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The American electroencephalographic society
SOCIETY PROCEEDINGS Edited by J o h n KNOTT THE
AMERICAN
ELECTROENCEPHALOGRAPHIC
SOCIETY t
SECOND ANNUAL MEETING J u n e 12, 13 a n d 14, 1948 - - Atlantic City, N. J.
A C T I V A T I O N O F T H E EEG 1. A Review of M e t h o d s used to elicit A b n o r m a l i t y in the Electroencephalogram. 2 u I. CHARLES KAUVMAN and C. W~:sL~v W^TSON, Boston. 2. Flickered Light as a Provocative Test in Electroencephalography. - - MORTIMER OSTOW, New York. This study is based upon a standardized test for susceptibility to photic driving administered to 302 male patients at classified diagnostically as: psychopathic personality, psychosis, organic brain disease. epilepsy, and simple adult maladjustment. Eighty-eight per cent of all subjects exhibited susceptibility to driving. DrLving appeared through a frequency range from 4 t o 30 cycles. In 12 per cent of the subjects, this was detected at frequencies of I/~, I/~, or 2 or 3 times the flicker frequencies. The effect was most prominent posteriorly: no lateral differences were observed. W i t h quantitative analysis of the data, two factors of interest emerged: the incidence of driving in each of three frequency ranges, less than 8, 8 to 12, and over 12 per see.; and the prominence, persistence, regularity, and amplitude of the phenomenon, collectively termed "quality". There was a relationship between the amount of following in the slow range and the amount of spontaneous (sporadic or serial) slow activity. Paroxysmal slow activity, however, failed to show this relation. A similar relation appeared between the incidence of driving in the 8 to 12 per sec. range and spontaneous per cent time alpha. Also, there was a relationship between driving at faster frequencies and the amount of spontaneous fast activity. No direct relationship was found between specific spontaneous and driven frequencies, other than the range relationships. "Quality" of driving was better among those who showed alpha blocking to light. There was a relation between good "quality" and increased age. Slow driving was 0router among the younger patients, and fast driving among the older ones, presumably in consequence of the inverse relation of spontaneous slow, and the direct relation of spontaneous fast, with a~e.
Clinical diagnosis per se, or normality of the spontaneous E E G record, could not be related to driving. 1 Editor's note: It has been necessary, due to space limitations. to shorten the discussion of the papers. This task was difficult, and was done by using the criteria of critical pertinence and reader interest. A great deal of nevertheless valuable material has, perforce, had to be left unpublished. (]. R. K.) 2 Published in full in this journal, pages 237-240.
Testing for photic driving is a means of facilitating the demonstration of (sporadic or serial) slow or fast activity and of discriminating these from paroxysmal slow activity. Impaired cerebral function, or physiologic aging, is suggested by unusually good "quality" of the driving.
Discussion Dn. BICKFOaO: The suggestion that the response to photic driving can be taken as an index of physiologic maturity is opposed to Dr. W a i t e r ' s evidence: he regards good driving as an indication of immaturity. In our own experience, repeated tests on the same subject suggest that a number of variables have an effect on the response. 3. Routine Seconal Sedation; A M a j o r Aid to Clinical Electroencephalography. ~ FR£DERIC A. Glans a n d EaNA L. Glues, Chicago. Since sleep more than doubles the information obtained from the electroenceph:logram, the search for an ideal substance for the production of sleep has been continued. For the past six months, seconal, a shortacting barbiturate, has been used routinely to increase the chances of obtaining sleep during the examination. Adults are given one and one-half 0rains before electrodes are applied. Children are given three-quarters grains, and infants are given threeeighths of a grain, just before the electrodes are applied. If sleep is not obtained after three-quarters of an hour of recording, the initial dose is repeated. No untoward effects have been noted, and the occurretice of sleep may be raised from 20 per cent to 80 per cent, with a consequent increase in positive findings. Comparison of natural sleep with that induced by seconal has failed to reveal an instance in which abnormalities that appeared during natural sleep did not appear during seconal-induced sleep. However, if more than the initial dose of seconal is required, fast activity may be produced, and this interferes slightly with interpretation of the record, Seconal is most advantageous when employed not as an anesthetic, or to produce sleep in an unwillin0 subject, but in low dosage as a soporific to increase the likelihood of obtaining "natural" sleep.
Discussion Dn. BicgFono: I would like to ask Dr. Gibbs whether he has any evidence that patients having attacks only at night are more likely to have an abnormal sleep record than the average epileptic. DR. GraBs: Such patients do show a little less abnormality during the waking state than patients whose seizures are in the daytime.
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4. The Localizing Value of Asymmetrical Electroencephalographic Tracings Obtained Simultaneously by Homologous Recording. - - R. B. Amp and D. ZEALEAR, San Francisco. A statistical analysis of simultaneous homologous electroencephalographic tracings has provided data with respect to the differences of potential, form, frequency and the synchronism of hemispheric discharge which has been found to be of value for purposes of localization. The relative incidence and localizing value of such hemispheric differences has been analyzed by a cor,'elative study of clinical, pathologic, electroencephalographic and pneumoencephalographic data in 412 patients. Inequalities cf homologous potentials and asynchronism of hemispheric discharge are primarily of localizing value, but alone do not indicate the side of the lesion. Differences of wave form and frequency are chiefly of value in lateralizing and verifying a focal diagnosis. A focal hyperpotentia ("irritative" focus) occurred on the side of the lesion in a high percentage of brain tumors and twice as commonly as hypopententias in convulsive states secondary to trauma and in arachnoidal adhesive processes. In degenerative diseases, focal hypopotentia predominated on the side of the lesion. Although combinations of minor differences were found alone in 18 per cent of this group, and correlated as well with focal findings by pneumo-encephalo9raphy and clinical examination as did gross focal dysrhythmias, such changes occurred rarely in surgical conditions.
Discussion DR. JOHN KEUSHMAN: W h a t is the significance of asymmetries in scalp-ear records not shown in scalpscalp records ? Which element (form, frequency, potential or synchrony) is most important in attempting to make a differential diagnosis ? DR, Amp: Differences in asymmetry with differences in recording are frequently difficult to explain. It is our impression that scalp-ear differences may represent subcortical pathology. W i t h regard to criteria for differential diagnosis, none has been obvious to US. ~. The Occurrence of Delta Activity in the Electro. encephalogram of the Adult. ~ Louis GREENSrElN and HANS STRAUSS, New York. A study was made of the EEGs of 100 adults varying in age from 17 to 70 years and showing no evidence of any organic cerebral disease, epilepsy or metabolic disorder. All records were taken under standard conditions, including the elimination of physiotogicaI hypoglycemia. The amount of delta activity present (waves of 6 per sec. or slower frequency with an amplitude of 20 microvolts or more) was measured and expressed in terms of the delta factor (per cent of total record occupied by delta waves). Sixty-two per cent of the subjects showed no delta activity. The remaining 38 per cent showed delta activity in one or more leads. This was always recorded from leads involving the ear lobes if recorded from other, bipolar leads. The highest delta factor was in frontal-ear leads and was 8. The highest factor from other leads was 5.
To evaluate last activity, 100 consecutive records were analyzed with reference to conspicuous fast ac tivity. The frequencies varied from 15 to 30 per sec. at amplitudes from 30 to 80 microvolts. The amom~t was graded as: little, moderate, much or almost con. tinuous. Thirty of these records showed frankly abnormal slow activity. In the remainder, fast was the only questionable finding, and 45 of these had no demonstrable cerebral disease, dysfimction or met~ abolic disorder. W e feel that the amounts of delta and fast activity described cannot be considered abnormal. A better correlation between E E G normality and clinical normldcy obtains when they are classified as normal.
Discussion DR, MARGARET RHEtNBERGER: My own experience has been that a percentage of delta of approximately 10 is present in so many records that the concept of normality is stretched by calling this an indication of abnormality. Similarly, frequencies above 12 per second are common, and often cannot be called abnormal. DR. FREDEmC GraBS: Only large statistical studies can give the word "normality" meaning. One can have slightly, exceedingly and paroxysmally abnormal records, expressed as the differential between normal controls and epileptics. DR. GREENSTEIN: Small amounts of diffuse slow can be classified as "normal" only in the sense that they do not indicate the existence of cerebral disease, epilepsy or cerebral dysfunction due to toxic or metabolic disorder.
