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Computer-assisted analysis of leg movements in sleep
Society proceedings/ Electroencephalography and clinical Neurophysiology 95 (1995) 4P-8P The reason is that the sedative hypnotic compound in mixed analgesics was withdrawn by regulative measures. 16. The effect of stimulus parameter on amplitude and configuration of median nerve SEPs using the conventional Fz reference. - B. Schmitt, IL Sidler and L. Molinari (Zurich) Normal SEP amplitudes are incongruously defined, often without consideration of technical parameters. We evaluated the effect of different application techniques on SEP amplitudes after left median nerve stimulation in 20 normal adults (age 22-40 years). Each trial consisted of 2 × 256 artefact-free registrations, recorded over Erb, cervical C7, and cortical C3', all referred to Fz. Technical applications were: filter 10-3000 Hz; stimulus frequency: 0.5 Hz or 5 Hz; stimulus duration: 0.l, 0.2 or 0.5 msec; stimulus strength: brisk thumb twitch or maximal tolerance. Erb's amplitude was highest with stimulus duration of 0.5 msec or maximal strength; frequency had no influence. Cervical N13 amplitude was reduced at 0.1 msec stimulus duration. Cortical amplitudes were unaffected by strength and duration but showed alterations at 0.5 Hz stimulus frequency: 10-200% increase of the N20-P25/27 amplitude and modifications of wave configuration beyond P25, i.e., (i) M-shaped N35 (9 probands), (ii) replacement of N35 by " P 3 5 " (4), and (iii) a second positive wave P27 after P25 (7). Cortical amplitude values did not show Gaussian distribution, mean value and standard deviation were thus not applicable. The influence of technical parameters on the amplitudes should be considered in the evaluation of SEPs, especially when giant potentials are observed. 17. Computer-assisted analysis of leg movements in sleep. - R. Briellmann, C. Bassetti, J. Mathis, M. Gugger and C.W. Hess (Bern) One hundred and five consecutive patients with dyssomnias (90 men, 22 under CPAP therapy, mean age = 53 years) were studied by overnight polysomnography. Leg movements (LMs) were defined as anterior tibial muscle EMG activity of more than 200% of the baseline amplitude lasting 0.5 sec or more. The LMs were classified by visual analysis into periodic (PLM) and non-periodic leg movements (NLM) and expressed as index (e.g. LMI) per hour sleep. The diagnoses were sleep apnoea syndrome (SAS: 53% of pat.), narcolepsy, stroke (12%) and nocturnal myoclonus (PLMI > 5: 6%). In 29% dyssomnia was of unknown origin (DUO). LMI was 0.7-186 (mean 35), 43% of LMs were periodic. In addition to nocturnal myoclonus high PLMI ( > 20) was associated with severe SAS and narcolepsy. NLMI was high ( > 20) in moderate SAS and DUO. CPAP therapy decreased NLM but increased PLM. Conclusions: (1) PLMs are a non-specific finding in sleep patients. It was observed in isolation as well as in association with SAS and narcolepsy. (2) CPAP therapy only slightly reduced LM but increased PLM. This finding may support the hypothesis of a central pathogenesis for PLM. (3) NLMs are associated with dyssomnias of unknown origin. Further studies are needed to determine whether they are just a marker or rather a possible cause of dyssomnia. 18. Sleep-wake disturbances and polysomnographic (PSG) findings following paramedian thalamic infarction. Report of 11 patients. - C. Bassetti, J. Mathis, M. Gugger, K. L6vblad and C.W. Hess (Bern) Increased sleepiness after paramedian thalamic infarction (PTI) has been attributed to dysfunction of arousal control. In order to assess a broader disturbance of sleep-wake regulation, 9 men and 2 women (average age of 42 years, range of 17-60) with MRI-proven PTIs were studied clinically and polysomnographically. A total of 14 PSGs were
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recorded 1 week to 60 months (mean 9 months) after stroke and analyzed according to the Rechtschaffen and Kales criteria. All patients presented with reduced alertness, which in 4 patients normalized within few days. In 7 patients, chronic hypersomnia, as documented by abnormal MSLT test, actigraphy and 24 h PSG, persisted up to 2 years. In these patients the infarction was either bilateral or extended to the thalamo-mesencephalic junction. During the symptomatic phase PSG showed a reduction of NREM sleep II (mean 29%) and Ill-IV (3%) as well as of sleep spindles count ( 1 4 7 / h sleep), whereas NREM sleep I was increased. Some reduction of NREM sleep II-IV persisted after clinical symptoms had resolved. This study supports the hypothesis that paramedian thalamic structures are an essential "final common pathway" for both maintenance of wakefulness as well as sleep promotion. 19. Complex partial seizures with speech arrest (2 case reports with video-EEG demonstrations). - A. Hecker, M. Engelke and B. Findeis (Lobetai) We report a 26-year-old patient with complex partial seizures, beginning with an aura, followed by speech arrest with mild oral automatisms. Postictally the patient had a sensoric aphasia and a partial amnesia. In the video-EEG the seizure started left fronto-temporal and showed longlasting discharges in the left temporal region. The MRI showed a discrete structural lesion in the left gyrus parahippocampalis. The patient could not decide for a presurgical monitoring at the moment. However, in the case of a 30-year-old patient we found seizures with speech arrest, beginning with a special feeling in the head, starting in the video-EEG over the both fronto-precentral regions with significant rightsided predominance. Here we found in the MRI an cavernous hemangioma in the left frontal lobe. The operation was on February 10, 1994. Since then the patient is seizure-free. The different origins of speech arrest seizures are discussed. 