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Société d'électroencéphalographie et de neurophysiologie clinique de langue française
Electroencephalography and Clinical Neurophysiology Elsevier Publishing Company, Amsterdam - Printed in The Netherlands
637
SOCII~TI~ D'I~LECTROENCI~PHALOGRAPHIE ET DE NEUROPHYSIOLOGIE CLINIQUE DE LANGUE FRAN(~AISE Paris, March 6, 1968
Secretary: DR. G . C. LMRY Hdpital Henri-Rousselle, 1 rue Cabanis, Paris 14 (France)
I.
Choice of binocular and monocular derivations in electronystagmography. II. The influence of vertical eye movements. - - V. Gabersek (Paris).
The paper defines the effects of vertical and oblique movements of gaze on the horizontal monocular derivations. The eye movements were recorded from horizontal and vertical binocular and from horizontal (upper and lower) and vertical (nasal and temporal) monocular derivations. In order to compare the amplitude of the electrical changes with the eye movements, the subject was asked to make successive horizontal, vertical and oblique ocular displacements of 10°. A vertical eye movement, in addition to deflections in the monocular and binocular vertical derivations, produced potential differences in the upper horizontal monocular derivations. An oblique eye movement from above downwards and from right to left, or from below upwards and from left to right, at an angle of 45 ° to the vertical, gave deflections in the same sense in all the derivations, but there was no change in the right upper horizontal monocular derivation. For an oblique movement from the right lower to the left upper it was the left upper horizontal monocular derivation which remained isoelectric and the deflections in the vertical and horizontal derivations were in mirror image. A nystagmus with horizontal and vertical components can give electrical phenomena identical with those recorded during oblique movements, which made it possible to recognize in a record an oblique nystagmus already studied clinically. 2. Amygdalo-hippocampal interconnections in man. Physiological study during stereotaxic explorations. - - P. Buser, J. Bancaud, J. Talairach and G. Szikla (Paris).
In 16 patients the relationships between the amygdaloid nuclei, Ammon's horns and various points in the parahippocampal gyrus have been studied during stereotaxic explorations intended to localize the epileptogenic focus and consisting in the insertion of electrodes with multiple contacts to various levels of the rhinencephalon. Isolated electrical stimuli were given and the responses recorded were observed directly after suitable amplification. The connections of the amygdala with the ipsilateral
Ammon's horn were thus always demonstrated m the form of a long latency response (20J,0 msec), probable evidence of an indirect route (amydalo-entorhinal or amygdalo-septo-fornical). The relationships in the opposite direction, from Ammon's horn to the ipsilateral amygdaloid nucleus, have only been demonstrated in a relatively small number of cases of temporal lobe epilepsy. In patients with non-temporal epilepsy no amygdaloid response originating in Ammon's horn could be observed. Activation of the parahippocampal gyrus from the ipsilateral Ammon's horn was easily obtained, although the opposite relationship was usually difficult to observe. No proof of the involvement of the inter-amygdaloid connections could be found. The same negative observation held for the relationships between symmetrical Ammon's horns, with the exception of one case of bitemporal epilepsy. These observations do not prejudice the possibility of the spread of the after-discharges; they nevertheless demonstrate the preferred connections within the rhinencephalon and their possible modifications under pathological conditions. 3. Spatio-temporal study of the average somato-sensory potential evoked on the human scalp by stimulation of the median nerve at the wrist. - - I. Mezan, A. R~mond and N. Les~vre (Paris).
