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A comprehensive model description of motor unit potentials
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VIII CONGRESS OF EMG A N D RELATED CLINICAL NEUROPHYSIOLOGY
anterior muscle. An explanation for the pathomechanics involved in sustaining a long thoracic nerve palsy resulting from windsurfing is provided. In addition, a modified technique that facilitates obtaining valid needle electromyographic recordings from the serratus anterior muscle even in the most corpulent of subjects is described.
PS. A comprehensive model descrii~tion of motor unit potentials. - T , H d . M . Gootzen *, D.F. Stegewam * * , A. Van Oosterom * and H.M. Vingedmets * * (* Dept. Med. Physics and Biophysics, and * * Institute of Neurology, Clin. Ncmrophystolo~, University of Nijmegen, 6~00 l i b Nijntegen, The Netherlands) About 10 years ago the first models for the simulation of motor unit action potentials (MUAPs) were presented. Since then a number of papers appeared, each stressing a limited number of aspects of such a model or its use in quantitative EMG studies. The aim of the present study was to make an inventory of all essential factors in M U A P generation and to assemble them into one model description. Important aspects included are: (i) the influence of the motor end-plate region and of the muscle fiber endings, (ii) the capacitive properties of muscle tissue as a volume conductor, (iii) the statistics of nerve branching in the motor end-plate region, (iv) the limited spatial extension of the muscle and the limb as volume conductors, and (v) the contribution of large groups of distant fibers. We s u ~ e d in giving the model a compact and transparent mathematical basis. The essential separation between temporal and spatial aspects of volume conduction is maintained throughout the calculations. Matrices were introduced to describe the spatio-temporal source distribution and the frequency-dependent volume conduction. This appeared to be intuitively appealing and facilitates the numerical implementation. Results of MUAPs simulated under various conditions with respect to the mentioned aspects are presented. The role of a precise M U A P model in quantitative EMG analysis will be discussed.
PS. Further observations on Biekford's microreflexes as clinical testing. - G. Grampe, D. Porazzi and P. Rovetta (Neurology Dept. City Hospital, Busto Arsizio, Italy)
Bickford's microreflexes as tested by click sounds, light stimuli, or electric pulses to peripheral nerves were investigated in normal subjects and in patients with focal or systemic diseases of the central nervous system. As regards systemic illness, there was a useful trend in the clinical evaluation of Parkinson's disease, including the pharmacological responses. In patients with different kinds of localized lesions, the latencies of Bickford's responses were investigated in relation to the findings of the cortical evoked potentials related to the same sensory system.
PS. Computer analysis of F reslmuses. - A. Grasso, A. Scrofani and F. D'Allm (lstttuto di CUaiea N e u r o l o g t ~ Universi~ di Catanht, 95100 Catania, Italy)
F responses recorded from the hypothenar muscles were examined by a computer program. Parameters automatically determined were: shortest, mean and median latencies, chrono-dispersion, duration and amplitudes. The occurrence of each F response in series of 100 were then evaluated. Inter-trial and side-to-side variations of each parameter were determined. Series of 20-100 responses were compared to determine the reproducibility of the test.
PS. The nem'opathy of bronchogenic carcinoma; a time dispersed analysis. - W , ~ M. Drlicek and W. Popp (L. B o l t m a n n Inst. f. Idin, N ~ A-1138 Vienna, Austria) Peripheral neuropathy occurs frequently in association with bronchogenic carcionoma, although the incidence reported in literature varies widely. We have analyzed 4 groups of patients with bronchogenic carcinoma and studied the peripheral nervous system at the time of tumor diagnosis, in the course of the malignancy by means of nerve conduction velocities, conventional EMG and with SFEMG. Group 3 consisted of patients with small cell carcinoma with antineuronal antibodies to the cerebellum. In the fourth group, a combined clinical and morphologic study, we evaluated PNS structures not readily available for eleetrophysiologic measurements namely dorsal root ganglia, autonomic ganglia and posterior collumns. The involvement of PNS in patients with broncliogenic carcinoma, the characteristics of neuropathy at different stages of the disease, is described.
SY, Clinical syndromes in motor neuron diseases. G.C, Guazzi, A. Rossi and A. Federieo (Istituto di Scienze Neurolollkhe e Ceatro per Io Studio deHe EncefaloNeuro-Miolmtie Geaetiehe, Univemlti di Siena, Siena, Italy)
The so-called motor neuron diseases include a heterogeneous group of disorders mainly characterized by abiotrophy of the second motor neuron. From the clinical point of view, we can distinguish: (1) Werdnig-Hoffmann disease (WILD) with both a rapid and slow evolution; (2) Kugelberg-Welander disease (KWD); (3) Aran-Ducherme disease (ADD), generally characterized by chronic evolution. W H D and K W D are generally transmitted with autosomal recessive inheritance, while dominant inheritance with anteposition phenomenon can be found in ADD. Moreover, sporadic cases, without familial consanguinity, are reported. A D D sporadic cases can follow, 20-30 years later, acute anterior poliomyelitis. The second group of disorder is true amyotrophic lateral sclerosis (ALS) with its classic and pseudopolynevritic forms. Sporadic cases
VIII CONGRESS OF EMG A N D RELATED CLINICAL NEUROPHYSIOLOGY
anterior muscle. An explanation for the pathomechanics involved in sustaining a long thoracic nerve palsy resulting from windsurfing is provided. In addition, a modified technique that facilitates obtaining valid needle electromyographic recordings from the serratus anterior muscle even in the most corpulent of subjects is described.
