C. Plerro and and Areo Feliee)

The relationship between EEG and psychological performances is still uncertain. However, although the EEG and psychological tests measure different biological functions, there should be some link between them. In fact proper psychological performance requires the integrity of cortical structure and metabolism, both of which are monitored by the EEG. In this study 14 elderly subjects (mean age 65.1 +7.7 years) had 4 channel EEG recorded from temporal and occipital regions which was electronically analysed and transformed into 12 values (relative power, mean frequency and radius of inertia for each frequency band). Psychological variables were as follows: weighted detedoraton, raw deterioration, coding, picture completion, block design, object assembly digit span. The strongest negative correlation ( P < 0.01 ) was found in T6-O2 between coding and thBta mean frequency. Other significant correlations ( P <0.05) were the following: T3-T5, theta power-digit span, negative; T5-OI. beta power-picture completion, positive; beta mean frequency-digit span, positive; tbeta power-digit span, negative: T4-T6. alpha mean frequency-coding, positive; T6-O2, thcta mean frequency-picture completion, negative; theta mean frequency-object assembly, negative; alpha radius of inertia-digit span, negative. The results indicate the possibility of correlation between EEG and psychological parameters provided that quantified spectral data, subtests and cortical areas have been taken into account.

ITALIAN EEG SOCIETY

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14. High incidence of febrile convulsions in a family. - - M. Glardinl (Verona)

drugs in myoclonus and trazodone seems to be the most powerful of these drugs.

Four out of 5 brothers had febrile convulsions (FC); the father, a paternal and a maternal uncle also had FC. The EEG showed mild abnormalities in all subjects, including parents. FC stopped in all subjects within 6 years and anti-epileptic therapy was suspended in all without reappearance of convulsions. In 3 out of the 4 brothers with FC, nothing specific in the way of developmental abnormality was noted.

17. Post-traumatic coma: clinical, EEG, CT correlations. - A.M. Mauro, O. Scsrpino, P. Brunellini, U. Pasquini and D. Testasecca (Ancona)

15. Preliminary epidemiological results on epileptic patients at the Padua Centre for epilepsy. - - D. Giaretta, P. Paiola, A. Pellegrlni, R. Chemello, L Zanotto and G. Testa (Padua) A questionnaire concerning clinical and psycho-social data was given to 350 epileptic out-patients at the Padua Epileptic Centre. The most significant data obtained were the following: (I) The age of onset of the first seizure had its peaks at 5-11 and 14-20 years with a marked predominance of complex partial and partial secondary generalized seizures. (2) In 54% of patients no specific aetiological factors were found; perinatal pathology was reported in 23%; 15% of patients had febrile convulsions. (3) More than half the patients had first been seen by a general physician; however, specific and adequate prescriptions were given by a neurologist or a paediatrician with concomitant improvement in seizure frequency. (4) About 77% of patients had been hospitalized. In relation to routine examinations, CAT scan was performed in 121 patients, showing localized or diffuse abnormalities in 45%, mainly in those patients with partial complex seizures. (5) The highest percentage of people with epilepsy were in the lowest social group. 27% of these patients were unemployed and 12% were fired because of the disease. (6) In social and psychomotor terms epilepsy was found to be a major problem in 26%. This data confirms previous reports about the epidemiology of epilepsy. 16. Action myoclonu~ therapy with serotoninergie drugs. - - N. Leggiedro, M.G. Arena, A.E. Di Rosa and R. Di Perri (Messina) A deficiency of cerebral serotoninergic activity in the pathogenesis of 'intention or action myoclonus' has been demonstrated. Serotonin agonist treatment is, in fact, known to improve the myoclonic jerks. Our experience is related to a 52-year-old man with idiopathic myoclonic jerking prevalent at the onset of voluntary movements, which had developed over the last 12 years. Apart from 'action myoclonus,' the patient showed normal neurological, psychiatric and EEG findings. Acute administration of 5-HTP, clorimipramine, valproic acid, fenfluramine, trazodone and placebo was given orally. Since the best improvement was obtained with trazodone, this was also given for a longer period (300 rag/day). After 3 weeks of trazodone therapy the patient was able to stand, walk and manipulate. Metergoline (6 rag/day) added to the trazodone therapy interrupted the recovery of the patient. Our experience confirms previous reports on the efficacy of serotoninergic

Three parameters: clinical state, EEG and CT have been studied in 35 patients with post-traumatic coma. Clinically, the patients were classified on the basis of: (1) brain stem reflexes; (2) motor response to pain. CT gave information about ventricles, parenchyma and meningeal spaces. The EEG activity was classified as follows: changeable with or without sleeplike pattern; reactive and non-reactive borderline; monotonous slow; iscelectric. A good prognosis and changeable EEG activity characterized the group of patients with cortical-subcortical involvement. A similar evolution occurred in those patients with a diencephalic involvement and an EEG reactive to stimulation. If reactive, the borderline EEG was associated with a good prognosis regardless of the level of coma. On the other hand, a poor prognosis occurred in those patients whose CT showed no brain stem involvement. The combination of these three parameters gives more significant information as regards prognosis, than if each is considered separately. 18. Changes of both s p o n t l e m ~ and evoked electri~ cerebral activity with pituitary ablation and naloxone. - - G. Morleea, G.L. MattioU, A. Dottt, F. Camernta, G. Bersani, A.M. Benedetto, F. Saullo and L. Parisi (Rome) Spontaneous electrical cerebral activity was recorded before and after pituitary ablation using the CSA method; during pituitary ablation the EEG was recorded. In addition cerebral activity was also studied by recording potentials evoked by electrical stimulation of the second trigeminal branch. The same measurements were also made after i.v. administration of naloxone (0.8 rag). The most significant results were a marked decrease of both spontaneous and evoked cerebral electrical activity with pituitary ablation; naloxone administration caused an increase in amplitude. In our opinion the changes after pituitary ablation are probably related to a reduction of electrical cerebral activity caused by ethanol administration into the bypophyseal fossa. The action of naloxone is probably due to synchronizing effects in the CNS. 19. Alertness and incidence of seizures in patients with Lennox-Gastaut syndrome. - - M. Papini and A. Pasquinelli

(Florence) Sixteen subjects with Lennox-Gastaut syndrome (11 males and 5 females) ranging from 5 to 15 years of age (mean age 9 years 11 months) were followed for a period of 9 months to 5 years 9 months. They were studied during various hospital admissions for a total period of 2-9 months with the view of examining the distribution of epileptic seizures during four

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SOCIETY PROCEEDINGS

states of vigilance, evaluated from a behavioural point of view: sleep, drowsiness, inactive wakefulness and active wakefulness. It was ascertained that the overall average of 406 seizures daily, directly observed were distributed as follows: (I) 26 (6.40~) during sleep; (2) 128 (3L52~) during drowsiness; (3) 219 (53.94~) during inactive wakefulness; (4) 33 (8.12~) during active wakefulness. Comparison between the incidence of seizures observed during active wakefulness and those observed during both drowsiness and inactive wakefulness had yielded a significant result ( P < 0.001). The latter two states represent, in our study, the shortest period of the day (8 h, as compared with the 16 h of sleep and active wakefulness), thus making the result of the comparison even more ~ f i c a n t . The results of this study suggest the importance of a stimulating environment for children with Lennox-Gastaut syndrome. It is also pointed out that an overdose of anti-epileptic drugs, not uncommon in the treatment of this syndrome may cause an increase in seizure frequency. 20. ~ - ~

disease and L-aeayieamittne: a clinical and dec-

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A study of the effects of L-acetylcarnitine has been made in a group of 9 patients with Alzheimer disease of less than 1 year duration. Therapy was prolonged for a period of 30 days (1 g / d a y orally). The following mental tests were carried out on all patients before and after treatment: (1) age-relevant checklist (Birren); (2) physical self maintenance scale (Lawton); (3) instrumental activities of daily riving scale (Lawton); (4) mental status score (Bitten); (5) digit span and digit symbol (Wechsler-Ballevue), An electrophysiological study recording the Contingent Negative Variation (CNV) was carried out as such slow brain potentials can be correlated to attentiveness and associative functions. The results showed an improvement in attention, insight, sense of well-being; in some cases (3 out of 9) restlessness was observed. CNV voltage was increased in 4 patients; all patients characteristically had higher digit symbol scores in basal conditions. It is considered that the results found relate to a central effect determined by use of L-acetyicarnitine. This activity may be related to an increment in acetyl CoA brain level induced by this substance. Some possible influences on neurotransmitters (ACh) are also discussed. 21. Aithesin in drug-resistant status eptlepChms: a case report. - - A. Prinmverth E. Benessi, R. Piva and C. Guardineam

(Gmm) A 20-year-old male patient, suffering from Lermox-Gastaut syndrome, had grand mal status epilepticus. Therapy with clonazepam, diazepam, clorazepate, corticosteroids and sodium thiopentone anaesthesia were ineffective both in controlfing seizure pattern and in altering the diffuse spike activity occurring in the EEG. However, continuous i.v. infusion of althesin (up to 150 mi/day) was succeesful. Six days later, there was a relapse of the status epilepticus and again this was brought under control with i.v. althesin.

