Alcohol and the acoustic reflex: effects of stimulus spectrum, subject variability, and sex

Acoustic reflex thresholds were measured for eighteen young adults (9 men and 9 women) at four different blood alcohol levels: 0.00%, ascending 0.10%, 0.15% (peak level), and descending 0.10%. Reflex-eliciting stimuli consisted of three narrow-band noises (300 to 600, 600 to 1200, and 1200 to 2400 Hz) and three broad band noises (white noise, recorded rock music, and recorded factory noise). Prealcohol reflex thresholds were found to be significantly more sensitive than all postalcohol reflex thresholds for all stimuli, and broad-band stimuli demonstrated greater threshold shifts than did narrow-band stimuli. Significant sex differences were not observed for any blood alcohol level. Between subject variability was high, with 10 subjects showing little or no reflex threshold change and the other 8 subjects showing dramatic threshold changes.