The results were obtained in normal subjects. They aimed essentially at demonstrating the topography of the earliest components which culminated before 80 msec. The use of several successive montages, some of which partially overlapped, has made it possible to verify the course of events arising on the scalp in a transverse parietoRolandic plane, symmetrical and with a total length of 24 cm, following transcutaneous electrical stimulation of the median nerve at the wrist. These successive montages were, on the one hand, longitudinal, 6-8 cm to the right and to the left of the midline and, on the other, transverse, crossing the lateral longitudinal lines at various levels. The inter-electrode distance was always 2 cm. The stimuli were in general twice the subjective liminal intensity. The documents (topograms and spatio-temporal maps), obtained after analogue to digital conversion of the EEG and processing by a computer, showed the presence of a uniquely contralateral early component; this early
Electroenceph. clin. Neurophysiol., 1969, 26:637-640
638
SOCIETY PROCEEDINGS
component was a "source" with a maximum (phase reversal of the gradients) at 7 8 cm from the midline on a line going from a point situated in the region of the vertex (or slightly behind it) to the front of the external auditory meatus. This source began about 20 msec after stimulation, cuhninating around 35 msec, and lasted in all about 40 msec; it was sometimes diphasic; it was not tk~tmd with ipsilateral stimulation. In a transverse right to left montag e this early source suddenly changed at the moment of its termination into a large midline sagittal source (sometimes preceded by a sink of brief duration) the structure of which suggested the existence of bilateral projections (phase reversal of the gradients at the midline); this midline source lasted about one-third of a second and usually showed two successive maxima, one at about 75 msec, the other at about 115 msec. A sink followed this midline source; its maximum was also at the midline. These results, in particular those concerning the topography of the earliest component, are discussed in relation to the observations reported in the literature, and their functional significance is considered. 4.
Bilaterally synchronous and symmetrical E E G paroxysms revealing the presence of a temporal abscess. - - H. Gastaut (Marseille).
The author reports a case of "secondary bilateral synchrony", to which reference is often made without convincing proof. Numerous cases have been published concerning bisynchronous discharges during chronic diseases (tumours, scars, vascular malformations, etc.), involving the inferior or medial face of the frontal lobes, but it does not seem that the medical literature contains a single observation of a temporal abscess accompanied by bisynchronous discharges during the acute phase. The case was one of a girl of 18 years Who presented, in the space of a few days, disturbances of consciousness, first paroxysmal then continuous. The EEG showed discharges of bilateral spikes and waves, synchronous and symmetrical, in brief bursts, at first isolated (recalling the picture of petit real variant absences or somctimes even of petit real), then repeated, recalling a picture of petit real status. In addition, there was a focus of particularly slow delta waves in the temporal region of the left side. Furthermore, the patient had a generalized infection and a left otitis; a left temporal abscess was sought, found and removed. Soon afterwards the EEG became perfectly normal, apart from some minor signs of residual left temporal disturbance. 5.
Contribution of micro-physiological stereotaxic recording to the study of the inter-ictal and ictal cortical discharge in human epilepsy. - - M. Rayport, P. Buser, J. Bancaud and J. Talairach (Paris).
An investigation was made, by means of micro-electrodes introduced stereotaxically, of the unitary neuronal activity in and around epileptogenic zones in patients explored by SEEG with a view to defining the indications and methods of operation.
The truth of Jackson's hypothesis, proposing that the epileptic attack results from an excessive fast discharge from the grey matter, has been verified directly by recording from cellular units during spontaneous and induced electro-clinical attacks. However, an organization of epileptogenic foci which would make it possible to accept that the ictal and inter-ictal activity both represent an excessive discharge was not confirmed. Cortical spikes recorded up to now are considered as representing evoked potentials resulting from changes in the normal cortical mechanisms. The hypothesis is proposed that focal cortical epilepsy is a disturbance of neuronal organization, characterized by a local increase of neuronal discharge, resulting in hypersynchrony and probably due to a reduction of the inhibitory control of excitation. This reduction would require, in order to demonstrate it, a sufficient level of excitation. 6.
Low birth weight and E E G maturation. - - C. DreyfusBrisae and A. Minkowski (Paris).
Ninety-six children were studied. In all cases the exact duration of pregnancy, calculated from the first day of the last period, was known exactly. Ninety-one were born between 37 and 43 weeks and 5 before 37 weeks of gestation (average 39.1 weeks). All had weights considerably outside normal limits for the duration of pregnancy, varying from 890-2750 g (average 1895.4 g). Their length and head circumference were also too small for the gestationat age, although to a lesser degree. An EEG evaluation of cerebral maturation was made in all the children. Its precision was classified in four groups as follows: correct (or correct within 2 weeks); correct but imprecise: incorrect (error greater than 2 weeks); unclassifiable. Although a large number of these children were in a serious state, the evaluation was correct in 84 cases, 11 of which were classified with some imprecision. Eight cases could not be classified and 4 errors of evaluation were made. The causes of imprecision, errors or impossibility of classification were of two kinds: incomplete records, not including the different stages of waking and sleeping; very sick children, in particular comatose. 7.