PS. A comprehensive model descrii~tion of motor unit potentials. - T , H d . M . Gootzen *, D.F. Stegewam * * , A. Van Oosterom * and H.M. Vingedmets * * (* Dept. Med. Physics and Biophysics, and * * Institute of Neurology, Clin. Ncmrophystolo~, University of Nijmegen, 6~00 l i b Nijntegen, The Netherlands) About 10 years ago the first models for the simulation of motor unit action potentials (MUAPs) were presented. Since then a number of papers appeared, each stressing a limited number of aspects of such a model or its use in quantitative EMG studies. The aim of the present study was to make an inventory of all essential factors in M U A P generation and to assemble them into one model description. Important aspects included are: (i) the influence of the motor end-plate region and of the muscle fiber endings, (ii) the capacitive properties of muscle tissue as a volume conductor, (iii) the statistics of nerve branching in the motor end-plate region, (iv) the limited spatial extension of the muscle and the limb as volume conductors, and (v) the contribution of large groups of distant fibers. We s u ~ e d in giving the model a compact and transparent mathematical basis. The essential separation between temporal and spatial aspects of volume conduction is maintained throughout the calculations. Matrices were introduced to describe the spatio-temporal source distribution and the frequency-dependent volume conduction. This appeared to be intuitively appealing and facilitates the numerical implementation. Results of MUAPs simulated under various conditions with respect to the mentioned aspects are presented. The role of a precise M U A P model in quantitative EMG analysis will be discussed.
PS. Further observations on Biekford's microreflexes as clinical testing. - G. Grampe, D. Porazzi and P. Rovetta (Neurology Dept. City Hospital, Busto Arsizio, Italy)
Bickford's microreflexes as tested by click sounds, light stimuli, or electric pulses to peripheral nerves were investigated in normal subjects and in patients with focal or systemic diseases of the central nervous system. As regards systemic illness, there was a useful trend in the clinical evaluation of Parkinson's disease, including the pharmacological responses. In patients with different kinds of localized lesions, the latencies of Bickford's responses were investigated in relation to the findings of the cortical evoked potentials related to the same sensory system.
PS. Computer analysis of F reslmuses. - A. Grasso, A. Scrofani and F. D'Allm (lstttuto di CUaiea N e u r o l o g t ~ Universi~ di Catanht, 95100 Catania, Italy)
F responses recorded from the hypothenar muscles were examined by a computer program. Parameters automatically determined were: shortest, mean and median latencies, chrono-dispersion, duration and amplitudes. The occurrence of each F response in series of 100 were then evaluated. Inter-trial and side-to-side variations of each parameter were determined. Series of 20-100 responses were compared to determine the reproducibility of the test.
PS. The nem'opathy of bronchogenic carcinoma; a time dispersed analysis. - W , ~ M. Drlicek and W. Popp (L. B o l t m a n n Inst. f. Idin, N ~ A-1138 Vienna, Austria) Peripheral neuropathy occurs frequently in association with bronchogenic carcionoma, although the incidence reported in literature varies widely. We have analyzed 4 groups of patients with bronchogenic carcinoma and studied the peripheral nervous system at the time of tumor diagnosis, in the course of the malignancy by means of nerve conduction velocities, conventional EMG and with SFEMG. Group 3 consisted of patients with small cell carcinoma with antineuronal antibodies to the cerebellum. In the fourth group, a combined clinical and morphologic study, we evaluated PNS structures not readily available for eleetrophysiologic measurements namely dorsal root ganglia, autonomic ganglia and posterior collumns. The involvement of PNS in patients with broncliogenic carcinoma, the characteristics of neuropathy at different stages of the disease, is described.
SY, Clinical syndromes in motor neuron diseases. G.C, Guazzi, A. Rossi and A. Federieo (Istituto di Scienze Neurolollkhe e Ceatro per Io Studio deHe EncefaloNeuro-Miolmtie Geaetiehe, Univemlti di Siena, Siena, Italy)
The so-called motor neuron diseases include a heterogeneous group of disorders mainly characterized by abiotrophy of the second motor neuron. From the clinical point of view, we can distinguish: (1) Werdnig-Hoffmann disease (WILD) with both a rapid and slow evolution; (2) Kugelberg-Welander disease (KWD); (3) Aran-Ducherme disease (ADD), generally characterized by chronic evolution. W H D and K W D are generally transmitted with autosomal recessive inheritance, while dominant inheritance with anteposition phenomenon can be found in ADD. Moreover, sporadic cases, without familial consanguinity, are reported. A D D sporadic cases can follow, 20-30 years later, acute anterior poliomyelitis. The second group of disorder is true amyotrophic lateral sclerosis (ALS) with its classic and pseudopolynevritic forms. Sporadic cases