Effects of ethyl alcohol on the contralateral and ipsilateral acoustic reflex threshold

Contralateral and ipsilateral acoustic reflex thresholds were measured in response to 500-, 1000-, and 2000-Hz pure tones after the ingestion of a 50% alcohol solution. Acoustic reflex threshold measurements were obtained preingestion and at blood-alcohol concentrations of 0.03 to 0.10% in 0.01% increments. A linear relationship existed between acoustic reflex threshold and blood-alcohol concentration, with the greatest shift at 0.10% being 11 dB for contralateral stimulation and 7 dB for ipsilateral. No frequency effects were found. Results can be explained by the anatomical differences in the contralateral and ipsilateral pathways.