EEG IN L O B O T O M Y 6. Electroencephalographic Findings after Prefrontal Lobotomy. ~ MARGARET A. LENNOX and JOHN COOLIDGE, New Haven. Electroencephalograms were obtained in 48 patients before, and from one day to one year after prefrontal lobotomy. Abnormality was marked soon after operation, consisting of diffuse slowing, most prominent in the frontal leads. This may be lateralized. Slowing tended to decrease abruptly in degree and extent in the first two months. After nine weeks there "*'as very little change, and the E E G appeared to have reached the "permanent" post-operative picture for each individual. At the end of a year, 20 per cent of patients showed no abnormality and in 10~o the abnormality was still marked: Seventy per cent showed slowin 9 confined to frontal leads anterior to the plane of incision, usually as 0.5 to 1 per sec. "base line sway", with normal frequencies superimposed. This type of abnormality has not been encountered in any other clinical condition. Since it appears to be produced only by tobotomy, it is difficult to attribute it to trauma alone. Persistence of normal frequencies anterior to the plane of incision suggests that thalamo-cortico-thalamic reverberating systems may not be essential for the maintenance of alpha activity. If such systems are essential, they do not involve the medial thalamic nuclei, which presumably degenerate after prefrontal lobotomy. On 60 occasions the pre- and post-operative EEG included sleep induced by intravenous sodium pentothal. Twelve per sec. spindles, most prominent anteriorly before operation, failed to appear in any
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lead after operation. This confirms the findings of Morison and Bassett that pentothal spindles arise in the thalamus, and suggests that 12 per sec. spindles arise in the medial thalamic nuclei. Their absence after lobotomy is presumably due to degeneration of the nuclei rather than to cutting of the fiber tracts, since they do not appear in any lead after operation. By contrast, 14 to 15 per sec. spindles were more prominent in the central and parieto-occipital leads before operation, and their incidence was unaffected by prefrontal lobotomy. Presumably they arise in the lateral group of thalamic nuclei. (Discussion follows next paper). 7. Effect of P r e f r o n t a l L o b o t o m y ; A n Electroe n c e p h a l o g r a p h i c and Clinical Study. m MILTON GREENBLATT, SIDNEY LEVIN, MARIE M. HEALEY, and HARRY C. SOLOMON, Boston. Seventy selected cases were examined clinically and electroencephalographically before, and at intervals after, lobotomy (done by the Lyerly-Poppen technique). The majority had received shock treatment (electric, insulin) prior to lobotomy. T w e n t y cases developed convulsive seizures postoperatively. None of these had ever had spontaneous convulsions pre-operatively. Those who developed seizures had received more shock treatment, pre-lobotomy, than those who were seizure-free, and the pre.lobotomy incidence of E E G abnormality was higher. After lobotomy a "drowsy-anergic" state often appeared, lasting 4 to 8 days, during which diffuse delta activity was seen. W i t h alertness, the delta activity largely disappeared posteriorly and .concentrated about the operative site. Irregular, roiling slow waves of 1-3 per sec. were a regular feature of the post-operative E E G s and tended to persist. The operative trauma, the isolation of the frontal lobes, and the sleep-like phenomena appeared to play a joint role in producing early post-operative E E G changes. In the first weeks and months following lobotomy, increased amplitude, accentuation of alpha potentials, increased delta activity, asymmetries, and focal abnormalities were frequently observed. Delta was found over a wide area anteriorly; focal abnormalities tended to be present bifrontally or laterally but usually without focal neurological signs. The over-breathing "build-up" ",,gas greater and was emphasized in the region anterior to the operative site. In many individuals the dysrhythmia tended to persist. In some who developed convulsive seizures, it became aggravated. The seizures were essentially grand real in type; no petit real was observed either clinically or electroencephalographlcally. The study indicates that prefrontal lobotomy produces E E G dysrhythmia and a tendency towards convulsive seizures in those with pre-operative E E G abnormality. However, considerable cortical dysrhythmia may exist in patients who are neurologically negative, have no convulsive manifestations, and improve clinically.
Discussion DR. WARREN McCtlLLOCH: In these studies, and in animal preparations, cutting the cortex loose from the thalamic nuclei produces a loss in various fre-
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quencies. This may even be from leads posterior to Ihe line of section. It suggests that we are dealing with an interplay of thalamus and cortex at all times. W i t h regard to seizures, possibly the nuclei in which surface-positive spikes originate can be localized. If seizures develop in the isolated frontal lobe. two avenues of spread to the rest of the cortex are lost: careful study of these patients may identify the remaining paths. DR. PAUL F. A. HOEFER: W h y do these abnormalities persist ? W h y may they develop posterior to the plane of section ? DR. MARGARET LENNOX: W e do not feel that the abnormalities persist; the question might better be put: W h y do thev not? DR. GREENBLA'r:r: Abnormality certainly goes far behind the plane of section, and not during the anergic-drowsy state. Divergence of E E G data on this group may well result from lack of correlation between the damage the surgeon intends and damage actually performed. EEG A N D E N C E P H A L O P A T H Y 8. T h e I m p o r t a n c e of E E G ' i n Some Obscure En. cephalitides. ~ NICHOLAS A. BERCEL, Los Angeles. .. This study attempts to investigate the value of electroencephalography in establishing the role of obscure encephalo-meningitides in convulsive disorders. Infectious mononucleosis is such a disease, only 25 cases having cerebral complication being reported from 1931 to 19't8. Twenty-one patients were investigated, clinically, by laboratory procedures and by EEG. W h i l e C. N. S. irritation was present at some time in 16 cases, the E E G was normal. In 5 cases there was evidence of E E G abnormality. In 2 of these, focal paroxysmal activity persisted during a follow-up period of 1.5 to 2 years. One of these had paroxysmal aphasia at the acme of the encephalitis and at the same time had focal activity in the motor speech area. The other case showed focal seizure discharges in the right motor area. Preventive anticonvulsant medication was followed for 7 months; when the patient ceased following this regime, Jacksonian seizures involving the left arm and face developed. In view of the difficulty of clinical or laboratory diagnosis of cerebral involvement, until focal epilepsy develops, serial E E G studies seem indicated in infectious mononucleosis.
Discussion DR. JOHN ABBOTT: Dr. Bercel describes a waxing and waning ot non-specific focal or diffuse slow waves which, in waning, lag behind clinical improvement. This is one more instance of what has been ieported in other encephalitides. Even more challenging is the evidence of residual epileptogenic loci. 9. Eiectroencephalographic O b s e r v a t i o n s in H u n tington's Chorea. m D. BERNARD FOSTER a n d B. K. BAGCnl, A n n Arbor. There are some data on the electrophysiology oi the cortex in Sydenham's chorea, but little information in the Mendelian-dominant. heredo-familial, degenerative disease of Huntington's chorea. The pur-
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pose of this study is to investigate Huntington's chorea, in which caudate nucleus and putamen are known to be primarily and invariably involved, and to compare the findings with those in Sydenham's chorea, in which there is probably transient basal ganglia pathology in addition to cortical involvement. Twenty-two patients with Huntington's chorea were examined, using scalp-ear and scalp-scalp techniques. Three grades of severity of choreiform movements and four qualitative grades of intellectual enfeeblement were established. Nine of these cases {42 per cent) had continuous low to medium voltage, markedly abnormal, irregular slow activity {continuous 3 to 4 pet' see.); 2 19 per cent), mildly abnormal, slow activity (6 to 8 per see.); 7 (31 per cent), borderline, independent low voltage or medium voltage fast activity without alpha; and 4 (18 per cent), normal alpha. Very low voltage activity was superimposed on the slow waves. The degree of dementia, the duration of illness, the severity of involuntary movements and the EEG did not always show correlations. No convincing focal abnormalities were apparent. The patterns presented by these 22 patients do not resemble those present in Sydenham's chorea (17 active, 21 inactive cases), in whom a fair amount of medium to high voltage, single or serial slow activity, high voltage slow bursts, abortive spike-and-waves, or fast waves were seen. These findings may be discussed in relation to cortical and basal ganglia pathology and the function of suppressor areas.
Most of the cases showed clinical improvement after anti-malarial therapy; many showed a more normal EEG. Seizures often disappeared, after malaria was treated, without the use of anti-convulsants. It is a moot question whether malaria was the cause of clinical epilepsy or was the precipitating factor in a person with a low convulsive seizure threshold.
Discussion
Discussion
DR. JOHN ABBOTT: Especially interesting are these t~acts: in Wilson's disease the lesion is in the lentitular nucleus, the E E G is normal; in Huntington's chorea the corpus striatum, the white matter and the grey matter affected, and the E E G is abnormal; in both of these, intelligence is affected; however, in Parkinsonism, the corpus striatum and its efferent system are affected, but the E E G and intelligence are normal. DR, MILTON GREENBLATT: W e have seen about 40 cases, without chorea, having greatly dilated ventricles, whose EEGs are very similar to those reported here. The slow wave abnormalities seem non-specific with regard to the diagnostic entity. DR. BERNARD L. PACELLA: It has been noted by Dr. Kennard and by us that experimental lesions of caudate nucleus and various basal ganglia produce 5 to 6 per sec. activity. DR. BAGCHI: W e did not intend to convey the impression that the E E G findings in Huntington's chorea are diagnostic, although some cases have similar patterns. W i t h regard to experimental lesions, their pathophysiotogic expression may be different from that evoked by slow degenerative lesions.
