title: Study I: effects of 0.06% and 0.10% blood alcohol concentration on human postural control.
abstract: Alcohol intoxication causes many accidental falls presented at emergency departments, with the injury severity often related to level of blood alcohol concentration (BAC). One way to evaluate the decline in postural control and the fall risk is to assess standing stability when challenged. The study objective was to comprehensively investigate alcohol-related impairments on postural control and adaptive motor learning at specific BAC levels. 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.
authors.affiliation: Department of Clinical Sciences, Lund University, S-221 85 Lund, Sweden.
authors.forename: F
authors.initials: F
authors.lastname: Modig
authors.forename: M
authors.initials: M
authors.lastname: Patel
authors.forename: M
authors.initials: M
authors.lastname: Magnusson
authors.forename: P A
authors.initials: PA
authors.lastname: Fransson
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000435:Alcoholic Intoxication / Q000097:blood* / Q000503:physiopathology; D000704:Analysis of Variance; D000431:Ethanol / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D012016:Reference Values; D018570:Risk Assessment; D012494:Sampling Studies; D012678:Sensation Disorders / Q000139:chemically induced* / Q000503:physiopathology; D013997:Time Factors; D014732:Vibration; D055815:Young Adult
chemical_list: D000431:Ethanol