Introduction

Neuropathy is the most common complication and greatest source of morbidity and mortality in diabetes patients. It is estimated that the prevalence of neuropathy in diabetes patients is approximately 25%.¹ In diabetic neuropathy patients other part of neurological system is also affected such as autonomous system, sensory and motor pathways. Auditory Brainstem Response (ABR) audiometry.

First described by Jewett and Williston in 1971. There are seven waves traditionally designated with roman numerals from I to VII. Wave I and II represent activity in cochlear nerve, wave III in cochlear nucleus, wave IV in superior olivary complex, wave V which is biggest and most consistent represent activity in nuclei of lateral lemniscus while wave VI and VII in the inferior colliculus.² Interpretation of the BAEPs usually involves measuring the absolute latency of the three most prominent vertex positive peaks I, III, and V, along with analysis of their relative inter-peak latencies (IPLs), which may provide some anatomical localisation of lesions. Conduction through the eighth nerve and the caudal brainstem is represented by the I to III IPL, while the III to V IPL probably represents transmission through the rostral brainstem and midbrain. Neuropathy is the most frequent late complication of DM. So far most of the clinical and diagnostic studies on diabetic neuropathy have concerned only peripheral and autonomic nerve but recently with the refinement of evoked potential techniques detailed exploration of sensory pathway in central nervous system has been possible⁷. Brainstem auditory evoked potentials have obtained widespread clinical application in assessing neurologic and audiologic problems. ABR audiometry is considered an effective screening tool in the evaluation of suspected retrocochlear pathology. In general, ABR exhibits a sensitivity of over 90% and a specificity of approximately 70-90%8 (Schmidt.et al., 2001).

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Dr Shashikant Singh