A Study of Speech Phase in Dysarthria Voice Conversion System

Dysarthria is a communication disorder common in people with damaged neuro-muscular apparatus resulting from events such as stroke. For a dysarthric speaker, voice conversion (VC) is one of the well-known approaches to improve speech intelligibility for a dysarthric speaker. Most of the well-known VC methods focus on converting amplitude features without phase information. Previous studies indicated that phase is an important factor in the speech signal. Therefore, we are interested in adding the correct phase information to VC for dysarthria speech. The results of automatic speech recognition and spectrum analysis show that intelligibility is improved by replacing the dysarthria phase with the normal phase during the synthesis step. It implies that the correct phase information must be considered for the dysarthria VC system.