DR. JOHN ABBOTT: W e have seen one case in which supposedly epileptic seizures were febrile episodes with sudden loss of consciousness and prolonged stupor. The E E G was generalized, Type F-1, DR. ROBERT COHN: In a series of about 1,300 cases infected w~th plasmodium viuax, certain individuals showed persistent abnormalities in their EEGs akin to those discussed by Dr. Talbot. However, the distribution of abnormality coincided, to a high degree, with that of our control series i non-malarial) Apparently, plasmodium uiuax Mden mosquitoes did not limit their injections to normals, but infected individuals who were subject to. but not yet manifesting, clinical convulsions
10. Electroencephalographic Findings in a Series of Cases of Chronically Recurring Malaria. D ^ v l o R. TALao'r, Los Angeles. This study is based on a study of ~t0 cases of chronically recurring malaria seen in military veterans. None had evidence of epilepsy previous to malaria. These are divided into seven groups, on the basis of their clinical symptoms and the E E G findings:
Class I: Exhibit clinical grand mah had gross EEG dysrhythmia and diphasic spikes ~7 cases
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Class If: Exhibit clinical petit mal; had EEG dysrhythmia or classical wave and spike f4 cases ). Class Ill: Exhibit clinical psychomotor equivalents: EEG showed high voltage 2 to 6 per see., often flat-topped waves (2 cases). Class IV: Exhibit Jacksonian type of seizure: had E E G with lateralized slow and fast waves (1 case). Class V: Exhibit aphasia; slow waves were present in the left hemisphere: appropriate motor or sensory findings were present (2 cases). Class VI: Exhibit diverse acute encephalitic symptoms; EEGs showed 2 to 5 per sec. waves and often bursts of 20 to 30 per sec. waves (13 cases). Class VII: Exhibit diverse minor signs of postmalarial encephalopathy; EEGs were characterized by diffuse, random dysrhythmia, and 16 to 30 per sec. activity (13 cases).
11. Electroencephaiography in the Differential Diagnosis of Supratentorial Tumors. - J. KERSHMAN and A. CONDO, Montreal. A detailed analysis of the records of 100 consecutive patients presenting supratentorial tumors was made. in order to determine what features of the E E G would be of value in predicting the type of tumor. The data indicate that: 1. Re0ardtess of tumor type, 77 per cent were correctly, 20 per cent were poorly, and 3 per cent were wrongly localized {to the opposite hemisphere) by the E E G alone. Those incorrectly localized were due to interpretation of lower voltage as focally significant. 2. In the cerebral hemispheres, especially in the parieto-occipital regions, glioblastoma is suggested by the predominance of focal random 1-3 per sec. waves, and focal lells than 12 per sec. rhythms: astrocytoma, by the relative ab-
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sence of slow waves, the presence of focal sharp activity nearly always associated with history of seizures, and the occurrence of superficial phase reversals. A meningeal tumor shows mixed slow and fast waves, the latter often not associated with seizures, and freqeent spread of abnormality to the opposite side, 3. W h e n abnormality is localized to the frontal recdion, glioblastoma is infrequent: if localized to the temporal region or vicinity, meningeal tumor is infrequent. This makes differentiation between other major types simpler. 4. Tumors of the third ventricle are chiefly characterized by bilaterally synchronous, rhythmic 4 - 7 per sec. waves. There are often 2 - 3 per sec. forms, bilateral slowing of alpha background, and generalized sharp activity, 5. Focal ' t - 7 per sec. waves occur frequently in all hemispheral tumors and are of no differentiating] importance. Possible mechanisms for the production of these various patterns are proposed.
clinical E E G s in children with primary behavior disorders, records on parents may sometimes be of assistance.
Discussion DR. WILLIAM LENNOX: It is not surprising that children with behavior disturbances and disturbed brain rhythms should have parents with abnormal rhythms. Demonstration of a relationship between dysrhythmia and misconduct would be more complete if the personality disorders in the parents could be pointed out. It may seem strange that there may be a different abnormality in parents and children, but th~ child's record represents a complex inheritance. The evidence is more clear-cut in the study of monozygotic twins. DR. KNOTT: W e are collecting, by means of the Rorschach technique, extensive data on both parents and children. These will be reported, in relation to the EEG, at a later date. While the apparent dis~ parity in the type of abnormality of parent and child is perhaps surprising, other methods of analysis may show more direct relationships. ANIMAL
Discussion DR. PAUL F. A. HOEFER: Our data would place meningiomas last in ease of localization. Also, in 600 verified tumors, none of the slow frequencies were characteristic for a given type. Non-expanding lesions showed the same characteristics. Are the bilateral activities seen in meningiomas of the "'mirror" type ? DR. HANS STRAUSS: W h a t are the criteria for localization of a third ventricle tumor ? DR. KERSHMAN: Concerning "mirror" loci, what we reported was an independent discharge. T h e two most important criteria in third ventricle tumors are: (1) bilaterally synchronous 5 - 6 per sec. activity: (2) phase reversals at the nasopharynoeal lead. 12. A Familial Evaluation of the Electroencephalo. grams of P a t i e n t s with P r i m a r y B e h a v i o r Disorder a n d Psychopathic Personality. N J. R. KNOTT, J. S. GOTTLIE~, M. C. A s n a r a n d E. B. PLAT'r, Iowa City. An investigation of the E E G s of 82 patients diagnosed primary behavior disorder or psychopathic personality, and of the E E G s of both parents of each patient, has been conducted to study the hereditary. contribution to abnormalities in the patient group. It was found that one-third of the patient group whose parents both had normal records had E E G abnormality. (abnormality being defined on the Gibbs scale, i.e,, S-I, S-2, F-l, F-2 or Paroxgsmal). In those patients, whose parents (one or both) had an abnormal EEG, two-thirds had abnormal EEGs. This trend toward relationship of normality (or abnormality) in parents and in child was statistically sicmificant. Specific correlation between type of E E G in parent and child was not obvious. These data would appear to further extend the concept of the role of heredity in the determination of E E G characteristics into non-convulsive groups. They also shed li0ht on the problem of etiology of E E G abnormality in these nosolo~ical 0roups; and they suggest that, for more complete evaluation of
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13. Electrical Activity of the Cerebellum. J RoBEta'r STONE Dow, Portland, Oregon. A smooth flat folium of the cerebellum of the decerebrate cat was stimulated and action potentials were led. by needle electrodes, from adjacent portions of the surface and at graded depths through the layers of the cortex. Records were taken with the cathode ray oscillograph. Electrical stimulation at or near the surface of the folium of the cerebellum results in activation of elements thought to be molecular fibers. These conduct, in a lateral direction, at a rate of from 0.35 to 0.50 meters per sec.. and to a distance usually not exceeding 5 ram. These neurons, in turn. are capable of synaptically affecting the Purkinje cells, which exhibit a negative potential in or near their dendritic processes. The duration of this potential is from 5 to 25 msec. It may or may not be associated with an axon spike in the Purkinje cell fiber. The relationship between these potentials and the spontaneous activity of the cerebellum, and evoked potentials produced by stimulation of the afferent pathways to the cerebellum, is discussed.
Discussion DR. WARREN McCuLLOCH: There is one question, and that is concernin 9 the condition of the beast. which was, as I understand it, not anesthetized. Can these results be obtained in the presence of anesthesia ? DR. Dow: These animals were decerebrate. Local application of nembutal abolishes the responses discussed. W e know that cerebellar excitation is readily affected by anesthesia. 14. T h e Repetitive Discharges of the Cortico, T h a l a m i c Reverberating Circuit I n d u c e d by Af, ferent Stimulation. ~ HSIANo-TuNo CUANO
and Jom~ F. FULTON, New Haven. In response to an afferent volley, the specific sensory cortex gives rise to a localized primary response, followed by a train of regularly spaced slow
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waves with 9radually decreasing amplitude. The frequency of the subsequent repetitive discharges is different in different systems and species. In the cat, the interval between two consecutive waves evoked by sound stimulation is about 200 msec.. that by dorsal root stimulation, about 150 msec. The size of the repetitive discharge, unlike the primary response, is sdmewhat independent of stimulus strength. Anoxia produced by breathing pure N,2, or local application of novocaine on the surface of the cortex, abolishes the repetitive discharge earlier than the primary response, Local strychninization enhances the primary response with little effect on the repetitive discharge. A pattern of response similar to that recorded from the surface can be reproduced from the thalamus with intact cortical connection, but the repetitive discharges disappear after the cortical area is removed. Analysis of the time relations and the interaction of the primary response and the subsequent repetitive discharges indicates that the ascending pathway of the corticothalamic reverberating circuit does not use those fibers mediating the great afferent volleys. Reverberating circuits are believed present not only between the sensory cortex and thalamus, but also between motor cortex and basal ganglia, and possibly between cortex and cerebellum or other subcortical structures. It is suggested that E E G s are mainly a manifestation of the concerted activities of numerous reverberating circuits initiated by primary afferent volleys.
