Societa Italiana di elettroencefalografia e neurofisiologia

Societa Italiana di elettroencefalografia e neurofisiologia

Electroencephalography and Clinical Neurophysiology, 1980, 50: 65P--78P 65P © Elsevier/North-Holland Scientific Publishers, Ltd. Society proceeding...

1MB Sizes 3 Downloads 40 Views

Electroencephalography and Clinical Neurophysiology, 1980, 50: 65P--78P


© Elsevier/North-Holland Scientific Publishers, Ltd.


Secretary : Prof. R A O U L DI PERRI Clinica Neurologica, Policlinico, Messina (Italy)

1. Multivariate analysis in EEG power spectra evaluation. -- G.A. Zapponi, P. Ceccarelli and E. Ortolani (Rome) An important aspect in computerized EEG research is the study of adequate data reduction methods in order to provide relevant parameters for the identification of EEG effects induced by environmental stimuli or drug therapy. Power spectra obtained from human and animal EEG have been analysed with multivariate analysis methods. Principal components analysis was used to determine the minimum number of independent dimensions needed to account for most of the variance in the original set of power spectra data. The first four or five components accounted for about 80--90% of the variance of data. The first and the second co m p o n en t may be assimilated into total power and mean frequency of the spectrum, that is with the first and second parameter of Hjorth. After a varimax rotation of principal components, new factors were carried out which may be assimilated into EEG frequency bands. The use of discriminant analysis showed that components and factors were not always the most relevant parameters to classify different EEG power spectra.

2. CNV, alpha activity and RT: automatic analysis. - F. D e n o t h ,

C. N a v o n a and R. Z a p p o l i (Pisa and

Florence) A method for the analysis of the relationship between the vertex CNV, simultaneous changes in occipital alpha activity and RT is presented. A standard CNV paradigm, both with open and closed eyes, was used in normal subjects: S 1 (click) -- 1.5 sec ISI - - $2 (repetitive tones) -- response (quick 82 interruption). The CNV area between 350 msec after $1 and 150 msec before $2 with 800 msec pre-S I base line reference, was measured. Occipital alpha activity, selected by digital filtering between 8 and 13 Hz, was analysed over three different epochs, each of 500 msec

duration, by considering the rms value of the alpha amplitude. Processing was performed on a H P 2 1 0 0 / A computer connected with a HP5451/B FFA. There was some difficulty with the interpretation of the firstgroup of results which suggested an adjustment of the adopted method. The ISI should be prolonged to 2500 msec and the C N V area should be measured at least from 400 msec after Sl. On the other hand, the adopted filter has shown a perfectly adequate resolution both in time and frequency domain.

3. EEG power spectra and multivariate analysis for discrimination of quiet sleep, active sleep and wakefulness in premature children. -- C.F. Ricci, M.R. de Feo, R. Spallina, G. Gallozzi and A. Loizzo (Rome) EEGs were obtained from fronto-central and temporo-occipital regions bilaterally in 4 newborns of conceptional ages ranging from 34 to 39 weeks. Eye movements, chin EMG and respiration were also recorded both on paper and magnetic tape. After visual inspection, EEG artifact-free samples (60--90 s e c duration) from the fronto-central lead were fed into a minicomputer at a sampling rate of 128 points/sec over 8 sec periodograms, and transformed using standard F F T algorithms. Power spectra were built and recorded on digital tape over a band-width of 40 Hz (1 Hz width from 1 to 12 Hz; 8 Hz from 13 to 20 Hz; 20 Hz from 21 to 40 Hz). Mean frequency (MF) and total power (TP) of the spectrum were also computed. Multivariate analysis methods, particularly factorial analysis, were used to provide further data reduction. Seven factors were identified: cumulated 1--2 Hz; 3--7 Hz; 8--12 Hz; 13--20 Hz; 21--40 Hz; plus MF and TP. These factors accounted for about 91% of the information contained in the correlation matrices between frequencies. Our data suggest that it is possible to define quantitatively frequency band configurations for a statistical classification of the physiological state in newborns, and that with discriminant analysis, combina-



tions of parameters for the identification of EEG states can be expressed in terms of probability of classification error.

6. Recognition memory and learning alterations in head injury. -- A. Alexandre, P. Nertempi, C. Farinello, L. Rubini, D. Decima, G. Pistollato and F. Colombo (Vicenza)

4. Psychological applications of EEG spectral descriptors. -- F. Angeleri, S. Giaquinto, F. Marciani and G. Nolfe (Ancona and Senigallia)

Up till now the problem of quantifying and treating neuropsychological deficits following head injury has not been investigated by many research workers. In this study the recognition memory test has been carried out on 110 patients with the followin~ results: (1) Head injury reduces short-term memory and learning. The nature of this deficit may be a defective recording of information or a failure in recall of recorded data. (2) Age significantly influences recovery ability. (3) Cognitive defects correlate with the level of lesion as indicated by the neurological syndrome in the acute phase and not with the neurological condition. In our opinion the first aspect quantifies cerebral damage, structural or functional, which is also responsible for memory defects, while the second aspect is a variable parameter which expresses focal damage and is much less important for memory. (4) Temporal lobe damage causes the worst performances. This recalls Scoville and Penfield's experiences with temporal lobe resections and neuropathological findings in head injuries showing hippocampal ischaemia necroses. (5) Lesions on the right or left side confirm the hemispheric specialization for verbal and non-verbal material. (6) In agreement with Brooks and with Derouesn~ et al. we confirm the importance of early and intensive rehabilitation therapy.

A study has been made of the psychological applications of spectral descriptors, the weighted mean frequency (the barycentre), the mean power and the band width. These were calculated for the delta, theta, alpha and beta bands during sessions of conditioned learning (choice reaction time) as well as of hypnosis. It was observed in the two subjects under learning conditions that the decrease of performance was paralleled by a slowing of the alpha with an increase in its power, whereas the opposite was observed for the beta band. Thus the alpha gain was considered of no functional importance for the learning process itself. In the two subjects under hypnosis, an alpha gain was seen during induction followed by a power decrease and barycentre acceleration, possibly for the desynchronized slower components in the alpha band. The results suggest a wider application of the EEG spectral descriptors in both experimental psychology and psychiatry.

5. Automatic construction and evaluation of the hypnogram. -- F. Denoth, C. Navona, U. Barcaro, A. Muratorio, L. Mufti and A. Stefanini (Pisa) The visual inspection of an overnight EEG is tedious and the results are often operator-dependent. On the other hand, automatic analysis systems suffer from poor data-handling capability or are too expensive to use, especially for the enormous number of data to be handled during an overnight recording. We have developed a special purpose processor which reduces dramatically the amount of data to be processed in order to construct and analyse a hypnogram. In an off-line processing a time compression up to 128 : 1 can be achieved. The processor computes the rms value (A) and the mean number of the base-line crossing per second (0) of an analog signal. Values are averaged over an assigned interval (typically 1 rain). The hypnogram is constructed on the basis of 0 and of the amplitude of the band modulation referred to a single EEG recording. Experimental results have shown a consistent and good agreement between the automatic and the visual evaluation of the hypnogram.

7. Epileptogenic action of tranexamic acid. -- G. Andrioli, A. Pellegrini, G. Testa and R. Nori (Padua) The effectiveness of tranexamic acid (AMCA) in reducing the frequency of recurrent bleeds in patients with intracranial aneurysms appeared to be related to the AMCA levels in the CSF. For this reason it is suggested that this drug could be introduced into the subarachnoid space in such patients. In addition, because of the specific pharmacological properties of AMCA, its use during neurosurgical procedures could help provide better haemostasis of the surgical wound. In order to verify these clinical applications, experimental studies have been carried out in 7 acute cats. Some of these were submitted for the whole length of the experiment to different kinds of anaesthesia. AMCA was either introduced through the cisternal system into the CSF or applied topically to the cortex. In both situations AMCA showed clear epileptogenic activity after various delays in relation to the mode of administration. A 10% AMCA solution produced an EEG picture resembling GM status. Solutions lower than 0.05% were ineffective while at a

ITALIAN EEG SOCIETY concentration of 0.1--0.2% A M C A was able to induce epileptic activity lasting 4--5 h. These results need further investigations but reduce the possibility of the above-mentioned clinical applications and instead suggest that this m a y be a n e w powerful drug for studies in experimental epilepsy.

