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Epilepsy and photosensitivity
Sl12
Posher Session
the basal condition with eyes closed and during the performance of the three tasks. The slow and fast activities as well as the alpha reactivity remained immodified after starting treatment. Of all population, only three patients, presented seizures during VPA. Concerning the IEA. no significant changes were observed in patients without seizures during treatment, of the three having generalized attacks a significant increase was only noted in a single patient. These data demonstrated that VPA is a drug which seems to not modify the EEG background activity and not to alter the mental processes. In addition, although it reduced the seizures frequency, does not influence the level of IEA.
/ 47-05
A New Chronic Model of Spontaneous Generalized Epilepsy
Nonconvulsive
K. Ono. H. Baba, S. Sugai, % Matuzaka. Nagasaki University School of Medicine and Nagasaki Chuo National Hospital, Nagasaki, Japan y-butyrolactone (GBL) or y-Hydroxybutyrate. naturally occurring metabolites of y-aminobutyric acid in mammalian brain, can induce nonconvulsive generalized seizures which are analogous to the human absence with respect to the eiectroencephalographic and behavioral features as well as the pharmacological characteristics. While working on the GBL model in Wistar rats, we found that repeated exposure to GBL resulted in spontaneous nonconvulsive generalized seizures which were selectively suppressed by ethosuximide. Once the spontaneous absence-like seizure was developed, it persisted consistently throughout a follow-up period of 6 months, Because vehicle treated siblings never developed such seizure activities, newly developed spontaneous seizures were specific to GBL treatment and could not be attributable to genetically determined predisposition. Rather, it seems that daily injections of GBL produced long-lasting functional and structural changes responsible for the absence-like seizure by analogy with the kindling phenomenon as a model of partial onset seizure, More interestingly, callosal section significantly interfered not only with bisynchronization of seizure discharges, but also with occurrence of spontaneous seizures in accord with clinical outcome of the corpus callosotomy in human generalized epilepsies. This further suggests that the cerebral cortex might principally be involved in development of generalized seizures, and the callosally projecting cortico-cortical system could play a crucial role in concurrent recruiting cortical neurons in both hemispheres.
47-06 Epileptic Seizures Occurrence in Subjects Previously Affected by Disorders of Arousal Raoul Di Perri, Rosa lia Silvestri, Clinica Neurologica 98013 Contesse-Messina, Italy
I, Policlinico
Universitario,
Despite the fact that disorders of arousal (sleep-walking, night-terrors, confusional arousals) are commonly encountered among benign childhood transient events depending on the sleep architecture’s maturation process, we’ve collected evidence of several children or young adults who have previously suffered from clearcut classic disorders of arousal and lately developed predominantly nocturnal epileptic seizures. When the ictal events were clinically evident as complex partial seizures at times the differential diagnosis of the new episode, was difficult and not at all unambiguous. Anyway the abnormal distribution during night thirds or the late appearance of unclear disorders of arousal should always orient towards a possible ictal event. Extensive nocturnal sleep EEG and videopolygraphic recordings are mandatory and undoubtfully meaningful in such conditions as exemplified by a series of clinical-electroencephalographic documentations collected in several years.
47-07
Epilepsy and Photosensitivity
D. Pinto, J.A. Ribeiro, G. Sousa, M.J. Teixeira, C. Marinho. I. Pires, J. Dinis. M.L. Guimaraes. Neorophysiology Department S. Jolo Hospitai, Porte. Portugal The occurrence of photosensitivity was examined in 399 epileptic patients, >5 years of age, referred to our EEG Department during the period March 91-March 92. A non-epileptic group (288 patients -mean age = 28.8 years, age range = 5-81 years, sex ratio M/F = 0.6) was studied by using EEG methods applied to the epileptic patients.
intermittent Photic Stimulation (IPS) was performed with closed eyes, using a stroboscope, which produces flashes of growing - 0 to 60 Hz and then decreasing - 60 to 0 Hz frequencies, the trains of flashes of constant frequency were delivered for 5 seconds and the intervals between the successive trains lasted 5 seconds, The epileptic patients (mean age = 26.8 years, age range = 5-77 years, sex ratio: M/F = 1.1) were classified according to the type of epilepsy:-Generald epilepsy = 100 (mean age = 26.4 years, age range = 6-71 years: sex ratio = 0.8); Partia/epilepsy = 273 (mean age = 23.9 years, age range = 5-77 years, sex ratio = 1.2).Non-classified epilepsy = 27 (mean age = 30 years, age range = 5-59 years, sex ratio = 1.5). The EEG with IPS led us to a group of 16 patients (all epileptic patients), showing a photoparoxysmal response - a self-limited paroxysmal response (SPR) in 7 patients and a classical paroxysmal response (CPR) in 9 patients), which was analysed according to parameters such as: mean age, age range, sax ratio, type of epilepsy and medication, Our study reveals a Portuguese incidence of photosensitivity around 2.6% below the expected value-about 5% -for the general epileptic population, anyhow understandable in view of the geographic location of our country, Portugal (South Europe).
CPRgroup SPR group
147-08
Patients number
Age range (mean age) years
Sex ratio hl/F
Type of epilepsy gen.:part.
