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Spectral analysis of the EEG: Comparison of various spectral parameters
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specific questions arising in relation to the Attention was illness under investigation. paid to: a) the parameter scoring method mentioned before; b) outcomes of Kurtzke's Disability Status Score (D.S.S.) and the interrelationship possibly existing between the outcomes of a) and b). Sub a): The outcomes of the parameter scoring method for the group of patients sufferinq from M.S. were comparable with those from the-group of patients suffering from cerebral ischemia but with "normal" EEGs (Van Huffelen et al.). Sub b): The application of the Kendall Rank Correlation test to the outcomes of the parameter scoring method mentioned above and Kurtzke's Disabilitv Status Score (D.S.S.) showed that there was no significant relation between them. D-17.02 SPECTRAL ANALYSIS OF THE EEG: COMPARISON OF VARIOUS SPECTRAL PARAMETERS. P.Matthis, D. Scheffner and C. Benninger (Heidelberg, W. Germany) One of the main problems in spectral analysis of the EEG consists in finding relevant parameters which are capable of summarizing all information included in the power spectrum. The mathematical properties and the clinical applicability of four sets of parameters were compared: (1) percentages of power within the conventional frequency ranges, (2) mobility and complexity according to Hjorth, (3) the slope parameter according to Dumermuth, (4) the coefficients of the autoregressive model (AR They were applied to an EEG follow-up model). studv of a child with an inooerable brain-stem tumor durinq radiotherapv. The statistical analysis suqqests : The chanqes of the blackqrourd activity durjng the course 07 two months are-well described by most parameters.(I) There are only minor differences between the conventional frequency ranges, the immobility and the slope parameter. (II) The complexity gives less satisfactory results than the above mentioned paratrcters. (III) The first autoregressive coefficient of the AR model yields the best result. C-3.05 POLYNEUROPATHY IN POLYCYTHEMIA RUBRA J.G. McLeod, C. Yiannikas an J.C. Walsch VERA. (Sydney, Australia) Paraesthesia of the extremities is a common symptom of polycythemia Vera. Frank peripheral neuropathy is, however, a rare complication of the disease. There have been no previous clinical and electrophysiological studies reported on a group of subjects with polycythemia vera to determine the incidence of impaired nerve conduction. Thirty polycythemic subjects were examined clinicallv and electroohvsioloaicallv. The diagnosis was confirmed'by haematolog:cal investigation in each case, and other possible causes of neuropathy such as alcoholism, nutritional deficiency, diabetes or drugs were
The results were compared with those excluded. of control subjects. One subjectwasdemonstrated to have clinical evidence of a mild peripheral neuropathy, and 3 subjects of a group of 29 who had no clinical evidence of peripheral neuropathy were demonstrated to have abnormal nerve There was no significant decrease conduction. in the velocity in the median, ulnar and lateral popliteal nerves, nor was there an increase in the terminal latency. There was, however, a decrease in the amplitude of the median, ulnar and sural sensory nerve action potentials. These findings suggest that mild diffuse polyneuropathy may complicate polycythemia rubra Vera. B-9.01 EFFECTS OF OPTIMUM FILTERS ON AVERAGE H. Haresch, V. Koepruner, EVOKED POTENTIALS. G. Pfurtscheller and S. Schuy (Graz, Austria) Optimum filtering was introduced by D.O. Walter and developed by Nogawa et al. to achieve better results by using fewer averages. This promising outlook however could not be converted into a breakthrough in the clinical routine up to now. This contribution should show, by an investigation of several parameters such as mean square error with its two components (remaining noise and distortion of the signal by the filter) and the signal to noise ratio, what optimum filters really can effect on evoked potentials and which difficulties arise when attempting an improvement of the results. Based on this investigation, a new filter type for evoked potentials is proposed, which allows a more reliable filter estimation, especially at low signal to noise ratios, of the evoked potential. A-18.06 TOPOGRAPHIC DISTRIBUTION OF QUANTITATIVE EEG EFFECTS OF NEUROACTIVE DRUGS. W.G. Sannita, M. Cabri, A. Gris, C. Padovan and G. Rosadini (Genoa, Italy) The scalp distribution of drug effects on the background EEG signal was studied in epileptic patients (children never treated before, referred to single-drug therapy with ethosuximide, valproic acid or diphenylhydantoin) and in healthy volunteers receiving single oral doses of a novel, active benzodiazepine(SAS643) in a double-blind, placebo-controlled, study. The EEG was recorded prior to, and at regular intervals during therapy or after single-dose drug administration, and quantified by power spectral analysis on epochs free from epileptic potentials or artifacts. Spectral data from different leads within the same hemisphere, and from homologous leads of the two hemispheres, were compared by paired t test. Drug-dependent EEG modifications, significant and consistent across subjects, were identified for ethosuximide and valproic acid and found to be
