Auditory threshold reduction on alcohol ingestion

Abstract.

Rationale: Auditory threshold (AT) measurement method has become the standard behavioral procedure for describing auditory sensitivity. Therefore, the AT measurement method is applicable to evaluation of auditory function. However, only a few studies have been performed to clarify the alteration of audibility under the influence of alcohol on normal humans by measurement of AT. Objective: The fact that blood alcohol concentration (BAC) is influenced by the dose of alcohol and the time of measurement suggests that the effects of alcohol may also be altered by the same factors. The present study was conducted to elucidate how alcohol ingestion method affects the AT at a wider range from lower to higher frequency in the time course. Methods: Fifteen paid Japanese (seven men and eight women, 20–33 years of age) were employed in AT measurements at an octave frequency ranging from 250 to 8000 Hz before and 5, 30, 60, 120, 240 and 480 min after drinking various amounts (125, 250, 500 and 1500 ml) of normal beer (5% alcohol) or alcohol-free beer. Results: The AT was significantly reduced within 30 min after the ingestion of 250 and 500 ml of beer, occurring on and after peak BAC. The reducing effect disappeared 480 min after ingestion. Conclusions: Drinking extra small amounts of alcohol induces the reduction of AT. The effect of alcohol on AT is altered by the alcoholic dose used in testing.