Discussion DR. HERBERT H. JASPER: Regarding the interpretation in terms of thatamo-cortical reverberating systems, one link in the chain of evidence may be missing. One needs proof that this is cortico-thalamic reverberation, not simple after-discharge of cortical localization alone. One would have to destroy both ends of the chain and stimulate the radiations from the thalamus after it had been destroyed. DR. CHANG: Dr. ]asper's sug0estion for further work is valuable. W e feel the present evidence discriminates reverberation and simple after-discharge, since the two behave in different ways. 15. T h e Effect of Atropine on the Convulsing Brain. m THEODORE J. CASE a n d WILUAM H. FUNDERBURK, Chicago. Since it has been suggested that acetylcholine may be involved in the mechanisms of the convulsion, the study of the response to atropine, a drug which abolishes the action of acetylchotine, has theoretical value. The response to atropine (i. v.) was studied while the brain showed signs of convulsive activity induced by the topical application of penicillin and d-tubocurarine. Both of these latter drugs induce trains of spikes in the EEG, but not major "seizure patterns", with the dosages used. Following application of the spike-evoking drugs, atropine induces an increase in spikes, often in runs suggestin 9 major seizures. W i t h o u t the application of either drug, atropine tended to increase or to produce both slow and fast frequencies, and fast
spikes. It appeared, grossly, to increase the excitability of the cortex. Eucatropine, which produces the systemic effects of atropine, but does not enter the brain, had substantially no effect on the spikes induced by the topical application of penicillin. These results would suggest that a decrease in brain acetylcholine may well favor the development of convulsions, although the decrease is probably insufficient in the absence of other mechanisms.
16. Comparison of Metrazoi Seizures with those induced by N i t r o g e n T r i c h l o r i d e . T r e a t e d Pro. teins, m MAURICE L. SILVER and GEORGE H. POLLOCK, Chicago. Dogs fed a diet containing 75 per cent white wheat flour, bleached by nitrogen trichloride, showed characteristic progressive E E G changes ending in seizures. Dogs fed a control diet containing unbIeached flour did not. E E G s of the experimental animals, during the convulsive period, showed initial flattening of potentials, then random high voltage spikes, increasing in frequency, then a coupling of such spikes, and finally the cortical component of the tonic clonic seizure. The time course is slow. Identical abnormalities in E E G s could be produced by feeding a diet with 50 per cent agenized gliadin, glutenin, lactalbumin and casein; the effectiveness is in the order given. A pre-convulsive state exists when the diet has been insufficient to induce seizures, and the animal may then be precipitated into seizures by the injection (i.v.) of agenized hydrotysates or amino acid mixtures, or by breathing CO2, ( 1 5 - 2 5 per cent) and O~. Neither of these precipitating factors alone evoked seizures in control animals, although when hydrolysate injection was followed by CO2 a seizure was produced. W h i l e the clinical picture of metrazol-induced convulsions is very similar to the agene-seizures, the E E G picture is different in its time course, being rapid with metrazol. Also, when metrazol is administered below convulsive threshold, CO., mixtures at 20 per cent do not alter the EEG. Further differences are noted in the response to anti-convulsant drugs, the metrazol-induced convulsions requiring at least five times the amount of tridione or pentothaL
Discussion DR. WARREN GILSON: W e have been unsuccessful in inducing convulsions in "pre-convulsive" animals by the use of agenized amino acids. DR. BERNARD U PACELLA: W h a t happens to the E E G after the agene diet is discontinued ? DR. SILVER: W i t h regard to the apparent discrepancy between Dr. Gilson's findinqs on amino acids and ours, there may be some difference in the way the amino acids were subjected to gas in the treatment process. Concerning discontinuation of diet, we have never seen an E E G return to normal, even though no overt seizures have occurred. 17. Analysis of the Spike-and-Dome Complex by Means of High Speed Photography. - - ROBERT COI~N, Bethesda, Md. The utilization of multiple gun oscillography plus relatively high speed photography (around 30 centi-
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meters per second) gives rise to a resolved E E G pattern, particularly of "characteristic" complexes, that is capable of detailed analysis. The resolved domeand-spike complex presents interesting material. The "spike" element is not constant in duration; it ranges between 20 and 50 milliseconds. This is the order of duration of the majority of strychnine "spikes". Moreover, the "spike" may occur in volleys and actually be superimposed on the slower discharge (the "dome" element). Carefully placed electrodes over homologous regions of the head (particularly in the frontal regions) show an absence of synchrony of the "spike" element of the spike-and-dome complex. The lag (or lead) is not constant, even in the same individual; but it is of the order of 5-10 msec. The theoretical aspects of the results are discussed in detail. A comparison of the discharge time and synchrony of the elements of the K-complex of "sleep" and the "spike-anddome" complex is made. 18. Research o n the Skin Galvanic Response in M e n t a l Patients. ~ W . T. LlaERSON, Hartford. Records of the galvanic skin response, to auditory and visual stimuli, using one channel of a standard R-C coupled E E G system, were secured from more than 500 patients. T h e standard records were from palm-wrist electrodes; some responses were made from different regions and with altered blood circulation. Such observations suggested that the
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latent time ( ± 1.5 see.) was peripherally determined. Sex, age and diagnostic variables were investigat. ed. Amplitude of the response decreased through the age range. Amplitude showed significant differences in various diagnostic groups, being lowest in depressed and organic patients; it was decreased after frontal lobotomy. Comparison of palmar galvanic reactions with simultaneous E E G s showed no correlation with alpha continuity or with "normality" of the E E G record. No apparent relationship held between galvanic response and alpha depression to stimulation.
Discussion DR. CHESTER DARROW: The recording of accessory physiologic change with the E E G is commendable. W e should, however, be aware of some basic principles and the limitations they impose: (1) Galvanic skin response is a direct current phenomenon, not accurately reproduced by capacity-coupled devices; (2) neither voltage nor resistance factors in the circuit can be defined; (3) without an indifferent electrode, neither the locus of, nor the variables producing, change can be identified; (4) it is necessary to relate reactivity to level of resistance. Apparently, even though these principles have not been met entirely, there is consistency with other data on age and on toxic and related psychotic conditions. Our own work with lobotomy would suggest recovery at later dates.
EASTERN ASSOCIATION OF ELECTROENCEPHALOGRAPHERS
Brookhaven National Laboratory, Upton, New York October 22 a n d 23, 1948 1. Frequency Analysis of "Steady State" a n d " T r a n sient" Phenomena in the H u m a n Electroenceph. alogram. ~ PAUL F. A. HOEI'EB, CHARLES MARKEY a n d ROBERT L. SCHOENFELD 9 N e w York. An analyser consisting of twenty tuned filters continuously recording in separate cathode-ray oscilloscopes is described. The filter deflections, together with a timing signal and monitoring oscilloscope trace of the primary E E G record is photographed on slowmoving 35 mms. film by means of a camera with a wide-angle lens. The E E G frequencies amplitude modulate a 1200 cycle carrier. The filters are tuned to the lower sideband frequencies, performing an analysis in the audio range. Earlier methods of analysis were integrated over ten to thirty seconds of record. The present analyzer is designed to obtain the analysis within an interval of one-half second. Attention is focussed on the time sequence and frequency spectrum of brief runs of activity. It is felt' that this new method makes possible a more detailed study of both "steady state" and "transient" phenomena in the electroencephalo0ram. 2. T h e use of Bilateral N a s o p h a r y n g e a l , Tympanic, and Ear Leads in Recording the Basal Electroencephalogram, m ALEJANDRO ABELLANO and PAUL D. MACLEAN, Boston. A practicable method for registering electrical activity across a limited area at the base of the
brain, involving the use of two nasopharyngeal leads, two tympanic leads, and two leads placed on the ears, is described. This allows a succession of five linkages across the base of the brain, between the two ears. Activity at appropriate scalp leads can be simultaneously compared with that at the base. (A detailed description of the special type of nasopharyngeal and tympanic leads employed in this technique has been reported in this Journal (1949, I, 110113). Forty-three recordings have been made. Excerpts of records including tracings from patients without demonstrable brain disease, patients with temporal lobe tumor, and patients with epilepsy, are shown to illustrate the basal electrogram seen in various conditions. The basal electrogram just prior to and following sleep is also demonstrated. Although this method was developed primarily for the study of the electroencephalogram of patients with so-called psychosomatic disease, there is evidence that it may also be useful in the localization of brain lesions or epileptogenic loci. Two patients, for example, with symptoms of "psychomotor" epilepsy were put to sleep and examined by this technique. In each instance there occurred repeatedly a spike complex, which appeared to arise from the inferior portion of the right temporal lobe in one case, and from the inferior portion of the left temporal lobe in the other. The focal activity in both these patients was
AMERICAN
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SECOND ANNUAL MEETING J u n e 12, 13 a n d 14, 1948 - - Atlantic City, N. J.
