Società Italiana di elettroencefalografia e neurofisiologia

Società Italiana di elettroencefalografia e neurofisiologia

582 ELECTROENCEPHALOGRAPHY AND CLINICAL NBUROPHYSIOLOGY SOCIETii ITALIANA DI ELETTROENCEFALOGRAFIA E NEUROFISIOLOGIA Bologna, May 12th. 1963 Secreta...

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582

ELECTROENCEPHALOGRAPHY AND CLINICAL NBUROPHYSIOLOGY

SOCIETii ITALIANA DI ELETTROENCEFALOGRAFIA E NEUROFISIOLOGIA Bologna, May 12th. 1963 Secretary:

DR. H. TERZIAN

Clinica Neurologica dell’Universit& di Padova (Italy)

development of EEG patternsin the nwmal dug. -

The electrical activity of the paraflocculusduring labyrinthine stimulation and the distribution of the potentials evoked in the cerebralcortex by electrical stimulation of Only a limited literature is availableon the development the paraflocculus have been investigated in succinylof EEG patternsin the normal youngdog - in the papers choline-paralyzed,encPpha/eisok! cats. The presentstudy hy Charlesand Fuller and by Werner it is suggestedthat is connected with previous observations (Infantellina by the age of 5 weeks the EEG of the dog has reached et al. 1962) that dogs, submitted to angular acceleration adult patterns.From work in progressit appears,instead, after strychninizationof the paraflocculus,showedEEG that alteration in the EEG patternsof the dog occur not convulsive or synchronizedactivity. (I) During the rotaonly in the first few weeksbut also towardsthe end of the tion of the animal an increasein amplitude of the parasand month of life and as late as 4.5 months. Details of flocculus potentials was observed either in intact or in these changes appear in a short monograph on the [email protected] isof&animals; such a change, that appeared &wlqmant oj’ Cerebral Functiun in the Dog (Butterworth even after a 90” rotation of the animal, often outlastedthe 1963). end of the rotatory stimulation for 30-60 sec. (2) Single shockstimulation (0.5 msec;6-20 V) of the paraflocculus of CA3 commlssuralpotential, 3. evoked trnnsient reponses in the middle and anterior o and L. Sperti (Catanla), ectosylvian gyri (highest voltage responses)and sylvian The laminar profile of the transient responseevoked in gyri of both sides,and in the contralateralcoronal gyrus. the hippocampulAcid CA3 by Rymmetriccll contralateral The typical evoked patential consisted of a 7-9 msec on (CA3 eommisklural nsponnc; Anderson 1959) latencysurfaceqoeitivewave followed by a surfacenegnwti studied in the [email protected]~l beI& eat. htr tive component. h recordingalong radial pe Thou resultsindicntou marked activationof the parathat the initial diphwsic positive/n floeculueduring ltrbyrinthine8timulntion und subatttntlate volley the incoming 1\1Tercnt the view that the parwflocculustmd the cortical area of d only in the alveusand scr,orient; the following lobyrinthine projection of both cerebrttlhemispheresare tive wave t I24 msec),prcdominnntlya buwel connected. PSP, reachenu maximumin the atr. orIons,the layer of the bsrl den&i ere CA3 commiswural 5. Expsrlmonltrl opllupsy produced In cat84 by audltory stlmulrtlun rfiw rstryc tion of terminate, tmd un s a 180” phuw reversal sudltury nrcu. - F+l na, IL RI a line in thesrr. pyr c, bein rL%orddod in the and A. Urbana (Catnnla). atum and moleculare as a positive wave. The negative/positivespike superimposed,under most cirProlonged auditory stimulation (l/set high pitched cumstances(enhancedexcitability, repetitive stimulation, sounds) carried out in intact post4etanicpotcntiation), on the negative wave reaches cats, has been found to produc str. pyramidaleand is recordedwith the background EEG activity. and decreasingamplitude in the str. the cerebellar auditory projection area (decline, folium ulare. and tuber vermis) a convulsive pattern of EEG activity Single or repetitive firing of CA3 neurons has bl?n or, less frcqucntly, an EEG activation pattern, diffuse found to occurin phasewith the “stationary” dipolar field from the onset in all the cerebralco wasabservedto generatedby the basaldendriticEPSP and with the super- follow auditory stimulation,With re to the EEG conimposed spike which representsa nired post- vulsive pattern, the strychninizution of the ccr&ellar synapticdischargeof CA3 neurons,i antidromic- auditory projc%tionarea and the auditory stimulation ally the apical dendrites. appear to bc spccificcrllycomplementary; a convulsive EEG pattern was never produced by atferent somatic stimulation after strychninization of the cerebellarauditory projection area, or by auditory stimulation after strrchninization of cerebellar fields projecting to the cerebral cortex other than the auditory area (lobuli paramedianusand ansiformis). 2. m

