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Factors predicting the risk of relapse after AED discontinuation in children with partial epileptic seizures
6P
Society proceedings/Electroencephalography
Ten female patients (aged 48-82 years, mean 64 years), admitted over 25 years to our department because of a confusional state secondary to an NGSE, were retrospectively studied. Three patients had a positive history for GM epilepsy. Confusional state persisted from several hours up to 2 weeks and was characterized by attentional deficits (10), mental slowing (10), disorientation (6), mutism (4) and myocloous (4). Ictal EEG showed more or less regular 2-6 Hz generalized spike-wave or polyspike-wave activity with some focal accentuation in 6 patients. Metabolic disturbances (6), infections (6), abrupt stopping of phenytoin (1), brain atrophy (3) and focal CT lesions (3) were identified, often in combination. Two patients with sepsis and renal failure died within a few hours. Clonazepam i.v. was effective in 7 of 8 patients. Four patients were placed on chronic antiepileptic treatment (AT). During a mean follow-up of 2 years, 2 patients (one under AT) had seizure recurrence. In conclusion, (1) NGSE is rare but probably often unrecognized due to non-specific and subtle clinical symptoms; (2) EEG features and aetiology are very heterogenous and in some cases point to a focal origin of NGSE; (3) clonazepam i.v. is an effective acute treatment and long-term prognosis is favourable in most cases even without treatment. 11. Temporal lobe epilepsy (TLE) and early mental retardation (EMR). - G. Wohirab, H. Holthausen et al. (Epilepsiezentrum Bethel, Bielefeld) The data of 97 consecutive patients which had been admitted for presurgical evaluation caused by drug-resistant TLE were analyzed retrospectively. We identified 9 patients who had an undoubtful mental retardation by the age of 6 years, not explained by other causes. All 9 patients had benign tumours in the mesial temporal region. We compared the data of these 9 patients with TLE, tumours and early mental retardation (group I) with the data of 18 (out of 97) patients with TLE, who also had benign tumours in the mesial temporal structures but without any intellectual handicap (group II). There was a highly significant difference between groups I and II concerning the age of seizure onset, the occurrence of extratemporal interictal sharp waves and the development of extratemporal seizures during the course of the epileptic disease. There were no differences in terms of tumour localization, extend of tumour or histology. In surgical outcome group I patients did not as well as group II patients. In conclusion, the onset of temporal lobe epilepsy in the first (and to some degree in the second) year of life is a risk factor for mental retardation. If seizures cannot be controlled by drugs all efforts should be made to rule out possible surgically removable aetiologies like benign tumours. 12. Functional mapping of dyslexia in children using language-evoked potentials. - D. Brandeis, D. Vitacco and H.C. Steinhausen (Zurich) Neurophysiological processing deficits in developmental dyslexia were examined with functional brain mapping. We compared brain electric signs of visual, attentional and linguistic/semantic processing in dyslexic and control children (N = 12/group, mean age 11 years). Event-related brain potentials from 33 sites were mapped during sentence reading, lexical decision and visual search tasks. The average reference maps were subjected to adaptive segmentation, topographic component recognition, and true 3-dimensional map landscape analysis. Late deviant brain processes (250-800 msec) were largely confined to unexpected words. This deviance is best explained in linguistic/semantic terms and probably reflects delays of language-specific N400 microstates. In addition, exploratory analysis (t maps) revealed early signs (100-200 msec; P1-N1 microstate transition) of focally deviant brain processes in dyslexic children at non-standard left posterior electrodes. Similar deviance patterns were obtained in both groups when comparing expected to new, anomalous sentence endings. This suggests a cognitive, possibly
and clinical Neurophysiology 95 (199.5) 4P-8P visual-attentional origin of the early brain electric deviance in dyslexics and shows that cognitive task manipulations and extended spatial sampling are needed to detect and interpret such processing deficits. We conclude that both early cognitive-visual and later language-specific processing deficits characterize unselected dyslexics. 13. Factors predicting the risk of relapse after AED discontinuation in children with partial epilepfic seizures. - F. Donafi, R.L Hassink, J. Mathis and F. Vassella (Bern) The purpose of this study is to identify possible factors, which could influence the risk of relapse after antiepileptic drug (AED) discontinuation in children with partial epileptic seizures. From our computerized database, 155 children with partial seizures and a follow-up of more than 5 years could be selected. In 82 children the AED had been discontinued since a mean of 4.7 years after the last epileptic seizure. 