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, abnormal voice source timing (e.g. voice onset and offset controlled by a thumb button) and abnormal spectral characteristics (e.g., reduced energy below 500 Hz). 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 that can provide improved control over voice source timing and F0 for more intelligible and natural-sounding EL speech. The Phase I specific aims are 1) Produce a prototype wireless EMG sensor appropriate for EL control;2) Integrate wireless EMG signal reception and processing circuitry into a hand-held EL;and 3) Evaluate the prototype EMG-EL through testing with laryngectomy patients experienced in EL use. Assuming successful prototype development in Phase I, work in Phase II will further refine the EMG-EL by 1) Optimizing the control scheme of F0 and onset/offset from neck surface EMG signals;2) Determining which device parameters are appropriate for user adjustment which should be set by the clinician guiding speech rehabilitation;and 3) conducting extensive user testing of the device with iterative adjustment of its form and function based on user performance and structured feedback.
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.
| Heaton, James T; Robertson, Mark; Griffin, Cliff (2011) Development of a wireless electromyographically controlled electrolarynx voice prosthesis. Conf Proc IEEE Eng Med Biol Soc 2011:5352-5 |
