Real-time clarification filter of a dysphonic speech and its evaluation by listening experiments

This paper presents a digital filtering algorithm which clarifies dysphonic speech with the speaker’s individuality preserved. The study deals with the clarification of oesophageal speech and the speech of patients with cerebral palsy, and the filtering ability is being evaluated by listening experiments. Over 20,000 patients are currently suffered from laryngeal cancer in Japan, and the only treatment for the terminal symptoms requires the removal of the larynx including vocal cords. The authors are developing a clarification filtering algorithm of oesophageal speech, and the primal algorithm of software clarification and its effectiveness was reported in the previous ICDVRAT. Several algorithms for the clarification have been newly developed and implemented, and are being evaluated by questionnaires. The algorithms were extended and applied for the clarification of the speech by the patients of cerebral palsy.