An E E G study of the child with superior intelligence. - - A. Harrison, S. Netehine and J. Rouzi/~res (Paris).
Two groups of 39 children between 6 and 12 years of age were studied, classified by verbo-intellectual tests as of high mental ability (1Q> 120). One of the groups consisted of normal subjects examined during a research on maturation and the other of neuropsychiatric patients. The two groups were strictly matched, each subject of the one group having his equivalent in the other as to mental level, socio-cultural background and chronological age. Fifteen aspects of the EEG were considered. Eight of them did not differentiate between the two groups (regularity, continuity, inter-hemispheral symmetry, spatial organization of alpha activity, predominance of the side of intermittent posterior stow waves, slowing and paroxysmal effects of overbreathing). Foci of spikes were
Electroenceph. din. Neurophysiol., 1969, 26:637-640
FRENCH SOCIETY a little more numerous in the patients and a little more frequent on the left (statistically non-significant). The patients differed significantly (Z 2) from the normal subjects for 6 EEG variables: presence of diffuse theta rhythm (at the 0.0001 level), abundance of theta rhythm (0.001), prominance of intermittent posterior slow waves (0.01), inter-hemispheral asynchrony of the posterior slow activity (0.01), moderate blocking response (0.I0) and rarity of mu rhythm (0.10). The sum of these six features increased the discrimination between the two groups. When comparison was made for each matched pair the "pejorative" features of the EEG were more numerous in the normal child in 4 pairs, equal in 5 and more numerous in the patients in 30 out of 39 pairs.
8. Study of the EEG of sleep under prolonged increase of pressure (the operation "Ludion II"). - - T. Serbanescu, P. Fructas and R. Naquet (Marseille). In the operation "Ludion II" two trained divers lived in a caisson in 86 m of water for 10 days. Twice a day the divers went for 2 h to do a job in another caisson at a depth of 125 m. Apart from numerous biochemical tests (which could be varied during the experiment), the two divers had EEGs before entering the caisson, in the caisson before compression, during their stay at 85 m, during decompression and on coming out of the caisson. The waking records (very different from each other before compression) did not vary during the whole of this period. Their sleeping records, recorded for 3 nights (in the caisson before compression, during compression and during or at the end of decompression) showed the following characteristics under increased pressure: the morphology of stage II sleep was more complex than before and after compression. This phase often had the appearance of an "intermediate" phase (Lairy et al. 1966); the percentage of stage II was clearly increased, particularly in one of the 2 subjects, at the expense of stages Ill and IV; the percentage of REM was not decreased but, on the contrary, slightly increased. It is of interest that under increased pressure these 2 subjects showed phases of sleep considered as being frequent in psychotic subjects and, on the whole, a less deep sleep than normal. Life in the caisson cannot be incriminated since controls made before increased pressure and in the period of decompression were different from those made under increased pressure. Two factors may be involved in the lightening and modification of sleep, either the pressure factor itself (gas mixture of oxygen and helium) or the anxiety consequent on the insecurity of this unusual life, leading to emotional disturbances.
9. An EEG study of water intoxication in the SchwartzBartter syndrome. - - B. A. Schwartz, C. Faye, M. Seguy and J. Chretien (Paris). Three EEGs were carried out at different times during water intoxication in a 57-year-old patient suffering from an anaplastic bronchial carcinoma and in whom a
639
Schwartz-Bartter syndrome had been diagnosed. The severity of the neurological and psychiatric disturbances, the degree of hyponatraemia and the severity of the EEG abnormalities did not correspond well. In fact, the most disturbed record was the second, made when the neuropsychiatric disturbances were improving and the natraemia had become normal. The problem of the asymmetry of EEG abnormalities occurring during severe metabolic disturbances is mentioned and the various types of inappropriate secretion of antidiuretic hormone occurring in cancer patients, with or without cerebral metastases, are compared.
