The effect of bolus volume on hyolaryngeal muscle activity in Parkinsons Disease

Abstract

Purpose: The purpose of this study was to investigate the differences in submandibular hyolaryngeal muscles activation during swallowing in individuals with PD and healthy older adults (HOA) without PD. The study also investigated effects of bolus volume on submandibular hyolaryngeal during swallowing for people with PD and HOAs. Methods: Participants included 14 participants with PD and 10 HOAs who served as controls. Four swallow tasks were conducted. Three liquid swallow trials at 5ml, 10ml, and 15ml of water, and three trials of 1tsp of pudding was presented as the maximum voluntary contraction swallow. The sEMG signals were recorded during each swallow and were saved as separate files. This resulted in a total of 12 sEMG files for each participant (3 swallows of 5 mL of water, 3 swallows of 10 mL of water, 3 swallows of 15 mL of water, 3 swallows of 1 tbsp. of pudding). Results: The results from the MANOVA determined that 1) contraction amplitude of submandibular muscles differed for individuals with PD and healthy controls but contraction duration did not, and 2) bolus volume had no significant effect of contraction amplitude and contraction duration in either PD or HOA participants and 3) there is no group X condition interactional effect on either contraction amplitude or contraction duration.

Conclusion: Main findings from this study concluded contraction amplitude of submandibular muscles differed for individuals with PD and HOAs and bolus volume had no significant effect on contraction amplitude or contraction duration in both PD and HOA groups. Contraction duration was not found significantly different but descriptive statistics demonstrated a shorter duration than HOAs. This study gives us a better understanding about what is happening to the muscular physiology of the submandibular muscles. People with PD with subclinical dysphagia may be utilizing compensatory strategies to effect contraction timing. The findings from this study may support the theory of compensatory neuromuscular adaptions utilized by people with PD during the earlier stages of disease severity. Further studies should be completed to verify and expand on these findings.