Encephalosyncope or larval epilepsy; a follow-up

ENCEPHALOSYNCOPE

OR LARVAL EPILEPSY, A FOLLOW-UP'

JOaN KEaSHMAN, M . D

a n d R. C. A HUNTER, M . D

Department o[ Neurology and Neuro~urgery, McGdl University, Montreal Neurologzcai In~tltute and Q u e e n Mary Vettran~ Hospital, Montreal

INTRODUCTION In two previous reports ( K e r s h m a n 19qga 19q9b) a series of 180 patients were described w h o had infrequent spells usually associated with special stress of some kind T h e s e spells consisted of sudden episodes of dizziness, blurred vision sudden loss of consciousness and more rarely, a convulsmn Characteristically, all these patients had an abnormal electroencephalogram in the resting state between spells, or abnormalities could be easily precipitated by simple agents such as hyperv e n t d a t m n or small amounts of alcohol H a l f the pattents showed m their E E G a continual diffuse d y s r h y t h m m (table I) and nearly all the others had paroxysmal, bilaterally synchronous disorders

instances it was felt that an attempt should be made to avoid the use of the word 'epilepsy" altogether and the term encephalos y n c o p e " was coined to describe the qroup T h e original study of these patients qho,~ed some correlation between the nature of the EEG abnormality and the type of clinical spells that occurred T h i s is illustrated m table II which shows that patients with dlffuqe d y s r h y t h m i a were more likely to have simple spells of loss of consciousness (or syncope) while those with 3/sec spike and slow wa~e abnormalities usually had a history of a convulston (It should be emphasized that patmnts with a history of more than three convulsions were arbitrarily relected from this study and considered clinically to be epdep-

TABLE I EEG ABNORMALITIES IN PATIENTS WITH LARVAL EPILEPSY (ENCEPHALOSYNCOPE) Type of EEG Abnormahty

No

qo

Diffuse dysrhythmm Bdaterally synchronous disturbances : 3/sec wave ~ sp~ke, and variants 6/sec rhythms and varmnts Focal abnormahtle,

91 83

51 46 23 23 3

'~1 42 6

Total Because of the m f r e q u e n c y and character of the spells it was felt that the clinical diagnosis of epilepsy was unlustlhed and the term larval or subchmcal epilepsy was used indicating a close relattonship to w h a t G o w e r s (1907) described as " T h e Borderland oi E p i l e p s y " For various reasons, in m a n y i T h i s w o r k w a s carr,ed out under the ausp,ces of

the Institute of Aviation Medicine, Royal Canadian Atr Force, Department of National Defence, correlated through the Defence Research Board

180

100

t i c ) Patients m whom paroxysmal 6 sec w a v e s were the predom,nant E E G a b n o r m a h ty were about equally divided between those h a v m q syncopal and convulsive spells F o r purposes o1 th,s study patients m whom a convulsion had occurred were grouped together though m a n y m a y have also had simple spells of loss of consciousness A history of nervousness, dizziness blurred vision and frank anxiety was fairly common m patients with spells of simple loss of 169 ]

170

JOHN KERSHMAN

and R C A H L I N T E R

consciousness O f t e n the latter was preceded by a brief aura of dizziness, weakness, bdlousness or blurred wsmn. Complaints hke these auras occurring suddenly and without .loss of consciousness were also seen in patients who had an abnormal E E G T h e y constitute the group of "eplso&c disturbances" and most of them (14 out of 22) had a diffuse dysrhythmla (table II)

in 1945 H e was referred because of a convulsmn which had occurred the mornlnq after a night of rather heavy drmkm,q T h e r e was a history of two other convulsions each following many hours after the consumption of large amounts of alcohol T h e r e was also a history of two relatively minor head mlunes preceding the first convulsmn by about three and nine years respectively

TABLE II RELATION BETWEEN EEG ABNORMALITIES AND KIND OF SPELLS

Ep,sod~c Diffuse dysrhythmta (91 patients) Bdaterally synchronous 3/sec spike ~ slow w a v e and variants (41 pahents) 6 / s e c and variants (~t2 patients)

FOLLOW-UP It ~s now 4-6 years since these patients were seen originally and the following report deals with their interval h~story and present condition T h r o u g h questionnaires, it has been possible to trace 111 of the 180 pahents or 62 per cent T h e proportion of replies was about equal in the three chmcal groups (table Ill) m&catmg that an accurate cross section of the patients was followed