I0. Polygraphic study of carotid and Sylvian obstruction: value of controlled carotid compression. - - P. Taillandier, M. Revol, F. Quoex, P. Guerin and J. Courjon (Lyon). The recording technique included, apart from the EEG and the ECG, a photo-electric transducer placed on the ear on the side of the compressed carotid, which ensured the efficacy of the digital compression; a second transducer was placed on a finger below a compression cuff; this made it possible to detect the effect of the compression on the systemic blood pressure. The compressions were made as low as possible in order to avoid any fall in pressure. The sign of the healthy carotid (bilateral and repeated slowing of cerebral activity on compression of the supposedly healthy side and a negative response to compression of the supposedly affected carotid) was found in 75 % of thromboses and 70 % of stenoses; apart from a case of turnout, it was never found with other aetiologies. The unilateral responses corresponded with multiple causes and could not provide precise information. Provided that the compression is low and that the blood pressure is watched, this method is without danger. If it fails to distinguish stenoses from thromboses, it can very often, in the case of a cerebro-vascular disease, draw attention to the carotid axis and indicate arteriography.
11. Polygraphic findings in the insomnias. - - G. Velok, P. Passouant, J. Cadilhac and M. Baldy-Moulinier (Montpellier). E~,rlier findings on false insomnias, with a wrong evaluation of sleep, and on some characteristics of "bad sleep", with a decrease of deep slow sleep, are reviewed. The different responses of the two types of sleep were investigated. Slow sleep is of a light type, interrupted by numerous awakenings; it can be lacking at different times during the night and sometimes throughout the course of a sleep cycle; it can be absent during the whole night although periods of fast sleep persist. The polygraphic characteristics were analysed and the question of the "intermediate stages" was raised. Fast sleep is both unstable and resistant to insomnia; its duration, compared with that of slow sleep, is decreased and the periods of fast sleep can be interrupted by awakenings. On the other hand, fast sleep can persist alone and be the only expression of sleep during a night of insomnia. The period
Electroenceph. clin. Neurophysiol., 1969, 26:637--640
640
SOCIETY PROCEEDINGS
of transition between fast and slow sleep appears to favour the occurrence of insomnia in the middle or at the end of the night. The different effects of increased awakening on slow and fast sleep are discussed in relation to the duality of the two sleeps and in particular to the ontogenesis.
12. EEG changes in children treated by Depakene. - J. Miribel and R. Marinier (Saint-Marcel-lesValances). With a few exceptions, the action of Depakene on the EEG of epileptic children can be considered as analogous in its modes of operation to that of the diones and the succinimides, in spite of the considerable chemical differences between these various products; progressive disappearance of abnormalities, at first in repose, then during overbreathing, then during flicker, with transitory slowing of background activity, which disappears with increased dosage. The action of Depakene, on the other hand, seems greater, although far from being absolute, on the abnormalities induced by flicker. The absence of fast rhythms deserves to be emphasized. Depakene can in certain cases reveal the underlying atrophic processes by causing focal slow waves to appear, which generally spread widely from the site of atrophy as determined by other methods.
13. Activation by Megimide in the topographic diagnosis of focal cortical epilepsies (clinical EEG and SEEG study). - - J. Bancaud, J. Talairach, P. Waltregny, M. Bresson and P. Morel (Paris). The use of chemical activators with a view to positive and differential diagnosis of epilepsy has given rise to lively controversy. On the other hand, rather few works have been devoted to the use of Megimide (bemegride) in the topographic diagnosis of a focal cortical fit. This problem, particularly important for the indications and types of operation in certain epilepsies, is reconsidered on the basis of 50 patients who have had one or more SEEG explorations. This material was selected on the basis of recording in the EEG laboratory one or more spontaneous attacks with the aim of obtaining a correct understanding of the ictal semiology by comparing case histories with the electro-clinical observations obtained during the attacks themselves. Having established these criteria, we kept patients who had had several activations by Megimide, at first with EEG and then during SEEG. By comparing the anatomo-electro-clinical findings typical of the attacks induced by chemical activation and those defining spontaneous attacks in the same patient, it was possible, by taking into account a series of factors, to assess the confidence which one can put in Megimide in the determination of an epileptogenic zone.
Electroenceph. olin. Neurophysiol., 1969, 26:637-640
ERRATUM Electroenceph. clin. Neurophysiol., 1969, 26:395-398
p a g e 397, c o l u m n 2, line 14: Delete: "histograms obtained from a unit responsive".
