Abstract: Stroke frequently results in oral-motor deficits that lead to difficulty speaking and eating. The recovery of oral-motor function after stroke is critical for both health and quality of life, yet these problems are understudied, and clinical care is often limited to compensatory strategies.

Neural and muscular plasticity allow for substantial recovery of motor function after stroke and are the primary targets of most rehabilitation strategies. However, most of what we know about neuromuscular plasticity after stroke is specific to the corticospinal tract. A better understanding of the unique mechanisms of corticobulbar neuromuscular plasticity after stroke is needed as this knowledge gap is a limiting factor to improving interventions for dysphagia and dysarthria.

Using a pre-clinical rodent model allows for detailed studies of function and physiology that tie together multilevel plastic changes including the cortex, brainstem motor nuclei, muscles, and functional behavior. The middle cerebral artery occlusion (MCAO) rat stroke model develops a range of deficits in cranial function including changes is swallowing, mastication, and vocalization as well as chronic lingual weakness, a common feature of post stroke dysphagia and dysarthria.

Key findings on the underlying neural and muscular changes contributing to these deficits include reduced central activation as a driving factor in lingual weakness, hemispheric differences in the motor cortex plasticity of tongue and jaw muscles, and preliminary data indicating secondary degeneration of lingual motor neurons in the brainstem.

Future work will expand on these findings and look at the neuromuscular impact of clinically based interventions, such as tongue exercise and neuromuscular stimulation with the long-term goal to improve rehabilitation by optimizing interventions to better match physiological targets with the most potential for recovery. 

This year’s SHRP schedule is available here: https://purdue.edu/TPAN/hearing/shrp_schedule

Titles and abstracts of all SHRP talks are here: https://purdue.edu/TPAN/hearing/shrp_abstracts