Impact of alcohol on vestibular function in relation to the legal limit of 0.25 mg/l breath alcohol concentration.
The aim of this study was to investigate the effect of alcohol on sacculocollic and vestibulo-ocular reflex systems, when the breath alcohol concentration (BrAC) is close to the legal limit of 0.25 mg/l. Twenty healthy male volunteers underwent vestibular evoked myogenic potential and caloric coupled with visual suppression tests. These tests were conducted prior to imbibing alcohol at a dosage of 0.5 g/kg to achieve a peak BrAC of around 0.25 mg/l. Once the peak BrAC was reached, these tests were performed again. Predosing and postdosing analytical results were compared, as were those with BrAC levels > or = 0.25 mg/l and <0.25 mg/l. After ingesting alcohol, 36 ears (90%) showed vestibular evoked myogenic potential responses, with a significantly increased latency of peak p13. The mean slow-phase velocity of caloric nystagmus in 40 ears after dosing was significantly reduced, and that with BrAC > or =0.25 mg/l was significantly less than that with BrAC <0.25 mg/l. Likewise, the visual suppression index decreased considerably after alcohol ingestion. In conclusion, from the perspective of vestibular function, the 0.25-mg/l BrAC limit gains clinical significance, because the vestibulo-ocular reflex performance deteriorates further, when the BrAC exceeds 0.25 mg/l. However, impaired performance of sacculocollic reflex and vestibulocerebellar interaction has occurred, when the BrAC was <0.25 mg/l, suggesting that a lower legal threshold is appropriate.
Chiang
Hou-Hsien
HH
Department of Otolaryngology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
Young
Yi-Ho
YH
D000328:Adult; D001944:Breath Tests; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000009:adverse effects*; D000431:Ethanol / Q000008:administration & dosage / Q000009:adverse effects*; D005071:Evoked Potentials / Q000187:drug effects; D006801:Humans; D008297:Male; D009760:Nystagmus, Physiologic / Q000187:drug effects; D012027:Reflex, Vestibulo-Ocular / Q000187:drug effects*; D014722:Vestibule, Labyrinth / Q000187:drug effects*; D014920:Wine / Q000009:adverse effects*
D002492:Central Nervous System Depressants; D000431:Ethanol