Electroenceph. clin. Neurophysiol., 1969, 26:640
637
SOCII~TI~ D'I~LECTROENCI~PHALOGRAPHIE ET DE NEUROPHYSIOLOGIE CLINIQUE DE LANGUE FRAN(~AISE Paris, March 6, 1968
Secretary: DR. G . C. LMRY Hdpital Henri-Rousselle, 1 rue Cabanis, Paris 14 (France)
I.
Choice of binocular and monocular derivations in electronystagmography. II. The influence of vertical eye movements. - - V. Gabersek (Paris).
The paper defines the effects of vertical and oblique movements of gaze on the horizontal monocular derivations. The eye movements were recorded from horizontal and vertical binocular and from horizontal (upper and lower) and vertical (nasal and temporal) monocular derivations. In order to compare the amplitude of the electrical changes with the eye movements, the subject was asked to make successive horizontal, vertical and oblique ocular displacements of 10°. A vertical eye movement, in addition to deflections in the monocular and binocular vertical derivations, produced potential differences in the upper horizontal monocular derivations. An oblique eye movement from above downwards and from right to left, or from below upwards and from left to right, at an angle of 45 ° to the vertical, gave deflections in the same sense in all the derivations, but there was no change in the right upper horizontal monocular derivation. For an oblique movement from the right lower to the left upper it was the left upper horizontal monocular derivation which remained isoelectric and the deflections in the vertical and horizontal derivations were in mirror image. A nystagmus with horizontal and vertical components can give electrical phenomena identical with those recorded during oblique movements, which made it possible to recognize in a record an oblique nystagmus already studied clinically. 2. Amygdalo-hippocampal interconnections in man. Physiological study during stereotaxic explorations. - - P. Buser, J. Bancaud, J. Talairach and G. Szikla (Paris).
In 16 patients the relationships between the amygdaloid nuclei, Ammon's horns and various points in the parahippocampal gyrus have been studied during stereotaxic explorations intended to localize the epileptogenic focus and consisting in the insertion of electrodes with multiple contacts to various levels of the rhinencephalon. Isolated electrical stimuli were given and the responses recorded were observed directly after suitable amplification. The connections of the amygdala with the ipsilateral
Ammon's horn were thus always demonstrated m the form of a long latency response (20J,0 msec), probable evidence of an indirect route (amydalo-entorhinal or amygdalo-septo-fornical). The relationships in the opposite direction, from Ammon's horn to the ipsilateral amygdaloid nucleus, have only been demonstrated in a relatively small number of cases of temporal lobe epilepsy. In patients with non-temporal epilepsy no amygdaloid response originating in Ammon's horn could be observed. Activation of the parahippocampal gyrus from the ipsilateral Ammon's horn was easily obtained, although the opposite relationship was usually difficult to observe. No proof of the involvement of the inter-amygdaloid connections could be found. The same negative observation held for the relationships between symmetrical Ammon's horns, with the exception of one case of bitemporal epilepsy. These observations do not prejudice the possibility of the spread of the after-discharges; they nevertheless demonstrate the preferred connections within the rhinencephalon and their possible modifications under pathological conditions. 3. Spatio-temporal study of the average somato-sensory potential evoked on the human scalp by stimulation of the median nerve at the wrist. - - I. Mezan, A. R~mond and N. Les~vre (Paris).