9 7
9-38 (20.11 9-71 (29.9)
z/7
8.1 4:J
l/6
1 Vascular Epilepsy: EEG and Neuroradiological Findings
M.L. Vaccario, A. Rossi, G. Di Lella, S. Mazza, PA. Tonali. Catholic UniversiQ Roma Acute cerebrovascuiar disease is the most frequent cause of epilepsy in the elderly as reported byseveral authors (Lesser et al., 1985; Daniele et al., 1989). We evaluated 290 patients affected by stroke, hospitalized in our Neurological Department between 1988-l 991, In order to point out some possible risk factors of developing seizures, we considered clinical, EEG and neuroradiological findings of all patients in acute phase. We can summarize our most important results as follows: - 62 patients (21%) had one or more seizures; - EEG with focal paroxysmal abnormalities was four times more frequent in patients with seizures (32% versus 1% in patients without seizures) - Cortical lesions (especially parietal) on CT scan were more common in patients with seizures (88%) in comparison with patients without seizures (47%). Therefore, on the basis of our data, we may hypothesize that the patients with paroxysmal EEG abnormalities and cortical CT lesions in acute insult phase, have a higher risk for the occurrence of seizures.
47-09
Epilepsy: Simultaneous Positive and Negative Statistical Long Latency EP Abnormalities
G. Vatti. E Donati, F.H. Duffy. Children’s Hospital, Boston Statistical analysis and topographic display of scalp derived data facilitate new insight into brain pathophysiology. We studied the visual (VER) and auditory (AER) long latency evoked responses of 1354 subjects referred to our quantified EEG laboratory from 1987 to 1993. We noticed, as an atypical finding, the presence of significantly abnormal positivity and negativity in different regions of the head over the same post stimulus post latency epoch and persisting 20 msec or longer. We observed these simultaneous “dipolar abnormalities” on the significance probability mapping (SPM) of 203 subjects. 151 (74.38%) suffered from epilepsy while the remaining 52 (25.62%) presented with other etiologies (depression, head trauma, developmental delay, schizophrenia, and others). 102 demonstrated dipolar abnormalities on VER, 66 on AER. and 35 on both modalities. Epilepsy accounted for65.68% of VER dipoles and for 78.78% of AER dipoles. Interestingly, 91.42% of patients showing dipole abnormalities on both VER and AER were epileptic. When differentiated from time locked alpha and when an age matched database is employed, the finding of SPM positive and negative abnormalities (>2 SD) during long latency EP may prove helpful in establishing the diagnosis of epilepsy.
Posher Session
the basal condition with eyes closed and during the performance of the three tasks. The slow and fast activities as well as the alpha reactivity remained immodified after starting treatment. Of all population, only three patients, presented seizures during VPA. Concerning the IEA. no significant changes were observed in patients without seizures during treatment, of the three having generalized attacks a significant increase was only noted in a single patient. These data demonstrated that VPA is a drug which seems to not modify the EEG background activity and not to alter the mental processes. In addition, although it reduced the seizures frequency, does not influence the level of IEA.
/ 47-05
A New Chronic Model of Spontaneous Generalized Epilepsy
Nonconvulsive
K. Ono. H. Baba, S. Sugai, % Matuzaka. Nagasaki University School of Medicine and Nagasaki Chuo National Hospital, Nagasaki, Japan y-butyrolactone (GBL) or y-Hydroxybutyrate. naturally occurring metabolites of y-aminobutyric acid in mammalian brain, can induce nonconvulsive generalized seizures which are analogous to the human absence with respect to the eiectroencephalographic and behavioral features as well as the pharmacological characteristics. While working on the GBL model in Wistar rats, we found that repeated exposure to GBL resulted in spontaneous nonconvulsive generalized seizures which were selectively suppressed by ethosuximide. Once the spontaneous absence-like seizure was developed, it persisted consistently throughout a follow-up period of 6 months, Because vehicle treated siblings never developed such seizure activities, newly developed spontaneous seizures were specific to GBL treatment and could not be attributable to genetically determined predisposition. Rather, it seems that daily injections of GBL produced long-lasting functional and structural changes responsible for the absence-like seizure by analogy with the kindling phenomenon as a model of partial onset seizure, More interestingly, callosal section significantly interfered not only with bisynchronization of seizure discharges, but also with occurrence of spontaneous seizures in accord with clinical outcome of the corpus callosotomy in human generalized epilepsies. This further suggests that the cerebral cortex might principally be involved in development of generalized seizures, and the callosally projecting cortico-cortical system could play a crucial role in concurrent recruiting cortical neurons in both hemispheres.