Electroenceph. c/in. Neurophysiol., 1964, 17: 582487

ITALIAN EEG SOCIETY The fact that strychninization of the cerebeiiar auditory area (connected with the cerebral one) makes the auditory stimulation convuisant,pointsout theimportance of the connections between cerebeilar and cerebral cortical auditory areas. The simultaneous appearance of the convulsive EEG pattern all over the cerebral cortex suggeststhe possible involvement of the reticular system in the process. 6. ParaMet study of neurophystokgtcatvartabiesin pro-

gressivebypotbermtawithout drugs. D. Willis (Naples).

F. Rit

and

The following phenomena were continuously examined in rabbits during progressive cooling to 20°C (rectal temperature& A: spontaneous activity of cortical and subcortical centres; E: responses to midbrain reticular formation stimulation (RFS); C: thaiamo-corticai recruiting potentials (RP); D: cortical responses to direct superficial stimulation (DCR); E3:ECG, BP, rectal and epidurai temperature; F: impedance of the cerebral cortex, according to Van Harreveid and Gchs. Development of changes occurs in four stages: Isf stwe of persistent “aiertness” of cerebral electrical patterns; other parameters vary within physiological limits (38-34X’); 2,rrl srage of gradual decline of hippocampal 4-7 c/set waves; RP threshold increases; DCR amplitude diminishes; low voilage fast aclivity remains in ail ccntres (34-29 ‘C); 3rd stage of rapid disappearance of hippocampal 4-7 c/set waves; RFS induces high voltage 16-20 C/NC hippocampai responses; threshold, latency and duration of RP increase; duration of DCR increasesand ion rate decreases (29-24°C); 4th stuge of spontaneous activity, interrupted by multi. focal convnisive bursts; chunges of RP nnd DCR increase critically; cortical impedance rises signitlcantiy (24-20°C). Thcu Ilndings may rcflcct un alteration of membrane properties and of electrolyte distrib dcndritio function. The change hc h u critical phase ut u

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121 out of 168 units were isolated within the boumjaries of these nuclei. The great majority of them were spontaneously active and clustered firing in the form of bursts of 3-6 spikes at high frequency was commonly Observed.

Of the 121 units, eighteen were specifically responsive to photic stimuli and to no other mode of sensory stimulation. The remainin g 103 units could not be activated by any sensory stimulus available to us. Single ffashes of light caused responsive units to discharge short high frequency trains of impulses. The mean iatencies of the responses fell between 16 and 25 msec. Driving occurred from either contraiaterai or ipsilaterai eye and peripheral receptive fields were generally large. Binocitiar interaction was not ob::erved in any of these units. None of them followed rates ktf repetitive photic stimuli higher than 4-6 sec. These findings provide further confirmation of the existence of a “focus” specifically influenced by photic ‘* “‘si;muii within the thaiamic “association area” (BusJ>r et al. 1959). 8. The electroencephaiographic mudtthttuns in three casesof a chronicform of subacutescierdrmg encepha. Ms. - H. Tenian and A. Turinese (Padova). The authors describe the modifications CJI’the EEG in three casesof chronic subacute scierosing encephalitis; in Iwo the evolution of the disease lasted more than 7 years; in the third more than 4 years, after an atypical onset. Ail three are female. in the first two cases the illness developed in 3-4 phases, with intervening quiescence extending for months and years; in the last one,, in one prolonged phase. The authors describe the EEGs, showing the progressive and rndunl disappenranc’eof Ihe specific periodic deitu complexes (as well us of thts corre. sponding myocionic jerks) and the progressive norm&&on of the buckground rhythms (corrcuponding to some very slow remission of the pronounced mental deterioration). The EEGs are actually in rrii three cases practically normal. Finully, the authors discussthe prob.