The results were obtained in normal subjects. They aimed essentially at demonstrating the topography of the earliest components which culminated before 80 msec. The use of several successive montages, some of which partially overlapped, has made it possible to verify the course of events arising on the scalp in a transverse parietoRolandic plane, symmetrical and with a total length of 24 cm, following transcutaneous electrical stimulation of the median nerve at the wrist. These successive montages were, on the one hand, longitudinal, 6-8 cm to the right and to the left of the midline and, on the other, transverse, crossing the lateral longitudinal lines at various levels. The inter-electrode distance was always 2 cm. The stimuli were in general twice the subjective liminal intensity. The documents (topograms and spatio-temporal maps), obtained after analogue to digital conversion of the EEG and processing by a computer, showed the presence of a uniquely contralateral early component; this early
Electroenceph. clin. Neurophysiol., 1969, 26:637-640
638
SOCIETY PROCEEDINGS
component was a "source" with a maximum (phase reversal of the gradients) at 7 8 cm from the midline on a line going from a point situated in the region of the vertex (or slightly behind it) to the front of the external auditory meatus. This source began about 20 msec after stimulation, cuhninating around 35 msec, and lasted in all about 40 msec; it was sometimes diphasic; it was not tk~tmd with ipsilateral stimulation. In a transverse right to left montag e this early source suddenly changed at the moment of its termination into a large midline sagittal source (sometimes preceded by a sink of brief duration) the structure of which suggested the existence of bilateral projections (phase reversal of the gradients at the midline); this midline source lasted about one-third of a second and usually showed two successive maxima, one at about 75 msec, the other at about 115 msec. A sink followed this midline source; its maximum was also at the midline. These results, in particular those concerning the topography of the earliest component, are discussed in relation to the observations reported in the literature, and their functional significance is considered. 4.
Bilaterally synchronous and symmetrical E E G paroxysms revealing the presence of a temporal abscess. - - H. Gastaut (Marseille).
The author reports a case of "secondary bilateral synchrony", to which reference is often made without convincing proof. Numerous cases have been published concerning bisynchronous discharges during chronic diseases (tumours, scars, vascular malformations, etc.), involving the inferior or medial face of the frontal lobes, but it does not seem that the medical literature contains a single observation of a temporal abscess accompanied by bisynchronous discharges during the acute phase. The case was one of a girl of 18 years Who presented, in the space of a few days, disturbances of consciousness, first paroxysmal then continuous. The EEG showed discharges of bilateral spikes and waves, synchronous and symmetrical, in brief bursts, at first isolated (recalling the picture of petit real variant absences or somctimes even of petit real), then repeated, recalling a picture of petit real status. In addition, there was a focus of particularly slow delta waves in the temporal region of the left side. Furthermore, the patient had a generalized infection and a left otitis; a left temporal abscess was sought, found and removed. Soon afterwards the EEG became perfectly normal, apart from some minor signs of residual left temporal disturbance. 5.
Contribution of micro-physiological stereotaxic recording to the study of the inter-ictal and ictal cortical discharge in human epilepsy. - - M. Rayport, P. Buser, J. Bancaud and J. Talairach (Paris).
An investigation was made, by means of micro-electrodes introduced stereotaxically, of the unitary neuronal activity in and around epileptogenic zones in patients explored by SEEG with a view to defining the indications and methods of operation.
The truth of Jackson's hypothesis, proposing that the epileptic attack results from an excessive fast discharge from the grey matter, has been verified directly by recording from cellular units during spontaneous and induced electro-clinical attacks. However, an organization of epileptogenic foci which would make it possible to accept that the ictal and inter-ictal activity both represent an excessive discharge was not confirmed. Cortical spikes recorded up to now are considered as representing evoked potentials resulting from changes in the normal cortical mechanisms. The hypothesis is proposed that focal cortical epilepsy is a disturbance of neuronal organization, characterized by a local increase of neuronal discharge, resulting in hypersynchrony and probably due to a reduction of the inhibitory control of excitation. This reduction would require, in order to demonstrate it, a sufficient level of excitation. 6.
Low birth weight and E E G maturation. - - C. DreyfusBrisae and A. Minkowski (Paris).
Ninety-six children were studied. In all cases the exact duration of pregnancy, calculated from the first day of the last period, was known exactly. Ninety-one were born between 37 and 43 weeks and 5 before 37 weeks of gestation (average 39.1 weeks). All had weights considerably outside normal limits for the duration of pregnancy, varying from 890-2750 g (average 1895.4 g). Their length and head circumference were also too small for the gestationat age, although to a lesser degree. An EEG evaluation of cerebral maturation was made in all the children. Its precision was classified in four groups as follows: correct (or correct within 2 weeks); correct but imprecise: incorrect (error greater than 2 weeks); unclassifiable. Although a large number of these children were in a serious state, the evaluation was correct in 84 cases, 11 of which were classified with some imprecision. Eight cases could not be classified and 4 errors of evaluation were made. The causes of imprecision, errors or impossibility of classification were of two kinds: incomplete records, not including the different stages of waking and sleeping; very sick children, in particular comatose. 7.
