Phonatory control in adults with cerebral palsy and severe dysarthria

Abstract

Augmentative and alternative communication (AAC) users with severe dysarthria may benefit greatly from using residual vocalizations to enhance communication efficiency and naturalness. Many individuals use their residual vocal control to gain attention, express emotions, and convey intentions to familiar care givers. This research was designed to test the hypothesis that speakers signal such information through the control of phonatory features such as pitch and duration, despite severe degradation of segmental speech sounds. The study examined whether eight speakers with severe dysarthria caused by cerebral palsy could control the pitch and duration of sustained vowel productions at three distinct levels. The results indicated that all speakers were able to consistently control sustained production of the vowel /a/ at three durations (short, medium, and long). Speakers were more variable, however, in their ability to control pitches (low, medium, and high). Seven of the eight speakers were able to produce at least two distinct pitches. The potential impact of harnessing residual phonatory control as an additional channel of input for AAC users with severe speech and motor impairment is discussed.