8. Glutamate injection in the rat brain as an experimental model of epilepsy. -- M. Avoli, P.F.A. Barra and A. Brancati (Rome) Our previous work showed that topical cortical application of glutamate (GLUT) is able to evoked paroxysmal EEG patterns limited to the site of application, i.e. without propagation to other cortical areas. Further investigations of the effects of GLUT have now been made in order to (1) observe the epileptic EEG activity induced in various brain structures by the amino acid injected into some subcortical structures as well as into the cisterna magna, and (2) investigate if the paroxysmal discharges can propagate and produce convulsive movements. GLUT injected into the caudate nucleus, the thalamus, the hippocampus and the cisterna magna induced an epileptic EEG pattern both in the cortex and in the subcortical structures examined without spreading to lower levels or producing convulsive movements. When the amino acid was injected into the mesencephalic periaqueductal grey area, local activation of the EEG and tonic muscular activity were noted without propagation to the cortex. These preparations are proposed as an experimental model of epilepsy which reproduces the dissociation between paroxysmal waves and convulsive movements frequently found in human epilepsy.

9. Applications o f multivariate analysis in the classification of psychotrophic drugs: effects o f LSD-25 on the EEG o f the rabbit. -- P. Ceccarelli, E. Ortolani, G.A. Zapponi and A. Loizzo (Rome) EEG recordings from 4 rabbits chronically implanted with cortical and subcortical (left and right dorsal hippocampus) electrodes have been made. On experimental days, subjects were 15laced in an observation chamber and connected to the EEG and an analog tape recorder. The following experimental schedule was used: during a 60-min recording session at random intervals (10--20 min) rabbits were aroused by 120 sec epochs of intermittent noise (90 dB). After this period the drug (2, 4, 16, 32 ~g/kg of LSD-25) or saline was given i.v. and further recording for 3 h or more was made using the same procedures. After visual inspection artifact samples were fed into a minicomputer using standard fast Fourier transform

67P algorithm; sampling rate was 128 points/sec over 8 sec epochs; power spectra were constructed and recorded on digital tapes with a bandwidth of 64 Hz and 0.5 Hz discrimination. Later, larger bandwidths (1 Hz width from 0.5 to 12 Hz; 2 Hz from 13 to 24 Hz; and 10 Hz from 25 to 44 Hz) were computed. Values obtained for different bandwidths were analysed with the aid of statistical multivariate analysis. It was of interest to determine whether the drug LSD-25 produced changes in the EEG bands which are significantly different from those occurring spontaneously during wakefulness, and to construct a dose--effect relationship of the drug on the EEG of the rabbit. Discriminant analysis allows further identification of the most significant parameters for the qualitative and quantitative classification of the effects induced by psychotrophic drugs on the EEG of experimental animals.

10. Electro-oculographic analysis o f oculomotor impairment in patients affected by tectal lesions. -F. Girotti, A. Cefal~, A. Sghirlanzoni, M. Savoiardo and G. Avanzini (Milan) Different pathological conditions affecting visuomotor integration mechanisms may result in significant changes of saccadic parameters (i.e. amplitude and/or velocity). Results of a study of ocular movements (EOG) carried out on 4 patients affected by tectal lesions, diagnosed by radiological examination, are reported. All patients presented an upward gaze paralysis and retractory nystagmus (convergent nystagmus was also present in 2 cases). The EOG analysis was performed only on horizontal refixation saccades. The most prominent defect found in these patients was a tendency to perform undersized saccades followed by two or more corrective movements. This tendency was particularly pronounced in 'searching' saccadic movements. Refixation saccades improved when elicited by asking the patients to fixate alternately on two points at a fixed distance. These results are discussed in relation to different types of saccadic alterations observed in other pathological conditions affecting basal ganglia and cerebellum and related to the well-known participation of tectal and pre-tectal regions in oculomotor control. The results suggest that in the different pathological situations which interfere with the mechanism of visuomotor integration, 'foveation' of the target is obtained by different and typical modifications of the motor strategy.

11. IntraceHular study o f brain-stem reticular influences on motor cortical neurones. -- V. Mohan

68P Kumar, M. Mariotti, M. Schieppati, D. Esposti and M. Mancia (Milan) In acute enc4phale isol6 cats, curarized and artificially ventilated, electrical stimulation both at low (7/sec) and high frequency ( 7 0 - - 2 0 0 / s e c ) of the bulbar ( B R F ) and mesencephalic ( M R F ) reticular formation induced postsynaptic effects in a high percentage of m o t o r cortical neurones intracellularly recorded and identified by bulbar pyramid stimulation as PT or non-PT. The main effect of B R F low f r e q u e n c y stimulation was inhibition of firing in 50% of neurones with or w i t h o u t h y p e r p o l a r i z a t i o n of the m e m b r a n e potential, accompanied by recruiting-like electrocortical responses. S o m e t i m e s postsynaptic e x c i t a t i o n was observed followed by inhibition. Inhibitory effects were mainly observed in PT neurones. High f r e q u e n c y stimulation of B R F induced both e x c i t a t o r y and inhibitory responses, mainly in non-PT cortical neurones. L o w - f r e q u e n c y M R F stimulation influenced 33% of the neurones studied. EPSPs and IPSPs were observed in equal percentage and EPSPs-IPSPs sequences could be induced. High-frequency M R F stimulation generally evoked facilitatory effects mainly in non-PT cortical neurones.

12. EEG modes; standing alpha wave two-dimensional analysis. -- R. Sferlazzo, M. Nistri, V. Cappellini and E. del Re (Florence) An analysis of the standing alpha wave is first developed f r o m measurements at a distance of 2 cm from a line connecting nasion to inion. Alpha modes are then analysed. This technique can be applied to clinical work. By using a simple recording set-up, a direct two-dimensional display of alpha waves is obtained. The technical requirements are: 16 channel EEG, unipolar m e t h o d , 2 4 0 - - 4 8 0 m m / s e c speed, high amplification (20 pV = 15 or 20 m m ) ; two 14-electrode arrays, one over each hemisphere, with electrodes set in the nodes of a square array having a constant sampling distance of 5 cm. This space sampling value is considered sufficient for map definition on a planar surface of 20 × 15 cm per hemisphere. The electromagnetic wave and vibrating surface models have been used for m o d e classification. In one-dimensional analysis the wave-length of an alpha wave was determined as 50 cm. In two-dimensional analysis a single transversal m o d e line is observed dividing the hemisphere into two parts having opposite sign; maps analogous to L e h m a n n ' s diagrams are obtained. The two-dimensional analysis shows that the alpha wave can be considered in part standing or progressive depending on different directions. As in the one-

SOCIETY P R O C E E D I N C ~ dimensional case, discontinuities and asymmetries m the wave characteristics and modes, time and space instability and longitudinal nodal lines can be related to different pathological conditions in the clinical setting.

13. Further observations on an experimental model o f epilepsy in rats using parenteral penicillin. P. Tanganelli, E. Benassi, G. Besio, C.W. Loeb and G.A. O t t o n e l l o (Genoa) Parenteral penicillin has recently been used in rats to produce an experimental m o d e l of epilepsy. The purpose of this study has been to obtain a more constant and long-lasting epileptogenic effect of parenteral penicillin in rats. 40 male Sprague-Dawley adult rats, weighing 2 5 0 - - 3 5 0 g were used in the experiments. A single i.p. administration of D e p o t penicillin (Benzathine 800 000--1 100 000 U/kg or Procainic G 400 0 0 0 - 6 0 0 000 U/kg) p r o d u c e d long-lasting activity w i t h o u t giving a c o n s t a n t dose--effect ratio in different animals. On the o t h e r hand, repeated i.p. injections of penicillin G ( 7 0 0 0 0 0 - - 1 0 0 0 0 0 0 U/kg), every 90 min, p r o d u c e d diffuse, high voltage, subcontinuous m o n o - and diphasic spikes a c c o m p a n i e d by m y o c l o n i c jerks. Occasionally tonic-clonic seizures were observed associated with paroxysmal spike activity. The periodicity of the electrical pattern was shown by computer-calculated autocorrelograms. Spikes were evoked by visual a n d / o r a u d i t o r y stimulation in rats treated with low doses of penicillin; these animals did n o t show s p o n t a n e o u s pathological a c t i v ity. Threshold doses of penicillin that p r o d u c e d this p h e n o m e n o n were studied. In addition, spikes were triggered by the same kind of stimuli in epileptic animals and frequently tonic-clonic seizures were produced. Possible analogies of this experimental m o d e l with periodic E E G patterns are discussed and the reliability of this m o d e l for studies concerning anticonvulsant drug effects is outlined.

