Study II: mechanoreceptive sensation is of increased importance for human postural control under alcohol intoxication.
Standing postural stability relies on input from visual, vestibular, proprioceptive and mechanoreceptive sensors. When the information from any of these sensors is unavailable or disrupted, the central nervous system maintains postural stability by relying more on the contribution from the reliable sensors, termed sensory re-weighting. Alcohol intoxication is known to affect the integrity of the vestibular and visual systems. The aim was to assess how mechanoreceptive sensory information contributed to postural stability at 0.00% (i.e. sober), 0.06% and 0.10% blood alcohol concentration (BAC) in 25 healthy subjects (mean age 25.1 years). The subjects were assessed with eyes closed and eyes open under quiet standing and while standing was perturbed by repeated, random-length, vibratory stimulation of the calf muscles. Plantar cutaneous mechanoreceptive sensation was assessed for both receptor types: slowly adapting (tactile sensitivity) and rapidly adapting (vibration perception). The correlation between recorded torque variance and the sensation from both mechanoreceptor types was calculated. The recorded stability during alcohol intoxication was significantly influenced by both the tactile sensation and vibration perception of the subjects. Moreover, the study revealed a fluctuating association between the subjects' vibration perception and torque variance during balance perturbations, which was significantly influenced by the level of alcohol intoxication, vision and adaptation. Hence, one's ability to handle balance perturbations under the influence of alcohol is strongly dependent on accurate mechanoreceptive sensation and efficient sensory re-weighting.
Department of Clinical Sciences, Lund University, S-221 85 Lund, Sweden.
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Modig
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Patel
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Magnusson
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Fransson
D000222:Adaptation, Physiological; D000328:Adult; D000435:Alcoholic Intoxication / Q000097:blood* / Q000503:physiopathology; D000704:Analysis of Variance; D015331:Cohort Studies; D000431:Ethanol / Q000097:blood*; D005080:Exercise Test / Q000379:methods; D005260:Female; D005528:Foot / Q000294:innervation / Q000502:physiology*; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D011434:Proprioception / Q000502:physiology*; D012016:Reference Values; D018570:Risk Assessment; D019415:Torque; D014732:Vibration; D055815:Young Adult
D000431:Ethanol