Brain stem evoked responses in patients with diabetes mellitus

Diabetes mellitus is a systeihic disorder which targets multiple organs. The neurological involvement is not only in the form of peripheral neuropathy, but may also lead to central neuropathy. To evaluate the presence of central neuropathy auditory brain stem evoked responses were recorded from 25 normal hearing diabetic subjects aged 28 years to 49 years (Mean age 44.28 years) at 2KHz, 4KHz, & 4KHz, frequencies. The results obtained were compared with those obtained from 10 subjects with normal hearing of matched age and sex. In diabetic subjects, abnormal wave latencies were correlated with blood glucose level, duration of illness and peripheral neuropathy.The absolute latencies and inter peak latencies were significantly impaired (P<.001) in diabetic subjects as compared to control subjects at 2, 4, & 6KHz frequencies. The incidence of delayed wave latencies was 64%, 72%. & 84% at 2KHz, 4KHz, & 6KMz respectively suggesting that if brain stem evoked response audiometry is conducted at higher frequency like 6KBz in diabetic patients, the involvement of central neural axis can be detected earlier. This study is the first to demonstrate that brain stem evoked response audiometry is a useful non-invasive test for earlier detection of damage in central neural axis in patients of diabetes mellitus. There is no relationship between the delayed wave latencies and the blood glucose level, however there exists a significant relationship between the delayed wave latencies and the duration of disease & peripheral neuropathy.