14. Study of corneal reflex evoked by electrical stimulation in normal and pathological p a t i e n t s . - A. Berardelli, F. Contratti, M. Manfredi and A. Sasso (Rome) The orbicularis oculi reflex can be elicited in man by electrical stimulation of the cornea. A short cott o n thread soaked with saline was placed over the cornea, the thread being thin enough n o t to produce t r o u b l e s o m e sensations. This was c o n n e c t e d to an electrical stimulator and a square wave pulse was delivered at a m o m e n t w h e n the eye was maintained wide open. The reference electrode was placed on one arm. The response of the orbicularis oculi was

ITALIAN EEG SOCIETY recorded from surface electrodes placed on the lower eyelids, the reference being placed on the nose. The electrical stimulus evoked a bilateral muscle response which in normal subjects had a latency varying from 35 to 50 msec and which corresponds to the latency of the second component (R2) of the blink reflex. The early ipsilateralresponse, equivalent to RI of the blink reflex was not observed in 30 subjects. In normal subjects the activation threshold was strictly comparable in the two eyes. In patients with unilateral trigeminal lesions the threshold was increased about ten times.

15. Autonomic function and peripheral neuropathy in juvenile diabetes. -- G. Comi, N. Canal, M.

Rodocanachi, V. Saibene and L. Lozza (Milan) 50 patients aged 15--35 years with juvenile onset of diabetes had tests of peripheral nerve and autonomic function. (1) Motor and sensory nerve conduction and needle EMG were carried out to evaluate peripheral neuropathy ; (2) Valsalva manoeuvre, handgrip test and orthostatic hypotension were used for evaluation of the autonomic nervous system. Abnormalities of both peripheral and autonomic nerves were very c o m m o n even in clinically normal patients. In addition patients without EMG signs of a peripheral neuropathy showed a significant decrease in motor conduction velocity of the deep peroneal nerve compared with controls matched for age. Correlations have been made between alterations of autonomic function and peripheral neuropathy and, in addition, the relationship between neuropathy and duration of disease is discussed.

16. Complementary techniques in the study of the soleus motor nucleus by an exteroceptive reflex. -- P. Martinelli and P.J. Delwaide (Bologna, and Liege, Belgium) In 14 healthy volunteers and in a group of selected patients with neurological diseases, the characteristics of the reflex response evoked in the soleus muscle by stimulation of the posterior tibial nerve at the ankle were examined. The following features were studied: best conditions of stimulation, possible appearance of reflex activity in muscles other than soleus, effect of vibratory stimulation (100 Hz), interaction with voluntary contraction, amplitude variations as a function of stimulation frequency. The excitability curves of the reflex responses have been compared with those obtained as a result of interaction of two successive stimuli to the posterior tibial nerve, of stimulation of this nerve and the soleus H reflex and of two successive H reflexes. The electrophysiological lea-

69P tures of the response evoked in soleus by stimulation of the posterior tibial nerve were compared both to the reflex response evoked in the same muscle by stimulation of purely cutaneous afferences, and to the characteristics of the Achilles tendon reflex. The main results were: variability in latency of the reflex response; possible appearance of reflex responses in flexor muscles; increase in amplitude of the response during vibration or voluntary contraction; peculiarity of recovery curves obtained by interaction of two similar stimuli; absence of any relationship between reflex response in the soleus and electrical or mechanical activity evoked in the muscles of the sole of the foot; similarity of behaviour to the reflex activity evoked by a purely cutaneous stimulation; different behaviour from that of a monosynaptic reflex.

17. Clinical and electrophysiological observations in a case of botulism: the effects of guanidine hydrochloride. -- C. Messina, R. Dattola and P. Girlanda

(Messina) Twenty-four hours after eating home-canned peppers, a 29-year-old woman developed typical symptoms and signs of mild botulin intoxication with vomiting, dry mouth, abdominal cramps, nearly total ophthalmoplegia, dysarthria, dysphagia and limb weakness. EMG studies showed no spontaneous activity; decreased mean action potential duration and amplitude; reduced interference pattern with full effort. The muscle action potential evoked by a single supramaximal nerve stimulus was quite small (1.5 mV); its amplitude increased at low and more obviously at fast rates of repetitive nerve stimulation. Neuromuscular facilitation could also be induced using pairs of supramaximal stimuli. The amplitude of the muscle response to a single nerve stimulus was mildly enhanced by single doses of guanidine hydrochloride (0.12--0.40 mg/kg). The patient's clinical state and muscle action potential facilitation as detected by low and fast rates of repetitive supramaximal nerve stimulation and by paired nerve stimuli were not modified by guanidine administration.

ischaemic syndrome: EMG and peripheral nerve findings. -- C. Pagani, R. Schoenhuber and F. Prattichizzo (Modena)

18. Volkmann's

Volkmann's syndrome is an ischaemic contracture of the medial and especially deep muscles of the anterior forearm which usually follows trauma. The only previous electrophysiological study is by Kaeser (1965) w h o found a reduction in the M C V of median

70P a n d u l n a r nerves in 2 p a t i e n t s . In t h e p r e s e n t s t u d y 14 cases o f this s y n d r o m e h a v e been investigated. E M G studies s h o w e d severe n e u r o g e n i c d a m a g e in t h e intrinsic h a n d muscles. M o s t areas o f t h e i s c h a e m i c f o r e a r m muscles were electrically silent because of t o t a l necrosis; in t h e few active p o i n t s the E M G was n e u r o g e n i c . P a t i e n t s e x a m i n e d q u i t e early a f t e r t h e t r a u m a s h o w e d signs of severe d e n e r v a t i o n ; p a t i e n t s t e s t e d after 6 m o n t h s or m o r e s h o w e d e v i d e n c e of reinnervation. T h e findings f r o m t h e p a t i e n t s e x a m i n e d early suggest t h a t t h e E M G p a t t e r n is related to t h e ischaemic d a m a g e o f t h e f o r e a r m i n t r a - - e x t r a m u s c u l a r nerves as well as to f o r e a r m muscle damage. T h e E M G findings r e c o r d e d in later stages s u p p o r t t h e view t h a t n e r v o u s r e g e n e r a t i o n m a y o c c u r p r o v i d e d ischaemia of t h e n e u r o m u s c u l a r tissue has n o t b e e n t o o severe. Nerve c o n d u c t i o n studies c o n f i r m e d t h a t a large n u m b e r of p a t i e n t s (70%) h a d r e d u c e d or n o n - r e c o r d a b l e m o t o r a n d sensory c o n d u c t i o n velocity in t h e m e d i a n a n d u l n a r nerves.

19. Motor nerve conduction velocity in rats with different diets. -- A. Rossi, C. Firenze, V. Gallai, L. Mattelli and L. Agostini (Perugia) A s t u d y has b e e n m a d e of the effects d i f f e r e n t diets can have o n t h e p e r i p h e r a l n e r v o u s s y s t e m in rats. E x p e r i m e n t s were carried o u t o n 72 a d u l t Wistar rats w h i c h were divided i n t o 3 g r o u p s o f 24 (12 female a n d 12 male). T h e first g r o u p was fed a comm o n t y p e of f o o d , t h e s e c o n d g r o u p w i t h f o o d cont a i n i n g 15% p e a n u t oil m i x t u r e a n d t h e t h i r d w i t h 15% colza oil. 3 a n i m a l s f r o m e a c h g r o u p h a d c o n d u c t i o n velocity m e a s u r e m e n t of t h e s c i a t i c - p o s t e r i o r tibial nerve. A m o d e r a t e decrease in t h e MCV in rats with seed oil e n r i c h e d diets a n d a great decrease in rats with colza oil e n r i c h e d diets c o m p a r e d to c o n t r o l rats was f o u n d . This decrease was m o r e o b v i o u s in males t h a n in females.

