Evaluation of orofacial force-related measures using a novel measuring device: explanation of associations with speech rate in dysarthria.

Background: The aim of this study was to examine the potential associations between orofacial force-related measures and speech rate in matched groups of 23 adults with dysarthria, and 69 healthy adults.

Research design and methods: A novel piezoresistive sensor-based device was utilized to obtain the orofacial maximum forces (OMFs) and rate of force development (RFD) measures. The study computed alternating motion rates (AMRs), sequential motion rates (SMRs), and articulation rate (AR) for all participants. The analysis included between-group comparisons and correlation analyses. The study also examined the reliability of the OMFs and RFD measures.

Results: Individuals with dysarthria exhibited significantly slower speech rates (approximately 41.89% to 56.53% slower) compared to the control group. Except for a few exceptions in the jaw, the dysarthria group demonstrated significantly lower OMFs and RFD measures. The correlation analysis revealed that OMFs were weakly to moderately correlated (r = .488-.674) and RFD measures were very weak to moderately correlated (r = .047-.578) with speech rate measures.

Conclusions: The findings suggest that reduced OMFs and RFD measures may contribute to the slowed speech rate observed in adults with dysarthria. The study also highlights that OMFs are significantly more reliable (day-to-day) than RFD measures.