Effects of acute alcohol ingestion on neuromotor functions.

To scrutinize the neuromotor effects of acute alcohol ingestion, postural sway, hand tremor, and reaction time were measured before and after alcohol or juice ingestion in 13 healthy volunteers at 20-22 years (mean 20.7) of age. The dose of ethanol consumed by the subjects (mean+/-S.D.) was 0.59+/-0.07 g/kg body weight, and the blood ethanol concentrations were estimated to be 0.86+/-0.23 g/l at 30 min after ethanol ingestion; 0.88+/-0.19 g/l at 70 min; 0.74+/-0.27 g/l at 130 min. The 1-h and 2-h changes in sway area, total transversal sway (Dx), and Dx at 0-1 Hz with eyes closed were significantly larger after alcohol ingestion than after juice ingestion. Similarly, the 2-h changes in sway area, total Dx, and Dx at 0-1 Hz with eyes open were significantly larger after alcohol ingestion than after juice ingestion. No significant differences were seen between alcohol and juice ingestion regarding changes in hand tremor or reaction time. These data suggest that the static balance due to acute alcohol ingestion is characterized mainly by transversal sway of low frequency (0-1 Hz) with eyes closed, which seems to differ from the characteristics of postural sway in alcoholics.