Controllable artificial larynx using neck myoelectric signal

We developed a novel artificial larynx with on/off and pitch control for Speech Production Substitutes (SPSs) users, particulary an electrolarynx control based on the myoelectric signal of the laryngeal muscles located near the body surface (such as the sternohyoideus). For patients who have lost their vocal cords or its function for vocalization, various SPSs have been developed and widely used. However, these substitutes have the limitation -that they cannot match with the vocalization of healthy human larynx. The measurement of the surface myoelectric potential was performed and we studied its efficiency for voice on/off and pitch frequency control. The results show that there is a quadratic relation between the measured myoelectric potential and the pitch frequency. Using this relation, it was possible to control the pitch frequency of the generated sound in three levels with 86.7% of accuracy (condition of linear relationship lead 68.9%). This confirms that the surface myoelectric potential was a suitable control signal for the artificial larynx. In this paper, the capability of novel controllable artificial larynx controlled by myoelectric signal of sternohyoideus was described.