Improved LAboratory Prototype ELectrolarynx (LAPEL): using inverse filtering of the frequency response function of the human throat.

The electrolarynx (EL) provides a valued means of verbal communication for people who have lost their larynx. Existing ELs have some drawbacks such as harsh, raucous, and unpleasant sound and the presence of background noise. This study presents an experimental analysis of two commercial ELs and describes the development and testing of an improved LAboratory Prototype ELectrolarynx (LAPEL) which more accurately simulates the sound of a natural larynx and has lower background noise. This natural sound is obtained by determining the frequency response function (FRF) of the tissue of the human neck and using this information to tailor the input signal to the EL by inverse filtering such that its output spectrum resembles that of the natural larynx. The result was subjectively judged to have a superior and more natural sound than existing electrolarynxes.