A study of auditory brainstem evoked responses in type 1 and type 2 diabetes mellitus patients with normal hearing

Abstract

<p class="abstract"><strong>Background:</strong> Diabetes mellitus (DM) is one of the most common metabolic disorders with millions of cases world-wide. Its effect on functioning of the central nervous system (CNS) and the peripheral nerves is a matter of current neurological research. Our study aimed to find out changes in auditory brainstem responses if any, in patients with type 1 and type 2 DM patients with apparently normal hearing.</p><p class="abstract"><strong>Methods:</strong> 50 cases each of type 1 and type 2 diabetic patients with normal hearing were chosen along with 50 healthy controls. Pure tone audiometry and brainstem evoked response audiometry (BERA) was performed in all cases. The BERA results were interpreted for the latencies of waves I, II, III, IV and V and inter-peak latencies I-III, I-V and III-V. </p><p class="abstract"><strong>Results:</strong> Significant delay in absolute latency of wave I, III, IV, V and inter-peak latencies I-V and III-V was seen in Type 1 diabetic patients. In Type 2 diabetic patients, latencies of waves I, II, III, IV and V and inter-peak latencies I-III, I-V and III-V were significantly delayed. There was no statistically significant difference in latency delay between type 1 and type 2 DM. No relation was found with the duration of DM.</p><p><strong>Conclusions:</strong> BERA is a non-invasive and easy to perform test that can detect minor CNS changes and can be used to detect peripheral (auditory nerve) and central neuropathy in diabetics even in absence of clinical signs and symptoms of deafness.</p>