km of Ihe chronic form of subacutesciernsingenccphu-

t analy& of the pulvhuwlateraiis ptmterior pof thethnismusof the cat. - M. CQCC~CRO, litis in the light of the clinical, radiological, and EEG data of these three cases and of the hislopathoiogical obserCordellr, V. Mta Rosa, A. L&l and V. Nizd valionsgatheredbyGutewaandGsetowska(EncL,phlrllrkles, ~punur). Elsevier, Amsterdam, 1961: 386). This is a preliminary report of a study of the functional properties of the puivinar-iateraiis posterior nuclear group 9. Concerning the synaptic organization of the Herink?of the thaiamus by the method of single-unit analysis, in Breuer reflex. - E. Fadin, T. Gemi and T, Mmzoni unanesthetized cats immobilized by d.tubocurarine mMm chloride. in decerebrate cats the inhibitory elfects exerted by pul168 units were recorded extraceiiuiariy in fifteen monary Inflation on the inspiratory activity, as recorded tungsten micro-electrode penetrations, stereotaxicaily from the phrenic nerve (central stump), have been studied oriented through the lateral thalamus of twelve cats. Ail before and after ablation of the pneumotaxic ccntre. brains were examined histologically in serial sectionsand The study was performed comparatively in untreated the positions at which single neurons had been isolated animals and in animals treated with strychnine (O.iOwere identified after complete reconstruction of the IS m?/kg i.v.) and picrotoxin (0.9-I .O mg/kg i.v.1. Blood electrode tracks. pressdre was adequately controlled throughout the Ail penetrations of this series passed in a dorsoexperiments, While in the untreated animals (as already ventral direction through the oral pole of the puivinar known) pneumotaxic ablation was inconsequential with and the ventroiateral part of n. lateralis posterior. Electroenceph. din.

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respectto the Hering-Breuer reflex, the same ablation proved to be critical in the treated cats, its effectsbeing oppositein sign dependingon the drug used.ACCOrdingto the evidence obtained before the ablation both drugs inducedmild reduction of the inhibito-inspiratory effbcts of lung inflation. After the ablation, in strychnine-treated thii reductioncompletelydisappearedand the reflex backto normal, while in the cats treated with pica toxin the reductionclearlygrewinto completesuppression of the reflex. Startingfrom the assumptionthat both strychnineand picrotoxin probably act through non-inhibitory mechanisms, the above results seem to suggestthat along the central pathwaysof the Hering-Breuerreflexsomeinhibitory synapses are only affectedby strychnine and others only by picrotoxin; moreover, that the selectivelysensitive relaysare locatedat ditferent brain-stemlevels.

Si.Requmsesevokedbyt&ha&&a ofthe visaalpathways [email protected], C. Loeb and M. ManBedi (Gewva).

The experimentshavebeencarried out on-unanaesthetixed freely moving cats, carrying implanted electrodes in the optic tracts and optic radiations and on visual cortex. Results: (1) in the great majority of cased, both postand pre-synaptic components of the potentials evoked in the visual cortex and the potential evoked in the optic radiation, upon stimulation of the optic tract, increased in amplitude during arousal from light sleep. An even greater increasein amplitude of both radiation and cortical responsescould be observedin the deep sleepphase; (2) the post-synapticcomponentsof the visual cortical responsesevoked by stimulation of the optic radiation decreased in amplitude during arousal from both light and deep sleep. When the animal shifted from light to deep sleepthe responsesbehavedvariably, sometimesan increase,sometimesa decrease,or no changein amplitude, oanpbBresfu=sdurino aad J. A. Bunrater-Smith being observed. These data seemto suggestthat: (1) the transmission of aH?erent impulsesat the level of the lateral genicuiate Twenty chronically implanted cats were studied; fifteen body is facilitated during arousal and even more during with electrodeson the sensori.motorcortex and five with deep sleep; (2) the responsivenessof the visual cortex is electrodeson the sensori-motorand acousticcortex and decreasedduring arousal;(3) there are great variationsin in the hippocampus, the medini nicuiatc body, the the responsivenessof the visual cortex during the deep sleepstage. The resultsof I and 2 are in agreementwith former data yielded by the study of somatic pathways(Bavaie, Loeb and Manfredi 1962, 1963). 12, depth of slwp, EEG, eyemovements,EKG ant!EM6 In and the appearanceof type A; type D, with a

