Brain stem auditory evoked potentials in type 2 diabetes mellitus patients at varying frequencies

As per the World Health Organization, in 2005, more than 180 million people had diabetes worldwide. This figure will be more than double by 2030. Neuropathy is common and late complication of diabetes mellitus (DM). Sensory neural hearing loss which is severe at higher frequencies has been reported in Type 2 DM patients. Auditory nerve tract damage increases the latency and reduces the amplitude of the response. Evoked potential recordings evaluate the neural pathways in the central nervous system. Brainstem auditory evoked potentials (BAEP) localize anatomic structures using different waves and detect acoustic and central neuropathy (CN). Hence, brainstem evoked response of audiometry (BERA) is used widely in clinical set up.

1. To record BERA waves in normal subjects with normal blood sugar levels (hemoglobin A₁C [HbA1C] <5.4. 2. To record BERA waves in Type 2 DM patients. (HbA1C >6.5).

To study the BERA parameters with the normal subjects with blood sugar subjects and compare them with Type 2 DM patients.

n = 30, Type 2 DM patients between the age of 35-50 years of either sex were chosen from the Diabetic Clinic of GMC, Aurangabad, Maharashtra. HbA₁C test for glycemic control and BERA waves to assess CN were recorded. n = 30 normal subjects with normal blood sugar with age and sex-matched above tests were performed.

Unpaired Student's t-test.

Mean ± Standard deviation of the absolute latency and interpeak latency of BERA waves at 2, 4, and 6 KHz at 80 dB in Type 2 DM patients were delayed and found to be significant as compared to control group.

The above study explains that if BAEP is recorded at higher frequencies like 6 KHz and at 80 dB, CN involvement can be detected earlier in diabetic patients. Hence, it is recommended to carry out BERA in diabetic patients at least once in a year.