Società Italiana di elettroencefalografia e neurofisiologia

Società Italiana di elettroencefalografia e neurofisiologia

1P Electroencephalography and Clinical Neurophysiology, 1978, 45: 1P--5P © Elsevier/North-Holland Scientific Publishers, Ltd. Society proceedings SO...

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Electroencephalography and Clinical Neurophysiology, 1978, 45: 1P--5P © Elsevier/North-Holland Scientific Publishers, Ltd.

Society proceedings SOCIETA ITALIANA DI ELETTROENCEFALOGRAFIA E NEUROFISIOLOGIA Siena, November 13--14, 1975

Secretary: Dr. R. MUTANI, Clinica Neurologica, Via Cherasco 15, Turin (Italy)

1. Evolution o f the EEG during the first year o f life in normal and pathological conditions. - - G . B . Cavazzuti, E. della Giustina and S. Forese (Modena) The main EEG features which evolve during the first year of life are: (1) In the waking state a progressive organization of 4--6 c/sec parietal-occipital activity appears from the 2nd month increasing in frequency up to 7 c/sec by 7 m o n t h s and more by 12 months. (2) During sleep a large amount of slow waves, especially posteriorly, together with parietal asymmetrical spindles of low voltage seen from the 2nd m o n t h ; then, from the 4th month, slow hypersynchrony in drowsiness, abundant and synchronous spindles and irregular humps in moderate sleep; by the second half "of the year there is a clear distinction between all sleep phases. While mild EEG asymmetries, especially in the temporal region, have no particular significance, the absence of the occipital r h y t h m in the waking state and the absence of slow waves and sleep spindles during sleep do have a pathological significance. Convulsive discharges seen in the course of the 1st year may be reminiscent of those seen in the same patients as neonates; more often, however, they have particular features usually associated with grand mal attacks, myoclonic or focal attacks. Interictal irritative changes (focal spikes or spike and wave, slow waves) are nearly always associated with marked organic cerebral damage and sometimes are the early signs of temporal lobe epilepsy or of epileptic encephalopathy. Characteristic features typical or atypical of West's syndrome and indicating an early phase of the Lennox--Gastaut syndrome are quite frequent. Inflammatory cerebral pathology is expressed by slow and diffuse dysrhythmia or by marked electrical depression.

2. Electrophysiological findings in four cases of muscular dystrophy. -- V. Cosi (Pavia) In 4 children affected by muscular dystrophy, and in the mother of one of them, repetitive stimulation

of the ulnar or median nerves and the lateral popliteal nerve was carried out at rates of 5, 10, 20 and 50 c/sec. The m o t o r conduction velocity was measured in the same nerves. The first 100 responses for each rate of stimulation were considered. Motor conduction velocity was normal although a borderline value was obtained in one determination. With repetitive stimulation the results were as follows. (1) In one nerve there was a significant decrease in response at a rate of 10--20 c/sec (early exhaustion with return to normal values before the 20th stimulus). (2) In the other 9 nerves there was a rapid increase in response, which in some cases was not significant (below 30%), while in 5 nerves (4 times in the lateral popliteal nerve and once in the median nerve) it was above 30%. The increases seen were generally greater at higher stimulation rates. The increases above 30% were present once in 10 trials at 5 c/sec, 4 times at 10 c/sec, 5 times at 20 c/sec and 3 times out of 4 at 50 c/sec. The results are discussed in relation to those reported in the literature. The finding of an increased response is exceptionally reported by previous authors. It could be interpreted as the result of a partial presynaptic block but more probably is a 'pseudo-facilitation' phenomenon.

3. Clinical and physiopathological problems of the extramuscular ocular manifestations o f muscular dystrophy. -- G. Nappi, M. Poloni, U. Manfredini and R. Scelsi (Pavia) The fundamental extramuscular alterations of the eye in muscular dystrophy are discussed. Slit-lamp examination revealed myotonic cataract in 82% and congenital cataract in one patient. All of the Fleischer types demonstrated a marked decrease in visual acuity. Tonographic recordings showed low intraocular pressure related to a significantly reduced production of aqueous humour. Histological studies showed hyaline degeneration in the stroma of the ciliary processes without vascular alterations; the basal membrane of the ciliary epithelium was thickened and PAS positive. Babel's microangiopathic hypothesis is questioned. The b-wave of the ERG was

SOCIETY PROCEEDINGS always significantly reduced with photopic and scotopic stimulation even without ophthalmoscopically visible retinopathy. Flicker results were similarly altered. An attempt has been made to correlate the electrophysiological anomalies with an alteration in the membrane of the retinal bipolar cells. It is suggested that there is a membrane defect c o m m o n to several or all tissues which may be detectable clinically and/or electrophysiologically in one or more organs.