20. EEG and computerized axial tomography. - - M . Antonelli, E. Bertini, A. Bianehi, M.C. Brachino, C. Colonnese, V. Guerrisi, M. Manfredi, G. Sided and F. Vigevano (Rome) A c o m p a r a t i v e s t u d y b e t w e e n E E G a n d computerized axial t o m o g r a p h y h a s b e e n m a d e in 207 n e u r o logical p a t i e n t s w h o s u f f e r e d f r o m diffuse c h r o n i c ( 4 3 ) a n d a c u t e (19) encephalopathies, focal b r a i n lesions ( 6 4 ) and epilepsy (18). Each patient h a d pathological findings for at least one e x a m i n a t i o n . P a t h o l o g i c a l E E G s w i t h n o r m a l C A T s were f o u n d m a i n l y in acute, diffuse cortical damage and epileptic s y n d r o m e s . Conversely p a t h o l o g i c a l CATs a n d nor-

SOCIETY PROCEEDINGS real EEGs were o b s e r v e d in p a t i e n t s with cortical an(t s u b c o r t i c a l a t r o p h i e s a n d p o s t e r i o r fossa s y n d r o m e s . In focal brain s y n d r o m e s the C A T gave p a t h o l o g i c a l findings in 68% of cases a n d the E E G in only 50% of cases; h o w e v e r , in 30% of cast,s with /ateralized lesions o n t h e CAT, t h e E E G gave e i t h e r the w r o n g i n d i c a t i o n o f the side or diffuse a b n o r m a l i t i e s . In 15% of p a t i e n t s w i t h n o r m a l neurological e x a m i n a t i o n and n o r m a l E E G the C A T gave re}evant p a t h o l o g i c a l information.

21. Polygraphic r e c o r d i n g o f e p i s o d e s o f cluster headache and c o m m o n migraine. -- F. C i r i g n o t t a , T, Sacquegna, R. d ' A l e s s a n d r o a n d G. C o c c a g n a (Bologna) C o n t i n u o u s r e c o r d i n g of s y s t e m i c arterial pressure a n d h e a r t rate was carried o u t in p a t i e n t s d u r i n g a t t a c k s of cluster h e a d a c h e a n d c o m m o n migraine, During t h e cluster h e a d a c h e a t t a c k s , t h e r e was an increase in t h e arterial pressure w i t h h y p e r t e n s i v e p e a k s c o r r e s p o n d i n g to t h e p a i n f u l p a r o x y s m s ; t h e h e a r t rate was r e d u c e d a n d t h e r e was a n a r r h y t h m i a . On t h e o t h e r h a n d , d u r i n g c o m m o n migraine a t t a c k s , t h e arterial pressure was n o t m o d i f i e d a n d s h o w e d only a few h y p e r t e n s i v e p e a k s c o r r e s p o n d i n g t o t h e painful p a r o x y s m s ; t h e h e a r t rate was increased b u t t h e r e was n o a r r h y t h m i a . T h e s e results a p p e a r to corn firm t h a t a d i f f e r e n t m e c h a n i s m is r e s p o n s i b l e for these t w o t y p e s o f vascular h e a d a c h e .

22. F o l l o w - u p o f 64 young patients with early post. traumatic seizures. - - A. de Santis, C.A. Pagni and P. R a m p i n i ( T u r i n ) S i x t y - f o u r y o u n g p a t i e n t s (aged 2 m o n t h s to 14 years) w h o h a d p o s t - t r a u m a t i c seizures w i t h i n 2 weeks following a c r a n i o c e r e b r a l t r a u m a have h a d follow-up studies. All t h e p a t i e n t s h a d a clinical a n d E E G e x a m i n a t i o n 1 to 17 years a f t e r t h e t r a u m a . A f t e r discharge f r o m hospital, 13 o u t o f 64 p a t i e n t s (20.3%) h a d epileptic seizures: partial seizures w i t h c o m p l e x s y m p t o m a t o l o g y in 3 cases; generalized t o n i c - c l o n i c seizures in 3 cases; partial m o t o r seizures in 1 case; partial m o t o r seizures w i t h s e c o n d a r y generalization in 3 cases; 2 p a t i e n t s h a d loss of consciousness only a n d 1 p a t i e n t h a d b r e a t h - h o l d i n g spells; 10 p a t i e n t s h a d o n l y 1 or few a t t a c k s , while 3 p a t i e n t s h a d m o n t h l y seizures. In all cases t h e seizures were easily c o n t r o l l e d b y a n t i c o n v u l s a n t t h e r a p y . Only 2 o u t of 13 p a t i e n t s with late p o s t - t r a u m a t i c epilepsy h a d c o n t i n u e d t r e a t m e n t a f t e r leaving t h e hospital. D u r i n g h o s p i t a l i z a t i o n , 9 of these 13 p a t i e n t s were c o m a t o s e , 12 p r e s e n t e d w i t h frequent epileptic seizures or epileptic s t a t u s a n d 5 o f t h e m h a d surgery.

ITALIAN EEG SOCIETY These data suggest that patients with early posttraumatic seizures have a higher risk of developing late epilepsy than those without early seizures. The patients with early seizures who are more likely to develop late epilepsy are those who have cerebral lesions requiring surgery or signs suggesting severe cranial injury.

71P levels: 40 rag/l). DPH was reduced (6.6 mg/kg/day) and serum levels declined to 25.5 rag/1 and the child recovered. In the second episode of DPH intoxication, neuroleptic-induced hypersensitivity of the dopaminergic receptors in the basal ganglia may explain the DPHinduced choreoathetosis in so far as DPH increases dopaminergic and serotoninergic activity.

23. Importance of EEG findings in the diagnosis of hepatic encephalopathy. -- D. Mancia, M.G. Terzano, O. Zacchetti, A. Lechi, D. Sacchini and G. Pelosi (Parma)

25. EEG evolution of a case of Reye's syndrome with atypical course. -- F. Pinto, M.C. Stefanini, G. Segni and O. Ranno (Rome)

The clinical findings concerning 120 patients in hepatic failure are described. The correlation between clinical and EEG patterns was stated according to the classification suggested by Kurtz. Wakefulness on the one hand and amino acidaemia and blood ammonia levels on the other hand were of special interest. In most patients the clinical findings of hepatic encephalopathy were accompanied by EEG alterations proportional to the severity of the hepatic trouble. In some patients it was possible to establish the blood content of ammonia bodies and of amino acids (and particularly of the open chain amino acids -- AACR -- aromatic amino acid ratio) which could be used as a biochemical -- EEG correlation in so far as a diminution of this ratio below normal values (3--3.5) was paralleled by hepatic encephalopathy and proportional alterations in the EEG. Therapy with balanced amino acids produced good effects detectable biochemically and by the EEG. Prognosis was facilitated by the establishment of correlations between biochemical-clinical and EEG findings both for short-term outcome and for the evaluation of the effects of the therapy. The EEG cannot be used alone as prognostic indicator given the high incidence of deaths from non-hepatic causes.

The syndrome described by Reye et al. in 1963 is characterized by a fatty degeneration of viscera with a severe acute or subacute encephalopathy. The present study concerns a case of Reye's syndrome with atypical clinical and EEG evolution. The 3-year-old boy who survived after being treated intensively with IV therapy was at first in deep coma with decorticate rigidity (the EEG showed diffuse monomorphic delta activity) which later evolved into a typical clinical and EEG 'coma vigile'. During this time, daily polygraphic and four nocturnal records (for 12 h) were made and in addition metabolic data were collected. One and a half months from the onset of illness he had a spastic tetraparesis which is exceptional in this syndrome and raises some interesting speculations about the neuropathological lesions causing the clinical picture. At the same time the EEG showed a gradual regularization of the rhythm during wakefulness followed by progressive normalization of sleep activity. Specific pathological lesions in Reye's encephalopathies have not been described until now; one possible interpretation is discussed on the basis of the clinical-EEG evolution of the case reported as well as the typical pathological and EEG findings of the apallic syndrome. It thus seems possible to suggest multiple aetiological factors in Reye's syndrome.

