Sixty-five outpatients with photoparoxysmal response (PPR) during routine EEG were studied. The PPR showed prevalence in women (75.4%). Seizures were found in 66.1% of cases. The rest recordings were abnormal in 41.8% with prevalence of generalized paroxysm. Eight patterns of PPR were observed, being polyspike mixed to slow wave the most frequent (53%). The epileptic group showed a bimodal distribution in the several bands of photic stimulation, near 8 and 20-24 Hz. A sustained paroxysmal abnormality persisting after the photic stimulation was present in 6 epileptic patients.Foram estudados 65 pacientes de ambulatório que apresentaram resposta fotoparoxística (RF) no EEG intercrítico. Houve predomínio da RF no sexo feminino (75,4%) e 61,1% dos casos tinham história de crises epilépticas. Dos 8 padrões de RF observados, o padrão poliponta-onda lenta foi o mais freqüente (53%). Em relação às faixas de fotostimulação, o grupo epiléptico apresentou distribuição bimodal (8 e 20-24 Hz). Os autores discutem seus achados em relação aos descritos na literatura.Escola Paulista de Medicina Departamento de Neurologia e Neurocirurgia Setor de Investigação e Tratamento das Epilepsias e Setor de EletrencefalografiaUNIFESP, EPM, Depto. de Neurologia e Neurocirurgia Setor de Investigação e Tratamento das Epilepsias e Setor de EletrencefalografiaSciEL

Campos, Carlos J. Reis De

Guimarães, Rosana M.

Muszkat, Mauro

Silva, Ademir B. Da

Arquivos de Neuro-Psiquiatria

Muszkat, Mauro [UNIFESP]

Guimarães, Rosana M. [UNIFESP]

Silva, Ademir B. Da [UNIFESP]

Campos, Carlos J. Reis De [UNIFESP]

