The effects of ethyl alcohol on visual pursuit and suppression of the vestibulo-ocular reflex

A comparison of the frequency characteristics of the pursuit reflex and the suppression of vestibular nystagmus has been carried out in humans under carefully matched stimulus conditions, with and without the influence of ethyl alcohol (blood level approximately 77 mg/100 ml). In the pursuit task the ratio of eye displacement to target displacement was not significantly impaired by alcohol, but there was a significant decrease in the ratio of slow-phase eye velocity to target velocity. When subjects attempted to fixate a head-fixed target during whole-body angular oscillation the degree of suppression of the slow-phase velocity of the vestibulo-ocular response was also significantly impaired by alcohol and in both this and the control condition there was no significant difference between the amplitude ratio of suppression and the velocity error of the pursuit response.