Acute alcohol intoxication impairs segmental body alignment in upright standing

Balance control when standing upright is a complex process requiring input from several partly
independent mechanisms such as coordination, feedback and feedforward control, and adaptation.
Acute alcohol intoxication from ethanol is recognized as a major contributor to accidental falls
requiring medical care. This study aimed to investigate if intoxication at 0.06 and0.10% blood alcohol
concentration affected body alignment. Mean angular positions of the head, shoulder, hip, and knee
were measured with 3D‐motion analysis and compared with the ankle position in 25 healthy adults
during standing with or without perturbations, and with eyes open or closed. Alcohol intoxication
had significant effects on body alignment during perturbed and unperturbed stance, and on
adaptation to perturbations. It induced a significantly more posterior alignment of the knees and
shoulders, and a tendency for a more posterior and left deviated head alignment in perturbed
stance than when sober. The impact of alcohol intoxication was most apparent on the knee
alignment, where availability of visual information deteriorated the adaptation to perturbations.
Thus, acute alcohol intoxication resulted in inadequate balance control strategies with increased
postural rigidity and impaired adaptation to perturbations. These factors probably contribute to the
increased risk of falling when intoxicated with alcohol.