Repositório Institucional UNIFESP

PHOTOPAROXYSMAL RESPONSES MAURO MUSZKAT * — ROSANA M. GUIMARÃES * — ADEMIR B. DA SILVA * CARLOS J. REIS DE CAMPOS * S U M M A R Y — Six ty- f ive outpatients wi th photoparoxysmal response ( P P R ) during routine E E G were studied. T h e P P R showed prevalence in women (75.4%). Seizures were found in 66.1% of cases. The rest recordings w e r e abnormal in 41.8% wi th prevalence of gene-ralized paroxysm. E igh t patterns of P P R were observed, being polyspike mixed to s low wave the most frequent (53%) . The epileptic group showed a bimodal distribution in the several bands of photic stimulation, near 8 and 20-24 H z . A sustained paroxysmal abnormali ty persisting after the photic stimulation was present in 6 epileptic patients. Resposta iotoparoxística. Foram estudados 65 pacientes de ambulatório que apresentaram resposta fotoparoxística ( R F ) no E E G intercrítico. Houve predomínio da R F no sexo feminino (75,4%) e 61,1% dos casos tinham história de crises epilépticas. Dos 8 padrões de R F observados, o padrão poliponta-onda lenta foi o mais freqüente (53%) . E m relação às faixas de fotostimulação, o grupo epiléptico apresentou distribuição bimodal (8 e 20-24 H z ) . Os autores discutem seus achados em relação aos descritos na literatura. The relationship between epilepsy and visual stimulation has been reported since the end of last century. The first reference to photosensitive epilepsy was made by Gowers (1883), who described two patients presenting seizures when exposed to bright lights. There followed references by Radovicci ( 1 9 3 2 ) « Cobb (1947)2, Bickford et al. (1952)1. More recently the papers from Jeavons & Harding 10 and Gastaut et a U described the most important clinical and electroencephalographic aspects of the photosensitive epilepsy. T w o concepts encompass the relationship between light and epilepsy: ( 1 ) protosensitivity — abnormal response to the visual stimulation observed in laboratory, not necessarily associated to seizures; it probably represents a suscepti-bility pattern, genetically determined 9.20; the photosensitivity can be found in roughly 3% of patients who underwent a routine EEG recording H.15; ( 2 ) photosensitive epilepsy — it includes the cases of patients with seizures and photosensitivity. According to Jeavons 9 and Jeavons & Harding 10 the photosensitive epilepsy can be distinguished in two forms; a. pure photosensitive epilepsy — it is a relative common form of reflex epilepsy, where the seizures are triggered only by visual stimulation of the retina 3; its most common type is the so-called «television epilepsy» 6,18; b. epilepsy with photosensitivity — it includes the cases of patients with seizures not related to light stimulation, but with photosensitivity in electroencephalographic studies 9.20. The diagnosis of photosensitivity is made by the presence of «photopa-roxysmal response» ( P P R ) in intermittent photic stimulation on the E E G recordings. The P P R consists of generalized discharge recorded in all regions of the scalp during intermittent photic stimulation. Usually, it consists of spike and wave and polyspike and wave complexes. The localized response in anterior (photomyoclonic response) and posterior regions (photic driving) are considered «physiological» and are excluded * Setor de Invest igação e Tratamento das Epilepsias e Setor de Eletrencefalografia, Departamento de Neuro log ia e Neurocirurgia, Escola Paul is ta de Medicina. This paper was supported in part by grants from C N P q . Dr. Carlos J. Reis de Campos — Disciplina de Neurologia, Escola Paulista de Medicina -Rua Botucatu 740 - 04023 São Paulo SP - Brasil. from the concept of P P R 12,19. The photosensitivity is genetically determined, fre­quently related to familiar trait, with clear prevalence in women 6,10,15. Doose et a l . 3 and Doose & Gerken* reported that the P P R can be linked to susceptibility to develop «centrencephalic seizures». Oastaut et al . 6 considered that the P P R is frequently limited to patients with «subcortical primary epilepsy», observing this response patterns, in 40% of «petit mal» cases and 20% of «grand mal» cases. Wilkins et al.20.21 found P P R frequently associated to «generalized primary epilepsy». Although uncommon, the P P R can be found in patients without epilepsy, in cases of migraine, hysteria, anxiety, toxic and metabolic states 12,13,19. The purpose of this paper is to report the study on graphic-elements that compose the P P R , as well as analyzing them in epileptic and non-epileptic groups. M A T E R I A L A N D M E T H O D Sixty-f ive outpatients seen at the Neuro logy Department, Escola Paulista de Medicina, were selected when photic stimulation induced P P R during 1 routine E E G . A l l the patients had standard E E G recordings done using a 8-channel Grass Model E E G Machine. Electrodes were attached to the scalp according to the 10-20 system of the International Federat ion. Photic stimulation was applied to all the patients in the frequency of 6, 8, 16, 20, 24 H z in addition to mixed frequency. Clinical and E E G data were collected. The E E G data include: ( a ) background ac t iv i ty ; ( b ) resting paroxysmal changes; ( c ) morphologic analysis of P P R . R E S U L T S A . Clinical data: The P P R showed clear prevalence in women (75.4%). The average age was 13.5 ^ 11 year, ranging from 1 to 69 years. Seizures w e r e found in 66.1% of cases (n—-43) and the remaining 22 were distributed into the paroxysmal non-epileptic disturbance ( n = 1 0 ) including migraine, dizziness, syncope; and other disturbances ( n = 1 2 ) including stroke, behavioral disorders and metabolic states. The distribution of seizure type found in 43 patients is shown in table 1. I t can be easily seen a clear prevalence of the tonic-clonic type (62.8%). The pure photosensitive epilepsy was found in just one case, in which the seizures w e r e t r iggered when the patient was watching television. B. Elec t roencephalograph^ data: 1. Background act ivi ty —• In 54 cases the background activi ty was normal. In 11 cases it was not possible to record the background activity, because recordings w e r e carried-out during sleep. N o change was observed in background activity after intermittent photic stimulation (be fo re : 9.83±1.10 H z ; after: 9.56±1.60 H z ) . 2. Rest ing paroxysmal abnormali ty — The rest recordings were normal in 38 cases (58.2%). In 27 cases a prevalence of general ized paroxysm was observed, characterized by slow spike-wiave, spike and polyspikes complexes ( T a b l e 2 ) . 