Quantification of Motor Unit Firing Patterns

• Main Authors: Wu, Chrong-Min, 吳崇民
• Other Authors: Jia-Jin Chen
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/46893074048891162051

碩士 === 國立成功大學 === 醫學工程研究所 === 86 === AbstractAnalysis of single motor unit (MU) discharge patterns provides an understanding of the neurophysiologic basis for quantifying the motor control ability. The aim of this research is to apply the surface motor unit action potentials (MUAPs) measured with noninvasive multielectrode for studying the firing characteristics of stroke, neuropathy, myopathy, and healthy volunteers.To investigate the firing rate variation, the measures of singular value decomposition (SVD), joint interval histogram (JIH), and autoregessive model (AR), derived from interpulse interval (IPI) train, were adopted in this research. This study first verifies the JIH parameters, including slope and area obtained from the AR model of simulated IPI sequences. Our simulation results indicate that the JIH slope reflects the stability of firing sequence and the JIH area indicates the whole firing variation. However, the measurement of SVD slope is too sensitive to the data distribution which is discarded in later clinical studies. Furthermore, this study extends the JIH representation to the second-order AR model. For second-order AR model, the firing characteristics can be observed from the location of poles, in terms of radius and phasic angle in z- plane. The phasic angle of the dominated pole, i.e. with larger radius, can be used to quantify the firing stability. An IPI sequence with larger radian of phasic angle indicates better controllability and vice versus.For each of the recruited subjects, sessions of the electromyographic (EMG) signal from the first dorsal interosseus (1st DI) during voluntary and isometric contraction were recorded. A multistage approach, including spatial filtering for peak localization and spatial decomposition for overlapping MUAPs, was utilized for the MU activity analysis of stroke patients. From limited numbers of clinical cases, the changes of firing characteristics of stroke patient, a upper motor neuron disease, significantly differ from the normal mainly in JIH slope indicating lower firing stability. However, the subjects with neuropathy and myopathy have higher firing variation in comparison with that of normal subjects. Our results indicate that the extracted parameters of the JIH ellipse as well as AR model can provide quantitative assessment for motor control ability in stroke patients.