Objectives/hypothesis: Patients with sleep-disordered breathing have reaction time deficits that may lead to catastrophic accidents and loss of life. Although safety guidelines do not exist for unsafe levels of sleepiness, they have been established for unsafe levels of alcohol consumption. Since reaction time performance is altered in both, we prospectively used seven measures of reaction time performance as a comparative model in alcohol-challenged normal subjects with corresponding measures in subjects with sleep-disordered breathing.
Study design: Institutional Review Board-approved, nonrandomized prospective controlled study.
Methods: Eighty healthy volunteers (29.1+/-7.5 y of age, 56.3% female subjects) performed four reaction time trials using a psychomotor test at baseline and at three subsequent rising alcohol-influenced time points. The same test without alcohol was given to 113 subjects (47.2+/-10.8 y of age, 19.3% female subjects) with mild to moderate sleep-disordered breathing.
Results: Mean blood alcohol concentrations (BACs) in the alcohol-influenced subjects at baseline and three trials were 0, 0.057, 0.080, and 0.083 g/dL. The sleep-disordered subjects had mean respiratory disturbance indices of 29.2 events per hour of sleep. On all seven reaction time measures, their performance was worse than that of the alcohol subjects when BACs were 0.057 g/dL. For three of the measures, the sleep-disordered subjects performed as poorly as or worse than the alcohol subjects when alcohol levels were 0.080 g/dL. These results could not be explained by sex or age differences.
Conclusion: The data demonstrate that sleep-disordered subjects in this study (with a mean age of 47 y) with mild to moderate sleep-disordered breathing had worse test reaction time performance parameters than healthy, nonsleepy subjects (with a mean age of 29 y) whose BAC is illegally high for driving a commercial motor vehicle in California. This comparative model points out the potential risks of daytime sleepiness in those with sleep-disordered breathing relative to a culturally accepted standard of impairment.