Thus the use of this steroid anaesthetic agent seems advisable in drug-resistant status epilepticus. More work is needed to elucidate its mechanism of action. Nevertheless we consider the previous hypothesis attributing its action to reducing intracranial pressure hard to maintain, In fact sodium thiopentone, which has an analogous effect on intracranial pressure and oxygen consumption, proved to be ineffective in our case. We suggest althesin has a direct anti-epileptic action. 22. Electroctinical effects of ketamine in epileptic patients. - A. Quattdni, A.M, Minas, A. Ortettzi, A. Pal~L, O. Scarpino

and D. Temmeea ( A m ) There is controversy concerning the effects of ketamine in epilepsy. Mori (1971) claims that it has an epi[eptogenic effect while others, Celesia (t974), deny this action. Twenty-five epileptic patients were studied (12 male, 13 female; average age 28 years). The attacks presented were: simple partial, partial with complex symptomatology, and generalized. The average seizure frequency was monthly. Data was obtained by polygraphic recordings during ketamine administration (2.5 mg/kg using a slow i.v. injection). Background EEG activity showed no variation from that which may be seen in normal subjects during ketamine administration. Interictal activity was, in general, reduced (except in one case appearing as a temporal focus), becoming again obvious after awakening. In the cases with spike-and-wave complexes such activity was isolated, appearing early in the anaesthesia, and mixed with the ketamine complexes. One patient had a brief focal attack in which EEG ictal activity showed a desynchronized pattern with superimposed EMG activity. Cardiac rate was increased during the test. Ocular movements were absent in the synchronization phase. Muscle tone was higt'dy elevated. In our study ketamine did not show any particular e p ~ effect. There still remains, however, considerable doubt as to the action of this substance. 23. M a l p t e t ~ (MAEG) and EEG in brain disor6~ ~ ~ . - - G.B. mcci, L M o d e ~ S. Barhanera and G.L P.ammni (Rome) In this clinical study the majority of subjects were epileptic patients. The results are of great importance for the future of MEG in the foUowing two areas: (1) the diagnosis of brain disorders; (2) the furthering of knowledge of brain function. There are several s ~ f i c advantages of the MEG which can now be elaborated. In comparison with the simultaneous EEG, the MEG shows a higher power of spatial resolution. The magnetic signal is influenced by the distance and by orientation of the source but not by the intervening tissues (bone, scalp, etc.). Conscglmmtly some of the MEG recordings lo0k similar to those of electrococticog~phy. In addition, the MEG can indicate the direction of the signal. Although the advantages can be seen directly on the tracings, an exact comparison of the MEG and EEG requires a mathematical elaboration selected in the frequency domain (Fourier transform). At present there is only the possibility of utilizing just one SQUID. For this reason we have not been able to obtain either

ITALIAN EEG SOCIETY bilateral, symmetrical MEG recordings or simultaneous perpendicular directional recordings of the same area. These limits restrict the field of practical clinical application to localized lesions (tumours, focal epilepsy, ~tc.). 24. Spectral and topographical analysis of the modifications induced by intermittent photo stimulation (IPS) on the alpha 'mode.' - - R. S f e r l a z ~ V. Cappellini, A. Ragazzoni, C. Caparrini, P. Martlnelli and V. Roma (Florence) EEG alpha waves have marked similarities with physical waves (Nunez 1974): they show a distinctive spatial distribution and stable phase relationships between different recording electrodes, appearing therefore as standing waves which develop on the scalp surface to form a 'mode.' As standing waves represent a pattern of space interference, the alpha ' mode' can result from the space interference between waves travelling on a closed surface, such as the cortex. In the present work, the IPS-induced modifications of the alpha 'mode' were studied in order to define the constructive and destructive interferences due to photic driving. Prolonged trains of light flashes (3 different energies; 8 stimulation rates) were delivered to normal adults. EEG activity (recorded from a grid of 30 equispaced scalp electrodes) was analysed by two techniques: 'off-line,' using an OTE Biomedica Berg-Fourier Analyzer PEU; 'on-line,' with a numeric analyser (composed of 16 digital filters, each with a 2 Hz bandwidth; Cappellini et al. 1980) for direct visualization of the filtered EEG. Alpha 'mode' changes observed during IPS suggest that photic stimuli interact with the normal alpha' mode' and therefore with its interference pattern: alpha waves appear as free, damped oscillations, whose 'mode' can be properly identified only during ' resonance.' 25. Spectral and topographical analysis of the alpha rhythm: the alpha 'mode.' - - R. Sfedazzo, A. Ragazzoni, V. CappeHini, C. Caparrini, P. Martinelli and V. Roma (Florence) The spatial-temporal characteristics of spontaneous alpha rhythm were studied using visual as well as Fourier analysis of the EEG in order to obtain a map displaying mean scalp topography. Several multichannel recordings were carried out in 6 normal adult volunteers, using a grid of 30 equispaced scalp electrodes with an average common reference. EEG signals, stored on-line on digital tape, were subsequently evaluated both visually (plotted out with high paper speed and enhanced amplification) and with an OTE Biomedica Berg-Fourier Analyzer PEU (analysis epochs varying between 8 and 32 sec). Maximal alpha power values were localized in two areas: a frontal, extended one (lower alpha peak with narrow bandwidth) and an occipital, more restricted area (higher alpha peak with wider bandwidth). Minimal alpha power values were distributed over a parietal-temporal line between these two areas. Visual inspection of EEG tracings revealed a phase

41P reversal between frontal and occipital regions with fairly stable phase relationships between channels, as well as a transversal node. Alpha waves are, therefore, characterized by two branches and a node: they appear as standing waves developing on the scalp surface and presenting a distinctive topography which can be properly defined as the alpha 'mode.' 26. Csrotid compression test: methodological aspects. - - G. Siderk E. Zanette, C. Geraldini and C. Butttnelli (Rome) An EEG study has been made on 150 cerebrovascular patients, tested by carotid compression: 50 were studied by the standard method only (A) and 50 were studied at the same time by means of ophthalmic dopplersonometry (B). In the other 50 (C), the compression and the ophthalmic dopplersonometry were preceded by detection of the internal carotid artery (ICA) origin using dopplersonometry. The incidence of EEG changes was about 26% in A, 3g~ in B and 42~ in C. In every group and especially in C the EEG abnormalities were more frequent compressing the ICA than compressing the common carotid artery (CCA) and appeared only when there was absence or marked reduction of flow in the ophthalmic artery. Blood pressure and heart rate during the test were considered in group C. These changes (vagal hyperexcitability) during 31 out of 200 compressions (32 ICA and 5 CCA). Pathological EEG patterns (54%) accompanied these cardiovascular changes. These results show that the detection of ICA origin and ophthalmic artery control by dopplersonometry increase the reliability of the carotid compression test. 27. 'Startle epilepsy': a neuruphysiologicai ease s t u d y i Striano and S. Vitolo (Naples)

S.

Startle epilepsy (SE) is a reflex epilepsy precipitated by stimuli of different kinds, the common factor being unexpectedness. According to Gastaut, an important aspect in the genesis of such epilepsy is an increased excitability of the brain stem reticular formation. Baneaud et al., using SDEEG, showed that the epileptic discharge originates in the motor cortical area and that the startle is the trigger. These authors concluded that SE is a reflex epilepsy precipitated by movement. A 20-year-old male, with perinatal brain damage (spastic tetraparesis and dystonia) showed typical SE. Phenobarbitone and clonazepam decreased the frequency and the severity of the seizures and allowed a more detailed EEG analysis. Assuming that, in SE, the startle is always a pathological feature, that the motor response depends on the 'startle subcortical pathway,' and that probably the EEG and EMG phenomena occur at the same time, we stress the importance of the role played by the subcortical structures (brain stem reticular formation), even though these structures do not represent the site of origin of the epileptic discharge.

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SOCIETY PROCEEDINGS

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wave') ~

~p

('tonic

~ ¢~aic

patiatts. - - C.A. T ~ i n m t , O. D a n l ~ , F. Cidrat& C.

Vmvet ~

J. ~

0Sao~ ~

~

l~rtn~)

Spinal cord changes involving dorsal root potentials and motoneurone excitability can occur during epileptic seizures (Ajmone Marsan and Maronero, Electro¢nceph. din. Neurophysiol., 1950; lkmou and Abdeloumene, ibid., 1970). The present study is a preliminary attempt to elucidate precisely if and how various types of paroxysmal discharges, observed in various types of epileptic syndromes and seizures, can modify spinal cord excitability. The H reflex was studied in relation to two types of paroxysmal discharges: (i) Subclinical rhythmic diffuse spike discharges as observed in 'tonic' seizures, during sleep in patients with Lennox-Gastaut syndrome. During 45 of these seizures the H reflexes (135 reflexes) were significantly increased. (2) Spike and wave discharge of various types in relation to morphology, frequency, clinical correlates, topography, etc. In this study generalized spike and waves, which occur in patients having the so-called 'electrical status epilepticus during sleep' syndrome (Tassinari et al. 1977) were considered. Allowing for the fact that the spike and wave discharges are continuous during sleep, a large number of H reflexes were delivered to either the spikes or the waves. The H reflex was not modified in relation to either the spike (or its various components) or the slow waves. 29. Visual ehrmamic tempm~ resolution. - - N. Acenroero, F. Fabimm and M. Mdatfr~ (Rome) A simple method for testing visual sensitivity to flickering light sources is proposed. The method uses a triangular function generator which modulates the luminance of a chromatic light source. Amplitude and frequency of the triangular pattern are adjusted until the subject perceives a periodic variation of luminance. In normal subjects the maximum sensitivity was found at a frequency modulation of 5-10 Hz. The sensitivity decreases from red to green. In multiple sclerosis patients the method proved to be more accurate than flicker fusion frequency in revealing subclinical damage of the visual pathway. 30. API~ ~ .

3L l~uma prtlactin levels in lmtieats treated with phenobarbitone. - - U. ~ G. M t a q t i ~ V. Sealori, L. Murri and A. Polk.H ~ ~ Genoa)

- - N. Acenrnero and M. Manfr¢~li (Rome)

The clinical application of automated perimetry has been prevented by high cost and operation difficulty. The reliability of today's microcomputers has allowed us to assemble at low cost a method for automated control of the Bjerrum screen examination. A 12 Kbyte program controls the presentation of 5 levels, 200 light spots on a 25 o n TV screen. A push-button controlled by the subject switches on the presentation. The level and position of the light spot is memorized in an Apple II microcomputer and floppy disk. At the end of the test the visual field map is visible on the screen or printed out.