3. Morphologic analysis of P P R — Eight patterns of P P R were observed (in frequency o r d e r ) : (1) polyspike mixed to s low wave , 55.3%; (2) polyspike, 26.1%; (3) spike-wave complex, 20%; (4) spike, 20%; (5) spike and slow wave , 16%; (6) i rregular spike--wave, 12.3%; (7) polyspike-wave complex, 13.8%; (8) rhythmic s low-wave, 9%. In 50 cases (76.9%) association of patterns was observed. T h e most frequent association was the «1» with «2i> patterns ( n = 4 4 ) . T h e « 2 » pattern prevailed in 8 H z band of photic stimulation, whereas other patterns were more frequent in 16 to 24 H z . The « 2 » pattern showed in average 4 to 6 spikes for each complex. 4. Epileptic x non-epileptic group — A comparison between epileptic and non-epileptic group showed a closer homogenei ty in the several bands of photic stimulation in non-epileptic patients, whereas in epileptic group a bimodal near 8 and 20-24 H z was observed ( F i g . 1 ) . Both groups showed similar distribution in relation to E E G patterns, wi th prevai l ing of 1 pattern. Nevertheless, the polyspike-wave complex pattern was observed only in epileptic patients. A sustained paroxysmal abnormali ty persisting after the intermittent photic stimulation («af te r -d i scharge») was present in 6 cases (9 .2%) , all of them from epileptic group. C O M M E N T S The prevalence of P P R in women and the average age of patients found in our paper is similar to literature data, although their causes are still unknown 9-n. One factor probably related is the oscilating level of estrogen 9. Jeavons & H a r d i n g 1 0 reported cases where the P P R was associated to menstrual cycle phases. W e have found a larger frequency of P P R (33 .4%) in non-epileptic group than the reported in literature ( 3 % ) . W e ascribed this finding to our sample selection, where the EEG was performed in patients showing signs of central nervous system abnormalities, whereas in the literature the data are generally obtained from routine EEG recordings with a general population sample. Gastauts found P P R in 40% of patients with absence seizures and in 20% of patients with tonic clonic seizures, üoose & Jerkin 4 and Jeavons & Harding io found clear trend to photosensitive epilepsy in nomozygotic twins, and Newmark & Penryi5 reported familial history of epilepsy in 25 to 39% of protosensitive patients. Takahashi 19 points out the prevailing of P P R in generalized primary epilepsy. Few papers described the EEG aspects of P P R 12,13. Spike-wave and the polyspike-wave mixed with slow wave are the most common pattern found 15. Diffe­rences between epileptic and non-epileptic patients were not found in specialized lite-raturt', except in reference to EEG response duration. Reilly & Peters 17 considered that the prolonged after-discharge beyond the phetestlmulation period suggest epilepsy, since the authors found it in 90% of photosensitive epileptic patients. In our series, the after-discharge was found in only 6 epileptic cases ( 9 . 2 % ) . T h e polyspike^wave complex found only in epileptics can suggest that in photo­sensitive epileptic patients there is a prevalence of the excitatory component of the complex (the polyspike) over the inhibitory (s low w a v e ) . However, for its better comprehension such supposition demand further prospective study of neurophysiological nature. R E F E R E N C E S 1. Bickford R G , Sem-Jacobsen C W , W h i t e P T , Da ly D — Some observations on the mechanisms of photic and photo-metrazol activation. Electroenceph Clin Neurophysiol 4:275, 1952. 2. Cobb S — Phot ic dr iv ing as a cause of clinical seizures in epileptic patients. Arch Neurol Psych 58:70, 1947. 3. Doose H , Gerken H , Hien-Volpel K F , Volzke E — Genetics of photosensitive epilepsy. Neuropedia t 1:56, 1962. 4. Doose H , Gerken H — On the genetics of EEG-abnormali t ies in chi ldhood: I V . Pho to¬ convulsive reaction. Neuropediat 4:162, 1973. 5. Gastaut H , Broughton R — Crises epilépticas: f isiopatologia y clínica. In Gastaut H , Broughton R : Ataques Epilépticos. Toray , Barcelona, 1975. 6. Gastaut H , R e g i s H , Bosten F — Attacks provoked b y television and their mechanism. Epilepsia 3:438, 1962. 7. Gastaut H , Trevlsan C, Naquet R — Diagnost ic value of electroencephalographic abnormalit ies provoked by intermittent photic stimulation. Electroenceph Clin Neuro¬ physiol 10:194, 1978. S. Gowers W — D e l 'Epilepsie. Masson, Par is , 1883. 9. Jeavons P M — T h e use photic stimulation in clniical electroencephalography. P roc Electrophysiol Technol Ass 16:225, 1969. 10. Jeavons P M , Hard ing G F A — Photosensi t ive epi lepsy: a r ev iew of the l i terature and a study of 460 patients. Clin Dev Med 56:31, 1975. 11. Jeavons P M , H a r d i n g G F A — Photosensi t ive epi lepsy: part two . I n L a i d l a w J, Richens A ( e d s ) : A Tex tbook of Epilepsy. Churchil Liv ings tone , Edinburgh, 1982, p g 195. 12. K o o i K A , Tucker R P , Marshal R E — Fundamentals of Electroencephalography (Cap 6: Cerebral reactions to s t imulat ion) . Harper & R o w , N e w York , 1978. 13. K o o i K A , Tucker R P , Marshal R E — Fundamentals of Electroencephalography (Cap 8: Electrographic signs of cerebral d isorders) . Harper & R o w , N e w York , 1978. 14. Naquet R , Meldrum BS — Photogenic seizures in Baboon. I n Purpura D P , P e n r y J K , T o w e r D , W o o d b u r y D M , Wa l t e r R ( e d s ) : Exper imental Models of Epi lepsy: a Manual for the Labora tory W o r k e r . Raven Press, N e w York , 1972, pg 375. 15. N e w m a r k M , P e n r y K — Photosensi t ivi ty and Epi lepsy : a Rev iew. Raven Press, N e w York , 1979. 16. Radovicci A — Epilepsie ref lexe provoquée par excitations optiques des rayons solaires. R e v Neurol 1:305, 1932. 17. R e i l l y E, Pe ters J K — Relationship of some variet ies of electroencephalographic photosensit ivity to clinical convulsive disorders. N e u r o l o g y 23:1040, 1973. 18. Stephansson SB, Darby CE, W i l k i n s A J , Binnie CD, Mar l ton A P , Smith A T , Stockley A V — Telev is ion epilepsy and pattern sensit ivity. B r M e d J 2:88, 1977. 19. Takahashi T — Act ivat ion methods. In Niedermeier E, Silva F L ( e d s ) : Electroencepha­lography. Urban & Schwarzenberg, Bal t imore, 1982. 20. Wi lk ins A J , Darby CE, Binnie C D — Neurophysiological aspects of pattern-sensitive epilepsy. Brain 102:1, 1979. 21. Wi lk ins A J , Darby CE, Binnie CD, Stefansson SB, Jeavons P M , H a r d i n g G F A — Televis ion epi lepsy: the role of pattern. Electroenceph Clin Neurophysiol 47:163, 1979. 

