Publication:

Brainstem auditory responses in type-2 diabetes mellitus

Background Diabetes mellitus causes pathophysiological changes at multiple organs. Brainstem Evoked Response Auditory (BERA) represents a non-invasive tool to detect diabetes related sensorineural hearing loss. The aim was to assess diabetes related central auditory pathway involvement using BERA.

Methods The study comprises two groups, (i) Diabetic group (n=15), (ii) Control group (n=15). The controls were matched for age and sex with the study group. BERA was done for all these patients after detailed clinical examination and relevant blood investigations.

Results There was significant latency differences found in wave III, V and interpeak latencies I-III, III-V and I-V between control and study groups at 70 dBnHL and 80 dBnHL. At 90 dBnHL the diabetic group demonstrated significant latency differences in waves I, III and V and interpeak I-III, III-V and I-V compared to controls. The duration of DM was 5-10 years in 8 patients (53.3%) out of which 7 subjects (87.5%) had prolonged BERA. 7 patients (46.6%) were diabetic for more than 10 years of which all patients (100%) had prolonged latencies.

Conclusions The wave I latency was found non significant which suggests that the pathway from 8th nerve to cochlear nucleus is not affected in diabetic patients. The delay in latencies III and V and interpeak latencies I-III, III-V and I-V in diabetic patients compared to the controls suggests brainstem and midbrain involvement. So the study suggests that BERA helps in early detection of central neuronal axis involvement in type-2 diabetes mellitus.