From Speech Function to Communicative Participation in Dysarthria - PROJECT SUMMARY Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with a prevalence of over 5 cases per 100,000 people. People with ALS (PALS) typically develop bulbar motor symptoms throughout the course of the disease, often leading to dysarthria, a neuromotor disorder of speech execution. Dysarthria interferes with successful communicative interactions by reducing intelligibility, increasing the effort required by listeners to understand the speech signal, and reducing speech naturalness. Gaps in our understanding of the underlying speech production factors contributing to communicative participation are significant barriers to identifying treatment targets, identifying the onset of communicative participation restrictions, and monitoring progress. To address these gaps, a better understanding of the acoustic and perceptual attributes of dysarthria that degrade communicative participation is critical. The purpose of this project is to identify causal links between speech acoustic features, perceptual speech features, and communicative participation. In Aim 1, we test the hypothesis that listener effort and speech naturalness will be strongly associated with communicative participation using bivariate correlations and multiple linear regression. In Aim 2, we test the hypotheses that (1) acoustic features related to speech clarity will be strongly associated with listener effort, and (2) that acoustic features representing prosody will be strongly associated with speech naturalness, using bivariate correlations and multiple linear regression. In Aim 3, we test the hypothesis that speech acoustics will predict communicative participation and that this relationship will be primarily mediated through clinical impressions of listener effort and speech naturalness using a mediation analysis. The long-term goal of the proposed research is to maximize communicative participation, and thereby improve the quality of life of PALS. Results will inform treatment by (1) guiding the use of evidence-based clinical tools (e.g., listener effort and naturalness rating scales) that are associated with communicative participation for assessment and monitoring, and (2) identifying specific treatment (e.g., articulatory precision, speech prosody) targets to support communicative participation. This project falls under NIDCD’s Priority Area 3 in Voice, Speech, and Language Research, as it investigates a causal framework that could support diagnosis, treatment, and progress monitoring in individuals with speech impairments. Furthermore, this work is in line with NIDCD’s mission to further our knowledge and understanding of communication disorders.
