Smoking induced alterations in auditory pathways: Evidence from evoked potentials

Abstract

Objectives: Auditory Brainstem Responses (ABR) are used for assessment of integrity of auditory pathway. Given the widespread prevalence of smoking, interpretation of ABR data must be done in light of smoker/nonsmoker status. Materials and Methods: The present study was done on 30 normal, healthy non-smoker males and 30 healthy, smoker males in the age group of 18-40 years. Approval of Institutional Ethics Committee and written informed consent was taken from all volunteers. ABR was recorded using Biopac MP 150 system. The recordings were done in a state of abstinence of 12 hours (chronic smoking state) and 10 minutes after smoking (acute smoking state). In the non-smoker group, only one set of recordings were done. The peak latencies and amplitudes of the ABR waves were analyzed. Results: Analysis of data revealed a significant prolongation of the latencies of wave I and II and Inter-peak latency I-III in chronic smoking state as compared to non-smoking state. The amplitudes of waves I, II and V were also significantly reduced in chronic smoking state. A comparison between the non-smokers and acute smoking state revealed significantly prolonged latency of waves I and II in the acute smoking state accompanied by a significant decrease in the amplitudes of all waves of ABR. There were no significant differences in latencies and amplitudes of the chronic and acute smoking state. Conclusion: Smoking led to an increase in latency and decrease in amplitude, thereby indicating that it adversely affected the auditory pathway. Thus, interpretation of data of ABR should consider smoking as a confounding variable.