High frequency audiometry and stapedius muscle reflex thresholds in juvenile diabetics

Sixty-one juvenile, insulin-treated diabetics below 50 years of age with a duration of diabetes mellitus longer than 10 years underwent impedance audiometry with determination of stapedius reflex thresholds at 500 Hz, 1, 2, and 4 kHz, conventional pure tone and speech audiometry, and high-frequency audiometry up to 20 kHz. The results were compared with a normative material of non diabetic subjects selected after exactly the same criteria. No significant differences in hearing or stapedius reflex thresholds were found. Among half of the subjects there was a diabetic retinopathy. A comparison between those with and those without retinopathy did not reveal any significant difference in audiological findings. Even subjects with severe diabetic complications and almost life-long diabetes had normal hearing. Recent investigations on plasma-lipoids have discussed the possibility that insulin might prevent a premature ageing of hearing which has been reported by other authors. It is concluded that no statistical data exist that confirm a correlation between hearing impairment and diabetes.