I after tone cessationun electric

muscular tone; (3) Slow (i-3 c/set) wavesof very large amplitudein the EEG; no eye movements;heart rate and inhibition the following were ob- musculartone as in 2; (4) EEG patternsas in 1; rapid eye tiation; (b) Conditioned inhibition; movements;nu constantheart rate: usually low muscular zi Delay; (d) Extinction; (e) Disinhibition, provokedby tone, an unexpectedacoustic stimulus previous to the cessaA measureof the depthof sleepis given by the intensition of the inhibited tone. The EEG responsesreappeared, ty of the cai stimulation of the skin, or of acoustic The interesting results are: (I) that we have verv stimuli, n ry to producearousal. The depth of sleep frequentlyobservedan EEG arousalwithout any behav- ischaract by greatvariability. Marked variationsare iourai response,but behaviouraiperformanceswerenever presenteven within the same phase of skip. In spita of seen without an EEG arousal;(2) that the cortexrespond- this, it appears that the depth of sleep during the first ed with an arousal to a non-signifk%tnt well-known and is definitely lighter than during the other three repeatedstimulus. as is the caseat the initiation of the There is no significant difference between the bituation and extinction. These respon ‘of sleepin phases2,3 and 4. rded during natural sleep. From thesepreliminary resultsit is possibleto suppose x has a prominent role during habituation. is not finishedand we cannot give definitive results. Electricalactivity during sleepand its responseto auditory Electroettceph.din. Neurophysiol., W&4,17: 582-581

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stimulation in twentypatientswith unilateral and bilateral Parkinson’s syndrome were compared with those of twenty control subjectsof the same age. In al! casessteepwas promoted by oral administration of 300 mg of secobarbital;in *veraI subjectsintra-

The typical evoked potential sonsistsof: (I) a first response(recordedbetween20-25 and 8e)-100msecafter the s;imulus) which consists of two positive-negative waves; of these only the second, with a higher voltage, is always r~-og?lized in every subject; (2) a secondary revenous injection of SOmg of chlorpromazinewas added. sponse (beuveen 80-100 and NO-230 msec)which has a In Parkinsonian patients typical abnormalities of deep posirive deflectionfollowed by uu elevated negative steep spindle formation were noted during Loomis Stage wave.Theu rhythmicalafterdischargesarerecorded which C and also abnormalitiesof spindles associated with K have the sameappearance,frequency,and topographical complexresponses. distribution as the background rhythm. The underlying In thesecasesall types of spindles,exceptthe frontal mechanisms for thesephenomenadependon rhythmical ones, either fail to appearat all, or appear at long interpost-synaptic synchronizedchanges of the membrane vals in the sametracing, are of smaller amplitudeand of potentialsof the cortical cells. shorter duration than in the control subjects. In the anterior records(precentrai),with a reference These abnormalitiesare more marked for the parietal electrode on the chin, two negativewavesare recorded and generalizedspindles,are symmetricalin the tracing (the second is often duplicated) which through their from both sides of the head, and equally seen both in morphologyand latency, are impossibleto correlatewith patients with unilateral and bilateral Parkinsonism. the primary and secondaryresponsesof the occipitalarea. The depressionof sleepspindle formation, associated The authorsthink that it is an anteriorsecondaryresponse, with Parkinson’sdisease,is interpretedasan expressionof similar to that describedby Davis, or the *‘point-vertex’* malfunction of pacemakersand circuits in the thalamus of Y. Gastaut, and not a muscularartefact. and basal ganglia centres,which are also the routine site With increaseof stimulusfrequencyto 4/set therewas disappearanceof the postdischarges;at blO/sec, disof pathologicaldamage. appearanceof the secondaryresponse;and at 1!3-2O/sec there was a sinusoidalrhythm, the small wavesof which idEvtdeaee for aa arehieertieul control 01 neoeartieal are correlatedwith the flash. tonarea&-Pp.L.P In the pathologicalcaseswe observed:(a) the second. ary dischargeis enhanced in the majority of epileptics, The present results stem fro unanaesthetixedcurarizedcats, and deal with the effects especiallyin those with spoutaneoussharpwaves;(h) the producedby sciaticstimulation (0.5-3 V, 1 msec,IOO/sec) brain lesions,such as tumours, vasculardiseasesor injuon the neocortical responses to auditory (clicks) and ries, showeda diminution of the secondaryresponseand photic (Rashes)stimuli both before and after preventing of the after-discharges,circumscribedto the area of the theta rhythm from appearingin the hippocampalrecord- lesion, correspondingwith the decreaseof alpha rhythm by meansof coagulationof the septum(Parmeggiani in the PEG; the slow alpha wavescannot be t (G) the old head traumas, without focal PEG neurologicalsymptoms,rarely show changeso potentials.