Syncope No --% 60 ~ 66

11 - - 27 15 ~ 36

Convulston Ehsturbances No --% No --% 17 ~ 19 14 - - 15

29 ~ 71 20 ~ 48

1 ~

2

7 ~

16

His mmal E E G in 1945 showed (fl 0 1) typical paroxysmal bursts of 3/sec spikes and waves, increasing m amount during hyperventdatlon T h e latest record in 19"t9 showed the same abnormahty During the follow-up interval, he has been attending agricultural college and was getting along satisfactorily. H e was not taking any medication but during the four years, three or four spells of loss of conscmusness without convulsive movements had occurred, each

TABLE III REPLIES RECEIVED

Ortg,nal Group Rephed At least one convulsion Syncopal spells Episodic disturbances Total

In a smaller number of pahents, ~t was possible to repeat the eleetroencephalo0rams In every instance, the follow-up E E G was essentially the same as the prewous record T w o examples wdl dlustrate the chmcal characteristics and the E E G patterns. T h e hrst patient, W . W . P . , was a 22 year old heutenant in the army when first seen

%

66 92 22

40 56 15

61 61

180

l 1t

62

68

ttme following the consumption of alcohol T h e second pataent, A K D , was a 22 yr. old Air Force navigator who was originally referred m 1944 because of fainting spells comm o on when he was under stress during flying or when he was very tired N o convulslve movements had ever been witnessed. T h e spells began while he was on operational

ENCEPHALOSYNCOPE

d u t y overseas a n d during a period of extremely dantierous flymti. Physical examination, mcludmti blood pressure tests with postural chanties w a s normal. Carotid sinus st~mulation a n d tilucose tolerance tests were also normal. 1945

#

I

F

-

R

Pt W W P

F

.

.

F

'

L

F

~

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: I00~ Ilkll F~g 1 Pabent W W P See text for history LF-LE m the record from the left frontal regmn to the left ear lobe. RF-RE m the record from the right frontal regton to the right ear lobe The hrst 2 hnes were recorded m 1945, the lower 2 hnes m 1949 His E E G m 1944 (hti. 2) showed a d J f u s e d y s r h y t h m i a . T h e normal backtiround alpha w a s virtually absent, a fmdmti characteristic of this tiroup a n d it w a s replaced b y lrretiular slow a n d occasional sharp waves. Pstressmhydration produced an increase m the voltatie of the lrretiular slow w a v e s In 1949, his E E G showed a v e r y similar dlsortian|zation and 1944 ,.O-L"~

'

,

-

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~

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+

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Pt Ag D e

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,'~+'~++~`~`~+~+

Hyd

-

R f ,,, i $oli +

Social Adjustment.

TABLE IV 111 PATIENTS W I T H LARVAL EPILEPSY OR ENCEPHALOSYNCOPE Employed Unemployed Sattsfactonly adjusted to ctvdtan hfe Recetvmg a penmon No spells of any kind

% 92 8 71 19 20

No Further Symptoms. T w e n t y per cent of the 111 patients w h o rephed have had no spells of a n y kind durra0 the 4-6 y e a r interval a n d none of these were on medlcatson (table V ) O f those w h o ontimally had either a convulsion or rumple loss of consciousness, 20 and 23 per cent respecttvely have been free, but of those w h o ontimally had episodic disturbances without loss of consciousness, only 10 per cent have remained free while 90 per cent have had mmdar or more ser;ous episodes since TABLE V 22 PATIENTS FREE OF ANY SPELLS (20%) NONE ON MEDICATION %

1949 I.O--LE R O

diffuse d y s r h y t h m i a . Durmti the 5-year penod, no spells of a n y land had occurred and he was not on medlcatlon H e has been w o r k lnti as a section supervisor, taking orders and keepmti stock m a lartie store

T h e social adjustment of this tiroup of patients as a whole, is an interesting measure of their relauve detiree of sickness T a b l e I V shows that 92 per cent are gainfully employed E n c e p h a l o s y n c o p e or larval epilepsy Is a minor dlsabdity since this httih proportion earmnti a hvmti must be m sharp contrast to the e m p l o y m e n t statistics of patients with chmcal epdepsy.