4. Ontogenesis of posterior slow activity. -- A. Carnibori (Milan) A total of 220 EEGs were taken on 45 children during the first 4 years of llfe. The first EEG was recorded during the first week of life while the babies were in Hospital recovering from respiratory distress syndrome and/or asphyxia. In the group of 20 preterm babies born after 26--36 weeks gestation, 4 showed marked delta waves (as described by Grey Walter) and 4 theta 'm(dang~e' (as described by Dreyfus--Brisac). No case with marked delta waves had sequelae or disorders of the nervous system; 3 cases with posterior theta activity mixed with alpha waves had nervous system disorders. In the group of 25 full-term babies, 7 showed marked delta waves (none had neurological sequelae), 4 theta 'm~lang~e' (none had disorders of the nervous system or personality abnormalities) and one with abnormal theta r h y t h m (as described by Doose) had severe behaviour problems. Moreover marked delta waves appeared when the child reached 4 years of age and these were generally preceded by posterior theta or delta waves and sometimes sharp components (posterior slow activity of childhood as described by Gastaut). Posterior theta waves (theta 'm~lang(~e') also appeared when the child was 3 years old or before at a time when the alpha rhythm was n o t yet well organized. Abnormal theta rhythms appeared suddenly at the age of 3 years over the occipital and parietal regions.

5. Clinical correlations o f posterior slow activity. -L. Gervasio (Milan) A review of 2000 records taken on 1622 subjects aged 3--15 years has been made and 320 cases showing posterior slow activity were selected. A total of 1085 records were taken on these cases and some subjects were observed for a period of 15 years. Slow alpha variant as described by Goodwin was observed in 13 subjects (4% of the group with posterior slow activity). Abnormal theta rhythms as described by

2P Doose were found in 5 cases (1%). Slow rhythmic waves over the posterior regions were observed in 67 subjects (21%); in 58 records these were at 4--5 c/ sec and in 9 at 3--4 c/sec. Marked delta waves as described by Grey Walter were found in 235 cases (74%). In addition, 76 cases of 'petit real' were considered. The records were carried out over a period of 17 years and 37 showed occipital delta rhythmic waves as described by Cobb. Prematurity, immaturity, neonatal asphyxia and labour difficulties occurred in l l 5 c a s e s (36%); febrile convulsions in 42cases (13%); epilepsy with or without specific disorders of the EEG in 38cases (12%); mental defect in 104 cases (33%); cerebral palsy in 17 cases (5%); disorders of behaviour and personality without mental retardation in 91cases (28%). Seventy subjects without any damage of the nervous system had EEG studies because of headache, speech disorders, tics, payor nocturnus, enuresis, or because their siblings suffered from nervous disorders. The incidence and evolution of the different posterior slow activities are discussed and compared with a control group of 100 normal school children.

6. EEG and polygraphy in t h e pre-term newborn. -C. Cianchetti, D. Fabiani, A. Favilla, G.F. Perticoni and P. d'Allesandro (Cagliari, Pisa and Perugia) Between 6 and 9 months of conceptional age there is a rapid evolution of the EEG and polygraphic features from an undifferentiated stage of sleep--wakefulness to a progressive differentiation of these two neurophysiological states and subsequently to a differentiation of sleep into the two main phases of active sleep (characterized by phasic polygraphic phenomena and rapid eye movements) and quiet sleep. The polygraphic parameters (EEG, EOG, aetogram, EMG, pneumogram, ECG) develop from a primitive stage when there is no coordination between them to a progressive organization in pattern typical of the different states. The EEG further progresses from discontinuity (long periods of electric silence at 24 weeks of conceptional age) to a continuous pattern which is reached early (about 32-34 weeks of conceptional age) in the states of wakefulness and of active sleep, but in quiet sleep may persist (quiet sleep showing 'trac~ alternant') until the end of the first m o n t h after term. Moreover in the EEG of the pre-term newborn there is a morphological aspect which must be considered as spikes may frequently be present without other EEG alterations of clinical abnormalities. During the newborn period isolated spikes have no prognostically unfavourable significance but focal spikes or focal discharges of

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delta and theta waves suggest there is 'neurological risk '.

