The function of tensor veli palatini muscles in patients with aural symptoms and temporomandibular disorder. An EMG study.

This preliminary study investigated Myrhaug's neuromuscular hypothesis by means of audiological and electromyographic assessment. After a clinical examination of the TMJ system, the activity of the tensor veli palatini muscles in the state of rest and during swallowing was investigated in 16 patients with the help of an EMG recording, and the tube-opening function was evaluated endoscopically. Results showed that 6.25% of the patients suffered from mild joint-dysfunction (group I), 81.25% from a moderate dysfunction (group II), and 12.5% from severe dysfunction (group III). Although five patients suffered from tinnitus and 11 from fullness in the ear, both the audio- and tympanogram performed on 15 patients displayed normal recordings. Only one patient suffered from moderate sensorineural hearing loss. In the EMG recording, 11 of the 16 subjects displayed normal EMG patterns in state of rest and during swallowing contraction. In two cases, abnormal EMG recordings were obtained due to incorrect insertion of the EMG needle. The study's results indicate that spasm in the masticatory muscles of TMJ patients neither seems to cause reflex spasm of the tensor palatini muscles nor to effect significant alterations in Eustachian tube function.