24. Phenytoin-induced paroxysmal choreoathetosis in a retarded epileptic child. -- M. Papini, S. Guerri and G. Zaccara (Florence) A 9-year-old retarded epileptic child had diphenythydantoin (DPH) intoxication with ataxia, drowsiness a n d severe EEG abnormalities (2--4 c/sec diffuse irregular high amplitude waves). DPH was discontinued and the child recovered. Neuroleptic drugs were afterwards administered in order to control the aggressive behaviour of the child. Three years later the epileptic seizures became increasingly frequent and the neurolept~c drugs were discontinued while DPH (12 mg/kg/ day) was again administered. The child began having daily episodes of choreoathetosis and again showed signs and symptoms of DPH intoxication (DPH serum

26. Clinical significance of pseudoperiodic lateralized EEG discharges. -- A. Primavera, M. Giunchedi and E. Caneva (Genoa) Out of 14,600 EEGs performed at the Department of Neurology, University of Genoa over a period of 5 years, only 37 from 19 patients (0.24%) showed pseudoperiodic lateralized discharges (PLDs). The aetiology was cerebrovascular disease in 10 patients, while neoplasm was implicated in 4" cases, subdural haematoma in 1 and post-traumatic epilepsy in another case. Two patients had herpes simplex encephalitis confirmed at autopsy in 1 case and by abnormal result of the complement fixation test in the other. One patient, with pathological evidence of Jakob-Creutz-

72P feldt disease had this EEG pattern at the onset of the illness. The present series resembles the earlier studies on PLDs in which the most common causes of this EEG pattern were tumours, strokes and inflammatory diseases. However, the incidence of PLDs is very low in patients with strokes or tumours (less than 2%) while we found PLDs in both cases of herpes simplex encephalitis studied. Recent literature has confirmed the presence of PLDs in almost all cases of herpes simplex eneephalitis. Thus the appearance of repetitive lateralized EEG complexes, although relatively non-specific, suggest the diagnosis of an acute necrotizing encephalitis. This finding is extremely important because therapy (particularly adenine arabinoside) must be given early in the course of this infection with benefieial effect. 27. Preliminary results of statistical analysis of recurrent stereotyped activities in periodic EEG patterns. -- A. Seitun, C. Gandolfo, A. Primavera and M. Maffini {Genoa) Stochastic point process analysis (Perkel et al. 1967) has been applied to some periodic EEG patterns: 1 case of subacute sclerosing leucoencephalitis (SSLE), 1 case of Creutzfeldt-Jakob disease (CJ), 1 case of herpes simplex encephalitis (HSE). In each case, on selected sequences (time analysis: 5--10 rain), time intervals between stereotyped EEG complexes were calculated and analysed by computerized auto- and serial correlation methods. In all cases autocorrelograms (bin resolution = onetenth of the mean time interval, 20 convolutions) showed a great periodicity which was scarcely influenced by a prolonged random shuffling of ordered intervals. Such an outcome can be interpreted as due to a stationary process having a constant renewal density. At the same time, serial correlograms (lag = 1--50) revealed a constant negativity with irregular low-lag oscillatory pattern. This trend is slightly modified by shuffling. These data suggest the existence of a small jitter of stereotyped complexes, followed by compensatory delay, as well as a fair stability of the mean frequencies. The present results strongly support the hypothesis of a c o m m o n trigger mechanism in SSLE, CJ and HSE, mainly sustained by non-synaptic, 'pacemaker-like' processes, involving basic properties of nervous tissue.

28. Two additional waves of human SEP: the N16 and N17 components. -- M. Abbruzzese, E. Favale, M. Leandri and S. Ratto (Genoa) Ear (A2) referential recordings of the cortical SEP with left median nerve stimulation (at the wrist) show

SOCIETY PROCEEDINGS two diphasic waves, apparently disregarded by previous authors (Goff et al. 1977) occurring between P~ 5 and N20 components. These two waves have been called N16 and N17 though in fact their peak latencies are 15.8 ± 0.8 and 17.3 -+ 1.0 msec, respectively. A particular method of approach, based on changes in polarity of each component of the SEP according to placement and combination of electrodes has been devised. In this way it was demonstrated that distinct generators are responsible for the different components occurring during the first 20 msec following the stimulus. Moreover, it has been found that both N16 and N17 waves are prevalent over the hemisphere contralateral to the stimulus. Pertinent experimental findings (Iragui-Madoz and Wiederholt 1977) are discussed in relation to these results.

29. Comparison between ipsilateral and contralateral somatosensory evoked potentials in normal man. -- A. Amantini, A. Ragazzoni, O. Ronchi, L. Rossi and R. Zappoli {Florence) Ipsilateral and contralateral SEPs were recorded in 22 healthy adults. Needle electrodes were placed in the scalp overlying the 'hand area' of the left and right post-rolandic somatosensory cortex. Electrical stimuli were applied to the left median nerve at the wrist. Averages of 50 artifact-free responses were obtained with an analysis time of 300 msec. A contralateral response appeared with a small positive wave and latency of about 15 msec (Pls) and the following components were denoted as N20, P2s, N35, P45, Nss, Pss, N120, Piss, N200, P245. The first peak clearly identified in the ipsilateral SEP was designated as P's0, corresponding to the contralateral t P~9s. The later ipsilateral waves were named N 70, r ~ t t s, N 120, P l s s , N 200, P 24s. In each subject differences in the peak tateneies of the ipsilateral and contralateral responses were computed. The difference in the mean latencies between Pts0--P45 , N'y0--Ns5, P'gs--Pss was found statistically significant (P always < 0.02). The later components did not show statistically significant latency differences (P always > 0.4). These results indicate that ipsilateral SEP compo~ nents, occurring in the first 100 msec, show greater latencies than the corresponding contralateral responses. Later responses appear almost simultaneously over both hemispheres. It is therefore suggested in agreement with other studies, that there are two types of ipsilateral SEP components. The former are apparently the result of subsequent activation of the ipsilateral hemisphere via an interhemispheric pathway, possibly involving the corpus callosum. The later ones may be mediated by a slowly conducting ascending pathway projecting to both hemispheres.


30. Motor-related potentials in hemiparetic subjects. -- B. Bergamasco, P. Benna, M. Gilli, F. Lacquaniti, G. Quattrocolo and W. Troni (Turin)

73P msec and in 33% of cases was higher than 10 msec. Many cases showed delayed latencies in the absence of optic nerve involvement.

Ten patients with hemiparesis caused by a stroke in the middle cerebral artery territory, clinically welldocumented, were studied. Five had a lesion of the right hemisphere and five a left hemisphere lesion. All subjects executed self-paced thumb finger flexions pressing a button which triggered the averager. The scalp EEG was recorded from C'3 and C'4 (1 cm anterior to C3 and C4) referred to linked ears and 100 artifact-free responses were averaged, time-locked to the response for flexion of each thumb finger. The following results were obtained: (1) In healthy people the MRP pattern constantly showed the three classical waves N1, N2 and P2. No significative differences between interhemispheric amplitude ratios of the single waves with right thumb flexion and those with left thumb flexion were found; (2) In the group of hemiparetic subjects the behaviour of the MRP was not homogenous but in 6 out of the 10 patients normal MRPs were seen from both the healthy and affected hemispheres and the interhemispheric ratios were normal with both healthy and paretic thumb flexion.

42 patients suffering from adhesive polyneuropathies aged from 14 to 63 years have had EEGs, standard and quantitative EMG as well as VEP and SEP studies serially from the onset of the illness until they became clinically normal. Slowing of the latency of the first VEP components with reduction in mean amplitude have been frequently observed in patients even when the clinical and EEG parameters were within normal limits. In addition the SEP with median and peroneal nerve stimulation also showed an increase in latency of the first components with reduction in mean amplitudes, and this finding was also frequently observed when other clinical or EMG parameters had returned to normal values. The significance of these results in relation to central impairment in these toxic syndromes is discussed.

31. Visual evoked potential abnormalities in multiple sclerosis. -- A. Ghezzi and R. M0ntanini (Gallarate)

33. The SEP in sensory-motor screening of multiple sclerosis. -- P.M. Rossini, P. David, M.F. Laureati and D. Sollazzo (Rome)

Delayed visual evoked potentials (VEPs) have been found in multiple sclerosis (MS) patients in a percentage varying from 50% (Mastaglia) to 96% (Halliday). The aim of this study was to verify such results and then to investigate other components of the VEP, namely the waves preceding the major positive wave (MPW). VEPs were recorded in 35 MS patients and in 35 normal subjects in response to 64 flashes (0.6 joule, duration 10 msec, reddish light, interval 1 sec) from occipital-vertex silver/silver chloride electrodes. The mean latency of the MPW ( P l l 0 ) was 110.7 msec in the control group. Assuming 130 msec as the upper limit, 27 out of 35 MS subjects (77%) showed a delayed latency, in contrast with only 1 out of 35 controls (P < 0.001). Abnormal latencies were noted in the other waves and the mean values were for P45: controls 46.7 msec, MS patients 49.7 msec; for P65: controls 66.1 msec, MS patients 82.0 msec; for N85: controls 84.3 msec, MS patients 102.0 msec; for P l l 0 : controls 110.7 msec, MS patients 138.8 msec; for P135: controls 136.8 msec, MS patients 163.4 msec. Each eye, when separately stimulated, showed similar latencies for each c o m p o n e n t in controls (mean difference + 5.1 msec) only 1 case exceeding 10 msec. In MS patients the mean difference was 14.5

Previous papers have emphasized the usefulness of the SEP in the diagnosis and prognosis of MS based on the theoretical and experimental hypothesis that there is a conduction block and loss of function of demyelinated fibres. In this study the SEP has been recorded in 20 healthy control subjects, 20 patients suffering from non-demyelinating diseases and 40 patients affected by definite (22 cases, 55%), probable (10 cases, 25%) and possible (8 cases, 20%)MS. Before recording the SEP each patient was rated on the partially modified 5-point scale of Rose. Rectangular pulses of 0.1 msec duration and 10 V intensity above motor threshold were given and the responses were recorded from the scalp with electrodes placed on the hand and leg projection areas referred to linked earlobes. The median nerve at the wrist and the popliteal nerve on each side were stimulated. Scores of the SEP and of the sensory and pyramidal systems (from 0 to 5), obtained separately by two different examiners, were matched in statistical correlation by means of Pearson's r test. In conclusion, the morphological characteristics of the SEP in d em y el i nating diseases seem to correlate well with the clinical course and therapeutic response in MS.

