Abstract
We are developing an electrolarynx of implant type controlled by the EMG of the sternohyoid muscle. In this paper, first of all, we researched the possibility that speech functions such as pitch frequency and voiced and unvoiced sounds can be voluntarily controlled by the EMG of the sternohyoid muscle. In addition, we developed an electrolarynx controlled by the EMG of the sternohyoid muscle, and examined the properties of the electrolarynx. For this purpose, we performed three experiments to test the physical properties of the EMG of the sternohyoid muscle assuming the following conditions. First, the on/off control of the vibrator of the electrolarynx is synchronized with the activity of the sternohyoid EMG. Second, the higher pitch frequency of the electrolarynx is produced according to the lower amplitude of the sternohyoid EMG, and vice versa. Third, the period of firing or not firing of the sternohyoid EMG corresponds to the period of voiced sound or unvoiced sound of the electrolarynx. As a result of the experiments, we found that the on/off of the vibrator, the pitch frequency and the voiced/unvoiced sounds of the electrolarynx can be controlled by using the sternohyoid muscle. Then, we performed the same three experiments using the developed electrolarynx. We found that the electrolarynx controls the on/off of the vibrator and the pitch frequency and may control the voiced/unvoiced sounds. This study may aid the development of an implant type electrolarynx in the future.