Conflicting results concerning prolactin (PRL) secretion in patients treated with phenobarbitone (PB) have been reported. In a group of 57 epileptic patients (31 males and 26 females) aged 10 to 69 years, plasma levels of PRL and PB were measured. In another group of 14 male subjects aged 10 to 63 years undergoing prophylactic treatment with PB for posttraumatic epilepsy, the same determinations were performed. No subject in the second group had ever had a seizure. Plasma samples were collected between 8 and 9 a.m. and PRL levels measured by RIA double antibody method (Biodata, Milan; reference preparation WHO 222/71, Ing being equal to 23 micro IU). PB plasma levels were determined by gas chromatography. Plasma PRL levels above the normal range were most common in male patients (22%). There was no relationship between PRL values and blood levels of the drug in different groups. No side-effects due to elevated PRL values were observed. 32. A peculiar phakoamtosis: cutaneous hyperpipmntation (nmlaly over t H ~ m d ~ area), bone hypertml~ in the commpondi~ ~ off the same areas, severe ilmihtterai cerebral ~ - - F. Bravaecio, V. Peemtta, M.R. Tats, A. Guiz~,o, E. Voipe, C. Paolozzi, A. A m m a n ~ a and G.C. Guaz~ (Naples and Siena) Two female subjects, aged 11 and 36 years, have been studied. There was no family history of a similar pathology in either case. The clinical picture suggested a congenital neurocutaneous syndrome with the following characteristics: (1) cranio-facial hemi-hypertrophy and corresponding cerebral asymmetry due to a globally increased volume of the ipsilateral hemisphere; (2) cafe-au-lait spots over trigeminal cutaneous distribution, in the same areas affected by hypertrophy; (3) epilepsy with onset in the first year of life, initially with partial seizures which have subsequently become generalized, spontaneously remitting and with little response to the usual anti-epileptic therapy. EEGs have shown a marked epileptogenic abnormality with a focus in the affected hemisphere, tending to become diffuse and persisting over many years; (4) signs of hemipyramidal involvement opposite to the affected hemisphere and a mild-to-moderate degree of mental impairment; (5) karyotype has been normal in both patients. Although these 2 cases are suggestive of the phakomatoses they cannot be included in any of the known syndromes. In summary, this syndrome is characterized by cutaneous neuromelanosis, hypertrophy of the corresponding bone areas and cerebral ipsilateral hypertrophy-dysplasia. These 2 cases are sporadic. 33. Hypothesis coneemiag the neurophysiologieal correlate of heroin a~ktion. - - V. Ceeeoni and G. Doke (Rome) EEG investigations have been carried out on heroin addicts following 3 months' treatment with butorphanol tartrate (potent

ITALIAN EEG SOCIETY analgesic, narcotic agonist-antagonist). The EEG recordings were processed and the Star Index (SI) of spectral power values was computed. The right-left SI ratio was 0.71 (normal values 0.9-1.1). The ratio between the alpha power recorded on eye closure and that recorded on eye opening (AR), which expresses the alpha-blocking effect, was 9.72 in addicts and 2.30 in normal volunteers. The administration of butorphanol tartrate (I mg i.e.) induced a 50% increase of AR in addicted subjects, while no change was observed in normal subjects; it also induced in normal subjects a decrease of right-left SI ratio from 0.99 to 0.79. These results with the marked right-left asymmetry and the increased reactivity to drug stimulation, suggest the following hypothesis concerning the neurophysiological correlate of heroin addiction: the addict presents a lability of the vigilance regulation system and the long-term administration of narcotics induces a particular functional condition (EEG asymmetry) as described in psychotic patients. 34. An electrophysiulogical analysis of interactions between benzodiazepines and inhibitory neurotrausmitters. - - C. Frank, V. Taneredi, G. Leonelii, M. Avuli and A. Braneati (Rome)

The effects induced by benzodiazepine flurazepam (Flu) on neuronal responses to the inhibitory neurotransmitters yamino-butyric acid (GABA) and glycine (Gly) were analysed in the rat cortex. Standard microiontophoretic and extracelhilar recording techniques were employed. In 78% of neurones studied, spontaneous firing was depressed by the iontophoretic application of Flu (5.50 hA, cationic current) in a dose-dependent manner. The firing decrease became evident 8-20 sec after Flu current onset and continued 20-150 sec after Flu cessation. These changes were not observed when current controls were performed. During Flu ejection (10-30 hA, 60-400 sec) both the GABA- and Gly-induced responses seemed to be enhanced. However, because of the concomitant decrease of spontaneous firing by Flu, it was difficult to draw any definite conclusion. The use of low doses of Flu (3-10 hA) allowed analysis of the neuronal responses to GABA and Gly on an almost steady spontaneous firing. Using this experimental procedure, only GABA-induced inhibitory responses were seen to increase during Flu application, whereas Gly effects remained unchanged. These data, demonstrating that Flu mainly enhances responses to GABA, strongly suggest that benzodiazepines potentiate selectively synaptic mechanisms which are presumed to be GABA-mediated. 35. A polygraphic analysis of the 'tilting reaction' after labyrinthine stimulus. - - M. Frascarelli and V. Mariueci (Rome)

The tilting reaction is the dynamic change of the body after a quick angular displacement of the supporting base. A polygraphic study has been carried out on 9 healthy, right-handed

43P subjects, without scoliosis, neurological or otorhinolaryngological lesions, during a lateral fall in the sitting position. These volunteer subjects were placed with the eyes closed in the sitting position and then projected sideways before and after caloric stimulation of the vestibule. The polygraphic recording was made with contact electrodes on the paravertebral muscles at level CA-C5, and on the deltoid muscles of the two limbs. The results showed first a tonic period, a second phasic period and a third tonic period which was gready accentuated at the level of the paravertebral muscles after labyrinthine stimulation. The labyrinthine stimulation indicates that during lateral fall there is a more rapid and prolonged activation of the paravertebral muscles in an attempt to keep the barycentre within the supporting base. 36. Effects of L-DOPA on motor control during fast arm abduction in patients with Parkiuson's disease. - - T. Pentaleo, L. Fantini, F. Urbani, A. Baroni and F. Benvenuti (Florence)

Patients with Parkinson's disease seem to manifest a deficit in the pre-programming of accelerative forces for ballistic movements larger than a certain amplitude. The present study was carried out on patients with Parkinson's disease who had never been treated. The purpose was to investigtate the effects of L-DOPA on the patients' motor performance in a step-tracking task requiring fast arm abduction movements aiming at a target light; some spatio-temporal parameters of movements and surface electromyography (EMG) of agonist and antagonist muscles were studied. L-DOPA treatment decreased the duration of the initial movement towards the target and increased its mean velocity without loss of accuracy. No significant changes in visual reaction times were observed. EMG patterns of previously untreated patients displayed various degrees of alteration, and were improved consistently after treatment: initial agonist activity became more clustered and intense, while the timing of muscular actions looked more like that of ballistic movements. Moreover, the patients' motor performance and EMG patterns improved, even in motor tasks, with expected perturbations. The present results strengthen the hypothesis of a role of the basal ganglia in planning ballistic movements and indicate a mechanism of action of L-DOPA in counteracting bradykinesia. 37. Effects of gamma-globulln on the frequency of attacks and

EEG changes in epileptic child~n. - - M.R. de Fen, M.M. Formica and L. Rocchi (Rome) A study has been made of the clinical and EEG effects of IgG administration in 10 children, 3-9 years old (mean age 7 years), suffering from epileptic seizures. These children showed focal or generalized interictal epileptic abnormalities in the EEG. Clinical and EEG studies have been performed before and after IgG injections. After the first dose of IgG there was a decrease of epileptic EEG abnormalities in 5 cases. This effect lasted no longer than 15-20 days. Further injections of the drug did not change the

44P

SOCIETY PROCEEDINGS

clinical and EEG features. In only 3 out of these 10 patients was there also a long-lasting (2-3 months) decrease of epileptic seizures. There were no changes in the plasma levels of anti-epileptic drugs in all the patients tested. 38. The risk of r e e u ~ n e e in febtUe convulsions as evaluated by EEG. - - D. Porazzi and P. P e n ' . h e (Bust. Arsizlo) Fifty children, 5-8 years of age, who had a past history of febrile convulsions (FC), were examined. The EEGs were taken in order to analyse the background 4 - 7 Hz rhythms of Doose et al. (1972) as a possible expression of risk of recurrence. The EEGs were normal, with alpha rhythm of 8-10 Hz, in 35 subjects, 17 of whom had recurring FC. In the other 15 cases (8 with recurring FC) there were some variants in the records, but not in the background 4-7 Hz rhythms. EEG variants included: (a) occipital 4 Hz rhythms (6 eases); (b) localized slow rhythms (5 cases); (c) bursts of spikes (4 cases). Three patients also had seizures without fever: the EEG was normal in 2 cases and showed unilateral slow rhythms in the other case. 39. Vadaticms in H-wave mnptltode in relation to different body positions in man. - - I. Aiello, M. C a n e ~ G. lles,,qi, G. Serra, V. ' I ' u g ~ l and M. M m e a (Ferrara) Variations in ampfitude of the H-reflex of soleus muscle have been used in order to explore the influence of body position on soleus alpha mot,neurone pool. Ten normal adult volunteers have been studied. Standard methods have been used to elicit the H-reflex of soleus muscle. Each subject has been fixed to a rigid plane inclinable from the horizontal to the vertical position and vice versa. The head and the lower limbs have been immobilized and the eyes have been kept closed. In all subjects the average amplitudes of 10 H-reflexes have been calculated for each of the following positions, expressed in relation to the horizontal position: 0% 15° , 30 ° , 450 , 60 ° , 75 ° , 90 °, and 90 °, 75 °, 60 °, 45 °, 30*, 15 °, 00. Two cumulative curves have been obtained which are parabolic and are expressed by the following equations respectively: (1)