component of the Iatt tion; (2) aftercoagulation of the septum the samecomponentsnre no longerenhancedby sciaticstimulationasthey had been before. These results show that the variations of size and waveform causedto appear in sensoryresponsesby the repetitive electrical stimulation of sciatic nerve depend not only on the ascending influences of the reticular systembut alsoon a peculiararchicorticalinfluencelinked to the appearence of theta rhythm in the hippocampal recording. It is concludedthat the theta rhythm might be concernedwith an archicorticalcontrol of sensoryme&a= nisms.

16. ClInkal and&Et; qr&kratleits an epllkpsyIn and wnlle patient& - P, Gambettl and G.

The authors have examined 139 casesof epilepsy which beganafter the 50th year of age, dividing them into two main groups:epilepsieswith tumoral evolution (70 cases) and epilepsieswith no tumoral evolution (69 cases).The patientsbelongingto the secondgroupare further selected according to the different clinical signs, into: cerebra= vasculardisease(27 cases):cerebralatrophywithout signs of arterio.sclerosis (13 cases);chronicalcoholics(l2cases); cardiacdisease(!kases); post-traumatic(2 cases); children with cerebral disease(1 case); observations without an exact pathology (9 cases). Prom the analysisof the various groups the authors aim to stress,from aetiologicaland pathogeneticpoints of view, the very high incidenceof the neoplasticforms, the The visual evoked potentialswere studied with an elec- certain value of the vascular disease,and the importance of chronic alcoholism; from the clinical and electrotronic computer(CAT A 400of the MnemotronCoJin53 subjects, 16 normal and 37 with cerebral diseases. encephalographicpoints of view, the high percentageof Monopolar recordingwasused,with a referenceelectrode psychomotor^types,the existenceof statistical data to differentiatethe non-tumoral cpilepsiesfrom the tumora!, on the vertex or on the chin. Electroenceph. c/in. Neurophysiol.,1

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the possibility of distinguishing from the EEG the epilepsy of the patients with vascular disease from that of the atcoholics. 17.

terIntheEECofehildren.-

steep is an important techniquethat activatesthe electroencephalogramof children; however, we know pafectly the difficultiesthat are to be overcometo induce small children to sleepwhen they undergothe necessarypreparatioa far electroencephalographic recordings. Fluathane, a volatile anaestheticused to causesleep, has been tested in order to obviate the inconvenience presentedby the conspicuousalterations in the tracing causedby the giving of barbiturates or phenothiazines. This drug. given properly by means of anaesthesia, hasthe propertyof getting the patient to sleepvery rapidover, the patient elimiTwenty small children to 12 years, who were system diseases, were Sleepinduction has in numerouseasesshown clectrophio foci and convulsiveactivity which were not clearly evident in tracingsrecordedwhen the patient w3s awake, or asleep when sleep WBJcaused by other pharmacologicalmethods. to the studyof paver noetumus,-