A C T I V A T I O N O F T H E EEG 1. A Review of M e t h o d s used to elicit A b n o r m a l i t y in the Electroencephalogram. 2 u I. CHARLES KAUVMAN and C. W~:sL~v W^TSON, Boston. 2. Flickered Light as a Provocative Test in Electroencephalography. - - MORTIMER OSTOW, New York. This study is based upon a standardized test for susceptibility to photic driving administered to 302 male patients at classified diagnostically as: psychopathic personality, psychosis, organic brain disease. epilepsy, and simple adult maladjustment. Eighty-eight per cent of all subjects exhibited susceptibility to driving. DrLving appeared through a frequency range from 4 t o 30 cycles. In 12 per cent of the subjects, this was detected at frequencies of I/~, I/~, or 2 or 3 times the flicker frequencies. The effect was most prominent posteriorly: no lateral differences were observed. W i t h quantitative analysis of the data, two factors of interest emerged: the incidence of driving in each of three frequency ranges, less than 8, 8 to 12, and over 12 per see.; and the prominence, persistence, regularity, and amplitude of the phenomenon, collectively termed "quality". There was a relationship between the amount of following in the slow range and the amount of spontaneous (sporadic or serial) slow activity. Paroxysmal slow activity, however, failed to show this relation. A similar relation appeared between the incidence of driving in the 8 to 12 per sec. range and spontaneous per cent time alpha. Also, there was a relationship between driving at faster frequencies and the amount of spontaneous fast activity. No direct relationship was found between specific spontaneous and driven frequencies, other than the range relationships. "Quality" of driving was better among those who showed alpha blocking to light. There was a relation between good "quality" and increased age. Slow driving was 0router among the younger patients, and fast driving among the older ones, presumably in consequence of the inverse relation of spontaneous slow, and the direct relation of spontaneous fast, with a~e.
Clinical diagnosis per se, or normality of the spontaneous E E G record, could not be related to driving. 1 Editor's note: It has been necessary, due to space limitations. to shorten the discussion of the papers. This task was difficult, and was done by using the criteria of critical pertinence and reader interest. A great deal of nevertheless valuable material has, perforce, had to be left unpublished. (]. R. K.) 2 Published in full in this journal, pages 237-240.
Testing for photic driving is a means of facilitating the demonstration of (sporadic or serial) slow or fast activity and of discriminating these from paroxysmal slow activity. Impaired cerebral function, or physiologic aging, is suggested by unusually good "quality" of the driving.
Discussion Dn. BICKFOaO: The suggestion that the response to photic driving can be taken as an index of physiologic maturity is opposed to Dr. W a i t e r ' s evidence: he regards good driving as an indication of immaturity. In our own experience, repeated tests on the same subject suggest that a number of variables have an effect on the response. 3. Routine Seconal Sedation; A M a j o r Aid to Clinical Electroencephalography. ~ FR£DERIC A. Glans a n d EaNA L. Glues, Chicago. Since sleep more than doubles the information obtained from the electroenceph:logram, the search for an ideal substance for the production of sleep has been continued. For the past six months, seconal, a shortacting barbiturate, has been used routinely to increase the chances of obtaining sleep during the examination. Adults are given one and one-half 0rains before electrodes are applied. Children are given three-quarters grains, and infants are given threeeighths of a grain, just before the electrodes are applied. If sleep is not obtained after three-quarters of an hour of recording, the initial dose is repeated. No untoward effects have been noted, and the occurretice of sleep may be raised from 20 per cent to 80 per cent, with a consequent increase in positive findings. Comparison of natural sleep with that induced by seconal has failed to reveal an instance in which abnormalities that appeared during natural sleep did not appear during seconal-induced sleep. However, if more than the initial dose of seconal is required, fast activity may be produced, and this interferes slightly with interpretation of the record, Seconal is most advantageous when employed not as an anesthetic, or to produce sleep in an unwillin0 subject, but in low dosage as a soporific to increase the likelihood of obtaining "natural" sleep.
Discussion Dn. BicgFono: I would like to ask Dr. Gibbs whether he has any evidence that patients having attacks only at night are more likely to have an abnormal sleep record than the average epileptic. DR. GraBs: Such patients do show a little less abnormality during the waking state than patients whose seizures are in the daytime.
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4. The Localizing Value of Asymmetrical Electroencephalographic Tracings Obtained Simultaneously by Homologous Recording. - - R. B. Amp and D. ZEALEAR, San Francisco. A statistical analysis of simultaneous homologous electroencephalographic tracings has provided data with respect to the differences of potential, form, frequency and the synchronism of hemispheric discharge which has been found to be of value for purposes of localization. The relative incidence and localizing value of such hemispheric differences has been analyzed by a cor,'elative study of clinical, pathologic, electroencephalographic and pneumoencephalographic data in 412 patients. Inequalities cf homologous potentials and asynchronism of hemispheric discharge are primarily of localizing value, but alone do not indicate the side of the lesion. Differences of wave form and frequency are chiefly of value in lateralizing and verifying a focal diagnosis. A focal hyperpotentia ("irritative" focus) occurred on the side of the lesion in a high percentage of brain tumors and twice as commonly as hypopententias in convulsive states secondary to trauma and in arachnoidal adhesive processes. In degenerative diseases, focal hypopotentia predominated on the side of the lesion. Although combinations of minor differences were found alone in 18 per cent of this group, and correlated as well with focal findings by pneumo-encephalo9raphy and clinical examination as did gross focal dysrhythmias, such changes occurred rarely in surgical conditions.
Discussion DR. JOHN KEUSHMAN: W h a t is the significance of asymmetries in scalp-ear records not shown in scalpscalp records ? Which element (form, frequency, potential or synchrony) is most important in attempting to make a differential diagnosis ? DR, Amp: Differences in asymmetry with differences in recording are frequently difficult to explain. It is our impression that scalp-ear differences may represent subcortical pathology. W i t h regard to criteria for differential diagnosis, none has been obvious to US. ~. The Occurrence of Delta Activity in the Electro. encephalogram of the Adult. ~ Louis GREENSrElN and HANS STRAUSS, New York. A study was made of the EEGs of 100 adults varying in age from 17 to 70 years and showing no evidence of any organic cerebral disease, epilepsy or metabolic disorder. All records were taken under standard conditions, including the elimination of physiotogicaI hypoglycemia. The amount of delta activity present (waves of 6 per sec. or slower frequency with an amplitude of 20 microvolts or more) was measured and expressed in terms of the delta factor (per cent of total record occupied by delta waves). Sixty-two per cent of the subjects showed no delta activity. The remaining 38 per cent showed delta activity in one or more leads. This was always recorded from leads involving the ear lobes if recorded from other, bipolar leads. The highest delta factor was in frontal-ear leads and was 8. The highest factor from other leads was 5.
To evaluate last activity, 100 consecutive records were analyzed with reference to conspicuous fast ac tivity. The frequencies varied from 15 to 30 per sec. at amplitudes from 30 to 80 microvolts. The amom~t was graded as: little, moderate, much or almost con. tinuous. Thirty of these records showed frankly abnormal slow activity. In the remainder, fast was the only questionable finding, and 45 of these had no demonstrable cerebral disease, dysfimction or met~ abolic disorder. W e feel that the amounts of delta and fast activity described cannot be considered abnormal. A better correlation between E E G normality and clinical normldcy obtains when they are classified as normal.
Discussion DR, MARGARET RHEtNBERGER: My own experience has been that a percentage of delta of approximately 10 is present in so many records that the concept of normality is stretched by calling this an indication of abnormality. Similarly, frequencies above 12 per second are common, and often cannot be called abnormal. DR. FREDEmC GraBS: Only large statistical studies can give the word "normality" meaning. One can have slightly, exceedingly and paroxysmally abnormal records, expressed as the differential between normal controls and epileptics. DR. GREENSTEIN: Small amounts of diffuse slow can be classified as "normal" only in the sense that they do not indicate the existence of cerebral disease, epilepsy or cerebral dysfunction due to toxic or metabolic disorder.