Resposta fotoparoxística

Foram estudados 65 pacientes de ambulatório que apresentaram resposta fotoparoxística (RF) no EEG intercrítico. Houve predomínio da RF no sexo feminino (75,4%) e 61,1% dos casos tinham história de crises epilépticas. Dos 8 padrões de RF observados, o padrão poliponta-onda lenta foi o mais freqüente (53%). Em relação às faixas de fotostimulação, o grupo epiléptico apresentou distribuição bimodal (8 e 20-24 Hz). Os autores discutem seus achados em relação aos descritos na literatura.Sixty-five outpatients with photoparoxysmal response (PPR) during routine EEG were studied. The PPR showed prevalence in women (75.4%). Seizures were found in 66.1% of cases. The rest recordings were abnormal in 41.8% with prevalence of generalized paroxysm. Eight patterns of PPR were observed, being polyspike mixed to slow wave the most frequent (53%). The epileptic group showed a bimodal distribution in the several bands of photic stimulation, near 8 and 20-24 Hz. A sustained paroxysmal abnormality persisting after the photic stimulation was present in 6 epileptic patients.Escola Paulista de Medicina Departamento de Neurologia e Neurocirurgia Setor de Investigação e Tratamento das Epilepsias e Setor de EletrencefalografiaUNIFESP, EPM, Depto. de Neurologia e Neurocirurgia Setor de Investigação e Tratamento das Epilepsias e Setor de EletrencefalografiaSciEL

LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas

Sixty-five outpatients with photoparoxysmal response (PPR) during routine EEG were studied. The PPR showed prevalence in women (75.4%). Seizures were found in 66.1% of cases. The rest recordings were abnormal in 41.8% with prevalence of generalized paroxysm. Eight patterns of PPR were observed, being polyspike mixed to slow wave the most frequent (53%). The epileptic group showed a bimodal distribution in the several bands of photic stimulation, near 8 and 20-24 Hz. A sustained paroxysmal abnormality persisting after the photic stimulation was present in 6 epileptic patients

Mauro Muszkat

Rosana M. Guimarães

Ademir B. da Silva

Carlos J. Reis de Campos

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Photoparoxysmal responses

Sixty-five outpatients with photoparoxysmal response (PPR) during routine EEG were studied. The PPR showed prevalence in women (75.4%). Seizures were found in 66.1% of cases. The rest recordings were abnormal in 41.8% with prevalence of generalized paroxysm. Eight patterns of PPR were observed, being polyspike mixed to slow wave the most frequent (53%). The epileptic group showed a bimodal distribution in the several bands of photic stimulation, near 8 and 20-24 Hz. A sustained paroxysmal abnormality persisting after the photic stimulation was present in 6 epileptic patients.</jats:p

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http://dx.doi.org/10.1590/S0004-282X1990000300006

Resposta fotoparoxística

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LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas

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