Comprehensibility assessment : the influence of familiar and unfamiliar partners

• Main Author: Johnston, Jana Kim
• Language: English
• Published: University of British Columbia 2009
• Online Access: http://hdl.handle.net/2429/16756

For many years, the primary focus of assessment and intervention in the field of dysarthria rehabilitation has been the speech output of the affected speaker, as measured by intelligibility. However, this narrow focus on the acoustic adequacy of the speech signal falls short of capturing the full spectrum of information available to speakers and their partners during naturalistic interaction. Alternatively, comprehensibility measures acknowledge that everyday communicative success is greatly affected by the presence of multiple types of signal-independent information (e.g., visual cues, listener familiarity), as well as the dynamics of dyadic interaction (e.g., breakdown repair strategies). In this way, comprehensibility measures may more functionally assess dysarthria severity and the extent to which persons with dysarthria experience disability. The goals of the present study were to establish evidence for the reliability of a structured assessment of comprehensibility for dysarthric speech (developed by Visser, 2004), to investigate how the assessment reflected the effects of listener familiarity on communicative success, and to investigate how strategy use may differ under different familiarity conditions. Two speakers with dysarthria secondary to primary lateral sclerosis (PLS) were each paired with two communication partners: one familiar partner and one unfamiliar partner, to form four dyads in total. Each of these partners scored the speaker’s intelligibility and participated in a dyad-based structured assessment of comprehensibility with the speaker. Results indicated that the assessment was scored with an extremely high degree of inter- and intra-rater reliability. In addition, comprehensibility scores were substantially better for both speakers with familiar versus unfamiliar partners, whereas substantial differences in intelligibility scores were noted for only one speaker. As predicted, unfamiliar dyads were found to use more strategies than familiar dyads, with some overlap across dyads in terms of the strategies used. Overall, the structured assessment of comprehensibility reliably differentiated familiar from unfamiliar dyads, suggesting it may be a clinically relevant assessment tool.