47-06 Epileptic Seizures Occurrence in Subjects Previously Affected by Disorders of Arousal Raoul Di Perri, Rosa lia Silvestri, Clinica Neurologica 98013 Contesse-Messina, Italy
I, Policlinico
Universitario,
Despite the fact that disorders of arousal (sleep-walking, night-terrors, confusional arousals) are commonly encountered among benign childhood transient events depending on the sleep architecture’s maturation process, we’ve collected evidence of several children or young adults who have previously suffered from clearcut classic disorders of arousal and lately developed predominantly nocturnal epileptic seizures. When the ictal events were clinically evident as complex partial seizures at times the differential diagnosis of the new episode, was difficult and not at all unambiguous. Anyway the abnormal distribution during night thirds or the late appearance of unclear disorders of arousal should always orient towards a possible ictal event. Extensive nocturnal sleep EEG and videopolygraphic recordings are mandatory and undoubtfully meaningful in such conditions as exemplified by a series of clinical-electroencephalographic documentations collected in several years.
47-07
Epilepsy and Photosensitivity
D. Pinto, J.A. Ribeiro, G. Sousa, M.J. Teixeira, C. Marinho. I. Pires, J. Dinis. M.L. Guimaraes. Neorophysiology Department S. Jolo Hospitai, Porte. Portugal The occurrence of photosensitivity was examined in 399 epileptic patients, >5 years of age, referred to our EEG Department during the period March 91-March 92. A non-epileptic group (288 patients -mean age = 28.8 years, age range = 5-81 years, sex ratio M/F = 0.6) was studied by using EEG methods applied to the epileptic patients.
intermittent Photic Stimulation (IPS) was performed with closed eyes, using a stroboscope, which produces flashes of growing - 0 to 60 Hz and then decreasing - 60 to 0 Hz frequencies, the trains of flashes of constant frequency were delivered for 5 seconds and the intervals between the successive trains lasted 5 seconds, The epileptic patients (mean age = 26.8 years, age range = 5-77 years, sex ratio: M/F = 1.1) were classified according to the type of epilepsy:-Generald epilepsy = 100 (mean age = 26.4 years, age range = 6-71 years: sex ratio = 0.8); Partia/epilepsy = 273 (mean age = 23.9 years, age range = 5-77 years, sex ratio = 1.2).Non-classified epilepsy = 27 (mean age = 30 years, age range = 5-59 years, sex ratio = 1.5). The EEG with IPS led us to a group of 16 patients (all epileptic patients), showing a photoparoxysmal response - a self-limited paroxysmal response (SPR) in 7 patients and a classical paroxysmal response (CPR) in 9 patients), which was analysed according to parameters such as: mean age, age range, sax ratio, type of epilepsy and medication, Our study reveals a Portuguese incidence of photosensitivity around 2.6% below the expected value-about 5% -for the general epileptic population, anyhow understandable in view of the geographic location of our country, Portugal (South Europe).
CPRgroup SPR group
147-08
Patients number
Age range (mean age) years
Sex ratio hl/F
Type of epilepsy gen.:part.
9 7
9-38 (20.11 9-71 (29.9)
z/7
8.1 4:J
l/6
1 Vascular Epilepsy: EEG and Neuroradiological Findings
M.L. Vaccario, A. Rossi, G. Di Lella, S. Mazza, PA. Tonali. Catholic UniversiQ Roma Acute cerebrovascuiar disease is the most frequent cause of epilepsy in the elderly as reported byseveral authors (Lesser et al., 1985; Daniele et al., 1989). We evaluated 290 patients affected by stroke, hospitalized in our Neurological Department between 1988-l 991, In order to point out some possible risk factors of developing seizures, we considered clinical, EEG and neuroradiological findings of all patients in acute phase. We can summarize our most important results as follows: - 62 patients (21%) had one or more seizures; - EEG with focal paroxysmal abnormalities was four times more frequent in patients with seizures (32% versus 1% in patients without seizures) - Cortical lesions (especially parietal) on CT scan were more common in patients with seizures (88%) in comparison with patients without seizures (47%). Therefore, on the basis of our data, we may hypothesize that the patients with paroxysmal EEG abnormalities and cortical CT lesions in acute insult phase, have a higher risk for the occurrence of seizures.
47-09
Epilepsy: Simultaneous Positive and Negative Statistical Long Latency EP Abnormalities
G. Vatti. E Donati, F.H. Duffy. Children’s Hospital, Boston Statistical analysis and topographic display of scalp derived data facilitate new insight into brain pathophysiology. We studied the visual (VER) and auditory (AER) long latency evoked responses of 1354 subjects referred to our quantified EEG laboratory from 1987 to 1993. We noticed, as an atypical finding, the presence of significantly abnormal positivity and negativity in different regions of the head over the same post stimulus post latency epoch and persisting 20 msec or longer. We observed these simultaneous “dipolar abnormalities” on the significance probability mapping (SPM) of 203 subjects. 151 (74.38%) suffered from epilepsy while the remaining 52 (25.62%) presented with other etiologies (depression, head trauma, developmental delay, schizophrenia, and others). 102 demonstrated dipolar abnormalities on VER, 66 on AER. and 35 on both modalities. Epilepsy accounted for65.68% of VER dipoles and for 78.78% of AER dipoles. Interestingly, 91.42% of patients showing dipole abnormalities on both VER and AER were epileptic. When differentiated from time locked alpha and when an age matched database is employed, the finding of SPM positive and negative abnormalities (>2 SD) during long latency EP may prove helpful in establishing the diagnosis of epilepsy.