EFFECTS OF TOBACCO SMOKING AND ABSTINENCE ON MIDDLE LATENCY AUDITORY-EVOKED POTENTIALS

Objective: To evaluate the effects of tobacco cigarette smoking and ov ernight abstinence on middle latency auditory evoked potentials among smokers and nonsmokers. Methods: Groups of 9 to 10 adult male and fema le nonsmokers and smokers participated in the study. Each person volun teered for two laboratory sessions conducted in the early afternoon on 2 separate days, Smokers abstained from tobacco products 6 to 15 hour s before the abstinent session and maintained their usual smoking beha vior before the smoking session. The nonsmokers had a similar laborato ry experience but sham smoked by means of inhaling air. Middle latency auditory evoked potentials were recorded from Ct to both ears as refe rence. Results: The latencies of the Na and Pa potentials during the s moking session were significantly (p < 0.01) shorter than those in abs tinent smokers and nonsmokers, After smoking, peak-to-trough amplitude s for the V-Na, Na-Pa, and Pa-Nb potentials were larger than those aft er abstinence and significantly larger than those among nonsmokers. Co nclusions: The shorter latencies of the middle latency brain wave comp onents in the smoking session suggest faster processing of sensory inf ormation after cigarette smoking. Larger Pa amplitudes after cigarette smoking suggest a higher arousal level than that among partially abst inent smokers and nonsmokers.