Impaired central auditory processing in type 2 diabetes mellitus

BACKGROUND: Diabetic neuropathy and microangiopathy are common complications that can cause central auditory processing (CAP) dysfunction. Most of the previous literature evaluated peripheral hearing loss and speech perception ability in populations with diabetes mellitus. The present study aimed to assess some CAP functions in adults with type 2 diabetes mellitus (T2DM).METHODS: Sixty adult individuals with T2DM participated as the diabetic group with 60 age and gender matched normoglycemic individuals as the control group. All subjects were submitted to full history taking, laboratory investigations (fasting blood sugar and HbA1c), Mini-Mental State Examination (MMSE), basic audiological evaluation and some behavioral CAP tests (Speech in Noise Test, Dichotic Digits Test and Auditory Fusion Test).RESULTS: The diabetic group had high frequency sensorineural hearing loss and poorer behavioral CAP when compared to their normoglycemic peers. Patients with longer disease duration and patients with mild cognitive impairment had poor behavioral CAP scores. Unexpectedly, no correlations were observed between CAP scores and HbA1C levels.CONCLUSIONS: T2DM has deteriorating effect on the CAP ability affecting the quality of life. Early detection of these complications is important to prevent more central deterioration. More studies should be directed to avoid the T2DM complications on the CAP levels.