0° ~

90°:

p = 99.98499999-

0.416214286

X +

0.006846032 X2; (2) 90 ° -~ 0°: ) = 83.91738097 - 0.054976191 X + 0,002771958 X 2. The correlation coefficients r are 0.998 ( P < O.OOl) and 0.953 ( P < 0.001), respectively. A significant facilitation ( P < 0.05) has been observed around the vertical position. It is suggested that static vestibular influences are primarily involved in the observed facilitation on soleus alpha motorneurone pool. 40. E i e e t m p h y ~ ~ siam, L. ~

identification of latent neuropathy in to hexme. - - G. A n m b k A. MesF. Pierela, G. p e u e s s e r e and G. Valonte

(Rome)

An electrophysiological study has been carried out in a shoe factory where a health risk has been identified concerning a

group of 45 workers exposed to aliphatic hydrocarbon solvents. In order to detect the presence of any possible neurotoxic agent in the working environment, analysis of the air by gas chromatography has been done. Hexane was shown to be present in a concentration below permissible limits. There were no obvious specific signs or symptoms of a neuropathy and no clinical symptoms or pathology relating to the spinal column in any of the workers. Neurological examination was negative in all workers. However, electruphysiologlcal tests (electromyograp r y and electroneuronography) showed a number of pathological findings: 22.2% of EMGs were abnormal and 31.1% were borderline. The results of the electrophysiological investigations confirmed the possibility of making an immediate diagnosis of peripheral neuropathy from EMG and ENG findings in all exposed workers. 41. Cardiac rhythmicity of sympalhetic activity to sweat glands ~ in htllmn ~ a e r v e s . - - G. Bhti, G. Cmccu, ICE. H q b a r t h and G. W i n Oitsne and Upi~da, Sweden) Records of sympathetic activity from human peripheral nerves show a marked cardiac rhythmicity in the spontaneous firing of vasoconstrictor neurones supplying the vascular bed of skeletal muscles. Such rhythmicity depends on the bar,reflex control of these neurones which are significantly involved in blood pressure regulation. The present study shows that when profuse sweating is induced by high ambient temperature, impulses to sweat glands also tend to occur in volleys timelocked to the cardiac cycle. The different latency of the SSA compared with the MSA bursts of impulses could be due either to a different peripheral conduction velocity or to a different coupling mechanism between heart and sympathetic activity. 42. The blink reflex (BR) in m i c patients on low protein tact. - - P. ~ a . ScheUhtJmr, P. Malavml and G. ~ i ¢Medena) In 16 uraemic patients on low protein diet the blood creatinine level ranged from 0:9 to 14.5 mg/100 ml. In these patients a study of the BR showed: (1) the mean latency of R~ is significantly higher than that of age-matched controls (12.56 5:0.85 vs. 11.55+0.63); (2) the Rl latency is pathological in 31%; (3) the R l latency correlates with the creatinine level (r = 0.4237). 43. Epidunl pm~mtanemm nenrostin~ation in spastic syndzomu: a ~

Moraei, A. A ~ M . L

study. - -

F. Bravaccio, A.

Tara and R. Milpinl (Naples)

A neurophysiological study has been carried out, before and immediately after epidural percutaneous neurostimulation in 5 spastic patients. Four had a marked paraparesis and I had a very marked post-traumatic tetraparesis associated with intractable pain and bladder sphincter dysfunction. EMG investigations of the lower limbs were done to evaluate the coordination of synergie movements and Hoffman reflex of sural triceps muscle (the H rnaximum/M maximum and the mot,neurone

ITALIAN EEG SOCIETY excitability cycle using a double stimulation method). Percutaneous electric neurostimulation, at epidural level, was given 3 times a day (each session of 1 h duration). Some significant modifications of electropbysiologicai findings together with a clear clinical improvement of spasticity, sphincter dysfunction and pain were found after neurostimulation therapy in 2 patients, one of whom suffered from tetraparesis. The electrophysiologlcal modifications consisted of: (a) a reduction of synerglc movements; (b) a lower H / M ratio; (c) a longer early inhibition phase and a reduction of late facilitation in the recovery curve of the H-reflex. These observations confirm, in some cases, the validity of spinal percutaneous neurostimulation in the treatment of spastic syndromes whether or not associated with pain and sphincter dysfunction. 44. Peripheral and autonomic nem-opathy in chronic alcoholic patients. - - G. Coati, G. Galardi, L. Lozza, P. Marchettlni and M. Zadra (Milan) Peripheral neuropathy is a well-known complication of chronic excessive ethanol consumption. However, clinical symptoms of autonomic dysfunction affecting the cardiovascular system are not common in alcoholic patients. In the present study we investigated autonomic and peripheral nerve involvement in alcoholics. Fifty-one patients, 46 males and 5 females, aged 28-65 years (mean age 45.2 years), entered the study. All the patients had drunk large quantities of ethanol for 5-30 years and all, at the time of examination, were hospitalized because of alcoholism. In order to evaluate autonomic cardiovascular function, Valsalva manoeuvre, hand-grip test and a postural hypotension test were performed. Motor conduction velocity in the ulnar and peroneal nerves as well as sensory conduction velocity in the median and sural nerves were measured. Electromyography was performed in first dorsal interosseus and tibialis anterior muscles. Normal values were obtained in 30 healthy controls, 23-65 years (mean age 43.2 years). Thirty.five per cent of patients had abnormalities in two or more nerves; 21~ of the patients had abnormalities in only one nerve; 12% of the patients had only signs of denervation in one muscle. One or more tests for cardiovascular autonomic function were altered in 46% of patients. Valsalva manoeuvre appeared to be the most frequently altered test (35%). Abnormalities in autonomic function tests were significantly correlated with abnormalities in nerve condition studies. 45. Peripheral damage due to carbamazepine treatment. - - C. Geraldini and G. Sided (Rome) This study was designed to examine the possibility of damage in the peripheral nervous system due to treatment with carbamazepine (CBZ). An EMG and nerve conduction velocity study (MCV of median and peroneal nerves and SCV of median nerve) was performed on 22 epileptic patients treated with CBZ. The mean values of MCV in peroneal nerve and MCV and SCV in median nerve were significantly reduced compared with

45P a group of healthy subjects and showed an increase in median nerve distal latencies. These changes were positively related to the amount of drug taken. In fact the most significant changes ( m e a n - 2 S.D.) were found in patients taking more than 1000 mg of CBZ. In addition, moderate neurogenic EMG signs were seen in 9 out of 22 subjects (40.9%). These findings suggest the possibility of peripheral nerve damage caused by CBZ, perhaps dose-related. 46. Single fibre EMG in 6 eases of inmum botulism. - - P. Girinnda, R. Dattoin and C. Messina (Meselna) In 6 cases of mild botulism intoxication conventional EMG and single fibre (SF) EMG were performed. In all but 1 case SF-EMG revealed the occurrence of potential pairs with abnormal jitter above 50 psec. The percentage of the potential pairs with increased jitter ranged in the different cases from 17% to 44%. Some of the potential pairs with abnormal jitter showed blockings ranging, in different patients, from 0% to 100%. The presence of blockings was not strictly related to jitter value; blockings occurred even at a jitter of 70-75 psec. On the contrary, some potential pairs with jitter above 150 psec did not show blockings. The data obtained are in agreement with those reported by Schiller and St/dberg in 1978 in 2 cases of botulism studied with SF-EMG. SF-EMG findings relate fairly well with conventional EMG data and clinical status. SF-EMG proved to be a valuable method for studying the neuromuscular transmission defect in botulism; it may also be useful in obtaining further information about the course and recovery of this syndrome. 47. EMG study of Imlbocavernosus reflex. - - L Merlink C. Grmmta and D. ~ 08~ogua) The bulbocavernosus reflex (BCR) is a segmental polysynaptic reflex with cross-over in the sacral sp/nal cord at S2-$3-$4 level. Usually this reflex is elicited by manual stimulation of the glans penis or clitoris. The response is a contraction of the bulbocavernosus muscle and the external anal sphincter. The BCR can be demonstrated clinically in only 70% of normal male subjects. A simple method for the study of the BCR is suggested involving bipolar electrical stimulation of the dorsal nerve of the penis or clitoris and recording the evoked potential via a bipolar electrode inserted into the anal sphincter or the bulbocavernosus muscle or with an anal plug. In the normal subject the evoked potential is polyphasic, appears after a latent period of 25-40 msec with an amplitude of 100-200 pV and duration of 5-20 msec. During spinal shock the BCR is absent. Spinal shock is quite transient, usually persisting less than 24 h, and is heralded by the return of the BCR. The BCR in dorso-lumbar paraplegia has a normal latency, the amplitude is often greater than 1-3 mV, somethnes repeatedly. In sacral spinal cord lesions the BCR remains absent. In incomplete lesions of the sacral cord, cauda equina or peripheral nerves, the BCR may be absent or reduced with a prolongation of latent period, invariably greater than 45 msec and sometimes more than 100 msec.

