Summary: | 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.
|