Design and in vitro testing of a voice-producing element for laryngectomized patients.

A voice-producing element has been developed to improve speech quality after laryngectomy. The design process started with the formulation of a list of requirements. The lip principle has the best potential for fulfilling the requirements. A numerical model was made to find the optimal geometry of an element based on the lip principle. Extensive in vitro tests were performed to check all requirements. For this a test set-up with realistic acoustic and aerodynamic properties was developed. Results show that the protruding lip length dominates fundamental frequency, cross-sectional area dominates flow resistance and relation between flow and fundamental frequency. Most requirements have been fulfilled; both for males and females a potentially good functioning prototype could be selected. Clinical experiments will be performed to confirm the quality of the voice-producing prosthesis.