24/82 experienced relapse and 58/82 did not have any relapse in the last 3 years after AED discontinuation. Abnormal neurological findings (8/24 vs. 8/58, P < 0.05, X ~ tes0, delayed psychomotor development (7/24 vs. 7/58, P < 0.05), and focal slowing (6/24 vs. 3/58), P < 0.01) in the last EEG before AED discontinuation, were significantly more common in children who relapsed. No statistically significant differences between the two groups were found concerning the age at the time of the first epileptic seizure (4.3 vs. 5.4 years), the duration of AED after the last seizure (4.5 vs. 4.8 years), the familial occurrence of epilepsies (6/24 vs. 12/58), background EEG abnormalities (6/24 vs. 17/58), and focal epileptiform discharges (5/24 vs. 5/58) in the last EEG before AED discontinuation. 14. Microsleep episodes in depressed patients during partial sleep deprivation treatment. - U. Hemmeter, E. Seifritz, M. Hatzinger, R. Kocher and E. Holsboer-Trachsler (Basel) Partial sleep deprivation (PSD) exerts an antidepressive effect, which is usually followed by a relapse into depression after the first recovery night. Short phases of sleepiness have been discussed as being responsible for this phenomenon. To test the hypothesis that daytime microsleep (DS) after PSD is related to the antidepressive response, we monitored a continuous EEG registration over 60 h, including a PSD in 10 patients suffering from major depression. After PSD in all patients DS episodes of 31.1 + 29.8 min (vs. 4.6 5:5.2 at baseline) and total DS time 34.9 5:34.7 min (vs. 12.0 _+ 16.7 min) were increased. PSD non-responders presented with twice as many episodes of DS than responders after PSD. Patients with a low (5.0 + 7.5 min) amount of DS rated their mood markedly better than patients with much DS (64.9 ± 20.3 min). These results illustrate that in depressed patients before and after PSD different amounts of DS can be detected objectively, which were subjectively unrecognized and not observed by the nursing staff. The amount of DS after PSD seems to be related to the PSD response. 15. The miniature spike-wave pattern during the withdrawal phase in substance dependency during 1974-1994. - R. Kocher and D. Ladewig (Basel) In 1974 we reported on 18 patients with 6 / s e c spike-waves localized with a maximum in the occipital area. These graphoelements were first described by Gibbs and Gibbs. A possible relation to a hyperreactivity during the withdrawal phase came from our observation that in 11 patients a chronic abuse of medicaments with a barbiturate-sedative component was known. In another 4 patients we proved by measuring the EEG 6 / s e c spike-waves the abuse of corresponding substances. During the last 10 years a miniature spike-wave pattern was found only very rarely, that means approximately 1-2 times in about 1000 EEGs/year.
Society proceedings/Electroencephalography
Ten female patients (aged 48-82 years, mean 64 years), admitted over 25 years to our department because of a confusional state secondary to an NGSE, were retrospectively studied. Three patients had a positive history for GM epilepsy. Confusional state persisted from several hours up to 2 weeks and was characterized by attentional deficits (10), mental slowing (10), disorientation (6), mutism (4) and myocloous (4). Ictal EEG showed more or less regular 2-6 Hz generalized spike-wave or polyspike-wave activity with some focal accentuation in 6 patients. Metabolic disturbances (6), infections (6), abrupt stopping of phenytoin (1), brain atrophy (3) and focal CT lesions (3) were identified, often in combination. Two patients with sepsis and renal failure died within a few hours. Clonazepam i.v. was effective in 7 of 8 patients. Four patients were placed on chronic antiepileptic treatment (AT). During a mean follow-up of 2 years, 2 patients (one under AT) had seizure recurrence. In conclusion, (1) NGSE is rare but probably often unrecognized due to non-specific and subtle clinical symptoms; (2) EEG features and aetiology are very heterogenous and in some cases point to a focal origin of NGSE; (3) clonazepam i.v. is an effective acute treatment and long-term prognosis is favourable in most cases even without treatment. 11. Temporal lobe epilepsy (TLE) and early mental retardation (EMR). - G. Wohirab, H. Holthausen et al. (Epilepsiezentrum Bethel, Bielefeld) The data of 97 consecutive patients which had been admitted for presurgical evaluation caused by drug-resistant TLE were analyzed retrospectively. We identified 9 patients who had an undoubtful mental retardation by the age of 6 years, not explained by other causes. All 9 patients had benign tumours in the mesial temporal region. We compared the data of these 9 patients with TLE, tumours and early mental retardation (group I) with the data of 18 (out of 97) patients with TLE, who also had benign tumours in the mesial temporal structures but without any intellectual handicap (group II). There was a highly significant difference between groups I and II concerning the age of seizure onset, the occurrence of extratemporal interictal sharp waves and the development of extratemporal seizures during the course of the epileptic disease. There were no differences in terms of tumour localization, extend of tumour or histology. In surgical outcome group I patients did not as well as group II patients. In conclusion, the onset of temporal lobe epilepsy in the first (and to some degree in the second) year of life is a risk factor for mental retardation. If seizures cannot be controlled by drugs all efforts should be made to rule out possible surgically removable aetiologies like benign tumours. 