Preliminary Findings of Contrastive Stress in Severe Dysarthria
R Patel, L Wayne
This pilot study sought to better understand whether speakers with severe dysarthria due to cerebral palsy could signal contrastive stress and the acoustic features they employed. Two speakers with severe dysarthria due to cerebral palsy (DYS) and two gender-matched non-impaired speakers (NIC) produced five 4-syllable phrases with contrastive stress placed on either the first, second, third, or fourth syllable and with neutral prosody. Their productions were analyzed acoustically to identify changes in syllable duration and fundamental frequency (F0) on stressed syllables. Preliminary results indicated that DYS speakers used elongated duration, increased peak F0, and increased average F0 to mark the target syllable. These cues, however, were not consistently employed on all stress locations. While NIC speakers also used duration and F0 cues contrastively, their stressed modifications were smaller in extent. We will discuss possible physiological constraints, which may explain our findings and that may be used to develop models of prosodic control in dysarthria. Implications on this work include the potential to develop new intervention methodologies that focus on prosody and to use this residual control to access AAC devices in order to improve communicative effectiveness of individuals with severe dysarthria.