9. Muscular dystrophy: genetic aspects and eytochemical investigations. -- F. Locurto, G. Nappi, M. Poloni and A. Castello (Pavia)

7. Analysis of bladder function during sleep. -- R. Di Perri (Bari)

Several methods have recently been suggested for the genetic screening of people with muscular dystrophy (Polgar et al. 1972). The possibility of prenatal prediction and selective abortion of carriers is discussed and the practical value of the cytochemical tests in the early postnatal detection of this disease has been emphasised (Locurto et al. 1973). The cytoplasm of cultured skin fibroblasts derived from 4 unrelated and from 3 related patients with muscular dystrophy exhibits high amounts of metachromatic granular material and alcianophilic material with Alcian blue containing 0.1 M MgC12. Alcianophilia disappears when the staining solution contains 0.3 M MgC12, i.e., it is probably due only to the carboxyl group of glycosaminoglycans. Whether or not excess glycosaminoglycans will be implicated in the pathogenesis of muscular dystrophy remains to be determined. We have carried out preliminary investigations which also show metachromasia and alcianophilia in cultured skin fibroblasts derived from unaffected relatives.

An electrophysiological technique, which allows artificial filling of the bladder during sleep, together with continuous recording of intravesicular pressure is described and findings in normal, enuretic and epileptic subjects are presented. In normal subjects the filling of the bladder during sleep causes a behavioural and EEG arousal reaction before the threshold is reached for micturition reflex by increased intravesicular pressure. In addition, the arousal reaction gives rise to an increase in bladder capacity. In enuretics reflex voiding is obtained in the absence of a clear behavioural arousal although there is a partial shift to lighter stages of sleep. In epileptics hypersynchronous, bilateral spikes or spike and wave complexes or polyspike and wave complexes, lasting more than 3 sec, are followed by a short-lasting increase in vesicle pressure. These findings are related to a small number of epileptic subjects and further investigation is required.

8. Nocturnal sleep in Shy-Dr/iger syndrome. -- P. Bengonzi, S. Mazza, G. Mennuni and G. Macchi (Rome) The study of all night sleep in Shy--Dr~ger syndrome seems of interest not only because of the rareness of the illness but also because of the complex anatomical and biochemical alterations involved. Four all-night polygraphic recordings during spontaneous sleep were carried out on a patient with an anatomo-clinical picture of Shy--Dr~iger syndrome. These showed high percentages of wakefulness, reduced slow sleep time and lowered incidence of REM stage and eventually there was a complete disruption of sleep patterns and the various sleep phases were no longer recognisable. Although these findings suggest likely correlations with the anatomo-functional alterations of the illness, a more comprehensive study including the behaviour of other related parameters (blood pressure, amines, etc.) which may be measured during sleep is still required before definite conclusions can be drawn.

10. Endocrine and metabolic aspects of muscular dystrophy. -- A. Barbarino, M.L. Vaccario, P. Tonali, C. Scopeetta, F. Martino and L. Troncone (Rome) Sugar metabolism, insulin secretion and growth hormone (GH) secretion have been studied in 12patients with muscular dystrophy (MD). The patients were given an oral load of glucose with subsequent determinations of blood sugar and insulin levels 30, .60, 90 and 120 min later. In addition 7 patients also had glucagon stimulation (1 mg i.m.) in order to determine the serum levels of GH as well as sugar and insulin. The results showed an exaggerated insulin secretion in MD patients compared with normals; however, the hyperinsulinaemia was not accompanied by hypoglyeaemia. Such results are discussed and compared with previous investigations and the authors' personal experience of the positive action that low-dosage insulin therapy can have on the muscle signs. It is concluded that MD patients secrete insulin of a low biological activity. The secretion of GH appears to be reduced in these patients but studies with a series of more specific stimulations are required.

SOCIETY PROCEEDINGS 11. The visual and auditory evoked responses in fullterm and pre-term newborn infants. -- D. Gambi, P. Rossini, M.C. Stefanini and M.G. Torrioli (Rome) The visual (VER) and auditory (AER) evoked responses have been used in clinical research as part of the neurological evaluation of full-term and preterm newborn infants. The latencies (msec to peak) of the evoked potentials using 40 random stimuli decrease proportionally with the increase of gestational age. This decrease is particularly noticeable for the first peak of the VER which appears after 244-345 msec in pre-term newborns at 28--32 w e e k s of gestational age; after about 226 msec in pre-term newborns at 33--37 weeks and at about 172 msec in full-term newborns. The EEG changes with p h o t i c stimulation are of greater value in full-term newborns who show a p r o m p t increase of the EEG frequencies after the first stimulus in contrast to the pre-term newborn. Neurophysiological methods of screening newborn infants of different gestational age can provide useful information.