32. Somatosensory and visual evoked potentials in chronic adhesive polyneuropathies. -- C. Serra, A. Rossi, D. Facciolla, A. Ruocco and A. Biondi (Naples)


34. A study of visual evoked responses with pattern reversal in normal subjects. -- D. Gambi, M. Onofri, P. Rossini, U. Colangelo and L. Aquilone (Chieti and Rome) The pattern reversal evoked responses of 15 subjects, 5 women and 10 men, have been recorded with normal psychophysical conditions. Three kinds of pattern reversal stimuli have been used: horizontal bars, vertical bars, checks. Each kind of pattern has been projected onto a television screen (26 inches) in two different levels of contrast (20%, 50%), and in two different shapes (0.5 cm and 1 cm on the screen). The distance of the subject from the screen was 114 cnl.

The contrast intensity variation and the different sizes of the pattern showed a clear change in amplitude of the ER; our interest has been mainly concerned with the 100 msec component. In addition, changes in the evoked response morphology due to the different projected patterns have also been observed. The results are discussed in relation to the basic structures in the optic pathways.

35. Sleep and altered cortisol secretion. -- P. Bergonzi, R. Coppi, C. de Rosa, S. Mazza and G. Mennuni (Rome) A study of night sleep patterns has been carried out in 4 patients with bilateral adrenal hyperplasia, 2 cases with bilateral adrenal hyperplasia plus pituitary adenoma, 1 case with Nelson's syndrome and 2 cases with iatrogenic hypercortisolism. In comparison with normal control subjects matched for sex and age, patients with adrenal hyperplasia showed an increase in stage I and reduction in stage II sleep; patients with adrenal hyperplasia plus pituitary adenoma also showed a decrease of stage II; the patient with Nelson's syndrome had a slight increase of stage I and a more obvious decrease of stage IV; cases with iatrogenic hypercortisolism showed an increase of interspersed wakefulness and a clear reduction of stage II. The possible relationships between corticosteroid hormones and sleep stages are discussed in relation to a comparison of these results with those obtained from the more commonly occurring alterations of adrenal function (such as Addison's or Cushing's diseases).

SOCIETY PROCEEDINGS 1973). However, L-DOPA is neither a direct nor ~ selective activator of dopamine receptors and ma) influence noradrenergic as well as serotoninergic systems. However, apomorphine has been shown to be a direct stimulant of dopamine receptors (Creese et ~] 1975). In the present study, the administration of a p o morphine has been carried out by continuous infusion before and during night sleep in subjects not affected by brain disease. A dramatic reduction of delta sleep and a suppression of REM sleep has been observed. After stopping the drug, an increase of delta and REM sleep occurred, similar to the weltknown rebound effect after selective stage deprivation using awakening techniques. Previous administration of a dopamine receptor-blocking agent inhibits such effects of apomorphine on sleep, indicating that these are probably due to a dopamine receptors activation. The results are discussed with regard to the types of receptors involved.

37. Sleep polygraphic investigation for the 'screening' of psychoactive compounds: a short-term trial. -C. Maggini, M. Guazzelli and M. Mauri (Pisa) The 'screening' of psychoactive drugs using polygraphic techniques is still in an experimental phase. The single-dose trial appears to give information only about the less specific psychotropic activity of the compound, while the short-term trial seems able to characterize the peculiar effects of each class of drug. In this short-term trial, 8 healthy volunteers were administered for 3 days, following a double-blind crossover design, placebo and increasing doses of amitriptyline (25, 50, 100 mg) and caroxazone {150, 300, 600 mg), a new antidepressant agent with MAO-I activity. Amitriptyline was effective after the first administration and showed modifications of sleep similar to those reported in previous studies with tricyclic antidepressant agents. Caroxazone, after the first night, could not be differentiated from placebo; in the following nights the new drug induced a reduction of REM sleep and an increase in latency of the first REM period. Such modifications are similar to those reported for other MAO-I agents.

36. Effects of dopamine receptor activation on sleep. - - C . Cianchetti, C. Masala and A. Mangoni (Cagliari )

38. Prolactin release during sleep in patients with midline cerebral tumours. -- L. Mufti, G. Parenti, U. Bonuccelli, C. Forli, F. Salvadorini, F. Galeoni and P. Saba (Pisa)

The role of dopaminic mechanisms on sleep is not clear. L-DOPA following acute parenteral administration in humans, reduces REM sleep (Giltin et al.

Human plasma prolactin (hPRL) concentrations exhibit daily maxima during night sleep, hPRL release is under the control of the hypothalamus and hypo-

ITALIAN EEG SOCIETY thalamo-mesencephalic structures are also involved in the regulation of the sleep-wake cycle. Hormone levels were measured by radioimmunoassay in 4 patients {group A) with tumours directly involving the hypothalamus and in 4 patients {group B) with turnouts involving indirectly the third ventricle. Blood samples were drawn at 60 rain intervals during the waking period and at 30 min intervals during polygraphically monitored sleep. There was a regular sleep-wakefulness rhythm in all subjects and a true insomnia or hypersomnia was never observed. There was no significant difference of sleep pattern in the patients of group A compared with group B. In 3 subjects of group A and in 2 of group B, abnormally high hormone levels were found especially during the nocturnal period. These data indicate that in group A the tumour alters the connection between the hypothalamus and hypophysis and that this lesion provokes an increase in the plasma concentration of hPRL. We have also found a similar result in 2 group-B cases in whom the tumour did not directly involve the hypothalamic structures according to clinical, radiological or neurosurgical observations.

39. Classification of myoclonic epilepsies. -- P. Pazzaglia, P. Giovanardi Rossi, F. Cirignotta, R. Moschen and E. Lugaresi {Bologna) Myoclonic epilepsies (ME) are characterized by massive myoclonias as the only or prevalent type of seizures and can be classified as follows: (1) ME with progressive encephalopathy. Ca)Unverricht-Lundborg syndrome {degenerative form, Lafora's disease; neurolipidosis). (b) Ramsay-Hunt syndrome. (c) Subacute sclerosing panencephalitis (SSPE). (2) ME with non-progressive encephalopathy. (a) West syndrome. (b) ME with 'fixed' encephalopathy: an acute brain lesion (usually occurring at birth) causes a severe encephalopathy resulting in mental and neurologic handicap complicated by myoclonic seizures during the second year of life. (3) ME without encephalopathy. (a) ME with slow spike-wave in which there are frequent, massive myoclonias accompanied by bilaterally synchronous discharges of spike-wave complexes at 1.5--2 Hz. Brain lesions are observed in one-third of cases, severe mental defect in one-fifth; mean a g e o f onset of seizures is 3 years. This form is regarded as the 'myoclonic variant' of Lennox-Gastaut syndrome. (b) True or cryptogenic ME is characterized by frequent, massive myoclonias, accompanied by bilaterally synchronous discharges of spike-wave complexes at 3 Hz. Brain lesions are absent; genetic factors are often involved; mean age of seizure onset is 3 years. Mental defect is

75P frequent according to some authors but absent according to others. (c) Myoclonic absences which differ from simple typical absences because the massive myoclonias occur approx. 3 times/sec during the attack; these are resistant to therapy and often associated with mental defect. (d) Myoclonic petit real differs from other types of ME because it begins in adolescence and is benign in almost all cases.

