Perceptual Training for Improved Intelligibility of Dysarthric Speech

There exist very few effective treatments that ease the intelligibility burden of dysarthria, and all of these require cognitive and physical effort on the part of the speaker to achieve and maintain gains. Therefore, individuals with intelligibility deficits whose cognitive and physical impairments limit their ability to modify their speech are currently not viable treatment candidates. This constitutes a significant health disparity that disproportionately affects those clinical populations with developmental, cognitive, and/or significant neuromuscular impairment.

To address this critical gap in current dysarthria management, the weight of behavioral change is shifted from the speaker to the listener. While a novel concept for dysarthria management, the idea is firmly rooted in the field of psycholinguistics and supported by a programmatic body of research showing that listener-targeted perceptual training paradigms (wherein listeners are familiarized with the degraded speech signal and provided with an orthographic transcription of what the speaker is saying) result in statistically and clinically significant intelligibility gains in dysarthria. Further, preliminary evidence suggests that these intelligibility outcomes may be influenced by hypothesis-driven speaker parameters, such as acoustic predictability of speech rhythm cues, and listener parameters, such as expertise in rhythm perception.

A requisite next step to bringing listener-targeted perceptual training closer to clinical implementation, and the overarching goal of this clinical trial, is the systematic and rigorous analysis of the speaker and listener parameters, and their interactions, that modulate, and in some cases optimize, perceptual training benefits of intelligibility improvement. To achieve this aim, an existing database of dysarthric speech (20 speakers with dysarthria) and a large cohort of listeners (n = 400) across two well-established testing sites, Utah State University and Florida State University are utilized. Thus, the key deliverable resulting from this work will be explanatory models that account for the unique and joint contributions of speaker and listener parameters on the magnitude of intelligibility improvement following perceptual training with dysarthric speech.