Effect of Smoking on Hearing: Evidence from Auditory Evoked Potentials

Abstract

IntroductionAuditory Brainstem Responses (ABR) are an important clinical tool for assessment of hearing. Acetylcholine is a neurotransmitter present in the auditory pathway and nicotine acts through acetylcholine receptors. Since smoking is widely prevalent, it is essential to know its effect on auditory pathways especially for interpreting the reports of ABR in smokers.MethodologyThe study was done on 15 normal, healthy non‐smoker males and 15 healthy, smoker males in the age group of 18–40 years. The study was approved by Institutional Ethics Committee and written informed consent was taken from all volunteers. The recordings of ABR were done using Biopac MP 150. A total of 1000 responses were averaged. The recordings of ABR were done in a state of abstinence of 12 hours (overnight abstinence) and 10 minutes after smoking in the smoker group. The smokers were allowed to smoke their own brand of cigarette. Only one set of recordings were done for non‐smoker group. The peak latencies and amplitudes of the ABR waves were analyzed.ResultsThe latencies of wave I and II along with Inter‐peak latency I–III and III–V were significantly longer in the smoker group (after abstinence) in comparison to the controls. The amplitudes of waves I, II and V were also significantly reduced. A comparison between the controls and smokers (10 minutes after smoking) revealed significantly prolonged latency of waves I and II in the smoker group accompanied by a significant decrease in the amplitudes of all waves of ABR. There were no significant differences in latencies and amplitudes of the smokers after abstinence and 10 minutes after smoking.ConclusionSmoking brings about a decrease in the amplitudes along with prolongation of latencies which is not affected by abstinence or acute consumption.Support or Funding InformationIntramural Grant of All India Institute of Medical Sciences, Jodhpur