Background:
Total laryngectomy is a surgical procedure to completely remove the hyoid bone, larynx, and associated muscles as a curative treatment for laryngeal cancer. This leads to insufficient swallowing function with compensative movements of the residual tongue to propel the food bolus to the pharynx and esophagus. However, the neurophysiological mechanisms of compensative swallowing after total laryngectomy remain unclear. Recently, swallowing-related cortical activation such as event-related desynchronization (ERD) during swallowing has been reported in healthy participants and neurological patients with dysphagia. Abnormal ERD elucidates the pathophysiological cortical activities that are related to swallowing. No report has investigated ERD in post-total laryngectomy patients.
Case:
We investigated ERD during volitional swallowing using electroencephalography in three male patients after total laryngectomy for laryngeal cancer (age and time after surgery: Case 1, 75 years, 10 years; Case 2, 85 years, 19 years; Case 3, 73 years, 19 years). In video fluorographic swallowing studies, we observed compensatory tongue movements such as posterior-inferior retraction of the tongue and contact on the posterior pharyngeal wall in all three cases. Significant ERD was localized in the bilateral medial sensorimotor areas and the left lateral parietal area in Case 1, in the bilateral frontal and left temporal areas in Case 2, and in the left prefrontal and premotor areas in Case 3.
Discussion:
These results suggest that cortical activities related to swallowing might reflect cortical reorganization for modified swallowing movements of residual tongue muscles to compensate for reduced swallowing pressure in patients after total laryngectomy.