46P 48. A case of hypokalaemic paralysis from licorice and earbenoxoione ingestion. - - P. Ptaem, C. Ravenna, G. Mezzina, S. lierobon, A. Borri and G. listollato (Venezia-Mestre and Padua) A case of hypokalaemic myopathy in a 53-year-old man caused by ingestion of 30 g of licorice and 100 mg of carbenoxolone daily for 2 years is reported. The serum potassium was 2 mEq/1, sodium 141 m E q / l and the arterial p H was 7.50; CPK was 2370 m U / m l , aldolase 11.2 m U / m l , LDH 387 m U / m l . Tests of kidney function were normal. The EMG showed a myogenic pattern and a muscle biopsy revealed myopathic changes; at electron microscopy lipofuscin bodies were seen in a subsarcolemmal position; the mitochondria were normal and no alteration of the sarcoplasmic reticulum was present. After administration of KCI there was a marked improvement in the clinical state and the serum potassium and serum enzymes became normal. 49. Automatic evaluation of the H-reflex in the study of muscle tone disorders. - - P. Pola, M. Onofrj and M. Scerrati (Rome) A method of automation has been developed with the purpose of improving the accuracy and reliability of the study of the H-reflex in patients suffering from disturbances in muscle tone. The method allows: (1) calculation of averaging of the H-responses and the Hmax/Mm~ ~ ratio; (2) identification of the lowest and highest amplitude values of H 2 at different time intervals; (3) conversion of the values reported in (2) into percentages of those of their respective conditioning H-reflexes, and (4) plotting of these values as a function of the time intervals. Our preliminary results seem to support the supposition that this technique is accurate and time-saving. 50. Neuromyot0mia and m r m o c a l c m ~ e tetany: a case report. - - B. ROUl, G. Meucei, U. Bonueeelii and F. Sartucci (ilsa)

The continuous muscle-fibre activity syndrome (Isaacs 1961) is a chronic and benign illness of unknown aetiology. Some cases have been reported as being paraneoplastic, others associated with polyneuropathy. A patient born in 1923 began in August 1980 to develop weakness, stiffness and myokymia in the muscles of the lower limbs. An EMG at first showed fasciculations and some duplets, then numerous multiplets present only in the lower limbs. Profuse sweathing, dyspnoea due to bronchial obstruction and sleep disturbances were also present, as well as a slight rise in serum LDH, SCK)T, SGPT, GT and a considerable increase in plasma catecholamine. Calcium, parathormone and calcitonin were normal. The myokymia disappeared after nerve block. Tetanic response with isehaemia in the arms was seen and during REM sleep a mild decrease in myokymia was observed.

SOCIETY PROCEEDINGS Carbamazepine (600 mg/daily) proved to be effective in controlling the myokymia and tetany. The clinical features and response to treatment were consistent with Isaac.s' syndrome. However, the patient differed in some major aspects: myokymia was not widespread, it was abolished by peripheral nerve block and also influenced by REM sleep. Finally, in this patient, carbamazepine had a beneficial effect on both the tetany and myokymia, two symptoms which correspond to a similar EMG pattern. This fact may be helpful in understanding the pathology of this syndrome. 51. Follow-up of sensory motor conduction velocities in diabetic patients u n d e r , rig insulin micmtnfusion pmnp treatment. - - P.M. Rossini, A. Flnarelli, D. Gambi, S. Sensi, F, Capani and M. lezzi (Chieti)

In 10 diabetic patients whose blood sugar concentration was poorly controlled by traditional insulin administration, treatment with insulin microinfusion pump was attempted. The sensorimotor conduction velocities of the median, external popliteal and sural nerves were evaluated together with the characteristics of the M and nerve responses at onset of treatment and at monthly intervals. Cleareut elinieal-eleetrophysiological abnormalities were found in 5 patients. An amelioration of the metabolic condition was achieved with the infusion pump. In 2 cases stable relief of the clinical symptoms and a significant increase in sensory conduction velocity were already observed at the time of the first follow-up. A prolonged follow-up will be provided to analyse late outcome and the stability of the patients who already show improvement. 52. Comwession n e u r o p a ~ in glue-exposed shoe workers. - R. S c h o e n h u ~ , G. 1 ~ amlG.B, itatfl ~ and Carpi)

In 36 shoe workers at risk for toxic polynenropathy, but without clinical signs of peripheral nerve involvement, the terminal latency (TL) of median and peroneal nerves was studied. Only 1 subject (2,7~) had an increased peroneal TL, while 14 (38.8%) had a pathological median nerve TL. This difference is highly significant (X 2, I3.82; P < 0.0005), but is in contrast with the general belief that toxic neuropathies of the dying back-type affect the distal part of longer nerves more severely, i.e. the peroneal more than the median nerve. However, it is possible that the median nerve is injured mechanically at the carpal tunnel by the repetitive flexion-extension wrist movements during work and by the vibrations from mechanical tools transmitted to the worker. Our data show that carpal tunnel syndrome may be an occupational disease and stress the importance of selecting appropriate neurophysiological methods in order to differentiate the factors involved in peripheral nerve damage.

ITALIAN EEG SOCIETY 53. Peripheral and autonomic nem'olmthy in diabetics: a nem-opby~e~ study. - - G. S i d ~ ¢. GeraUhi, V. Spanone,

S. G a m ~

F. Jaeoangdi, R. laumut, A. Colletti and

47P 55. Analysis of conduction velocity in the H pathway in alcoholic neumpathy. - - W. Troni, L Bergamini, R. CAmteUo, E. Rainero and W. Di Tizio (Turin)

G. Menzinger (Rome and Nalfles)

A study of 41 diabetics has been made and the presence of autonomic neuropathy confirmed on the basis of the evaluation of beat-to-beat variation in heart rate. The mean difference between maximum heart rate on inspiration and minimum heart rate on the following expiration was determined during deep breathing (mean rate difference: MRD). The peripheral neuropathy was investigated by measuring maximum motor conduction velocity (MCV) of peroneal and median nerves, and maximum sensory conduction velocity (SCV) of median nerve only. The difference between duration of muscle evoked potentials at proximal and distal stimulations were also considered ( M P D p s - MPDds). Sixteen of the diabetics showed MRD scores compatible with vagal denervation (MRD < 2) (group A); 16 showed MRD scores within the normal range (MRD < 6) (group B). Both groups A and B showed mean MCV and SCV values significantly lower than normal ( P < 0.01). Both mean MCV and SCV values were significantly reduced compared to B. Mean M P D p s - MPDds values were greater in group A than in group B, both for the peroneal and median nerves although they were statistically reduced in the peroneal nerve only ( P < 0.05). These findings suggest that damage of the autonomic and peripheral sensory and motor fibres in diabetics is related. M P D p s - M P D d s values also suggest there is a correlation between damage of small motor fibres and damage to autonomic fibres. 54. Carbamazep/ne (CBZ) and the peril~ral nervom system: an electrophysioJosic study in rats. - - S. Traccis, F. Monaco, R. Mutani, A. Arrigo, A. Tartara, F. Faasio, R. Sealsi and A. Moglia (Sassari and Pavia)

Recent reports in the literature claim that there is noticeable decrease in the motor and sensory conduction velocity in patients on chronic CBZ treatment with therapeutic doses and therapeutic plasma levels. This study was carried out on 60 Sprague-Dawley albino rats, 30 of which were given CBZ while the others acted as controls. The animals were similar for age and weight. The experiment was carried out in order to assess any presumed CBZ toxic effect on peripheral nerve from both an electrophysiological and histological point of view. CBZ was taken orally with food at a dose of 300 m g / k g daily. After 3 months of treatment, before killing the animals, electrophysiological tests were done on the tail according to previously described techniques (Moglia et al. 1979) and an attempt made to evaluate motor and sensory nerve response latency. Drug-administered rats showed a statistically significant latency increase of the evoked motor response when compared with the controls. CBZ plasma levels on the day before killing the animals were 6.35 ~tg/ml (S.D. 0.95). Electrophysiologic data were compared with histological and ultrastructural examinations of the sciatic nerve and the tibialis anterior muscle.

The conduction velocity in the partial segments of the monosynaptic pathway of the lower limbs has been assessed in 21 alcoholic patients in order to evaluate the distribution of conduction slowing in the entire course of peripheral nerves. According to methods previously described (Troni et al. 1979), the conduction velocity in the entire course (popliteal fmsa-tospinal cord), in the proximal tract (buttock-to-spinal cord) and in the distal tract (popliteal fossa-to-buttock) of the H pathway, has been determined and expressed by mixed (sensory-motor) conduction indices. In addition, the conduction velocity of the Ia afferent and of the motor fibres has been selectively evaluated in the distal tract. The results indicate that conduction slowing affects both proximal and distal tracts to the same degree, although in the distal tract, the conduction damage of Ia fibres is significantly greater than that of the motor fibres. Moreover the mean H / M ratio obtained by stimulation at the popliteal fossa is significantly more reduced than that obtained by stimulation at the buttock. This is consistent with a proximal-distal gradient of axonal degeneration a n d / o r dysfunction in alcoholic neuropathy. 56. Hypothyroid neuropathy, m A. ZampoUo, E. Cristofori and

O. Zacchet¢ (Leeeo) Even though neurological complications in hypothyroidism are well recognized, to the best of our knowledge there is only scanty data concerning peripheral neuropathies in such patients. The electrographic studies that have been carried out in this context are nearly all devoted to the well known association of myxoedema-carpal tunnel syndrome. Our data concerning 2 hypothyroid patients with neuropathy who had diffuse abnormalities of the investigated electrographic parameters (motor and sensory nerve conduction velocity, H-reflex, H-index). In one of these cases there was a marked segmental demyelination and axonal degeneration shown on pathological examination of the sural nerve (according to Dyck and Lambert 1970; Shirabe et al. 1975). 57. Paleo- and neoeerobellar contribution to human EEG sleep activity--F. Cieirata, A. Grauo, A. Scrofani, It. Biondl and V. Consoli (Catania) The paleo- and neocerebellar contribution to EEG sleep activity was studied comparing the side of cerebeUar lesion and EEG sleep anomalies. All night polygraphic recordings (EEG, EOG, EMG and EKG) were performed on 8 subjects of both sexes, 4 of whom had cerebellar atrophy (CA) and 4 surgical hemilateral lesions, 2 in the paleo (PCBL) and 2 in the neocerebeilum (NCBL). The sleep EEG of CA patients showed slow changing phases with prolonged intermediate phases, instability of synchronized sleep with frequent modifications of EEG activ-

48P

SOCIETY PROCEEDINGS

ity, subnormal measurement of both REM and slow-wave sleep and, in 2 patients, presence of spindles in REM sleep. The sleep EEG of PCBL patients showed alterations similar to those of subjects with CA. In sleep EEG of NCBL patients the anomalies, consisting of very slow activity during synchronized sleep, were especially reduced over the contralateral parietal cortical areas. Spindle activity was significantly reduced over the hemisphere contralaterai to the injured neocerebelhim. In conclusion, the paleocerebellum, probably via fastigioascending brain stem structures, exerts general effects on electrical activities of the cerebral cortex and contributes to the changing of sleep phases; the neocerebellum, by dentate efferents to thalamic relay nuclei, modulates the electrical activity of contralateral parietal cortex. 58. Meclumism of a p e m o r ~ n e effect on sleep in man. A study

with ~ o x o ~ a~l domperidme. - - C. ~ MMala, e. OUvari and G. Gioedmm (CNllhtd)

C.