An E E G study of the child with superior intelligence. - - A. Harrison, S. Netehine and J. Rouzi/~res (Paris).
Two groups of 39 children between 6 and 12 years of age were studied, classified by verbo-intellectual tests as of high mental ability (1Q> 120). One of the groups consisted of normal subjects examined during a research on maturation and the other of neuropsychiatric patients. The two groups were strictly matched, each subject of the one group having his equivalent in the other as to mental level, socio-cultural background and chronological age. Fifteen aspects of the EEG were considered. Eight of them did not differentiate between the two groups (regularity, continuity, inter-hemispheral symmetry, spatial organization of alpha activity, predominance of the side of intermittent posterior stow waves, slowing and paroxysmal effects of overbreathing). Foci of spikes were
Electroenceph. din. Neurophysiol., 1969, 26:637-640
FRENCH SOCIETY a little more numerous in the patients and a little more frequent on the left (statistically non-significant). The patients differed significantly (Z 2) from the normal subjects for 6 EEG variables: presence of diffuse theta rhythm (at the 0.0001 level), abundance of theta rhythm (0.001), prominance of intermittent posterior slow waves (0.01), inter-hemispheral asynchrony of the posterior slow activity (0.01), moderate blocking response (0.I0) and rarity of mu rhythm (0.10). The sum of these six features increased the discrimination between the two groups. When comparison was made for each matched pair the "pejorative" features of the EEG were more numerous in the normal child in 4 pairs, equal in 5 and more numerous in the patients in 30 out of 39 pairs.
8. Study of the EEG of sleep under prolonged increase of pressure (the operation "Ludion II"). - - T. Serbanescu, P. Fructas and R. Naquet (Marseille). In the operation "Ludion II" two trained divers lived in a caisson in 86 m of water for 10 days. Twice a day the divers went for 2 h to do a job in another caisson at a depth of 125 m. Apart from numerous biochemical tests (which could be varied during the experiment), the two divers had EEGs before entering the caisson, in the caisson before compression, during their stay at 85 m, during decompression and on coming out of the caisson. The waking records (very different from each other before compression) did not vary during the whole of this period. Their sleeping records, recorded for 3 nights (in the caisson before compression, during compression and during or at the end of decompression) showed the following characteristics under increased pressure: the morphology of stage II sleep was more complex than before and after compression. This phase often had the appearance of an "intermediate" phase (Lairy et al. 1966); the percentage of stage II was clearly increased, particularly in one of the 2 subjects, at the expense of stages Ill and IV; the percentage of REM was not decreased but, on the contrary, slightly increased. It is of interest that under increased pressure these 2 subjects showed phases of sleep considered as being frequent in psychotic subjects and, on the whole, a less deep sleep than normal. Life in the caisson cannot be incriminated since controls made before increased pressure and in the period of decompression were different from those made under increased pressure. Two factors may be involved in the lightening and modification of sleep, either the pressure factor itself (gas mixture of oxygen and helium) or the anxiety consequent on the insecurity of this unusual life, leading to emotional disturbances.
9. An EEG study of water intoxication in the SchwartzBartter syndrome. - - B. A. Schwartz, C. Faye, M. Seguy and J. Chretien (Paris). Three EEGs were carried out at different times during water intoxication in a 57-year-old patient suffering from an anaplastic bronchial carcinoma and in whom a
639
Schwartz-Bartter syndrome had been diagnosed. The severity of the neurological and psychiatric disturbances, the degree of hyponatraemia and the severity of the EEG abnormalities did not correspond well. In fact, the most disturbed record was the second, made when the neuropsychiatric disturbances were improving and the natraemia had become normal. The problem of the asymmetry of EEG abnormalities occurring during severe metabolic disturbances is mentioned and the various types of inappropriate secretion of antidiuretic hormone occurring in cancer patients, with or without cerebral metastases, are compared.
