Objective: The association of temporomandibular joint (TMJ) disorders with aural symptoms, such as tinnitus, otic fullness, and subjective decrease of hearing acuity, is a well-established clinical observation. Although several hypotheses have been made about the otic-conductive origin of these complaints, conventional 226-Hz tympanometry has failed to demonstrate any middle ear abnormalities. The aim of this study was to evaluate patients with TMJ disorders with multiple frequency tympanometry (MFT).
Study design: Prospective clinical study.
Setting: Outpatient clinic.
Patients: The population of this study consisted of 40 patients with unilateral TMJ disorders diagnosed for longer than 1 month.
Interventions: After verifying that there were no abnormal otoscopic findings, 226-Hz tympanometry, conventional pure-tone audiometry, brainstem auditory evoked potentials, and MFT were performed.
Main outcome measure: Resonant frequency (RF) values.
Results: With the exception of MFT, no abnormal audiologic findings were revealed. The ear ipsilateral to the lesion demonstrated significantly higher (p = 0.002) RF values in comparison to the contralateral ear. The difference in RF values was more obvious in patients aged 45 years or younger.
Conclusion: The results of this study imply an increase in the stiffness of the middle ear, which has not been detected by conventional tympanometry. This represents the first concrete documentation of minor alterations in the conductive properties of the middle ear and seems to support the various hypotheses on the middle-ear origin of aural complaints in patients with TMJ disorders. Further studies are needed before a clear insight on the presumably multifactorial pathophysiology of these complaints can finally be reached.