EEG IN L O B O T O M Y 6. Electroencephalographic Findings after Prefrontal Lobotomy. ~ MARGARET A. LENNOX and JOHN COOLIDGE, New Haven. Electroencephalograms were obtained in 48 patients before, and from one day to one year after prefrontal lobotomy. Abnormality was marked soon after operation, consisting of diffuse slowing, most prominent in the frontal leads. This may be lateralized. Slowing tended to decrease abruptly in degree and extent in the first two months. After nine weeks there "*'as very little change, and the E E G appeared to have reached the "permanent" post-operative picture for each individual. At the end of a year, 20 per cent of patients showed no abnormality and in 10~o the abnormality was still marked: Seventy per cent showed slowin 9 confined to frontal leads anterior to the plane of incision, usually as 0.5 to 1 per sec. "base line sway", with normal frequencies superimposed. This type of abnormality has not been encountered in any other clinical condition. Since it appears to be produced only by tobotomy, it is difficult to attribute it to trauma alone. Persistence of normal frequencies anterior to the plane of incision suggests that thalamo-cortico-thalamic reverberating systems may not be essential for the maintenance of alpha activity. If such systems are essential, they do not involve the medial thalamic nuclei, which presumably degenerate after prefrontal lobotomy. On 60 occasions the pre- and post-operative EEG included sleep induced by intravenous sodium pentothal. Twelve per sec. spindles, most prominent anteriorly before operation, failed to appear in any
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lead after operation. This confirms the findings of Morison and Bassett that pentothal spindles arise in the thalamus, and suggests that 12 per sec. spindles arise in the medial thalamic nuclei. Their absence after lobotomy is presumably due to degeneration of the nuclei rather than to cutting of the fiber tracts, since they do not appear in any lead after operation. By contrast, 14 to 15 per sec. spindles were more prominent in the central and parieto-occipital leads before operation, and their incidence was unaffected by prefrontal lobotomy. Presumably they arise in the lateral group of thalamic nuclei. (Discussion follows next paper). 7. Effect of P r e f r o n t a l L o b o t o m y ; A n Electroe n c e p h a l o g r a p h i c and Clinical Study. m MILTON GREENBLATT, SIDNEY LEVIN, MARIE M. HEALEY, and HARRY C. SOLOMON, Boston. Seventy selected cases were examined clinically and electroencephalographically before, and at intervals after, lobotomy (done by the Lyerly-Poppen technique). The majority had received shock treatment (electric, insulin) prior to lobotomy. T w e n t y cases developed convulsive seizures postoperatively. None of these had ever had spontaneous convulsions pre-operatively. Those who developed seizures had received more shock treatment, pre-lobotomy, than those who were seizure-free, and the pre.lobotomy incidence of E E G abnormality was higher. After lobotomy a "drowsy-anergic" state often appeared, lasting 4 to 8 days, during which diffuse delta activity was seen. W i t h alertness, the delta activity largely disappeared posteriorly and .concentrated about the operative site. Irregular, roiling slow waves of 1-3 per sec. were a regular feature of the post-operative E E G s and tended to persist. The operative trauma, the isolation of the frontal lobes, and the sleep-like phenomena appeared to play a joint role in producing early post-operative E E G changes. In the first weeks and months following lobotomy, increased amplitude, accentuation of alpha potentials, increased delta activity, asymmetries, and focal abnormalities were frequently observed. Delta was found over a wide area anteriorly; focal abnormalities tended to be present bifrontally or laterally but usually without focal neurological signs. The over-breathing "build-up" ",,gas greater and was emphasized in the region anterior to the operative site. In many individuals the dysrhythmia tended to persist. In some who developed convulsive seizures, it became aggravated. The seizures were essentially grand real in type; no petit real was observed either clinically or electroencephalographlcally. The study indicates that prefrontal lobotomy produces E E G dysrhythmia and a tendency towards convulsive seizures in those with pre-operative E E G abnormality. However, considerable cortical dysrhythmia may exist in patients who are neurologically negative, have no convulsive manifestations, and improve clinically.
Discussion DR. WARREN McCtlLLOCH: In these studies, and in animal preparations, cutting the cortex loose from the thalamic nuclei produces a loss in various fre-
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quencies. This may even be from leads posterior to Ihe line of section. It suggests that we are dealing with an interplay of thalamus and cortex at all times. W i t h regard to seizures, possibly the nuclei in which surface-positive spikes originate can be localized. If seizures develop in the isolated frontal lobe. two avenues of spread to the rest of the cortex are lost: careful study of these patients may identify the remaining paths. DR. PAUL F. A. HOEFER: W h y do these abnormalities persist ? W h y may they develop posterior to the plane of section ? DR. MARGARET LENNOX: W e do not feel that the abnormalities persist; the question might better be put: W h y do thev not? DR. GREENBLA'r:r: Abnormality certainly goes far behind the plane of section, and not during the anergic-drowsy state. Divergence of E E G data on this group may well result from lack of correlation between the damage the surgeon intends and damage actually performed. EEG A N D E N C E P H A L O P A T H Y 8. T h e I m p o r t a n c e of E E G ' i n Some Obscure En. cephalitides. ~ NICHOLAS A. BERCEL, Los Angeles. .. This study attempts to investigate the value of electroencephalography in establishing the role of obscure encephalo-meningitides in convulsive disorders. Infectious mononucleosis is such a disease, only 25 cases having cerebral complication being reported from 1931 to 19't8. Twenty-one patients were investigated, clinically, by laboratory procedures and by EEG. W h i l e C. N. S. irritation was present at some time in 16 cases, the E E G was normal. In 5 cases there was evidence of E E G abnormality. In 2 of these, focal paroxysmal activity persisted during a follow-up period of 1.5 to 2 years. One of these had paroxysmal aphasia at the acme of the encephalitis and at the same time had focal activity in the motor speech area. The other case showed focal seizure discharges in the right motor area. Preventive anticonvulsant medication was followed for 7 months; when the patient ceased following this regime, Jacksonian seizures involving the left arm and face developed. In view of the difficulty of clinical or laboratory diagnosis of cerebral involvement, until focal epilepsy develops, serial E E G studies seem indicated in infectious mononucleosis.
Discussion DR. JOHN ABBOTT: Dr. Bercel describes a waxing and waning ot non-specific focal or diffuse slow waves which, in waning, lag behind clinical improvement. This is one more instance of what has been ieported in other encephalitides. Even more challenging is the evidence of residual epileptogenic loci. 9. Eiectroencephalographic O b s e r v a t i o n s in H u n tington's Chorea. m D. BERNARD FOSTER a n d B. K. BAGCnl, A n n Arbor. There are some data on the electrophysiology oi the cortex in Sydenham's chorea, but little information in the Mendelian-dominant. heredo-familial, degenerative disease of Huntington's chorea. The pur-
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pose of this study is to investigate Huntington's chorea, in which caudate nucleus and putamen are known to be primarily and invariably involved, and to compare the findings with those in Sydenham's chorea, in which there is probably transient basal ganglia pathology in addition to cortical involvement. Twenty-two patients with Huntington's chorea were examined, using scalp-ear and scalp-scalp techniques. Three grades of severity of choreiform movements and four qualitative grades of intellectual enfeeblement were established. Nine of these cases {42 per cent) had continuous low to medium voltage, markedly abnormal, irregular slow activity {continuous 3 to 4 pet' see.); 2 19 per cent), mildly abnormal, slow activity (6 to 8 per see.); 7 (31 per cent), borderline, independent low voltage or medium voltage fast activity without alpha; and 4 (18 per cent), normal alpha. Very low voltage activity was superimposed on the slow waves. The degree of dementia, the duration of illness, the severity of involuntary movements and the EEG did not always show correlations. No convincing focal abnormalities were apparent. The patterns presented by these 22 patients do not resemble those present in Sydenham's chorea (17 active, 21 inactive cases), in whom a fair amount of medium to high voltage, single or serial slow activity, high voltage slow bursts, abortive spike-and-waves, or fast waves were seen. These findings may be discussed in relation to cortical and basal ganglia pathology and the function of suppressor areas.
Most of the cases showed clinical improvement after anti-malarial therapy; many showed a more normal EEG. Seizures often disappeared, after malaria was treated, without the use of anti-convulsants. It is a moot question whether malaria was the cause of clinical epilepsy or was the precipitating factor in a person with a low convulsive seizure threshold.
Discussion
Discussion
DR. JOHN ABBOTT: Especially interesting are these t~acts: in Wilson's disease the lesion is in the lentitular nucleus, the E E G is normal; in Huntington's chorea the corpus striatum, the white matter and the grey matter affected, and the E E G is abnormal; in both of these, intelligence is affected; however, in Parkinsonism, the corpus striatum and its efferent system are affected, but the E E G and intelligence are normal. DR, MILTON GREENBLATT: W e have seen about 40 cases, without chorea, having greatly dilated ventricles, whose EEGs are very similar to those reported here. The slow wave abnormalities seem non-specific with regard to the diagnostic entity. DR. BERNARD L. PACELLA: It has been noted by Dr. Kennard and by us that experimental lesions of caudate nucleus and various basal ganglia produce 5 to 6 per sec. activity. DR. BAGCHI: W e did not intend to convey the impression that the E E G findings in Huntington's chorea are diagnostic, although some cases have similar patterns. W i t h regard to experimental lesions, their pathophysiotogic expression may be different from that evoked by slow degenerative lesions.