1949

I

171

~ looln, I

Prevlous history of a convulsion

20 free

Previous htstory of syncopal spells Previous hmtory of eptsodtc disturbances

23 free I0 free

Fig. 2

Pauent A K D See text for history LO-LE ~s the record from the left occ~pttal regmn to the left ear lobe. RO-RE Is the right homologous regmn Hyd m the record from the same areas during the hydration-p~tressm regtme The first 4 hnes were recorded m 1944, the lower 2 hnes m 1949

T h e E E G of these s y m p t o m - f r e e patients is mterestmti M o s t of them (table V I ) had a ddfuse- d y s r h y t h m l a (64 per cent) and nearly all the others had 6 / s e c a b n o r m a h u e s or variants O n l y one patient with 3/sec.

172

JOHN KERSHMAN and R C A HUNTER

w a v e a n d s D k e & s c h a r q e s (or 't per c e n t ) has r e m a i n e d free of spells It m a y be c o n c l u d e d t h e r e f o r e t h a t the 3 , s e c v.ave a n d spike a b n o r m a h t y is m u c h m o r e likely to l e a d to c h m c a l smzures t h a n a n y of the o t h e r t y p e s O n the o t h e r h a n d , u n d e r f a v o r a b l e c o n d m o n s p a t m n t s with d i f f u s e d y s r h y t h m l a a r e least likely to h a v e c h m c a l spells TABLE VI 22 PATIENTS FREE OF ANY SPELLS (200/0I NONE ON MEDICATION Tqpe o[ EEG Abnormahty INo °/o Diffuse dysrh~thm,a 14 64 Bilateral s'ynchron~ 3/see ,xa,,e & ~ptke & variants I 4 6/s(c rh3,thms and vdrmnts 6 28 Focal abnormaht,, 1 4

Connnumg Symptoms. O f the 111 p a t m n t s w h o w e r e t r a c e d , t h e r e ~xere 89 w h o c o n t i n u e d to h a v e s y m p t o m s The commonest complaints (table VII) were spells of & z z m e s s , " b l a c k o u t s " a n d b l u r r m ~ of ,,~s~on A t least one c o n v u l s m n or s~mple loss of c o n s c m u s n e s s h a d o c c u r r e d in a b o u t a third of the p a t m n t s TABLE VII CLINICAL SYMPTOMS IN 111 PATIENTS Spells of dizziness Blackouts Spells of blurrmos of vmlon Loss of consciousness w~thout convulsmn At least one convulsmn Headache Nervousness No pensmn'

% 40 a~1 37 34 31 7 6

It w a s of i n t e r e s t to c o m p a r e the p r e s e n t c o m p l a i n t s w i t h t h e t y p e of spells t h a t h a d o r i g i n a l l y o c c u r r e d w h e n the p a n e n t first came under observatmn (table VIII) Forty p e r cent of t h o s e w h o orLqmally h a d a c o n v u l s m n h a v e h a d a t l e a s t one s e i z u r e since a n d a few i n d i c a t e d t h a t m a n y a t t a c k s h a d o c c u r r e d F i f t e e n o u t of this g r o u p or 40 p e r cent w e r e on m e d l c a t m n O u t of t h e total 9 r o u p of 111 p a t m n t s , 15 or 13 p e r c e n t w e r e patients w h o h a d convulsmns often e n o u g h

to t a k e m e d i c a t i o n c o n t i n u a l l y C h q , c a l l v these could l u s n f i a b l y be classffmd n o w as h a v m q e p d e p s y ' O n the o t h e r h a n d of the p a t m n t s w h o orLcjmally h a d a c o n v u l s , o n 60 p e r cent h a x e h a d n o n e since but onE, m i n o r s v m p t o m q ot n o n e at all IABLE VIII COMMONEST SYMPTOMS IN RELATION FO THE PREVIOUS SPELLS I i