12. Functional mapping of dyslexia in children using language-evoked potentials. - D. Brandeis, D. Vitacco and H.C. Steinhausen (Zurich) Neurophysiological processing deficits in developmental dyslexia were examined with functional brain mapping. We compared brain electric signs of visual, attentional and linguistic/semantic processing in dyslexic and control children (N = 12/group, mean age 11 years). Event-related brain potentials from 33 sites were mapped during sentence reading, lexical decision and visual search tasks. The average reference maps were subjected to adaptive segmentation, topographic component recognition, and true 3-dimensional map landscape analysis. Late deviant brain processes (250-800 msec) were largely confined to unexpected words. This deviance is best explained in linguistic/semantic terms and probably reflects delays of language-specific N400 microstates. In addition, exploratory analysis (t maps) revealed early signs (100-200 msec; P1-N1 microstate transition) of focally deviant brain processes in dyslexic children at non-standard left posterior electrodes. Similar deviance patterns were obtained in both groups when comparing expected to new, anomalous sentence endings. This suggests a cognitive, possibly
and clinical Neurophysiology 95 (199.5) 4P-8P visual-attentional origin of the early brain electric deviance in dyslexics and shows that cognitive task manipulations and extended spatial sampling are needed to detect and interpret such processing deficits. We conclude that both early cognitive-visual and later language-specific processing deficits characterize unselected dyslexics. 13. Factors predicting the risk of relapse after AED discontinuation in children with partial epilepfic seizures. - F. Donafi, R.L Hassink, J. Mathis and F. Vassella (Bern) The purpose of this study is to identify possible factors, which could influence the risk of relapse after antiepileptic drug (AED) discontinuation in children with partial epileptic seizures. From our computerized database, 155 children with partial seizures and a follow-up of more than 5 years could be selected. In 82 children the AED had been discontinued since a mean of 4.7 years after the last epileptic seizure. 24/82 experienced relapse and 58/82 did not have any relapse in the last 3 years after AED discontinuation. Abnormal neurological findings (8/24 vs. 8/58, P < 0.05, X ~ tes0, delayed psychomotor development (7/24 vs. 7/58, P < 0.05), and focal slowing (6/24 vs. 3/58), P < 0.01) in the last EEG before AED discontinuation, were significantly more common in children who relapsed. No statistically significant differences between the two groups were found concerning the age at the time of the first epileptic seizure (4.3 vs. 5.4 years), the duration of AED after the last seizure (4.5 vs. 4.8 years), the familial occurrence of epilepsies (6/24 vs. 12/58), background EEG abnormalities (6/24 vs. 17/58), and focal epileptiform discharges (5/24 vs. 5/58) in the last EEG before AED discontinuation. 14. Microsleep episodes in depressed patients during partial sleep deprivation treatment. - U. Hemmeter, E. Seifritz, M. Hatzinger, R. Kocher and E. Holsboer-Trachsler (Basel) Partial sleep deprivation (PSD) exerts an antidepressive effect, which is usually followed by a relapse into depression after the first recovery night. Short phases of sleepiness have been discussed as being responsible for this phenomenon. To test the hypothesis that daytime microsleep (DS) after PSD is related to the antidepressive response, we monitored a continuous EEG registration over 60 h, including a PSD in 10 patients suffering from major depression. After PSD in all patients DS episodes of 31.1 + 29.8 min (vs. 4.6 5:5.2 at baseline) and total DS time 34.9 5:34.7 min (vs. 12.0 _+ 16.7 min) were increased. PSD non-responders presented with twice as many episodes of DS than responders after PSD. Patients with a low (5.0 + 7.5 min) amount of DS rated their mood markedly better than patients with much DS (64.9 ± 20.3 min). These results illustrate that in depressed patients before and after PSD different amounts of DS can be detected objectively, which were subjectively unrecognized and not observed by the nursing staff. The amount of DS after PSD seems to be related to the PSD response. 15. The miniature spike-wave pattern during the withdrawal phase in substance dependency during 1974-1994. - R. Kocher and D. Ladewig (Basel) In 1974 we reported on 18 patients with 6 / s e c spike-waves localized with a maximum in the occipital area. These graphoelements were first described by Gibbs and Gibbs. A possible relation to a hyperreactivity during the withdrawal phase came from our observation that in 11 patients a chronic abuse of medicaments with a barbiturate-sedative component was known. In another 4 patients we proved by measuring the EEG 6 / s e c spike-waves the abuse of corresponding substances. During the last 10 years a miniature spike-wave pattern was found only very rarely, that means approximately 1-2 times in about 1000 EEGs/year.