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Automatic measurement of MUP durations
$94
VIII CONGRESS OF EMG AND RELATED CLINICAL NEUROPHYSIOLOGY
for estimation of recruitment, risetime, amplitude and duration of (averaged) MUPs. Turns-analysis according to Willison can also be performed. Depending on the clinical situation the most interesting parameters of the curves are evaluated and documented.
PS. Crucial choices in mapping spontaneous and evoked EEG activity. - G. Sciarretta, M.G. Marciani and P.M. Rossini (Dept. Public ~ llnd University, 00173 Rome, Italy) The authors examine the construction process of a map of either spontaneous or evoked EEG activity, by analyzing some crucial aspects which remarkably influence its final aspect. In particular the following problems are treated: (a) positioning of the recording electrodes; (b) choice of the reference point; (c) reproduction on a flat plane of the curve surface of the scalp; (d) choice of the interpolation algorithm; (e) criterion for the color assignment. At the end of the discussion, a method is proposed for the extraction of quantitative data from the graphic representation of colored maps of spontaneous and evoked EEG activity.
PS. Automatic measurement of MUP durations. - P. Selmar, S. Andreassen and A. Rasmussen (Aalborg Hospital, Dept. Clin. Neumphys., DK-9000 Aalborg, Denmark) Motor unit potentials (MUPs) from 4 different muscles in 5 volunteers were acquired by a computer-aided classification and selection procedure. For each motor unit this procedure resulted in the selection of a triplet, i.e., the 3 most identical MUPs, selected from all the sweeps inspected by the computer. M U P duration was measured from the 3 MUPs of the triplet, averaged and low-pass filtered (500 Hz). For each muscle the mean duration was defined as the mean of durations of MUPs from 20 to 30 motor units. The automatically measured mean durations, averaged over all muscles and all volunteers, differed 0.2 msec from the reference material, although deviations for individual muscles averaged over all volunteers were up to 1.5 msec. The largest deviation observed in one muscle in one volunteer was 4.7 msec. Repeated measurements in a given muscle in a given subject showed little variability of mean durations (S.D. ---1 msec), while mean durations in the same muscle showed considerably larger variability (S.D. ~ 2 msec). Durations for individual MUPs measured automatically and manually by setting cursors on the computer screen had a correlation coefficient of about 0.7, while durations measured manually by two different EMGers had a correlation coefficient of 0.8.
PS. Peripheral neurophysioiogical alterations in patients with chronic obstructive tung disease. - J. Senant, D. Parain, G. lmelmms, N. Moore, G. Nouvet and D. Samson-Dollfus (Rouen, France) Chronic obstructive lung disease (COLD) has been described as a risk factor of peripheral nerve disease. We pro-
spectively studied 100 patients with COLD, and no other cause of peripheral neuropathy: 16 F, 84 M, mean age 63 + 10 years, mean duration of COLD 155:10 years, mean duration of hypoxia 6.45:4.2 years. They all had a clinical examination. Peroneat nerve motor conduction velocity (MCV), median nerve sensory conduction velocity (SCV) and sensory potential amplitude (SPA) were measured. Seven patients had overt clinical signs of peripheral neuropathy, 32 had one abnormal parameter (17 MCV, 3 SPA, 12 SCV), 24 had two abnormal parameters, and in 6 patients all three were abnormal. Overall 62 patients had at least one abnormal parameter. There were significant negative correlations between duration of hypoxia and MCV ( P < 0.05) but also between MCV and age ( P < 0.05). However, partial correlation between duration of hypoxia and MCV was also significant, for a given age. This is an argument for hypoxia as a causative factor of these peripheral neurophysiological alterations. Almitrine has been suspected of being neurotoxic and is frequently prescribed in COLD patients. These 100 patients had never taken almitrine. Thirteen went on to take almitrine and were followed up after 1 year. Initially they did not differ from the rest of the studied population. After I year of treatment with almitrine, there was no change in their clinical or electrophysiological parameters, even in those who had initial electrophysiological abnormalities.
PS. Electromyographic findings in neuromyotonia. A.M. ~ and K. Sainio (Dept. of Neurology, University of Helsinki, Helsinki, Finland) Neuromyotonic syndrome which is also called Isaacs' syndrome is characterized by slowly increasing muscular stiffness, diminishing muscular strength and muscular atrophy, as well as abundant visible fasciculations. The syndrome is rare. Electromyographic findings are remarkable and typical. We have studied 3 patients with this syndrome. All complained of fasciculations in their muscles, often increased by cold weather, and all had some stiffness in starting movements. The muscular twitches could be quite strong, one patient had noticed her big toe tapping rhythmically the floor. All the patients had profuse spontaneous activity in many muscles, this appeared as very long bursts of rhythmic discharges of a motor unit-like potential, it was also possible to notice simultaneously rhythmic discharges of 2 or 3 separate unit potentials. Similar continuous activity could be found with a needle electrode during spontaneous sleep during the day in 2 patients. One patient was studied with skin electrodes and a portable cassette recorder: discharges continued throughout the day and night. The patients have been treated successfully with carbamazepine.
