Study about improvement of walking ability of hemiplegia after therapeutic electrical stimulation by means of MMG, EMG and motion analysis

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Therapeutic electrical stimulation (TES) was applied to hemiplegic patients in chronic stage. All of them showed improvement of walking ability. Mechanomyogram (MMG) detecting system was established. However, it was impossible to detect signals by means of this system during gait because of noise. The noise was occurred at the attachment between a microphone and skin. This was a fundamental problem of our MMG system. MMG and EMG analysis during gait were canceled. Instead of them, MMG and EMG analysis during isometric contraction of the quadriceps femoris were done. The hip joint was fixed at 90 degrees and ankle joint at 0 degree. The knee joint was set to 60 and 90 degrees. Muscle contractile force was measured by KIN-COM (Chattanooga, TN). Based on the maximal voluntary contraction of knee extensor, the session was arranged as follows ; 20, 40, 50, 60, 70 and 80 %MVC. MMG data were processed by Fourier and Wavelet transform.Integrated EMG (IEMG) and integrated MMG (IMMG) increased according to increase of %MVC at 60 degrees of knee joint. While IEMG showed similar result at 90 degrees of knee joint, IMMG showed peak at 70 %MVC. This difference indicates characteristic of EMG and MMG. Both of IEMG and MMG showed higher activity at 90 degrees than at 60 degrees of knee joint. Only MMG of 80 %MVC at 90 degrees showed decrease. MMG might not vibrate enough at high level of muscle contraction because inner pressure of muscle compartment might be too high to vibrate.MMG showed different aspect of muscle activity. The information can be useful for estimate TES effect to paretic muscles.