Our previous studies (Cianchetti et al., Psychopharmacologia (Berl.), 1980, 67: 6) showed that apomorphine (AP) suppresses REM and delta sleep in man, an effect probably due to a dopamine (DA)-ergic action. However, this AP effect is similar to that observed after morphine injection (Kay et al., Psychopharmacologia (Berl.), 1969, 14: 404); moreover, animal studies (Margolin and Moon, J. neurol. Sci., 1979, 43: 13) indicate that naloxone (specific opiate antagonist) in high doses blocks AP-induced stereotyped behaviour. These data suggest a possible role of opiate receptors. In order to study this problem 4 volunteers were given naloxone, 3.2 nag i.v. 5 min before, and 1.2 rag 90 win after, starting on AP 8-10 p g / m i n infusion for 240 rain. At this dose naloxone did not significantly change the sleep pattern during AP infusion, although a slight increase of delta sleep was observed. Therefore, interaction between opiates and these DA effects on sleep seem unlikely. A further investigation with prior administration of 16 nag of domperidone, a DA receptor blocker which hardly crosses the blood-brain barrier, was made to see any possible modifications on sleep pattern during AP infusion. The AP effect did not significantly change indicating it is due to an action on receptors within the blood-brain barrier.

hypoxia. The ventilatory response to CO2, studied by means of a rebreathing test, was virtually absent. Cardiac catheterization, performed under general anaesthesia, did not show any abnormality but the patient only woke up from the anaesthesia 2 days later. During sleep the alveolar hypoventilation markedly worsened, without fluctuations in the different sleep stages. There were no periods of apnoea during sleep. 'True' primary alveolar liypoventilation differs from the syndromes of hypersomma with periodic apnoea because of the following features: (1) it is not associated with daytime sleepiness; (2) it is not associated with sleep apnoea; (3) the nocturnal hypoventilation does not show variations in the different sleep stages. 60. Sleep in o b ~ t y : potywaphic and neuroendocrinoiogic correlations. - - M. F r a m m ~ , F, Caviezel, F. Mintcueci, A.G. Cattaneo, O. Micheloni, P. Zamproni and S. Smirne (Mihn) The aim of the present study was to correlate polysomnography with the nocturnal secretion of growth hormone (GH) and prolactin (PRL) in obese subjects. Nine grossly obese subjects, 5 men and 4 women, aged 22-52 years, entered the study. None had any significant disease, or primary sleep disorder. Six healthy non-obese subjects, 3 men and 3 women, aged 25-35 years, were selected as controls. All the subjects received an 'ad lib.' diet and no medication. After 2 nights of adaptation to the laboratory, the subjects had all-night polysonmography, while blood samples were obtained every 30 rain via a long venous catheter system without waking up the subjects. GH and PRL were determined by radioimmunoassay. Sleep was scored according to Rechtschaffen and Kales. ANOVA was employed for statistical analysis. Obese subjects showed normal sleep patterns which were not significantly different from those of the controls or from standards reported in the literature. Obese subjects showed no significant rise of GH levels during slow wave sleep and the PRL levels were significantly lower than those of controls. Earlier studies obtained identical findings but disregarded sleep polygraphy and seemed inadequate. As sleep disturbances can be ruled out, it is suggested that there is dysfunction of the ponto-hypothalamic-pimitary system in human obesity.

F. CAriffaotta, and L L ~ r e s i

61. Palatal myoclonus: statistical observations on its rhythm during sleep and ~ - - A. Seitun, C. Gandolfo and A. Pdmavera (Genoa)

Some cases of primary alveolar hypoventilation not associated with apnoeic periods during sleep have been recently reported. We have studied a similar case using polysonmographic techniques. A 9-year-old child suffered from some episodes of bronchopneumonia associated with severe respiratory insufficiency and lethargy: After recovery, cyanosis developed during the night and later during the day. Pulmonary function tests showed normal pulmonary volumes and normal mechanics of breathing; gas analysis showed slight hypercaphic acidosis and

Palatal myoclonus (PM) like other abnormal recurrent phenomena having an all-or-none character, can be thought of as a stationary point process and thus can be submitted to time series analysis. Electrophysiological data (EEG, EOG, ECG, respiration, surface-EMG of m. orbicularis otis) were collected during two night sessions from a 73-year-old woman showing unilateral oropharyngeal myocionus a month after a cerebrovascular accident. Marked reduction of stage IV and absence of REM sleep resulted in hyposonmia. The mean PM frequency (quiet wakefulness: 184.94/rain+32.37, c.v. 0.17) was decreased during

59. Ondine'a etmm; a case report. - - C. ~ A. ~ G. a d t t a m l P. ~ (Belo~a and Pavia)

ITALIAN EEG SOCIETY N-REM sleep (157.77/rain+38.67, c.v. 0.24), especially coinciding with K-complexes. The time intervals between successive PM-related EMG transients were evaluated for periods of 120 sec. On these samples, correlograms failed to show any serial dependency both in wakefulness and N-REM sleep. However, the periodograms were more regular during wakefulness than during N-REM sleep, always being enhanced by the random shuffling procedures. On this basis PM could be explained as a renewal process generated by a noisy pacemaker, with fluctuations being magnified by sleep. 62. The chubby puffer syndrome. Polywaphic study of two children affected by obesity, diurnal hypersonmla and tachy-lmoea during sleep. - - F. Vigevano, E. Bertini, P. Borrelli, M. CAtppa, G. Caterer, M.L. Lncchina, F. Maccalpaani and M.A. Pinna (Rome) A boy aged 6 years and a girl aged 6 years and 8 months, both of whom were obese and suffered from diurnal hypersomnia and slight adeno-tonsillar enlargement, showed a peculiar tachypnoea during sleep. The boy had Prader-Willi syndrome and the girl a cranio-metaphyseal dysplasia; both of them presented with hypotonia during the 1st year of life. The respiratory features during sleep resembled those of the cases reported by Stool et al. (1977) who described them as the 'chubby puffer' syndrome. In the boy the EEG polygraphic study showed a respiratory rate of 35-40 during wakefulness which increased up to 85 during sleep. The girl showed a respiratory rate of 25-30 during wakefulness which increased up to 60 during sleep. In the boy during wakefulness and sleep, blood gas values showed hypoxia with a metabolic acidosis; in the girl definite results were not obtainable. After a loss of weight of 4.500 kg the respiratory rate of the girl returned to normal. In the evaluation of factors which could explain these findings, the obesity and sub-obstruction of the upper airway appear to be most likely as complete obstruction would have induced periodic apnoea during sleep. The diurnal hypersomnia is more difficult to explain but it is considered that this symptom could be ascribed to the hypoxia and respiratory distress during sleep. 63. BAEPs and autopsy findings in Wallenberg's syn&-ome. - A. Anumtini, G. Ametoli, L Rossi, F. Fenzi, A. Salviati, N. Rizzuto and R. Zappoli (Florence and Verona)

A 70-year-old man who had rapidly developed symptoms indicative of Wallenberg's syndrome died of extracerebral causes shortly after hospital admission. It was therefore possible to record BAEPs and then study brain stem lesions at autopsy. The patient had complained of symptoms such as disturbance of balance, dysphagia and dysarthria. Neurological examination showed right-sided impaired facial sensory perception to pain, Homer's syndrome and facial palsy, and, on the left side, Babinski sign and loss of pain and body temperature. At the time of BAEP recording the facial palsy had completely

49P cleared. The I-III, III-V, I - V interpeak latencies (IPLs) as well as the I V - V / I amplitude ratio were measured. With right ear stimulation an abnormal I - V IPL (value 3.0 S.D. greater than normal data) was found while the amplitude ratio was normal. Histopathological examination showed a typical right dorso-lateral medullary infarct. A detailed study of the acoustic pathways (including cochlear nuclei, superior olive, trapezoid body, lateral lenmiscus, inferior collicnlus) demonstrated their anatomical integrity. These findings suggest that BAEPs can give objective evidence of brain stem functional impairment even in the absence of anatomical damage. 64. Brain stem auditory evoked potentials in postconcussional syndrome. - - P. Benmh B. Bergamasco, C. Bianco, M. Gmi, S. Medaglini and L. Plnessi (Turin) A study has been made of the brain stem auditory evoked potentials (BAEP) in 30 subjects suffering from postconcussional syndrome following slight cranial trauma. The records were made from 3rd to 75th day (mean 18 days) following injury. All patients were normal on neurological examination. Although this syndrome is generally considered functional, the high incidence of dizziness in these patients may reflect subclinical alterations of brain stem function which could be verified by alterations of BAEPs. The interpeak iatencies between the first five positive waves of the BAEP were compared with the means of a control group (matched for age and sex with the patient group). In 10 patients (33%) there were altered BAEP with one or more interpeak latencies prolonged by more than the upper 95% confidence limit with both unilateral and bilateral stimulation. In addition the mean values of interpeak latencies in the patients with normal BAEP were more prolonged than those of our laboratory normal controls. These data indicate that organic lesions which are too insignificant to be objectively demonstrable may be revealed by techniques such as BAEP. 65. Short latency somatesensory evoked potentials in cervical spondylosis. - - F. D'Alpo and A. Grasso (Catanla) The SEP with stimulation of the right median nerve at the wrist, has been recorded from C3 with reference electrode on the back of the left hand, in 15 patients with moderate clinical and radiologic signs of cervical spondylosis. In 20 normal subjects the response showed a succession of waves with the first negative peak lateneies as follows: Ni ffi 7.16, NI = 10.15, N2 =11.93, N3ffi13.18. In the subjects with spondylosis the following mean values were obtained: Ni ffi 7.20, N1 ffi 10.08, N2 = 12.52, N3 = 14.20. On estimation of the inter-peak intervals, significant differences between N1-N2 (2.44 compared with 1.78 in the normal subject) and N2-N3 (1.68 compared with 1.25) were noted while other intervals were comparable between the patient and control groups. This data supports the hypothesis that, even in moderate cases, it is possible with the use of SEP techniques to prove the effect of cervical-joint pathology on the spinal cord.

