TYMPANOMETRY IN PATIENTS WITH INSULIN-DEPENDENT DIABETES-MELLITUS

Tympanograms were studied in 53 patients with insulin-dependent diabet es mellitus (IDDM) and 42 randomly selected non-diabetic control subje cts. aged between 20 and 40 years, using the Madsen Model ZO 73 Impeda nce Bridge. Subjects with abnormal tympanic membrane, conductive heari ng loss and known reason for hearing impairment (e.g. noise damage) we re excluded from the study. The mean tympanogram amplitudes in diabeti c patients were significantly lower in both ears than those of control subjects. The duration of diabetes and microvascular complications (n ephropathy and retinopathy) were associated with decreased amplitudes. These findings indicate that decreased tympanogram amplitudes in pati ents with IDDM are probably caused by diabetes of long duration and th e microvascular complications associated with it.