The most common artificial voice source for post-laryngectomy speech rehabilitation is the hand-held buzzer or electrolarynx (EL). This device is relatively easy to use and enables most laryngectomees to verbally communicate, but with reduced intelligibility and markedly degraded naturalness. In addition, EL speech is often described as robotic and monotone, attributable largely to the lack of normal fundamental frequency (F0) variation/control and abnormal voice source timing (e.g. voice onset and offset controlled by a thumb button). Previous research has demonstrated that neck surface electromyographic (EMG) signals can serve as an intuitive and effective control source for EL voice onset/offset timing and F0 modulation. The goal of this project is to develop an effective, practical, and user-friendly EMG-EL voice prosthesis that can provide improved control over voice source timing and F0 for more intelligible and natural-sounding EL speech. In Phase I we achieved the following specific aims: 1) Produced a prototype wireless EMG sensor appropriate for EL control;2) integrated wireless EMG signal reception and processing circuitry into a hand-held EL;and 3) evaluated the prototype EMG-EL through pilot testing with two laryngectomy patients experienced in EL use. In Phase II of this effort we will further refine the EMG-EL voice prosthesis by 1) testing the system with additional EL users both in the laboratory and though daily use with an at-home trial, 2) designing and building a new version of the EMG-EL prosthesis that can automatically adjust F0 range, onset/off thresholds, and EMG artifact rejection based on individual user's EMG signals, 3) testing the new system with EL users and performing perceptual assessment of their speech results by a large sample of listeners across a wide age range using an online interface, 4) application of visual and acoustic-based EMG biofeedback to improve EMG-controlled F0 modulation of vocal intonation, 5) conducting an extended at-home trial of the new EMG-EL system with EL users, and 6) creating a user guide and set of clinical instructions in preparation for EMG-EL system commercialization.
The most common voice prosthesis used after total laryngectomy is the hand-held buzzer or electrolarynx (EL), but EL speech typically lacks pitch variation and precise timing control, giving it a highly unnatural sound quality with reduced intelligibility. Previous research has shown that pitch variation can significantly improve EL speech, and that neck muscle electromyographic (EMG) signals can be used as an intuitive control source for controlling EL vocal intonation and timing (onset/offset). The objective of this project is to develop and test an EMG-controlled EL that can be offered commercially to improve the communication and therefore lives of thousands of EL users.