Tinnitus in temporomandibular disorders: Electrophysiological aspects

Objective: To evaluate the brainstem auditory evoked potentials (BAEPs) and the middle latency responses (MLRs) obtained in the patients with TMD and tinnitus in the hope of clarifying the electrophysiological aspects of this association. Materials and Methods: The study group consisted of 22 adults with unilateral TMD and ipsilateral tinnitus. Two were men, and twenty were women, with a mean age of 34.4 years, ranging between 18 and 54 years. Fifteen adults with normal hearing, free of tinnitus and neurologic disease, served as the control group. There were 5 men and 10 women, with a mean age of 29.4 years, ranging from 22 to 35 years. Bilateral BAEP and MLR were recorded and statistically compared between the groups. Results: BAEPs were not significantly different between these two groups (p>0.01). As for MLRs, the mean values of the latencies of the wave Pb and the wave Nc were significantly smaller than those of the control group (p<0.01). The mean values of the amplitudes of the waves Na, Pa and Pb were significantly greater in comparison with those of the control group (p<0.01). Conclusion: These findings indicate that TMDs cause electrophysiological changes in the higher brain centers, while classical lemniscal pathway is not affected. It might be concluded that, by the stimulation of the somatic pain, extralemniscal pathway might be involved in tinnitus perception in the patients with TMDs. © The Mediterranean Society of Otology and Audiology.