Electrophysiological tests of the hearing organ in Hashimoto's disease.

Thyroid gland diseases resulting from an autoimmunological process may influence the hearing organ. The aim of this study was to assess peripheral and central parts of the hearing organ in children with Hashimoto's thyroiditis. Thirty children (mean age 14.9 years) with Hashimoto's thyroiditis were examined. Patients were euthyroid, and presented high blood concentration of antithyroperoxidase (ATPO) antibodies. Pure tone audiometry, tympanometry, otoacoustic emissions (DPOAEs), and brain auditory evoked potentials (BAEPs) were performed. None of the patients had any complaints about hearing acuity; pure tone audiometry, tympanometry, and DPOAEs were normal in all patients. There were considerable disturbances in auditory nerve and brainstem neural conduction in BAEPs. There was positive correlation between the blood concentration of ATPOA and the extent of the disturbances in the central part of the hearing organ. One should consider the possible presence of subclinical Hashimoto's encephalopathy affecting the central part of the auditory organ.