I0. Polygraphic study of carotid and Sylvian obstruction: value of controlled carotid compression. - - P. Taillandier, M. Revol, F. Quoex, P. Guerin and J. Courjon (Lyon). The recording technique included, apart from the EEG and the ECG, a photo-electric transducer placed on the ear on the side of the compressed carotid, which ensured the efficacy of the digital compression; a second transducer was placed on a finger below a compression cuff; this made it possible to detect the effect of the compression on the systemic blood pressure. The compressions were made as low as possible in order to avoid any fall in pressure. The sign of the healthy carotid (bilateral and repeated slowing of cerebral activity on compression of the supposedly healthy side and a negative response to compression of the supposedly affected carotid) was found in 75 % of thromboses and 70 % of stenoses; apart from a case of turnout, it was never found with other aetiologies. The unilateral responses corresponded with multiple causes and could not provide precise information. Provided that the compression is low and that the blood pressure is watched, this method is without danger. If it fails to distinguish stenoses from thromboses, it can very often, in the case of a cerebro-vascular disease, draw attention to the carotid axis and indicate arteriography.
11. Polygraphic findings in the insomnias. - - G. Velok, P. Passouant, J. Cadilhac and M. Baldy-Moulinier (Montpellier). E~,rlier findings on false insomnias, with a wrong evaluation of sleep, and on some characteristics of "bad sleep", with a decrease of deep slow sleep, are reviewed. The different responses of the two types of sleep were investigated. Slow sleep is of a light type, interrupted by numerous awakenings; it can be lacking at different times during the night and sometimes throughout the course of a sleep cycle; it can be absent during the whole night although periods of fast sleep persist. The polygraphic characteristics were analysed and the question of the "intermediate stages" was raised. Fast sleep is both unstable and resistant to insomnia; its duration, compared with that of slow sleep, is decreased and the periods of fast sleep can be interrupted by awakenings. On the other hand, fast sleep can persist alone and be the only expression of sleep during a night of insomnia. The period
Electroenceph. clin. Neurophysiol., 1969, 26:637--640
640
SOCIETY PROCEEDINGS
of transition between fast and slow sleep appears to favour the occurrence of insomnia in the middle or at the end of the night. The different effects of increased awakening on slow and fast sleep are discussed in relation to the duality of the two sleeps and in particular to the ontogenesis.
12. EEG changes in children treated by Depakene. - J. Miribel and R. Marinier (Saint-Marcel-lesValances). With a few exceptions, the action of Depakene on the EEG of epileptic children can be considered as analogous in its modes of operation to that of the diones and the succinimides, in spite of the considerable chemical differences between these various products; progressive disappearance of abnormalities, at first in repose, then during overbreathing, then during flicker, with transitory slowing of background activity, which disappears with increased dosage. The action of Depakene, on the other hand, seems greater, although far from being absolute, on the abnormalities induced by flicker. The absence of fast rhythms deserves to be emphasized. Depakene can in certain cases reveal the underlying atrophic processes by causing focal slow waves to appear, which generally spread widely from the site of atrophy as determined by other methods.
13. Activation by Megimide in the topographic diagnosis of focal cortical epilepsies (clinical EEG and SEEG study). - - J. Bancaud, J. Talairach, P. Waltregny, M. Bresson and P. Morel (Paris). The use of chemical activators with a view to positive and differential diagnosis of epilepsy has given rise to lively controversy. On the other hand, rather few works have been devoted to the use of Megimide (bemegride) in the topographic diagnosis of a focal cortical fit. This problem, particularly important for the indications and types of operation in certain epilepsies, is reconsidered on the basis of 50 patients who have had one or more SEEG explorations. This material was selected on the basis of recording in the EEG laboratory one or more spontaneous attacks with the aim of obtaining a correct understanding of the ictal semiology by comparing case histories with the electro-clinical observations obtained during the attacks themselves. Having established these criteria, we kept patients who had had several activations by Megimide, at first with EEG and then during SEEG. By comparing the anatomo-electro-clinical findings typical of the attacks induced by chemical activation and those defining spontaneous attacks in the same patient, it was possible, by taking into account a series of factors, to assess the confidence which one can put in Megimide in the determination of an epileptogenic zone.
Electroenceph. olin. Neurophysiol., 1969, 26:637-640
ERRATUM Electroenceph. clin. Neurophysiol., 1969, 26:395-398
p a g e 397, c o l u m n 2, line 14: Delete: "histograms obtained from a unit responsive".
Electroenceph. clin. Neurophysiol., 1969, 26:640