specific questions arising in relation to the Attention was illness under investigation. paid to: a) the parameter scoring method mentioned before; b) outcomes of Kurtzke's Disability Status Score (D.S.S.) and the interrelationship possibly existing between the outcomes of a) and b). Sub a): The outcomes of the parameter scoring method for the group of patients sufferinq from M.S. were comparable with those from the-group of patients suffering from cerebral ischemia but with "normal" EEGs (Van Huffelen et al.). Sub b): The application of the Kendall Rank Correlation test to the outcomes of the parameter scoring method mentioned above and Kurtzke's Disabilitv Status Score (D.S.S.) showed that there was no significant relation between them. D-17.02 SPECTRAL ANALYSIS OF THE EEG: COMPARISON OF VARIOUS SPECTRAL PARAMETERS. P.Matthis, D. Scheffner and C. Benninger (Heidelberg, W. Germany) One of the main problems in spectral analysis of the EEG consists in finding relevant parameters which are capable of summarizing all information included in the power spectrum. The mathematical properties and the clinical applicability of four sets of parameters were compared: (1) percentages of power within the conventional frequency ranges, (2) mobility and complexity according to Hjorth, (3) the slope parameter according to Dumermuth, (4) the coefficients of the autoregressive model (AR They were applied to an EEG follow-up model). studv of a child with an inooerable brain-stem tumor durinq radiotherapv. The statistical analysis suqqests : The chanqes of the blackqrourd activity durjng the course 07 two months are-well described by most parameters.(I) There are only minor differences between the conventional frequency ranges, the immobility and the slope parameter. (II) The complexity gives less satisfactory results than the above mentioned paratrcters. (III) The first autoregressive coefficient of the AR model yields the best result. C-3.05 POLYNEUROPATHY IN POLYCYTHEMIA RUBRA J.G. McLeod, C. Yiannikas an J.C. Walsch VERA. (Sydney, Australia) Paraesthesia of the extremities is a common symptom of polycythemia Vera. Frank peripheral neuropathy is, however, a rare complication of the disease. There have been no previous clinical and electrophysiological studies reported on a group of subjects with polycythemia vera to determine the incidence of impaired nerve conduction. Thirty polycythemic subjects were examined clinicallv and electroohvsioloaicallv. The diagnosis was confirmed'by haematolog:cal investigation in each case, and other possible causes of neuropathy such as alcoholism, nutritional deficiency, diabetes or drugs were
The results were compared with those excluded. of control subjects. One subjectwasdemonstrated to have clinical evidence of a mild peripheral neuropathy, and 3 subjects of a group of 29 who had no clinical evidence of peripheral neuropathy were demonstrated to have abnormal nerve There was no significant decrease conduction. in the velocity in the median, ulnar and lateral popliteal nerves, nor was there an increase in the terminal latency. There was, however, a decrease in the amplitude of the median, ulnar and sural sensory nerve action potentials. These findings suggest that mild diffuse polyneuropathy may complicate polycythemia rubra Vera. B-9.01 EFFECTS OF OPTIMUM FILTERS ON AVERAGE H. Haresch, V. Koepruner, EVOKED POTENTIALS. G. Pfurtscheller and S. Schuy (Graz, Austria) Optimum filtering was introduced by D.O. Walter and developed by Nogawa et al. to achieve better results by using fewer averages. This promising outlook however could not be converted into a breakthrough in the clinical routine up to now. This contribution should show, by an investigation of several parameters such as mean square error with its two components (remaining noise and distortion of the signal by the filter) and the signal to noise ratio, what optimum filters really can effect on evoked potentials and which difficulties arise when attempting an improvement of the results. Based on this investigation, a new filter type for evoked potentials is proposed, which allows a more reliable filter estimation, especially at low signal to noise ratios, of the evoked potential. A-18.06 TOPOGRAPHIC DISTRIBUTION OF QUANTITATIVE EEG EFFECTS OF NEUROACTIVE DRUGS. W.G. Sannita, M. Cabri, A. Gris, C. Padovan and G. Rosadini (Genoa, Italy) The scalp distribution of drug effects on the background EEG signal was studied in epileptic patients (children never treated before, referred to single-drug therapy with ethosuximide, valproic acid or diphenylhydantoin) and in healthy volunteers receiving single oral doses of a novel, active benzodiazepine(SAS643) in a double-blind, placebo-controlled, study. The EEG was recorded prior to, and at regular intervals during therapy or after single-dose drug administration, and quantified by power spectral analysis on epochs free from epileptic potentials or artifacts. Spectral data from different leads within the same hemisphere, and from homologous leads of the two hemispheres, were compared by paired t test. Drug-dependent EEG modifications, significant and consistent across subjects, were identified for ethosuximide and valproic acid and found to be