(

rlt~r)tl rill

%14ml~lO tl

S~,ncopal spells Blackouts iSpells of d~zzmes,, Spells of blurred vision

ORIGIN 4 L ' I 4SqlklC/tllO~,

i ( on~ u l ,,on 40 ](*attttzt~

~tcn~ o p t 56 l, l t t t n t ~

] ¢ ~sodt ,hsturb )r~{, s 15 r ltt(nt~

o °

o

o °

40 30 40 40

27 3~, 45 50

27 3; 33

50

41

40 33

In the 9 r o u p w h o o r i g i n a l l y h a d onl'~ ~yncopal spells or e p i s o d e s wqthout loss of c o n s c i o u s n e s s 27 per cent h a z e since h a d at least one c o n ~ u l s m n O t h e r c o m p l a i n t s such as e p i s o d e s of b l u r r i n g of vlsmn dzzzmess etc w e r e n o t e d with a b o u t the s a m e f r e q u e n c y in all the g r o u p s no m a t t e r w h a t the orlclmal s y m p toms w e r e Thas h o m o q e n m t y m & c a t e s t h a t t h e r e is some l u s n f i c a t l o n for m c l u d m q all these p a t m n t s m a s m q l e c h m c a l s y n d r o m e T h e r e w e r e 18 p a t m n t s m w h o m the first c o n v u l s m n o c c u r r e d o n l y d u r m q the followup p e r i o d M o s t of them ( t a b l e I X ) h a d diffuse d y s r h y t h m m m thmr LEGs TABLE IX EEG ABNORMALITY IN 18 PATIENTS W I T H SYNCOPE W H O HAVE SINCE HAD A CONVULSION No

Diffuse dysrhythmm Bdaterally synchronous abnormahty Focal abnormahty

15 2 I

o 0

83 11 6

A r e - e v a l u a t i o n of all the p a t i e n t s w i t h & f f u s e d y s r h y t h m l a s h o w e d t h a t since 1943

ENCEPHALOSYNCOPE when these observations began up to the present time, about 50 per cent have had at least one convulsmn In most instances, the attack was clearly related to definite physical or emotional strain or alcohol the seizure occurring only after some obvlosulv exceptional stimulus

T h e r e were 22 patients who originally had only episodes of dlzzlnes, blurred vision and blhousness without loss of consciousness F J t e e n of them have been traced and only 2 have remained free of s y m p t o m s (table X ) Four have had at least one convulsion and 6 have had spells of simple loss of conscioushess

TABLE X FOLLOW-UP OF 22 PATIENTS WITH EPISODIC DISTURBANCES No Rephes received Free of spells of any kind Has had at least one convulsmn Has had syncopal spells or blackouts Blurring of wslon dizziness, bdmusness

15 2 4 6 3

It m a y be concluded therefore that patients with such episodic disturbances as dizziness, etc and an abnormal E E G will subsequently have more severe spells and in about onethird of them a convulsion will eventually occur

DISCUSSION

T h e patients originally grouped together under the diagnosis of "larval epilepsy" or " e n c e p h a l o s y n c o p e " , after a period of q-6 years observation continue to form a relatively homogeneous chmcal entity N i n e t y - t w o per cent are gainfully employed and b y far the greatest proportion who were m the armed serwces when their first s y m p toms occurred have made a satisfactory adlustment to elvihan life This has occurred despite the fact that 80 per cent have contmued to have s~mdar spells T h e &sabdlty ~s therefore not a serious one and does not greatly interfere with ordinary cwdmn actlvines It follows therefore that such people should be employable In the armed servlces

173

m non-comba:,ve lobs H o w e v e r . the followup shows that 19 per cent of the group are now recelvlnq a pension Since their disability is shqht and should have little effect on their life expectancy the eventual total cost to the country will be qmte considerable N o n e of the patients in this qroup had received a head lnlury associated with their war activities T h e E E G abnormality they showed was m nearly every instance, the type wh,ch could not be ascribed to a n y particular etiological factor and probably antedated their enhstment Admittedly, it is much too time-consuming and would require much too large a staff to w a r r a n t taking an E E G record on every enlisted member of the armed services Such a procedure might be possible in future if a rapid economical technique is developed It should be recognized however that there ~s a group of these patients and they get along quite well despite s y m p toms m ClVlhan life. especially ~f they take simple precautions against h e a v y drinking and other matters of elementary hygiene O n the other hand. 13 per cent of all the patients have had more than 3 seizures smce they were first seen and lustily the dlaqnosls of clinical epdepsy T h e i r disease has developed very slowly and lnsldlously T h e employment of these people m occupations which are stress-producing leads to an increase in the frequency and s e v e n t y of their spells T h e occurrence of such spells not only ~s dangerous to the individual but very greatly increases the dangers to those who must rely on him, depend on his ludgment in a critical situation or w o r k with him m any hazardous occupation In view of these findings. it would be worthwhile to screen by electroencephalography those w h o might be in a position to be a source of danger to themselves, particularly in such occupatmns as mrcraft and tank operations T h e examination should include simple methods of stimulation such as hyperventllatmn, Metrazol in slow, divided doses and photlc stlmulatmn Sensitivity to a n y of these tests is an important prognostic sign

