Effects of alcohol intoxication at 0.06%and 0.10%BAC were examined with posturography when unperturbed or perturbed by calf vibration. Twenty-five participants (mean age 25.1 years) were investigated standing with either eyes open or closed.
Our results revealed several significant findings: (1) stability declined much faster from alcohol intoxication between 0.06%and 0.10%BAC (60-140%) compared with between 0.0%and 0.06%BAC (30%); (2) sustained exposure to repeated balance perturbations augmented the alcohol-related destabilization; (3) there were stronger effects of alcohol intoxication on stability in lateral direction than in anteroposterior direction; and (4) there was a gradual degradation of postural control particularly in lateral direction when the balance perturbations were repeated at 0.06%and 0.10%BAC, indicating adaptation deficits when intoxicated.
To summarize, alcohol has profound deteriorating effects on human postural control, which are dose dependent, time dependent and direction specific. The maximal effects of alcohol intoxication on physiological performance might not be evident initially, but may be revealed first when under sustained sensory-motor challenges.