Pharyngeal Stimulation in Head and Neck Cancer Patients with Dysphagia: Functional Outcomes and Transcranial Magnetic Stimulation Motor Evoked Potentials

Abstract

Purpose: Head and neck cancer patients often experience swallowing disorders, impacting health and quality of life. This study examined effects of electrical stimulation to the pharynx on swallowing outcomes in post-surgical head and neck cancer patients.Methods: Swallowing was assessed using video fluoroscopy before, and 30 minutes after, a ten-minute application of electrical stimulation to the pharynx in five patients experiencing moderate-severe dysphagia. Corticopharyngeal motor projections were measured before and after stimulation of the pharynx using transcranial magnetic stimulation of motor cortex and measurements of motor evoked potentials (MEPs) in the striated muscle of the posterior pharyngeal wall.Results: Short-term changes in swallowing function were observed post-stimulation in: pharyngeal transit time, cricopharyngeal opening duration, total number of swallows, penetration/aspiration score, and duration of contact between the base of tongue and posterior pharyngeal wall. MEPs could not be measured in two participants. In the remaining participants, the MEP measures were not strongly associated with changes in observed swallowing function as has been found for neurogenic dysphagia.Conclusions: These findings indicated that somatosensory input, generated by electrical stimulation of the pharynx, changes swallowing function in head and neck cancer patients. These changes are not strongly correlated with alterations of corticopharyngeal excitability as previously observed in acutely dysphagic stroke patients.