19.JIleWieal eormlatiens in depressive syndromes. C. Giove (Milan). The author analyses82 patientswhosebioelectricalactivity was divided, according to the clinical features, as

follows: 28. involutional melancholy; 22, endogenous depression; 14, endoreactive depression; 10, reactive depression; 8, depressive neurosis. Tracings are classified according to the dominant electrical activity as follows; normal, labile desynchronized, slow irritative, paroxysmal. Correlations between EEG patterns, clinical diagnosesand

patients’agesare reported. On the basisof personalresults,and thoseof the literature in this field, the author points out the non-existence of EEG features and anomalies typical of depressive syndromes.However, a significant prevalenceof abnormal tracings was observed,more particularly of the irritative type (42x), in involutional melancholy,3s well as in patients more than 50 yearsold. The author therefore interpretstheseresultsasrelatedtoconcomitantcomplications such as vascular,metabolicand endocrinediseases. In endogcnousand endoreactive depressions,labile tracings, and to 3 lesacr degree, normal ones, are more common. The analysisof alpha rhythm shows a prevalenceof rapid frequenciesin all depressivecasts, except in the endogenousand endoreactivegroups where middle and low frequenciesprevail. The alpha rhythm frequencydifferencesseem to sup. port the possibility of variations in subcortical pacemaker functions, particularly in diencephalicand mescncephalicstructurce,regulatingthe cerebral electrogencsis involved in depressive stateCt.

.-

theselast, sevenwerefoundto have progressive opathies (in 3, convulsive episodes with very ver, common to early childhood; in 3, abnormnl deiiveries; in I, cranial trauma); in six o!hers symptoms were present(in I, tics: in I,somnambuliem:in I, stutter. ing and in 3, difficultiesof character). It must be rememberedthatinallfunctionlaltroublcsof childhood pathologicat BEGS are to be found in a lesser degree,or equal to th.xt i’oundduring :he ;c%earch.Also, as the clinical developmentof these patients does not include the beginning of epileptic troubles, we want to point out the lack of specificcharacteristicsin reports of epileptic types and, above all, the fact that the crisesof paver nocturnus are not identifiable with psychomotor attacks,even if therapeuticresults,with or without EEG improvement,can be obtained with barbiturates, which are very useful :~.!90 for neurosistreatment. TO contirm this statementwe point out, in a certain percenta of cases, the disagreementof psychological resultswith thoseof the EEG (e.g., the former of neurotic type ami the latter of epileptic type, or lessfrequently the contrary).

V, Nlaxoll, N.

II) months, His pasthistorywusnot rcmnrknbleexceptfor the occurrenceof an acute tubercular nephritis when he was II). All seizuresoccurred after prolonged silent reading. Seizureshavr been always precededby a sudden senoation of numbness,followed by an inability to recognize the meaningof a whole written sentence,althoughhewas able to recognizethat of an individual word. Neurological examinationwas entirely normal. The electroencephalogramwas normal with the patient at rest and during 5 min overbreathing. Photic stimulation was without effect. An EEG recordedduring silent reading showed random sharp waves in the left temporo-occipitalregion, doubtfully increasedby a 5 ml i.v. injection of 0.5% Megimide. After the administration of the drug, reading was found to be the only effective stimulus for the appearanceof multiple spike and wave discharges,ditruseand bilaterally synchronous,following a strongactivationof the left temporo-occipitalabnormal activity. Tie possiblemechanismscausinggeneralizedseizures in associationwith mading are reviewed.The role of the

epileptic activation of a speech area in the dominant Ekctrotweph.

