An investigation of different degrees of dysarthric speech as input to speaker-adaptive and speaker-dependent recognition systems

Abstract

This study describes the feasibility of using speech recognition as a text input method for speakers with different degrees of dysarthria. The project investigated two different types of speech recognition systems: Prototype Swedish DragonDictate (PSDD), a speaker-adaptive phoneme-based system, and Infovox RA, a speaker-dependent, whole-word pattern-matching system. Individuals with mild and moderate dysarthria trained and then used 45 command words to input text independently into the PSDD. The results indicated that the PSDD system adapted well to the speech of individuals with mild and moderate dysarthria, but the recognition scores were lower than for a natural speaker. The PSDD system also adapted to the speech of two participants with different degrees of severe dysarthria, but they were unable to use this system independently. On the Infovox RA system, there was a wide range in the mean recognition scores for participants with dysarthria, whereas the natural speaker reached almost 100%. The recognition score for the participant with very severe dysarthria increased substantially with an adapted vocabulary on the speaker-dependent Infovox RA system. The results are discussed in terms of factors that should be considered before selecting a suitable speech recognition system for speakers with different degrees of dysarthria.

• dysarthria
• speaker-adaptive system
• speaker-dependent system
• speech recognition