20. Complex partial seizure; cause versus effect of cardiac arrhythmia. - E. Wilder-Smith and K. Karbowski (Bern) Thanks to the now routine use of simultaneous EEG and ECG recording, the relationship between cardiac arrhythmias and epileptic seizures is nowadays more precisely determined. Complex partial seizures may on the one hand directly cause cardiac arrhythmias, but on the other hand complex partial symptomatology may be the result of primary cardiac syncope. In this context we report two cases. A left temporal seizure discharge was registered in the EEG of a 56-year-old woman. This was followed by an epigastric aura and altered consciousness; 15 sec after the beginning of the EEG seizure discharge, cardiac rate slowed with subsequent development of complete atrioventricular conduction block with a regular ventricular escape beat of 30/min. The second case is a 40-year-old patient where the ECG revealed an asystole of 21 sec duration; 9 sec after the beginning of the asystole, bifrontal "delta rhythms" appeared in the EEG, followed by 15 sec of "electrical silence." Clinical manifestations were psychomotor restlessness, altered consciousness and oral automatisms. The authors emphasize that in these cases differentiation between primary and secondary (seizure-induced) cardiac arrhythmogenesis is vital to be able to initiate appropiate therapy. 21. Ictai case study of a versive seizure examined by 99roTe HM-PAO brain single photon emission computed tomography (SPECT). B. Weder a, R. Oettli ~, R.P. Maguire b and T. Vonesch a (~ St. Gailen and b Villigen) We analysed a case study of a versive seizure characterized by forced movement of head and eyes to the left side, preceded by a short version of the eyes to the right side, and correlated the seizure manifestation with
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recorded 1 week to 60 months (mean 9 months) after stroke and analyzed according to the Rechtschaffen and Kales criteria. All patients presented with reduced alertness, which in 4 patients normalized within few days. In 7 patients, chronic hypersomnia, as documented by abnormal MSLT test, actigraphy and 24 h PSG, persisted up to 2 years. In these patients the infarction was either bilateral or extended to the thalamo-mesencephalic junction. During the symptomatic phase PSG showed a reduction of NREM sleep II (mean 29%) and Ill-IV (3%) as well as of sleep spindles count ( 1 4 7 / h sleep), whereas NREM sleep I was increased. Some reduction of NREM sleep II-IV persisted after clinical symptoms had resolved. This study supports the hypothesis that paramedian thalamic structures are an essential "final common pathway" for both maintenance of wakefulness as well as sleep promotion. 19. Complex partial seizures with speech arrest (2 case reports with video-EEG demonstrations). - A. Hecker, M. Engelke and B. Findeis (Lobetai) We report a 26-year-old patient with complex partial seizures, beginning with an aura, followed by speech arrest with mild oral automatisms. Postictally the patient had a sensoric aphasia and a partial amnesia. In the video-EEG the seizure started left fronto-temporal and showed longlasting discharges in the left temporal region. The MRI showed a discrete structural lesion in the left gyrus parahippocampalis. The patient could not decide for a presurgical monitoring at the moment. However, in the case of a 30-year-old patient we found seizures with speech arrest, beginning with a special feeling in the head, starting in the video-EEG over the both fronto-precentral regions with significant rightsided predominance. Here we found in the MRI an cavernous hemangioma in the left frontal lobe. The operation was on February 10, 1994. Since then the patient is seizure-free. The different origins of speech arrest seizures are discussed. 20. Complex partial seizure; cause versus effect of cardiac arrhythmia. - E. Wilder-Smith and K. Karbowski (Bern) Thanks to the now routine use of simultaneous EEG and ECG recording, the relationship between cardiac arrhythmias and epileptic seizures is nowadays more precisely determined. Complex partial seizures may on the one hand directly cause cardiac arrhythmias, but on the other hand complex partial symptomatology may be the result of primary cardiac syncope. In this context we report two cases. A left temporal seizure discharge was registered in the EEG of a 56-year-old woman. This was followed by an epigastric aura and altered consciousness; 15 sec after the beginning of the EEG seizure discharge, cardiac rate slowed with subsequent development of complete atrioventricular conduction block with a regular ventricular escape beat of 30/min. The second case is a 40-year-old patient where the ECG revealed an asystole of 21 sec duration; 9 sec after the beginning of the asystole, bifrontal "delta rhythms" appeared in the EEG, followed by 15 sec of "electrical silence." Clinical manifestations were psychomotor restlessness, altered consciousness and oral automatisms. The authors emphasize that in these cases differentiation between primary and secondary (seizure-induced) cardiac arrhythmogenesis is vital to be able to initiate appropiate therapy. 21. Ictai case study of a versive seizure examined by 99roTe HM-PAO brain single photon emission computed tomography (SPECT). B. Weder a, R. Oettli ~, R.P. Maguire b and T. Vonesch a (~ St. Gailen and b Villigen) We analysed a case study of a versive seizure characterized by forced movement of head and eyes to the left side, preceded by a short version of the eyes to the right side, and correlated the seizure manifestation with