Perceptual Training to Improve Listeners' Ability to Understand Speech Produced by Individuals With Dysarthria

Perceptual Training to Improve Listeners' Ability to Understand Speech Produced by Individuals With Dysarthria

There exist very few effective treatments that ease the intelligibility burden of dysarthria. Perceptual training offers a promising avenue for improving intelligibility of dysarthric speech by offsetting the communicative burden from the speaker with dysarthria on to their primary communication partners-family, friends, and caregivers. This project, utilizing advanced explanatory models, will permit identification of speaker and listener parameters, and their interactions, that allow perceptual training paradigms to be optimized for intelligibility outcomes in dysarthria rehabilitation. This work addresses this critical gap in clinical practice and sets the stage for extension of dysarthria management to listener-targeted remediation-advancing clinical practice and enhanced communication and quality of life outcomes for this population.

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.

400 listeners will be recruited and enrolled. Each participant will be randomly assigned to receive perceptual training with one of 20 speakers with dysarthria, such that 20 listeners will be assigned to each speaker with dysarthria. All listener participants will receive the perceptual training intervention.

To examine the effect of perceptual training with speakers with dysarthria, we use a standard three-phase perceptual training protocol involving pretest, training, and posttest phases, in which speech samples from a single speaker with dysarthria are utilized for all three phases.

Each listener is familiarized/trained with a single speaker with dysarthria. Pretest/posttest transcription data will be used to build explanatory models of intelligibility improvement.

Inclusion Criteria: *Native speakers of American English Exclusion Criteria: No self-reported history of speech impairment No self-reported history of language impairment No self-reported history of cognitive impairment

Results of the proposed research will be disseminated through conference presentations and manuscripts submitted to academic journals. In addition, the de-identified data will be available for public access via a data repository at the University of Michigan (ICPSR). The study will be registered in ClinicalTrials.gov within 21 days of enrollment of the first participant. Results will be submitted within 1 year of completion of the study. Informed consent documents will contain a statement concerning posting of information to ClinicalTrials.gov. Utah State University's Investigator Handbook (Chapter 9) outlines a policy for reporting all ClinicalTrials.gov information, specifically stating that it is the PI's responsibility to do so according to NIH policy.

Information related to the protocol and statistical analysis plan will be shared in future publications. The analytic code will be shared via the Open Science website, with the link included in associated publications.

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