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hemisphere might appear to be of some sigMicance in the present case. in relatiM to infh-teatti aa! F. M.iroai (Parma). The EEG findings in 68 cases of infm-tentorial diseases are reported. The abnormal EEG patterns are classifiedas follows: theta and delta rhythms(localiiorgeneralised); arhythmic slow waves (theta and delta, localized or gencralised); paroxysmal activities (spikes, sharp waves, spikes and waves, etc.); abnormal background activity; abnormal response to bverbreathing and to sensory stimuli. These abnormalities are correlated with age and state of consciousness of the patients, nature and localisation of the lesions, occurrence of intrncranial hypertension. The possible mechanisms causing the EEG alterations in association with infra-tentorial pathology are reviewed. The diagnostic significance of the EEG in patients with infra-tentorial diseases is discussed. in amyotrophklateral I (pavla).

Serial aiectroencephalographic recordings were taken in 35 patients with amyotrophio lateral sclerosis. The results obtained may be divided as follows: twclvo patients presented normal findings, six were borderline cases, and seventeen exhibited definitely abnormal findings. The changes observed in the latter group are rather hcterogensus. In two cases there was fast background activity (IS-17 c/se& in six cases a significant fast activity, sometimes associated with theta activity: in the theta uctivity was present at 4-S c/se% tral leads, sometimes with ali&t prev!Aa8 borderline lance on one side. The t rhythm (10 to ahowedu random and IO also found in 30 @I). A low voltago al eight patients in the other two group; only In four cases out of 35 wns an alpha activity greater than 50 pV recorded.In three casesthere was si Meant ar;ymmetry of the alpha rhythm; however, no abnormalities were detected in the statistical distribution of alpha frequencies. No correlation can be found between clinical severity and EEG changes, even in subjects with prevalent bulbar involvement. Only one of the patients suffered from paroxysmal dyspnoea while presenting a normal tracing. Further, a marked rfactivity during hyperpnoea was noted in eighteen patients. The findings are compared with those of other inves= tigators in the same field and are discussed in the light of morbid anatomy data in the literature.

conlrldsatillterv&oftimeh Masci~i and E. SfomMni The authors have studied from the electroencephalographic aspect several groups of patients suffering from epilepsy;

they belonged to different age groups. The subdivision was made chronologically 8s follows: 1st group, age UPto 5 years; 2nd group, age from 5 to 10; 3rd group, age from 10 to 15; 4thgroup, age from 15 to20; Sthgroup, age from 20 years upward. They were of both sexes, belonging to various clinical and electroencephalographic forms (grand mal, petit ma!, petit ma1variant, temporal epilepsy) in whom the electroencephalographic examination was repeated several times at intervals of months and of years after prolonged treatments by means of anti-epileptic drugs. In each group the authors have been able to notice in the patterns at an interval of time, a profound change in the bioelectric characteristics, especiallyin those belonging to patients whose clinical and electroencephalographic diagnosis had been grand mal. These changes were more evident in the patients belonging to the first, second and third groups. In discussing their results the authors have taken into consideration the influence of the maturation processes, the frequency of the attacks and the therapy, pointing out the considerable plasticity of the electroencephalogmphic pattern in epilepticpatientswhen they are

still very young. 24.ModUicatioas iaducedin human EEG by three a derived from imlnudibeazyl derivatives (Mmeprimine, amitrlptyllneand dimethyllmipramine).- C. Ravaainl, F. Vlani and F. %rrattini (MUas).

The authorshavestudiedthe modifkationsin the EEGs of 36 patients, of both aexcBand aged from [email protected] 50 years, who have km treatedwith one of the above iminodiben. ayl derivatives. in human records the most severeand specificcha Very few moditkatione h liuc, slowing or increasedbeta rhythms bain After treatment with dimcthylimipramine,there was a~; enhancementof slowactivity andof corticalactivitywhich was often focal in the temporalregions. ‘fb mechanismsof action of the three drugs are briefly discussed. Cimethylimipramine, which is the active metabolitaof imipramine, presentsEEG patterns

very similar to those of its precursor; the biochemical and pharmacologicaldata about the same mechanism Of action of the two substance8thus appearto be confld.

Amitriptyline is presumed to act on subcoftica~ I’esiOns, while trimeprimine’s action appears to be msinlY Cortid inducing peculiar irriistive features. Electrocnceph.

din.

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