50P 66. T o p e g r a l ~ of the short-latency wavelets following flash stimulati~. - - D. C_mmbi, P.M. Romini and J. Lavezzo (Chleti)

Twenty healthy adult subjects with normal visual acuity were studied using flash stimulation (50 #see 0.2 J / c m z, 5 Hz, n = 1024). Scalp electrodes were placed midfrontally Fpz, Fz, Cz, Pz, Oz, Cl, C3, T3, Cz, C 2, C 4, T 4, of the 10-20 system and referred to the ipsi- a n d / o r contralateral earlobe and to a non-cephalic (NC) electrode. The electroretinogram (ERG) was simultaneously recorded with a corneal lens referred to the earlobe or N C reference during monocular stimulation. Three main groups of evoked wavelets were identified when the signal was passed through a 160-3200 Hz handless: the ERG components (anterior leads and earlobes); the VEP components (after 35 msec at mid-posterior leads); a bi-triphasic complex with latency of 25-35 msec which was poorly defined and obscured by the ERG recorded with earlobe reference, mostly ipsilateral to the stimulated eye. The possible genesis of the last flash-related even is discussed. 67. Flicker fusion test in multiple sclerosis: a simple test for the study of optic pathways. - - A. Ghezzl and D. Giussani (Gailarate)

Optic nerve involvement is quite frequent in multiple sclerosis (MS) producing delayed visual responses and impaired transmission of repetitive stimuli. In order to investigate this phenomenon 50 MS patients had flicker fusion tests (FFT). Normal values were defined in 30 healthy subjects. The flicker fusion threshold was 35.8 +_ 1.8 Hz in the control subjects. A successive determination in 10 eases gave values of 35.9-+ 2.1 with respect to the previous mean values of 35.1 -+2.1 Hz. In MS patients the threshold was 25.6 5: 8.9. With respect to - 2.5 S.D. of the mean normal values, 36 cases had a reduced threshold (72%) and 31 cases had a reduced threshold at - 3 S.D. (62%). An abnormal response was recorded in 66% of cases with no detectable involvement of optic pathways. The incidence of abnormal findings at FFT is slightly lower than that observed using VEP. However, in our series, we observed a reduced threshold in a relative high percentage of cases with no signs of optic neuropathy. The results appear quite reliable in both normal subjects and in MS patients and demonstrate the usefulness of the test, especially when the very low cost of the instrument is considered. 68. Visual evoked potenti,ds in multiple sdereais: comparison of patteraed and ~ stinmli. - - A. Ghe.zzi and O. Orsini (GaUerate) Stimulation by flash, intermittent LED pattern and reversing LED pattern were compared in 46 multiple sclerosis (MS) patients in order to define the most reliable method of stimulation. The LED pattern stimulator was built according to the description of Epstein (Electroenceph. din. Nenrophysiol., 1979). The results were analysed and compared with the re-

SOCIETY PROCEEDINGS sponses of 30 healthy subjects. In the controls the latency of the major positive wave was 108.1 -/- 13.4 msec in response to flash; 96,9-+ 5.5 in response to pattern reversal; 94.7 5:10.4 in response to intermittent pattern. The amplitude (peak to peak) was respectively: 11.4-+6.4; 7.2-+3; 7.4-+4.2/~V. In MS subjects the major wave latency was respectively: 130.1 _+ 19.8; 142.0±29.4; 125.7-+29.8 msec. The amplitude was respectively: 11.4-+6.6; 6.4_+3; 7.0_+3.8 #V. Considering the upper limit of + 2 S.D. of the mean latency of the major wave, abnormal responses in MS patients were observed in 60.7% of cases with flash, in 93.5~ of cases with pattern reversal and in 73.9% cases with intermittent pattern. At the more restrictive limit of + 3 S.D., the incidence of abnormality was respectively: 21.7%, 80.4%, 56.6%. In possible MS cases the incidence of abnormality was higher in response to, pattern reversal as was also found in patients with no detectable involvement of optic pathways. Flash responses were better defined in patients with reduced visual acuity. 69. The bioelectrtcal development of young rats following severe maternal hypertenskm ~ by VEils. - - F. Pinto, M. O r i o n , P. Pola, R. ~ i n ~ , GoG, Gerzettt and P. Meriotti

(Rome) The impairment of the EEG responses to photic stimulation (VERs) has been demonstrated by several authors after restricted conditions such as diet, starvation or unfavourable environmental conditions during development. Severe hypertension during pregnancy is known to produce poor foetal growth. In the present study the bioelectrical development of the VER in young rats following experimental maternal hypertension is reported. Thirty-nine Sprague-Dawiey pregnant rats had surgical induction of renal vascular hypertension by constriction of the left renal artery. The study of the offsprings showed a decrease of weight at birth. Great variations in the rate of poor foetal growth were observed in spite of similar values of maternal hypertension. The study of VERs carried out with averaging tecinaiques and using frequency analysis showed great variation. Alterations of the development of the evoked responses were found in some of the animals while normal values were obtained in others born following similar conditions of materhal hypertension. All the examined rats showed normal responses at the age of 30 days. The great variation found in our results suggests that the defective foetal development produced by maternal hypertension differs in some way from other disfavourable conditions as far as the bioelectrical development of the visual system is concerned. Further investigations are required. 70. l~ferentlal enimncem~at of early and late S E P components in relation to ~ ~ . - - S. Ratio, G. Abb r u z ~ e , M. Ah4M~zese, L Coeito, L Reni and E. Favale

(Genoa) The possible contribution of small diameter afferent fibres to the cervical and cortical SEP components was studied in 8

ITALIAN EEG SOCIETY healthy volunteers. An evaluation of the effect of increasing the stimulus intensity (from threshold to painful level) on the amplitude of both early and late components of the somaesthetic response evoked by stimulation of the first finger or of the median nerve at the wrist was made. In comparison with the amplitude of the SEP evoked by a threshold stimulus the late SEP components (N55, N~0 ) were significantly enhanced in amplitude by higher intensities of stimulation, the primary response (N20-P2s) being practically unchanged. Such differential enhancement of early and late SEP components suggests the existence of a relationship between the activity of different primary afferent fibres (including those of small diameter) and the SEP components. 71. BAERs in normals and in patients with various hearing deficits - - P.A. Rizzo, F. Plereill, G. Pozzessere, F. Nobtli-Benedetti and C. Moroentti (Rome) A study has been carried out on a group of 20 normal subjects recording the brain stem auditory evoked responses (BAERs) using different stimulation modalities. Similar recordings were performed in a group of 30 patients with conduction, cochlear and retrocochlear hearing deficits. The parameters considered were latencies of single waves and interpeak latencies (IPL). In all patients the intensity-latency (I-L) curve was derived in order to observe the acoustic threshold and individual reaction to stimulus intensity variations. The results showed that wave V appeared at l0 dB HL in normal subjects and also tended to be earlier as the stimulus intensity increased. I-L curves of waves I and V were parallel with no variations in I - V IPL. In patients with conduction loss an increased threshold level with a prolonged wave I and V latency was observed. In patients with endocochlear deficits a higher threshold with normal responses to higher intensity stimulations and normal IPL was seen. In retrocochlear deficits increased threshold and prolonged I - V IPL were found. The usefulness of IPL measurements in neurological studies is confirmed by our data. 72. Short latency SEPs during peroneal stimulation in man. - P.M. Rossini, W. House and R.Q. C'racco (Chieti and Brooklyn, N.Y., U.S.A.) SEPs were elicited during bilateral or unilateral stimulation of the peroneal nerve in 32 subjects. The active electrode was placed at Cz and referred to Fpz, earlobe and shoulder (NC). Wide (5-3000 Hz) and narrow (150-3000 Hz) bandwidths were utilized. From Cz-NC with wide bandpass, 3 positive and 1 negative peaks were usually identified while with the narrow filter setting up to 6 positive peaks and 3 negative deflections (PIA, PIB, P2A, No, P2B, P3A, P3B, Nl^, NIR) were evaluated. The PlA, P28 and P3A peaks were the most consistent components of these responses. Pl^ and PIe waves were widely distributed at all the scalp recording sites, P1A also had the same latency as the cervical bipolar response.'The P2^-P2s were distributed over the central-frontal region sometimes being better seen contralateral to the stimulated side. The P3AP3BN]