174

JOHN KERSHMAN and R C A HHNTER

T h e statistics shown here indicate that of the patients with 3 per sec spike and wave abnormality, only 4 per cent have remained free of symptoms. T h e occurrence of such an abnormahty in the E E G ~s the most strongly indicative of future spells Less portentous is the occurrence of 6/sec rhythms and its varmnts but here also only 28 per cent have remained free of symptoms over the 4-6 years of observation T h e least ominous is the diffuse dysrhythmla lap to the present time, about 50 per cent have had one convulsion though many more have had minor symptoms but it is in thin group w~th diffuse dysrhythmia that the greatest number of patients are found who have remained free of symptoms T h e prognosm in thin group is therefore best O f all those who originally had a convulsion, 60 per cent have had none since over a period of 4-6 years W h e n it has occurred, there has nearly always been a hmtory of severe unusual mental, emotional or physical stress, or alcohol has been an obvious prec~pitatmg factor. T h e s e facts would tend to lustily withholding the clinical diagnosis of epilepsy from most of them and continuing to use some term such as "larval or subchmcal epilepsy" or "encephalosyncope" It has been repeatedly emphasized that physical and mental strain as well as alcohol may precipitate symptoms m these patients M a n y of them in fact were originally referred for consultation with the diagnosis of hystema, neurosm, etc Yet ~t is obvious from the E E G that m their disability, there is a definite component of cerebral dysfunction Excessive strain may either precipitate a dormant paroxysmal disorder such as the 3 per sec. spike and wave discharges or it may accentuate a diffuse dysrhythmia to the point where clinical manifestations become apparent in the form of convulsmns, syncope, dizziness, etc. In a recent report, Gastaut (1949) showed that patients with Idiopathic epilepsy have a definite hypersensitivity to photic stimulation and Metrazol, with the production in their E E G s of high voltage spike and slow wave discharges Cumously, he

found that the same sensmwty was present m patients with obvious conversion hysteria (without chnlcal epilepsy) and a simdar type of paroxysmal E E G abnormality could be precipitated These observations, if confirmed, indicate that there may be a similar cerebral dysfunction underlying idiopathic epdepsy (of which latent epilepsy is a very mdd variety) and certain forms of psychological dmorder, and the same stimulus can be used to d~sclose both conditions T h e r e is an interesting analogy m the temporal lobe where epileptic discharge may produce episodic dream states, automatmms and slmllar disturbances in thought and behavlour as well as convulsions T h e cerebral disorder m latent epilepsy is m an area where certain stimuli can cause a sudden loss of consciousness with or w~thout a convulsion but under other conditions (of subhmmal stimulation for example) or from a closely related neuronal group, there might be more complex disturbances of the total reactionpattern or " p e r s o n a h t y " of the mdlvldual, sometimes accompamed by autonomic d~sturbances like those seen in the patients described here Further studies along these lines are bern 9 planned W i t h regard to the s~te of the disturbances in latent epilepsy, previous d~scussmn (Kershman 19"t9a) indicated that existing evidence favors a subcortlcal and diencephahc localization It seems that there are at least three separate types of E E G abnormality originating m the upper brain stem (a) T h r e e per sec paroxysmal spike and slow wave discharges, which Penfleld and Jasper (1947) recently associated with "highest level seizures", (b) Bilaterally synchronous 6 per sec discharges, and (c) Diffuse dysrhythmlas In the first type, the attack causes sudden loss of consciousnes without warning and ~s usually accompanied by a generahzed convulslon. In the type with diffuse dysrhythmia, the attack ~s usually preceded by autonomic symptoms such as dizziness, blurred vision. feehngs of anxiety and there may be loss of