DR. JOHN ABBOTT: W e have seen one case in which supposedly epileptic seizures were febrile episodes with sudden loss of consciousness and prolonged stupor. The E E G was generalized, Type F-1, DR. ROBERT COHN: In a series of about 1,300 cases infected w~th plasmodium viuax, certain individuals showed persistent abnormalities in their EEGs akin to those discussed by Dr. Talbot. However, the distribution of abnormality coincided, to a high degree, with that of our control series i non-malarial) Apparently, plasmodium uiuax Mden mosquitoes did not limit their injections to normals, but infected individuals who were subject to. but not yet manifesting, clinical convulsions
10. Electroencephalographic Findings in a Series of Cases of Chronically Recurring Malaria. D ^ v l o R. TALao'r, Los Angeles. This study is based on a study of ~t0 cases of chronically recurring malaria seen in military veterans. None had evidence of epilepsy previous to malaria. These are divided into seven groups, on the basis of their clinical symptoms and the E E G findings:
Class I: Exhibit clinical grand mah had gross EEG dysrhythmia and diphasic spikes ~7 cases
) .
Class If: Exhibit clinical petit mal; had EEG dysrhythmia or classical wave and spike f4 cases ). Class Ill: Exhibit clinical psychomotor equivalents: EEG showed high voltage 2 to 6 per see., often flat-topped waves (2 cases). Class IV: Exhibit Jacksonian type of seizure: had E E G with lateralized slow and fast waves (1 case). Class V: Exhibit aphasia; slow waves were present in the left hemisphere: appropriate motor or sensory findings were present (2 cases). Class VI: Exhibit diverse acute encephalitic symptoms; EEGs showed 2 to 5 per sec. waves and often bursts of 20 to 30 per sec. waves (13 cases). Class VII: Exhibit diverse minor signs of postmalarial encephalopathy; EEGs were characterized by diffuse, random dysrhythmia, and 16 to 30 per sec. activity (13 cases).
11. Electroencephaiography in the Differential Diagnosis of Supratentorial Tumors. - J. KERSHMAN and A. CONDO, Montreal. A detailed analysis of the records of 100 consecutive patients presenting supratentorial tumors was made. in order to determine what features of the E E G would be of value in predicting the type of tumor. The data indicate that: 1. Re0ardtess of tumor type, 77 per cent were correctly, 20 per cent were poorly, and 3 per cent were wrongly localized {to the opposite hemisphere) by the E E G alone. Those incorrectly localized were due to interpretation of lower voltage as focally significant. 2. In the cerebral hemispheres, especially in the parieto-occipital regions, glioblastoma is suggested by the predominance of focal random 1-3 per sec. waves, and focal lells than 12 per sec. rhythms: astrocytoma, by the relative ab-
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sence of slow waves, the presence of focal sharp activity nearly always associated with history of seizures, and the occurrence of superficial phase reversals. A meningeal tumor shows mixed slow and fast waves, the latter often not associated with seizures, and freqeent spread of abnormality to the opposite side, 3. W h e n abnormality is localized to the frontal recdion, glioblastoma is infrequent: if localized to the temporal region or vicinity, meningeal tumor is infrequent. This makes differentiation between other major types simpler. 4. Tumors of the third ventricle are chiefly characterized by bilaterally synchronous, rhythmic 4 - 7 per sec. waves. There are often 2 - 3 per sec. forms, bilateral slowing of alpha background, and generalized sharp activity, 5. Focal ' t - 7 per sec. waves occur frequently in all hemispheral tumors and are of no differentiating] importance. Possible mechanisms for the production of these various patterns are proposed.
clinical E E G s in children with primary behavior disorders, records on parents may sometimes be of assistance.
Discussion DR. WILLIAM LENNOX: It is not surprising that children with behavior disturbances and disturbed brain rhythms should have parents with abnormal rhythms. Demonstration of a relationship between dysrhythmia and misconduct would be more complete if the personality disorders in the parents could be pointed out. It may seem strange that there may be a different abnormality in parents and children, but th~ child's record represents a complex inheritance. The evidence is more clear-cut in the study of monozygotic twins. DR. KNOTT: W e are collecting, by means of the Rorschach technique, extensive data on both parents and children. These will be reported, in relation to the EEG, at a later date. While the apparent dis~ parity in the type of abnormality of parent and child is perhaps surprising, other methods of analysis may show more direct relationships. ANIMAL
Discussion DR. PAUL F. A. HOEFER: Our data would place meningiomas last in ease of localization. Also, in 600 verified tumors, none of the slow frequencies were characteristic for a given type. Non-expanding lesions showed the same characteristics. Are the bilateral activities seen in meningiomas of the "'mirror" type ? DR. HANS STRAUSS: W h a t are the criteria for localization of a third ventricle tumor ? DR. KERSHMAN: Concerning "mirror" loci, what we reported was an independent discharge. T h e two most important criteria in third ventricle tumors are: (1) bilaterally synchronous 5 - 6 per sec. activity: (2) phase reversals at the nasopharynoeal lead. 12. A Familial Evaluation of the Electroencephalo. grams of P a t i e n t s with P r i m a r y B e h a v i o r Disorder a n d Psychopathic Personality. N J. R. KNOTT, J. S. GOTTLIE~, M. C. A s n a r a n d E. B. PLAT'r, Iowa City. An investigation of the E E G s of 82 patients diagnosed primary behavior disorder or psychopathic personality, and of the E E G s of both parents of each patient, has been conducted to study the hereditary. contribution to abnormalities in the patient group. It was found that one-third of the patient group whose parents both had normal records had E E G abnormality. (abnormality being defined on the Gibbs scale, i.e,, S-I, S-2, F-l, F-2 or Paroxgsmal). In those patients, whose parents (one or both) had an abnormal EEG, two-thirds had abnormal EEGs. This trend toward relationship of normality (or abnormality) in parents and in child was statistically sicmificant. Specific correlation between type of E E G in parent and child was not obvious. These data would appear to further extend the concept of the role of heredity in the determination of E E G characteristics into non-convulsive groups. They also shed li0ht on the problem of etiology of E E G abnormality in these nosolo~ical 0roups; and they suggest that, for more complete evaluation of
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13. Electrical Activity of the Cerebellum. J RoBEta'r STONE Dow, Portland, Oregon. A smooth flat folium of the cerebellum of the decerebrate cat was stimulated and action potentials were led. by needle electrodes, from adjacent portions of the surface and at graded depths through the layers of the cortex. Records were taken with the cathode ray oscillograph. Electrical stimulation at or near the surface of the folium of the cerebellum results in activation of elements thought to be molecular fibers. These conduct, in a lateral direction, at a rate of from 0.35 to 0.50 meters per sec.. and to a distance usually not exceeding 5 ram. These neurons, in turn. are capable of synaptically affecting the Purkinje cells, which exhibit a negative potential in or near their dendritic processes. The duration of this potential is from 5 to 25 msec. It may or may not be associated with an axon spike in the Purkinje cell fiber. The relationship between these potentials and the spontaneous activity of the cerebellum, and evoked potentials produced by stimulation of the afferent pathways to the cerebellum, is discussed.
Discussion DR. WARREN McCuLLOCH: There is one question, and that is concernin 9 the condition of the beast. which was, as I understand it, not anesthetized. Can these results be obtained in the presence of anesthesia ? DR. Dow: These animals were decerebrate. Local application of nembutal abolishes the responses discussed. W e know that cerebellar excitation is readily affected by anesthesia. 14. T h e Repetitive Discharges of the Cortico, T h a l a m i c Reverberating Circuit I n d u c e d by Af, ferent Stimulation. ~ HSIANo-TuNo CUANO
and Jom~ F. FULTON, New Haven. In response to an afferent volley, the specific sensory cortex gives rise to a localized primary response, followed by a train of regularly spaced slow
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waves with 9radually decreasing amplitude. The frequency of the subsequent repetitive discharges is different in different systems and species. In the cat, the interval between two consecutive waves evoked by sound stimulation is about 200 msec.. that by dorsal root stimulation, about 150 msec. The size of the repetitive discharge, unlike the primary response, is sdmewhat independent of stimulus strength. Anoxia produced by breathing pure N,2, or local application of novocaine on the surface of the cortex, abolishes the repetitive discharge earlier than the primary response, Local strychninization enhances the primary response with little effect on the repetitive discharge. A pattern of response similar to that recorded from the surface can be reproduced from the thalamus with intact cortical connection, but the repetitive discharges disappear after the cortical area is removed. Analysis of the time relations and the interaction of the primary response and the subsequent repetitive discharges indicates that the ascending pathway of the corticothalamic reverberating circuit does not use those fibers mediating the great afferent volleys. Reverberating circuits are believed present not only between the sensory cortex and thalamus, but also between motor cortex and basal ganglia, and possibly between cortex and cerebellum or other subcortical structures. It is suggested that E E G s are mainly a manifestation of the concerted activities of numerous reverberating circuits initiated by primary afferent volleys.
