Examination of Validity of Low-cost electromyography feedback device by using smartphone

Abstract

Purpose : To spread the use of EMG biofeedback devices, we have developed a simple and low-cost electromyography (EMG) biofeedback device that can be used with the latest model of smartphones and tablet terminal (LC-EMG). The specific purpose of this study was to verify whether the performance of the LC-EMG fulfills the requirement of the use in EMG biofeedback therapy or not. For this purpose, here we compared the performance between the LC-EMG and the existing EMG device (Neuropack 8).

Methods : The muscle activity of the right extensor carpi ulnaris was recorded when the participants repeated the movement of wrist dorsiflexion and palmarflexion for 5 times in 10 seconds. The EMG signal was simultaneously recorded by the LC-EMG and Neuropack 8. We compared the waveform of these EMG signals and their root mean squared signals in appearance and by cross-correlation analysis.

Results : The EMG waveforms monitored by LC-EMG were similar to those of the Neuropack 8 and visually recognized on-line using smartphone. The cross correlation analysis also demonstrated that the delay and size of the waveforms of LC-EMG were almost equal to those of the Neuropack 8.

Conclusion : It is concluded that the LC-EMG device has a reliable performance to monitor the EMG signal as the existing EMG devices and is available for the use in EMG biofeedback therapy. We consider that the LC-EMG device has advantages in cost and handiness and will be widely used in various clinical situations.