ENCEPHALOSYNCOPE

175

3 20 per cent have remained free of symptoms without medication 4 80 per cent have had spells of some kind 5 13 per cent have had more than 3 convulslons and would lustily the chmcal dmgnosls of epdepsy 6 Aside from this 13 per cent, the others continue to form a homofleneous group and justify the distinctive &aflnoms of "larval epilepsy" or "encephalosyncope" Their commonest symptoms are dizziness. "blackouts" and spells of blurred vision 7 Of those who on, real l y had a convulsion, 60 per cent have had none since W h e n a convulsion has occurred, there has nearly always been a history of severe unusual mental, emotional or physical strata; or alcohol has been an obvious precipitating factor 8 Only 4 per cent of those who showed bilaterally synchronous 3/sec spike and wave patterns have not had a convulsion. 9 About 50 per cent of those who showed a dJfuse dysrhythmla have not yet had a convulsion, thouoh many have had other symptoms, such as sudden loss of consciousness. sudden dizziness, blurred vision, etc. 10 T he proflnosis of those w~th 6/sec. rhythms and variants Is between these two extremes and there were only 28 per cent who did not report a convulsion as yet. 11 Under clwhan condmons, the proonosis Is quite flood and only a few of these persons are disabled by their illness, If they take s,mple precautions. 12 Under stress-producm.q condmons. spells are much more likely to occur, with obwous danfler to the patients and those around them 13 Any person who has suflfleshve symptoms should have an E E G done especmlly SUMMARY AND CONCLUSIONS if he is placed m a posmon of responslbdity 1 One hundred and eleven of a group and stress If the E E G ~s abnormal, including of 180 patients who had "larval epilepsy" or hypersensit~vity to hyperventdatlon, Metra"encephalosyncope" have been followed for zol or photic stimulatmn, he should be ehmia period of 4-6 years. nated from aircrew, tank operations or similar hazardous occupations 2 92 per cent are ~lamfully employed

consciousness often without convulsive movements Th e attack m the six per second type of abnormahty may be of either kind. This suflflests that a different but closely related set of neurones Is activated by each type of disturbance and each of them quickly fires a common area or pathway producmq loss of consciousness It should be borne In mind that numerous observers have reported the occurrence of E E G abnormalities m normal adult control groups Th e most comprehensive survey Is that of Gibbs, Gibbs and Lennox (19't3) who showed that m 1000 adult control subjects, 0 9 per cent had paroxysmal disorders, 1 1 per cent had very abnormal records and 13 8 per cent had sliqhtlv abnormal E E G s It would be difficult to prove but it is temptmg to suflflest that this group of normal persons with an abnormal E E G are .mmdar to the patients reported here. who under certain exceptional circumstances m~qht develop spells. It has been stud that every person Is a potential epileptic if sufficiently provoked In the larger sense, this is true, e g. the administration of msuhn or Metrazol may produce an attack m otherwise normal people Yet, althouoh the exact relation between the abnormal E E G and the occurrence of a chmcal seizure Is not known, the existence of paroxysmal E E G abnormality is certainly very closely associated w~th the climcal occurrence of seizures Indeed m some laboratories (Jasper and Kershman 1944) usmfl adequate and complete methods of examination, at least 90 per cent of all patients with clinical seizures show abnormahty m their E E G records T h e existence of paroxysmal abnormalmes m the E E G is therefore fmrly stron 9 presumphve ewdence that under certain circumstances, a seizure is likely to occur

1 76

JOHN K F R S H M A N

14 T h e r e Is c o n s i d e r a b l e p r e s u m p t t ~ e e v > d e n c e t h a t t h e & s o r d e r ~s s u b c o r n c a l a n d that there are three types of EEG &sturbances which onqmate m the upper brain s t e m E a c h of t h e m a c n v a t e s a s e p a r a t e b u t
K~',HMaI,~ ] S'~m.op~ and seizures ] ~[~t~r,,I %e~lr~ ~ur~ P,q~hol 1949a 12 25 33 kI R'~t~,~ J The Borderland of Eptlep~ , re consideration Arch Neurot PStlch¢at Ch~caqo 1949b o~ :'51 559

md R C A HUN'I DR t , o w l u s R \% Borderland of epilepsy faints vaoal attacks v e m q o m~0rame sleep symptoms and thmr treatment London ] ~ A Churchill ll~i' C,~TAUT H The effect of photlc stimulation m the EEG Paper dehvercd to the Montreal NeuroIoqlcal Socwt,~ December 21 1949 Pt',FtHD W and ]ASPIR H Highest level smzure~ Re~ Publ A,, mrl' merit Dis The Wflhams and W d k m s Co Baltimore 1947 26 252-27t ( , l u h F' A GIBB', E L and LENNOX W G Th~ el~-tro~ ncephalocnaphL~ cl ~ss~ficatlon of epllept~. patmnt~ and control ~ubjects Arch Neurol Psqchlat Chicago 1943 50 I l l 128 J~-t.r-, H H and IXERSHMAN J Proceedings 5th Mtetmq Assoc Gommlttee Med Re,. Repolt ~t6123 N R C Canada t944

Montreal Neurological Insntute Reprint No 338 Reference KI~R>HMAN J and HUNTER R C A Entxphalosvncope or larval eplleps'~ (';Ira Neuroph~tslo[ 19r~ 2 169-176

a follow-up

EEG