40. Myoclonic encephalopathies in the first year of life. -- G.B. Cavazzuti, A. Nalin, F. Ferrari and B. Mordini (Modena) Different forms of myoclonic encephalopathies can be distinguished in the first year of life using chronological, aetiological, symptomatic and evolutionary criteria: (1) Early myoclonic encephalopathies which usually begin during the neonatal period and always before the third month of life characteristically show almost continuous erratic myoclonias, infantile spasms, EEG burst-suppression activity, poor prognosis including severe cerebral palsy. (2) Typical West syndrome consisting of spasms, hypsarrhythmia and mental retardation. (3) Partial West syndromes, with only 2 of the above-mentioned features, are as severe as the typical West syndrome and they often develop into the Lennox-Gastaut syndrome. (4) Metabolic encephalopathies {early ceroid lipofuscinosis or Hagberg-Santavouri disease; GM2 gangliosidosis or TaySachs disease; Christensen-Krabbe progressive polydystrophy of childhood or Alpers' disease). These show hypotonia {which evolves into spasticity), mental retardation, blindness, epileptic and non-epileptic myoclonias and eventually death. (5)Myoclonic epilepsies with encephalopathy which usually result from perinatal or post-natal anoxic damage. The patients show microcephaly and mental deficiency. These forms can be differentiated by the type of EEG pattern and forms of myoclonic phenomena. Kinsbourne's opsoclonic encephalopathy and LanceAdam's postanoxic encephalopathy fall into this group.

41. Epileptic myoclonic phenomena photically induced in children. -- L. Gervasio and W.G. Sannita (Milan and Genoa) An epidemiological, clinical and EEG study was performed on 307 children with photosensitivity. 100 subjects had clinical responses (myoclonic jerks in 82 cases) to repetitive photic stimulation; the response was restricted to EEG phenomena in the other 207 subjects who are referred to as the control group. Photosensitivity was more frequent in females

76P (62.3%). T h e age of o n s e t of the E E G r e s p o n s e was f o u n d to be m o r e f r e q u e n t b e t w e e n 5 and 11 years, while the m y o c l o n i c response usually a p p e a r e d b e t w e e n 8 a n d 13 years. Epilepsy was diagnosed in 125 cases (66% of subjects with m y o c l o n i c r e s p o n s e to s t i m u l a t i o n ) . Myoclonic epilepsies a n d the association of generalized convulsive a n d n o n - c o n v u l s i v e seizures were m o r e common among subjects with the myoclonic response, while generalized convulsive epilepsy was twice as f r e q u e n t in t h e c o n t r o l group. A generalized E E G r e s p o n s e to p h o t i c s t i m u l a t i o n , as well as the o c c u r r e n c e in the E E G o f spikes, spike a n d wave or p o l y s p i k e a n d wave discharges were f o u n d to be m o r e f r e q u e n t in s u b j e c t s w i t h m y o c l o n i c responses. 42. Subacute sclerosing panencephalitis (SSPE): electroclinical studies of four cases. -- L. Piattella, G. Ottoni and C. Cardinali (Ancona) S u b a c u t e sclerosing p a n e n e e p h a l i t i s (SSPE) is a degenerative disease of the n e r v o u s s y s t e m i n c l u d e d a m o n g t h e i n f e c t i o n s due to a slow or p e r s i s t e n t virus. I m m u n o l o g i c a l studies w i t h e l e c t r o n m i c r o s c o p y have i n d i c a t e d t h a t a m i x o v i r u s is involved w h i c h is e i t h e r a measles virus or a virus w i t h a n t i g e n i c c h a r a c t e r i s t i c s similar to t h a t of measles, a l t h o u g h n o t long ago SSPE was t h o u g h t to be r e l a t e d to rubella virus. Following investigations o n 4 c h i l d r e n aged 4 - - 1 0 years w h o were seen f r o m O c t o b e r 1975 to M a r c h 1 9 7 7 , f u n d a m e n t a l criteria for the diagnosis have b e e n e s t a b l i s h e d : (1) a h i s t o r y of measles or measles imm u n i z a t i o n ; (2) c h a r a c t e r i s t i c clinical course ( m e n t a l changes, m y o c l o n u s , c h o r e o - a t h e t o s i s , ataxia, spasticity); (3) m a r k e d l y elevated a n t i b o d y titre in s e r u m a n d c e r e b r o s p i n a l fluid; (4) c h a r a c t e r i s t i c E E G e v e n t s (periodic b u r s t of R a d e r m e k e r ) a n d typical electrom y o g r a p h i c findings in t h e p o l y g r a p h i c studies. In 2 cases t h e diagnosis has also b e e n c o n f i r m e d by a u t o p s y , 1 case s h o w i n g i n f l a m m a t o r y perivascular aggregates of l y m p h o c y t e s , m o n o c y t e s , eosinophiles, p l a s m a cells, focal areas o f necrosis a n d n e u r o n a l d e g e n e r a t i o n in spinal m a r r o w . In t h e o t h e r case macroscopic e x a m i n a t i o n s h o w e d a diffuse o e d e m a t o u s state with i n t e n s e v e n o u s c o n g e s t i o n a n d o n microscopic e x a m i n a t i o n t h e r e was i n f l a m m a t o r y r e a c t i o n of t h e whole of the b r a i n ( p r e d o m i n a n t l y localized t o w h i t e m a t t e r ) , perivascular aggregates of l y m p h o c y t e s a n d m o n o c y t e s as well as i n c l u s i o n b o d i e s in t h e nuclei o f t h e ganglion cells.

43. Observations on the therapy of the m y o c l o n i c epilepsies o f childhood. -- P. Benedetti, P. Curatolo, G. Porto and I. A n t o n o z z i ( R o m e ) The treatment of 15 cases of cryptogenic m y o elonic epilepsy (Aicardi) treated with PB associated

SOCIETY PROCEEDIN(;': with DPA a n d / o r CNZ are described. T h e dose/lew~i regression line of the PB has been calculated from ] 33 c h i l d r e n t r e a t e d with PB + DPA a n d 139 childre~ t r e a t e d with PB + CNZ in the same age group ( 2 i 2 years) a n d a f f e c t e d by o t h e r t y p e s of epilepsies. The, dose/level r e l a t i o n s h i p does n o t a p p e a r to be d i f f e r e n t in c h i l d r e n o f the ' m y o c l o n i c ' g r o u p c o m p a r e d with c o n t r o l s . All t h e data f r o m c h i l d r e n with m y o c l o n i e seizures a p p e a r to fall inside t h e 95 ~', c o n f i d e n c e limi~ a r o u n d t h e regression line. T h e r e f o r e n o significanl difference in the p h a r m a c o l o g i c a l b e h a v i o u r of the drugs t e s t e d has b e e n o b s e r v e d in c h i l d r e n with cryp togenic m y o c l o n i c epilepsy c o m p a r e d with c h i l d r e n suffering f r o m o t h e r t y p e s of epilepsy. 44. Possible role o f the serotoninergic system in t h e pathogenesis of m y o c l o n u s . Preliminary data of a clinical trial. -- G. Avanzini, L. Bossi, T. Caraceni, A. Consolazione, S. Franceschetti and R. Spreafico (Milan) Eight patients with different myoclonic syndromes were s t u d i e d : 3 w i t h m y o c l o n i c epilepsy, 1 w i t h clinical f e a t u r e s i n t e r m e d i a t e b e t w e e n m y o c l o n i c epilepsy a n d the R a m s a y H u n t s y n d r o m e , 2 with progressive m y o c l o n u s of u n k n o w n origin, ] w i t h bilateral massive m y o c l o n u s a n d 1 with a c t i o n a n d i n t e n t i o n myoc l o n u s related to a t h a l a m i c a n g i o m a . T h e y were given a single dose of the following drugs in a rand o m i z e d s e q u e n c e : L-5-HTP + c a r b i d o p a ; t h e serotoninergic agents q u i p a z i n e , f e n f l u r a m i n e , a n d trazod o n e ; the p r e s u m e d b l o c k e r of the 5-HT r e c e p t o r , m e t h y s e r g i d e ; a n d c l o n a z e p a m . Basal CSF levels of 5 - H I A A a n d H V A were m e a s u r e d . Clinical a n d neuro~ physiological p a r a m e t e r s were c o n t i n u o u s l y m o n i t o r e d d u r i n g t h e p h a r m a c o l o g i c a l tests b y p o l y g r a p h i c as well as film recordings. T h e a d m i n i s t r a t i o n of L-5-HTP a n d of serotonin-. ergic drugs h a d a significant positive e f f e c t in t h e p a t i e n t w i t h clinical c h a r a c t e r i s t i c s i n t e r m e d i a t e b e t w e e n the m y o c l o n i c epilepsy a n d the R a m s a y H u n t s y n d r o m e ; it caused a d r a m a t i c increase in E E G p a r o x y s m a l activity in 1 p a t i e n t with m y o c l o n i c epilepsy, while it did n o t have a n y significant e f f e c t in the r e m a i n i n g p a t i e n t s . T h e a d m i n i s t r a t i o n of m e t h y sergide caused a e l e a r c u t w o r s e n i n g of t h e clinical picture in 1 p a t i e n t with erratic progressive m y o c l o n u s . C t o n a z e p a m was highly effective in all p a t i e n t s after acute administration, while c h r o n i c treatment r e m a i n e d effective only in the p a t i e n t s w i t h m y o c l o n u s plus epilepsy.

