Electrophysiological change in the tensor veli palatini muscle after radiotherapy.

Conclusion: Electromyography of the tensor veli palatine (TVP) was abnormal and showed mainly myogenic impairment in patients with nasopharyngeal carcinoma (NPC) with secretory otitis media (SOM) after radiotherapy. The diseased ears showed impairment in opening functions of the eustachian tubes (ETs).
Objectives: To characterize electrophysiology of the TVP muscle using electromyography (EMG) in patients with SOM after radiotherapy of NPC.
Methods: Twenty healthy volunteers and 20 patients with NPC and SOM after radiotherapy were chosen for assessment of EMG of the TVP during swallowing.
Results: The measurements of average duration and amplitude of action potential, swallowing contraction duration, and peak voltage in NPC patients with both SOM (n = 25) and healthy ears (n = 6) were significantly lower than those of ears (n = 38) in healthy controls (p < 0.01). In patients with NPC, the average action potential duration and swallowing contraction duration in ears with SOM were lower than those of subjects with healthy ears (p < 0.05), whereas no significant difference was found in average amplitude of action potential and peak voltage between them.