Improving the Quality and Intelligibility of Electrolaryngeal Speech during Mobile Communication with Landline Analogous Bandpass Filtering.

The normal functioning of the larynx or voicebox gives humans the ability to converse with others effortlessly. However, if the larynx is permanently removed due to injury or illness, speech cannot be produced. The electrolarynx, a noninvasive device used to produce speech for such persons, has a motor-induced hum which hinders telephone-based communication among electrolaryngeal speakers. This adversely affects the morale of electrolarynx users, leading to abandonment of technology, psychological issues and decreased quality of life. This paper examines a technique based on bandpass filtering of electrolaryngeal speech which has the potential of increasing the quality and intelligibility of speech produced by means of an electrolarynx. Finite impulse response and infinite impulse response filtering with bandpass frequencies analogous to telephone landline and wideband filtering were investigated. Objective testing and subjective testing of quality and intelligibility of electrolaryngeal speech have been performed in each phase of the work. Statistical analysis based on one-way analysis of variance (ANOVA) has been conducted after each round of subjective testing. Results indicate that the quality as well as intelligibility of electrolaryngeal speech can be improved with the help of bandpass filtering.