VIII CONGRESS OF EMG AND RELATED CLINICAL NEUROPHYSIOLOGY
for estimation of recruitment, risetime, amplitude and duration of (averaged) MUPs. Turns-analysis according to Willison can also be performed. Depending on the clinical situation the most interesting parameters of the curves are evaluated and documented.
PS. Crucial choices in mapping spontaneous and evoked EEG activity. - G. Sciarretta, M.G. Marciani and P.M. Rossini (Dept. Public ~ llnd University, 00173 Rome, Italy) The authors examine the construction process of a map of either spontaneous or evoked EEG activity, by analyzing some crucial aspects which remarkably influence its final aspect. In particular the following problems are treated: (a) positioning of the recording electrodes; (b) choice of the reference point; (c) reproduction on a flat plane of the curve surface of the scalp; (d) choice of the interpolation algorithm; (e) criterion for the color assignment. At the end of the discussion, a method is proposed for the extraction of quantitative data from the graphic representation of colored maps of spontaneous and evoked EEG activity.
PS. Automatic measurement of MUP durations. - P. Selmar, S. Andreassen and A. Rasmussen (Aalborg Hospital, Dept. Clin. Neumphys., DK-9000 Aalborg, Denmark) Motor unit potentials (MUPs) from 4 different muscles in 5 volunteers were acquired by a computer-aided classification and selection procedure. For each motor unit this procedure resulted in the selection of a triplet, i.e., the 3 most identical MUPs, selected from all the sweeps inspected by the computer. M U P duration was measured from the 3 MUPs of the triplet, averaged and low-pass filtered (500 Hz). For each muscle the mean duration was defined as the mean of durations of MUPs from 20 to 30 motor units. The automatically measured mean durations, averaged over all muscles and all volunteers, differed 0.2 msec from the reference material, although deviations for individual muscles averaged over all volunteers were up to 1.5 msec. The largest deviation observed in one muscle in one volunteer was 4.7 msec. Repeated measurements in a given muscle in a given subject showed little variability of mean durations (S.D. ---1 msec), while mean durations in the same muscle showed considerably larger variability (S.D. ~ 2 msec). Durations for individual MUPs measured automatically and manually by setting cursors on the computer screen had a correlation coefficient of about 0.7, while durations measured manually by two different EMGers had a correlation coefficient of 0.8.
PS. Peripheral neurophysioiogical alterations in patients with chronic obstructive tung disease. - J. Senant, D. Parain, G. lmelmms, N. Moore, G. Nouvet and D. Samson-Dollfus (Rouen, France) Chronic obstructive lung disease (COLD) has been described as a risk factor of peripheral nerve disease. We pro-
spectively studied 100 patients with COLD, and no other cause of peripheral neuropathy: 16 F, 84 M, mean age 63 + 10 years, mean duration of COLD 155:10 years, mean duration of hypoxia 6.45:4.2 years. They all had a clinical examination. Peroneat nerve motor conduction velocity (MCV), median nerve sensory conduction velocity (SCV) and sensory potential amplitude (SPA) were measured. Seven patients had overt clinical signs of peripheral neuropathy, 32 had one abnormal parameter (17 MCV, 3 SPA, 12 SCV), 24 had two abnormal parameters, and in 6 patients all three were abnormal. Overall 62 patients had at least one abnormal parameter. There were significant negative correlations between duration of hypoxia and MCV ( P < 0.05) but also between MCV and age ( P < 0.05). However, partial correlation between duration of hypoxia and MCV was also significant, for a given age. This is an argument for hypoxia as a causative factor of these peripheral neurophysiological alterations. Almitrine has been suspected of being neurotoxic and is frequently prescribed in COLD patients. These 100 patients had never taken almitrine. Thirteen went on to take almitrine and were followed up after 1 year. Initially they did not differ from the rest of the studied population. After I year of treatment with almitrine, there was no change in their clinical or electrophysiological parameters, even in those who had initial electrophysiological abnormalities.
PS. Electromyographic findings in neuromyotonia. A.M. ~ and K. Sainio (Dept. of Neurology, University of Helsinki, Helsinki, Finland) Neuromyotonic syndrome which is also called Isaacs' syndrome is characterized by slowly increasing muscular stiffness, diminishing muscular strength and muscular atrophy, as well as abundant visible fasciculations. The syndrome is rare. Electromyographic findings are remarkable and typical. We have studied 3 patients with this syndrome. All complained of fasciculations in their muscles, often increased by cold weather, and all had some stiffness in starting movements. The muscular twitches could be quite strong, one patient had noticed her big toe tapping rhythmically the floor. All the patients had profuse spontaneous activity in many muscles, this appeared as very long bursts of rhythmic discharges of a motor unit-like potential, it was also possible to notice simultaneously rhythmic discharges of 2 or 3 separate unit potentials. Similar continuous activity could be found with a needle electrode during spontaneous sleep during the day in 2 patients. One patient was studied with skin electrodes and a portable cassette recorder: discharges continued throughout the day and night. The patients have been treated successfully with carbamazepine.