Discussion DR. HERBERT H. JASPER: Regarding the interpretation in terms of thatamo-cortical reverberating systems, one link in the chain of evidence may be missing. One needs proof that this is cortico-thalamic reverberation, not simple after-discharge of cortical localization alone. One would have to destroy both ends of the chain and stimulate the radiations from the thalamus after it had been destroyed. DR. CHANG: Dr. ]asper's sug0estion for further work is valuable. W e feel the present evidence discriminates reverberation and simple after-discharge, since the two behave in different ways. 15. T h e Effect of Atropine on the Convulsing Brain. m THEODORE J. CASE a n d WILUAM H. FUNDERBURK, Chicago. Since it has been suggested that acetylcholine may be involved in the mechanisms of the convulsion, the study of the response to atropine, a drug which abolishes the action of acetylchotine, has theoretical value. The response to atropine (i. v.) was studied while the brain showed signs of convulsive activity induced by the topical application of penicillin and d-tubocurarine. Both of these latter drugs induce trains of spikes in the EEG, but not major "seizure patterns", with the dosages used. Following application of the spike-evoking drugs, atropine induces an increase in spikes, often in runs suggestin 9 major seizures. W i t h o u t the application of either drug, atropine tended to increase or to produce both slow and fast frequencies, and fast
spikes. It appeared, grossly, to increase the excitability of the cortex. Eucatropine, which produces the systemic effects of atropine, but does not enter the brain, had substantially no effect on the spikes induced by the topical application of penicillin. These results would suggest that a decrease in brain acetylcholine may well favor the development of convulsions, although the decrease is probably insufficient in the absence of other mechanisms.
16. Comparison of Metrazoi Seizures with those induced by N i t r o g e n T r i c h l o r i d e . T r e a t e d Pro. teins, m MAURICE L. SILVER and GEORGE H. POLLOCK, Chicago. Dogs fed a diet containing 75 per cent white wheat flour, bleached by nitrogen trichloride, showed characteristic progressive E E G changes ending in seizures. Dogs fed a control diet containing unbIeached flour did not. E E G s of the experimental animals, during the convulsive period, showed initial flattening of potentials, then random high voltage spikes, increasing in frequency, then a coupling of such spikes, and finally the cortical component of the tonic clonic seizure. The time course is slow. Identical abnormalities in E E G s could be produced by feeding a diet with 50 per cent agenized gliadin, glutenin, lactalbumin and casein; the effectiveness is in the order given. A pre-convulsive state exists when the diet has been insufficient to induce seizures, and the animal may then be precipitated into seizures by the injection (i.v.) of agenized hydrotysates or amino acid mixtures, or by breathing CO2, ( 1 5 - 2 5 per cent) and O~. Neither of these precipitating factors alone evoked seizures in control animals, although when hydrolysate injection was followed by CO2 a seizure was produced. W h i l e the clinical picture of metrazol-induced convulsions is very similar to the agene-seizures, the E E G picture is different in its time course, being rapid with metrazol. Also, when metrazol is administered below convulsive threshold, CO., mixtures at 20 per cent do not alter the EEG. Further differences are noted in the response to anti-convulsant drugs, the metrazol-induced convulsions requiring at least five times the amount of tridione or pentothaL
Discussion DR. WARREN GILSON: W e have been unsuccessful in inducing convulsions in "pre-convulsive" animals by the use of agenized amino acids. DR. BERNARD U PACELLA: W h a t happens to the E E G after the agene diet is discontinued ? DR. SILVER: W i t h regard to the apparent discrepancy between Dr. Gilson's findinqs on amino acids and ours, there may be some difference in the way the amino acids were subjected to gas in the treatment process. Concerning discontinuation of diet, we have never seen an E E G return to normal, even though no overt seizures have occurred. 17. Analysis of the Spike-and-Dome Complex by Means of High Speed Photography. - - ROBERT COI~N, Bethesda, Md. The utilization of multiple gun oscillography plus relatively high speed photography (around 30 centi-
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meters per second) gives rise to a resolved E E G pattern, particularly of "characteristic" complexes, that is capable of detailed analysis. The resolved domeand-spike complex presents interesting material. The "spike" element is not constant in duration; it ranges between 20 and 50 milliseconds. This is the order of duration of the majority of strychnine "spikes". Moreover, the "spike" may occur in volleys and actually be superimposed on the slower discharge (the "dome" element). Carefully placed electrodes over homologous regions of the head (particularly in the frontal regions) show an absence of synchrony of the "spike" element of the spike-and-dome complex. The lag (or lead) is not constant, even in the same individual; but it is of the order of 5-10 msec. The theoretical aspects of the results are discussed in detail. A comparison of the discharge time and synchrony of the elements of the K-complex of "sleep" and the "spike-anddome" complex is made. 18. Research o n the Skin Galvanic Response in M e n t a l Patients. ~ W . T. LlaERSON, Hartford. Records of the galvanic skin response, to auditory and visual stimuli, using one channel of a standard R-C coupled E E G system, were secured from more than 500 patients. T h e standard records were from palm-wrist electrodes; some responses were made from different regions and with altered blood circulation. Such observations suggested that the
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latent time ( ± 1.5 see.) was peripherally determined. Sex, age and diagnostic variables were investigat. ed. Amplitude of the response decreased through the age range. Amplitude showed significant differences in various diagnostic groups, being lowest in depressed and organic patients; it was decreased after frontal lobotomy. Comparison of palmar galvanic reactions with simultaneous E E G s showed no correlation with alpha continuity or with "normality" of the E E G record. No apparent relationship held between galvanic response and alpha depression to stimulation.
Discussion DR. CHESTER DARROW: The recording of accessory physiologic change with the E E G is commendable. W e should, however, be aware of some basic principles and the limitations they impose: (1) Galvanic skin response is a direct current phenomenon, not accurately reproduced by capacity-coupled devices; (2) neither voltage nor resistance factors in the circuit can be defined; (3) without an indifferent electrode, neither the locus of, nor the variables producing, change can be identified; (4) it is necessary to relate reactivity to level of resistance. Apparently, even though these principles have not been met entirely, there is consistency with other data on age and on toxic and related psychotic conditions. Our own work with lobotomy would suggest recovery at later dates.
EASTERN ASSOCIATION OF ELECTROENCEPHALOGRAPHERS
Brookhaven National Laboratory, Upton, New York October 22 a n d 23, 1948 1. Frequency Analysis of "Steady State" a n d " T r a n sient" Phenomena in the H u m a n Electroenceph. alogram. ~ PAUL F. A. HOEI'EB, CHARLES MARKEY a n d ROBERT L. SCHOENFELD 9 N e w York. An analyser consisting of twenty tuned filters continuously recording in separate cathode-ray oscilloscopes is described. The filter deflections, together with a timing signal and monitoring oscilloscope trace of the primary E E G record is photographed on slowmoving 35 mms. film by means of a camera with a wide-angle lens. The E E G frequencies amplitude modulate a 1200 cycle carrier. The filters are tuned to the lower sideband frequencies, performing an analysis in the audio range. Earlier methods of analysis were integrated over ten to thirty seconds of record. The present analyzer is designed to obtain the analysis within an interval of one-half second. Attention is focussed on the time sequence and frequency spectrum of brief runs of activity. It is felt' that this new method makes possible a more detailed study of both "steady state" and "transient" phenomena in the electroencephalo0ram. 2. T h e use of Bilateral N a s o p h a r y n g e a l , Tympanic, and Ear Leads in Recording the Basal Electroencephalogram, m ALEJANDRO ABELLANO and PAUL D. MACLEAN, Boston. A practicable method for registering electrical activity across a limited area at the base of the
brain, involving the use of two nasopharyngeal leads, two tympanic leads, and two leads placed on the ears, is described. This allows a succession of five linkages across the base of the brain, between the two ears. Activity at appropriate scalp leads can be simultaneously compared with that at the base. (A detailed description of the special type of nasopharyngeal and tympanic leads employed in this technique has been reported in this Journal (1949, I, 110113). Forty-three recordings have been made. Excerpts of records including tracings from patients without demonstrable brain disease, patients with temporal lobe tumor, and patients with epilepsy, are shown to illustrate the basal electrogram seen in various conditions. The basal electrogram just prior to and following sleep is also demonstrated. Although this method was developed primarily for the study of the electroencephalogram of patients with so-called psychosomatic disease, there is evidence that it may also be useful in the localization of brain lesions or epileptogenic loci. Two patients, for example, with symptoms of "psychomotor" epilepsy were put to sleep and examined by this technique. In each instance there occurred repeatedly a spike complex, which appeared to arise from the inferior portion of the right temporal lobe in one case, and from the inferior portion of the left temporal lobe in the other. The focal activity in both these patients was