51P complex showed a steep amplitude gradient between Cz and Pz and parasagittally ipsilateral to the stimulated leg. All these peaks were between 15 and 30 msec after the stimulus. The PIA-P3A interpeak interval could represent the propagation time from the rostra] cord to the cortex (8.5 msec). 73. Modifleations of the elecUorettnogram (ERG) and of ¢l~ferent eoml~aents of the visual evoked potentials (VEPs) in

workers exposed to lead. - - M. Signm'ino, O. S e a r p h ~ L. Provindali, G.F. Marehesi, M. Valenttno and M. Governa (Ancona) In 8 workers exposed to lead for 3-20 years, with slightly raised blood lead values and without visual deficit, the ERG and VEP were studied to find possible variations of diagnostic value. In the ERG, the 'a' and ' b ' waves and oscillatory potentials were considered. In all cases both 'a' and ' b ' waves showed a normal latency and amplitude, while in 4 subjects the oscillatory potentials were slightly reduced in amplitude. In the VEP measurements the early oscillatory potentials (recorded from Fpz using a high pass filter) were examined separately from the other components of the VEP (recorded from Oz with usual technique considering only waves III and IV as these were more consistent in latency). In 6 subjects especially the last waves of the oscillatory potentials showed marked reductions in amplitude a n d / o r longer latencies. The VEPs were altered in 5 cases: in 1 case the wave IV latency was 1 S.D. above the normal average; in 2 others, latencies of waves III and IV appeared to be increased by I S.D.; in the remaining 2 the latencies of the same waves were increased 2 S.D. The VEP results were similar to those obtained in rats. Furthermore, the variations of early oscillatory potentials found suggest the possible application of this t~hnique in the diagnosis and prevention of lead poisoning. 74. Brain stem mUtory evoked potentials 0tAEP) in neffiological screening. ~ D. Sollazzo, G. ~ ' A . D'Amieo and F. Corsl (Rome) The BAEP is produced by neuronal activity of the acoustic nerve and ascending fibres (cochlear nuclei, superior olivary complex, lateral lenmiscos and inferior collicuins). These potentials are not modified by attention, consciousness or drugs; in contrast the responses are affected by lesions at different levels of the brain stem. We have carried out BAEP studies in 20 controls and 30 multiple sclerosis (MS) patients divided into (a) subjects with clinical brain stem involvement and (b) patients without clinical brain stem involvement; 10 patients with brain stem infarction; I patient with acoustic neuroma and a patient with olivo-ponto-cerebeliar atrophy. All subjects were tested using a series of 2500 clicks (100 psec duration at 95 dB HL intensity) at a repetition rate of 10 Hz. The first 10 msec were analysed by means of a neuroaverager (bandpass of 150-3000 Hz); components 1, 2, 3, 5 were evaluated in relation to latency and amplitude and interpeak intervals 1-2, 1-3, 1-5, 2-5, 3-5 were measured. The MS group with clinical brain stem involvement showed the greatest

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SOCIETY PROCEEDINGS

percentage of abnormalities; in addition, abnormalities were detected in a high percentage of MS patients without clinical involvement of the brain stem. The abnormalities detected in the other disease states were in agreement with the anatomical clinical data. 75. Modifleatinns of RNA s y n t h e ~ in cerebral ¢m'tex and lhalmnus of rat at different time intervals dm4~ motor recovery fellowing eembelleetomy. - - F. Cieirata, E. aml A. Vamdla (Oamin) Modifications of RNA synthesis were studied in cerebral cortex (Cc) and thalamus (Th) at different time intervals (3rd, 8th, 30th and 75th day) after cereb¢llectomy. At each time interval one group of 10 rats (5 cerebeUectomized (CBL) and 5 sham-operated (SO)) were utilized. The anirqals received an i.p. injection of [5-3H]uridine (0.5/~Ci/g b.w.; specific radioactivity 5 Ci/mmole). After i h they were decapitated and Cc and Th were removed by dissection. The experimental results are expressed as a percentage of control values (assumed to be 100~). The incorporation of precursor into RNA decreased in Th on the 3rd (33.1~, P < 0.01) and 8th day (24.9~, P < 0.01) whereas it increased on the 30th (302.2T, P < 0.01) and returned to normal values by the 75th day (114.5~) after cerebellectomy. In Cc RNA synthesis was unchanged on the 3rd (90.4~), 8th (89.7~), 30th (94.5T) days and increased significantly only on the 75th day (229~, 0.05 < P < 0.01). This study has shown that the incorporation of [5-3H]uridine into RNA was modified in the different brain regions at different time intervals after ~ l l e c t o m y and suggests that the motor compensation which follows cerebellectomy could be supported by a spatiotemporal orgamza/'tion of macromolecular synthesis in different regions of the CNS. 76. Epileptiform ~ cal performances,

elicited by visual patterns: report of --

E. Did Ri, L.

Rozza and

G. Ferrari

0rreato) This report concerns the interaction between EEG epileptiform discharges and impairment of neuropsychologlcal performance in a patient with pattern-sensitive epilepsy. The paroxysmal EEG activity was elicited by viewing line patterns. Maximum qaileptogenicity occurred with spatial frequency of 5.2 c/dog with horizontal pattern orientation. A considerable impairment of memory and calculation performance was observed, for 4-5 rain after stimulation with the critical visual pattern. 77. C_mnpu~ s i m a l ~ e a in myop¢ocemor design. - - G. Fimgol and N. Aeeomem (Rome) Features of different myoprocassors have been analysed by means of computer simulation techniques. It was found that a 2-order demodulator is the optimal design for estimation of muscular force from the surface EMG. Therefore an eightchannel device has been produced for practical applications.

78. The action of GABA and 81ycine on rat epileptic loci. - M.G. ~ N. ~ and P. Stanzioue (Rome) Biochemical studies on several types of experimental and clinical epilepsy suggest that seizure activity is associated with some changes in cerebral concentration of certain amino acids such as glycine, GABA, glutamic acid and aspartic acid. As it has recently been shown that glycine ((313') may play a role in rat cortical inhibition with a mechanism of action similar to that of GABA, the purpose of this study was to elucidate the action of Gly on rat epilcptogenic foci comparing its effect with that of GABA. The experiments were performed on male Wistar rats. Epileptogenic foci were produced by the application of strychnineHCI (3 g/l) or Sodium Penicillin G (500,000 I U / m l ) to the cortical surface. The eleetrocorticogram was recorded in the immediate vicinity of the application site and in the homologous contralateral area. Gly (450 mg/kg i.v.) completely blocked the spike activity. The inhibitory action of GABA (80 mg/kg i.v.) was more powerful in terms of threshold and duration than the action of Gly. When these amino acids were applied topically and intracisternally a similar inhibitory effect was observed. These results agre,¢ with our previous findings concerning the inhibitory effect of Gly and GABA iontophoretically applied to rat cortical neurones and strengthens the possibility of the role of Gly in rat cortical inhibition. 79. Superconducting imtnmentalion for neurnlosieal investigatinn--L ModeM, S, B a r b a a e ~ P. Carelli, R. Leoni, G.L. Ronuml and G,B. Rieei (Rome) In the last few years superconducting instrumentation for biomagnetic measurements has become increasingly feasible. This allows a shift from the purely experimental stage in the laboratory to the first clinical applications. Magnetoencephalographic measurements have been performed by means of a SQUID magnetometer coupled to a second-derivation gradiometer in an unshielded environment. The noise spectrum of the apparatus is flat in the frequency range 0.4-2000 Hz and is constrained within 40 fti/Hz. Simultaneous EEG recordings are usually taken using pure gold leads. Analogue recording of both MEG and EEG is processed off-line and the frequency domain analysed. High resolution (down to 15 MHz) power spectra are obtained for comparison as well as high resolution cross spectra. Preliminary observations for normal and pathological subjects show, at least for the alpha component, a rich frequency structure detectable only by high frequency resolution. The major spatial discrimination of the magnetic probe is confirmed by these measurements. 80. EEG findings during carotid endartereetomy. - - M. Mola, M. Comee and O. Arena (Milan) Fifty-one carotid endarterectomies have been performed in 47 patients using EEG monitoring as the main guide for placement of a temporary shunt (CCA-ICA). Case material and

ITALIAN EEG SOCIETY EEG records have been reviewed in an attempt to identify the EEG patterns that should be considered indicative of actual or potential ischaemia. All procedures have been carried out under general anaesthesia, normotension or moderate hypertension and normocarbia. Before clamping, two basic EEG patterns have been observed: (a) symmetrical or (h) asymmetrical theta activity. During arterial clamping, 40 cases (78~) did not show any EEG change; 5 cases showed early EEG changes (lateralized delta activity in 3, lateralized low voltage in 1, and lateralized disorganisation of the background rhythm in 1). Six patients showed later EEG changes with lateralized delta activity in 3 and low voltage in 3. In all patients with early changes, and in 1 patient with later changes, an internal shunt was placed. The EEG changes resolved in all cases except one. Two neurological deficits occurred in the series: in the patient in whom the EEG changes persisted after the placement of the shunt, and in a patient with late EEG changes, in whom a shunt was not used. A significant correlation between presence of neurological deficit and EEG changes has been observed.

53P 81. EEG features in cerebral contusion and their wognosfie value. - - P. Tanganelli, G. Regesta and G.A. Ottoneilo (Genoa) The diagnosis of cerebral contusion has, in the past, been rather doubtful. It is now possible with CT to recognize contusion (Vigouroux et al. 1976). This information provides the opportunity of verifying correlations with clinical and EEG features. One-hundred-and-two subjects have been examined. In 72 there was a single contusion and in 30 multiple contusions were present. The initial examination showed different clinical features ranging from pure post-traumatic amnesia to deep coma. Pure post-traumatic amnesia without focal signs was present in 22 patients with cerebral contusion but was associated with frequent focal EEG abnormalities (42~) in contrast with 16 patients, clinically similar but with normal CT, with either normal EEG (44~) or diffuse moderate EEG abnormalities (43%). As regards the prognostic value of EEG in relation to a single cerebral contusion, focal depression seems significantly correlated with poor outcome, while, in multiple contusions, a poor prognosis is correlated with the following EEG pattern of coma: 'changeable,' 'borderline,' 'slow monotonous.' Four months after the trauma, the focal slow abnormalities did not seem to correlate with the severity of the lesions but with the presence of a haemorrhagic component of the contusion (Courjon 1972).