12. CNV and neuropsychophysiology. -- B : B e r g a masco, P. Benna, A. Covacich and M. Gilli (Turin) Of the slow cerebral potentials that can be recorded in man in relation to psychological events (more precisely known as 'event-related slow potentials' (ERSPs)), a study has been made of the 'contingent negative variation' (CNV) of Grey Walter because it is easier to test from a psychophysiological point of view. There are several reports in the literature about the behaviour of the CNV during attention and distraction. It is possible to correlate some of these data with Tecce's hypothesis that maintains there exists a direct relation between the degree of selective attention of the subject and the amplitude of the CNV and a non-monotonic relation between the arousal induced b y attention and distraction and the amplitude of t h e CNV. This hypothesis is supported by our experimental data concerning the modification of the CNV provided by a 80--90 dB noise. These modifications are possibly correlated with the fact that in some subjects noise provokes either an increase in selective attention or distraction.

13. Event-related slow potentials in neuropathological conditions. -- R. Zappoli (Florence) The results of studies on event-related slow potentials (ERSPs) in various neuropathological conditions

4P are presented. These conditions include different kinds of organic brain lesions, mostly tumours (welllocalised, affecting one hemisphere or more generalized); hemispheric vascular lesions; hemiplegia and paraplegia; Parkinson's disease; head injury; epilepsy; speech and m o t o r disorders as well as relationship with cerebral dominance etc. The contrasting results obtained from analysis of the data by different authors even in the same neuropathological conditions are emphasised. Some problems of methods used and interpretation of results inherent in studies of ERSPs are discussed as well as the asymmetries that may be found, the variability in the same subject from m o m e n t to m o m e n t and the presence of frequent similar findings in quite normal subjects. Attention is also drawn to the limited research on neurological patients (as shown by the surprisingly small number of publications on the subject) and the reasons for this are discussed. It is concluded that the main obstacles to clinical application of ERSPs in neurology are the scant knowledge about their physiological origins, the lack of adequate data in normal subjects at all stages of development, and the conflicting results obtained on subjects with known brain lesions. These negative aspects give rise to considerable doubt about the real diagnostic value of ERSP 'abnormalities' or their value as a precise indicator of circumscribed brain lesions.

14. Contingent negative variation and event-related slow potentials in childhood and adolescence. -M. Papini (Florence) Following a review of contingent negative variation (CNV) and event-related stow potential (ERSP) studies in normal and abnormal children as well as adolescents and a discussion of the methods (sampling, paradigms, etc.) and techniques (eye movements, artefacts, etc.) used, some of the main problems and trends for future research are pointed out: (1) The need to use interesting semantic stimuli in the experimental paradigms is stressed in order to test children when most motivated; this technique also has the advantage of reducing eye movement artefacts. (2) As subjects with high grade mental deficiency do produce a CNV, this wave cannot prove high cognitive activity, but may be used more usefully to test afferent data processing (e.g. analysis of semantic stimuli). (3) For the same reasons the CNV should not be used to study learning disabilities in children because even if the task is difficult enough to involve and motivate the children, the CNV is apparently a phenomenon linked to temporary easy connection processing. (4) The sampling of the subjects needs to be done by the experimenter himself in order to

SOCIETY adjust the experimental paradigm to the child’s disturbance and attitudes. (5) Further studies must be carried out in children in order to determine the relationship between neurological disturbances (including states of consciousness), brain lesions and ERSPs. (6) Studies of ERSPs such as premotor potentials, the P300 and the negative waves produced by semantic stimuli should be carried out in children as a new field of neurophysiological research.

15.

Sleep and intracranial pressure. C. Di Rocco, G. Maira and A. Vignati

G.F. Rossi, (Rome)

The intracranial pressure (ICP), EEG activity, electromyogram from facial muscles, ocular movements (OM), heart rate (HR) and pneumogram during the

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REM phases of physiological sleep have been recorded in 20 patients, with varying types of central nervous system disease. An increase in ICP, appearing at the beginning and persisting throughout the REM phases (tonic increase), was observed in all patients. In some subjects, during the tonic increase of ICP, further relatively rapid pressure oscillations (phasic increases) of high amplitude were also recorded. A significant correlation between ICP changes and some EEG and EMG events as well as ocular movements was found. Any correlations with the HR variations were less obvious. There was no apparent relationship between tonic or phasic increases of ICP with the pneumogram. From the results of this study an attempt has been made to interpret the nature of ICP variations as well as of other physiological events occurring during REM sleep.

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CONTRIBUTIONS

Time shift evoked potentials (TSEPs): method and basic results by R. Halliday and E. Callaway (San Francisco, Calif., U.S.A.) ... . .. . A film projecting system as a diagnostic and training technique for eye movements of cerebral palsied children by G.M. Gauthier, J.M. Hofferer and B. Martin (Marseilles, France) . . . A single channel method for recording vertical and lateral eye movements by J.F. Connolly and K.M. Kleinman (London, England) .. . .. . .. . . . BookReviews

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International Federation of Societies for Electroencephalography and Clinical Neurophysiology. Proceedings of the General Assembly, September 8, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Society Index

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