A Comparative Analysis of Brainstem Auditory Evoked Potentials in Smokers and Nonsmokers

Background: Smoking is one of the most common adjustable risk factors that cause systemic and neurological disorders. Prolonged nicotine and other harmful compounds of tobacco smoke exposure cause oxidative stress, neuroinflammation, and vascular alterations, which can have a subtle influence on neural conduction. Brainstem auditory evoked potentials (BAEPs) are a sensitive, noninvasive test of the integrity of the functional operation of the auditory pathway, especially that of the brainstem. The changes in BAEP parameters can hence be utilized as early electrophysiological signs of subclinical neurotoxicity in smokers. Aim: This study aimed to compare the parameters of BAEP of smokers and nonsmokers and to determine the correlation between the duration and intensity of smoking and the changes in conduction of the auditory pathways. Materials and Methods: Eighty-eight adults will be used in the cross-sectional comparative study consisting of 44 chronic smokers and 44 age- and sex-matched nonsmokers. Individuals having a background of neurological disease, using ototoxic drugs or being exposed to noise at occupational sites will not include. The recording of BAEP will be done with a standard evoked potential recording system (RMS EMG EP MARK-II) with the click stimulus of 70–90 dB SPL of 0.1 ms. Wave I, Wave III, and Wave V absolute latencies and interpeak latencies (I–III, III–V, I–V) will be measured and compared. The statistical test will be conducted in the SPSS version 26 and defined P < 0.05 as significant. Expected Outcome: Early data and literature have indicated that smokers have longer relative latencies of Waves I, III, and V, the largest delay being in Wave V, and that interpeak intervals of I–III, III–V and I–V are also longer in smokers than nonsmokers, which reflected slowed neural conduction along the auditory brainstem. It will be expected to have a positive relationship between the smoking pack-years and the extent of latency postponement in individuals who have normal hearing thresholds. Subclinical neurophysiological changes manifested in BAEP analysis can be induced in chronic smoking, although auditory symptoms do not manifest themselves clinically. BAEP, in turn, has the potential to be a useful noninvasive method of early identification of auditory pathway dysfunction caused by smoking and neural conduction impairment. DMIHER Ethical Review Board has approved the study ethicically. Written informed consent to participate will be obtained from all participants