45, A u t o m a t e d analysis o f surface and intracellular potentials during interictal and ictal epileptiform discharges. -- M. Avoli ( R o m e ) Studies of intracellular activity in foei p r o d u c e d

ITALIAN EEG SOCIETY by topical drug application have provided valuable data about cellular activity underlying focal epileptiform discharges. However, when not involved in epileptogenesis, these neurones show normal spontaneous and evoked activity indistinguishable from that of neurones in normal cortex. In order to recognize some properties of paroxysmal behaviour, surface and intracellular neuronal activity was computer analysed during interictal and ictal discharges. Cellular and EEG signals, recorded from cortical foci produced by strychnine and pentylenetetrazol in rats, were passed through an analog-to-digital converter and then correlograms of the digital signals were calculated off-line on a minicomputer. Autocorrelations of function of the intracellular signal, both during normal and paroxysmal activity, clearly showed a periodicity whilst the surface autocorrelations revealed hidden periodicities. The presence of several periodicities in normal conditions was shown by cross-correlations; on the other hand both during interictal and ictal discharges, cross-correlations approached a periodic function which characterized the situation. Likely cross-correlations between the intracellular activity of a given unit and 'space average potentials', in the superficial zone around the individually observed cell, can show a variety of situations (e.g. before and after convulsant application).

46. Grand mal seizures and idiopathic hypoparathyroidism: Report of a case. -- E. Bertini, A. Bianchi, M.C. Liuzzo, M. Manfredi, G. Sideri and F. Vigevano (Rome) In a patient with primary hypoparathyroidism, generalized convulsions resistant to antiepileptic medication developed and were later complicated by bilateral cataracts. Low serum calcium and elevated serum phosphorus, found during a period of grand real status resistant to routine treatment and also to i.v. barbiturates, revealed the correct diagnosis. The seizures were suppressed by correcting the serum calcium level and disappeared during treatment with dihydrotachyster.olum. The mechanism of convulsive seizures during hypocalcaemia is discussed and the possibility is raised that anticonvulsive drugs could have contributed to the hypocalcaemia by causing vitamin-D deficiency.

47. Nerve conduction velocity in 150 diabetic patients: influences of age, sex, metabolic control and duration of diabetes. -- C. Firenze, V. Gallai, G.L. Piccinin, A. Rossi and L. Agostini (Perugia) Bilateral measurements of motor conduction velocity (MCV) in the peroneal and posterior tibial nerves

77P and sensory conduction velocity (SCV) in the median nerves were made in 150 diabetic patients of different age and sex. The MCV and SCV were then correlated with age and sex of the patients and to the duration and control of the diabetes using Schlichtkrull's index. Our data showed: (1) A high percentage of patients with decreased values of MCV and SCV. (2) The importance of determining the MCV and SCV in a large number of nerves. (3) A relationship between the degree of lowered MCV and SCV and both metabolic control and duration of the diabetes. (4) The incidence with which diabetes affects the various nerves and the importance of the conduction velocity decrement.

48. A VER study with pattern reversal in multiple sclerosis. -- D. Gambi, M. Onofri, P. Rossini, L. Aquflone and U. Colangelo (Rome) The visual function of 6 subjects, aged 28--53 years, suffering from MS has been studied using VER averaging techniques. Reversal stimuli projected on a television screen in three different patterns (horizontal bars, vertical bars, checks), each with two different contrast levels (20%, 50%), and two shapes (0.5 cm, 1 cm), have been used. The survey has been conducted with stimuli at a rate of 1 Hz and the angle of incidence was measured for a viewing distance of 114 cm. The study of the pattern reversal ER has shown that the averaging technique gives clearly more significant results than fundus examination. Moreover, the pattern reversal ER seems to be more selective than the response evoked with photic flash in the assessment of lesions in the optic pathway, particularly presumed retrobulbar neuritis.

49. The AER in MS: Middle and late components analysis. -- P.M. Rossini, D. Sollazzo and G. Albertini (Rome) The acoustic evoked response has been studied in 20 healthy control subjects, 20 patients suffering from non-demyelinating neurological diseases and 35 patients affected by definite (20 cases, 57%), probable (9 cases, 26%) and possible (6 cases, 17%) MS. Before the AER session, each patient was rated according to the partially modified 5-point scale of Rose. The AER was recorded from an active electrode placed on the vertex referred to linked earlobes; clicks of 60 dB SL intensity were used and the separate responses of each ear to 80 stimuli were averaged. Since the aim of this study was to include analysis of the middle components (20--30 msec), HF filters

78P were set at 7 5 - - 1 0 0 Hz. S c o r e s of A E R s a n d o f t h e b r a i n - s t e m s y s t e m ( f r o m 0 t o 5), s e p a r a t e l y o b t a i n e d by t w o d i f f e r e n t e x a m i n e r s , were m a t c h e d in statistical c o r r e l a t i o n by P e a r s o n ' s r test. These results c o n f i r m a n a b n o r m a l l y d e l a y e d A E R ( t h o u g h d i f f e r e n t l y a f f e c t i n g m i d d l e a n d late c o m p o n e n t s ) o n t h e same side a f f e c t e d by b r a i n - s t e m d e m y e l i n a t i n g plaques. T h e r e l a t i o n s h i p b e t w e e n t h e A E R scores a n d t h e scores f r o m o t h e r involved syst e m s t o g e t h e r with t h e practical value o f such tests in t h e diagnosis a n d p r o g n o s i s of MS were discussed.

50. Neurological screening in babies of drug-dependent mothers. -- M.G. Torrioli, F. Pinto, G. Casella, G. Albertini and E. Tempesta (Rome) A clinical e v a l u a t i o n has b e e n m a d e f r o m the neurological e x a m i n a t i o n as carried o u t by Prechtl a n d B e i n t e m a as well as a c c o r d i n g to a s c h e m e of s p o n t a -

S O C I E T Y PROCEEDIN(;~: n e o u s m o t o r activity i n t e n s i t y o n a g r o u p of child~'e~,~ b o r n to w o m e n w h o h a d used drugs for the whole, p e r i o d of p r e g n a n c y . T h e results have been compa~(~! w i t h data o b t a i n e d f r o m p o l y g r a p h i c records and t~ s t u d y of V E R s o n t h e same subjects. T h e rec(~:d.~: have b e e n t a k e n in t h e s e c o n d week of life, tha~ i.~ w h e n w i t h d r a w a l effects are m a x i m u m (earlier with h e r o i n a n d later with m e t h a d o n e ) . T h e data so ;at: c o l l e c t e d s h o w : (1) the V E R has a well-organized m o r p h o l o g y a n d a n o r m a l l a t e n c y in r e l a t i o n to th~ age; (2) p o l y g r a p h i c records do n o t s h o w any ~Icm e n t s w h i c h can be c o n s i d e r e d p a t h o l o g i c a l for tbv age. P a r t i c u l a r i m p o r t a n c e is giw~n to the analysis ol' sleep stages since it is well k n o w n t h a t m a n y drugs can p a r t i c u l a r l y a f f e c t this p a r a m e t e r . On t h e o t h e r h a n d , sleep o r g a n i z a t i o n is o n e of the main p o i n t s in r e l a t i o n to p r o g n o s i s in m a n y p a t h o l o g i c a l c o n d i t i o n s of the n e w b o r n . Our data s h o w e d a decrease of q u i e l sleep. A follow-up s t u d y is i n d i c a t e d to judge the ~ign i f i c a n c e o f these findings.