A method for quantitative SEMG decomposition and MUAP classification during voluntary isovelocity elbow flexion.

The purpose of this study was to develop an algorithm for surface electromyogram (SEMG) decomposition and classification of surface motor unit (MU) action potential (MUAP) detected during isovelocity elbow flexion. In our proposed algorithm, firstly the measured SEMG was extracted for 3 seconds by every 1.5 seconds. SEMG was decomposed with Independent Component Analysis (ICA) technique, and classified with template matching. Finally, the MUAP trains were identified under the firing time of the MUAPs classified in each extracted period. The SEMG was measured from the biceps short head muscle during voluntary elbow flexion of 0 to 90 degrees at constant velocity 9 degree/s against a constant load torque of 10%MVC and the MUAPs were classified with our proposed algorithm. As a result, calculated MUs firing rates were almost same as the results in the previous studies. It was shown that the proposed algorithm was useful for decomposing SEMG detected during flexion movements.

Analysis of spatial temporal plantar pressure pattern during gait in Parkinson's disease.

Spatial temporal plantar pressure patterns measured with sheet-shaped pressure sensor were investigated to extract features of gait in Parkinson's disease. Both six subjects of Parkinson's disease (PD) and elderly fourteen normal control subjects were asked to execute usual walking on the pressure sensor sheets. Candidate features were step length, step time, gait velocity and transition of center of pressure to foot axis direction. The step length and gait velocity were smaller in PD subjects than those in normal subjects. Time of step cycle in three PD subjects were longer than that in normal subjects while the times of other PD subjects were similar to those of control subjects. The length from heel contact to toe off within one footprint was small in the subjects with short step length. Such possibility was indicated that Parkinson's disease in gait could be separated from normal subjects by these features.

Experimental and analytical investigations of motor unit location for the precise estimation of muscle force with surface electromyograms.

Surface motor unit action potential (SMUAP) is generated from a motor unit (MU) located at certain depth from the skin surface. The depth is referred to as MU location in the present papers. The MU location affects the amplitude of MUAP, and smoothed rectified electromyogram (SR EMG) is used to estimate for the muscle force. The aim of this study is to investigate MU locations in the short head of biceps brachii (BIC) and the first dorsal interosseous (FDI), experimentally and analytically with eight-channel surface EMGs (SEMGs) in isometric voluntary contractions. In order to estimate the MU location, profiles of peak SMUAP at each channel were compared with those of different MU locations obtained from the tripole current source model. From the result, MU locations of BIC distributed in a certain range, and those of FDI seemed to be identical. Our method was practical and useful for estimating the approximated MU location.