SLEEP-DISORDERED BREATHING AND NEUROPSYCHOLOGICAL DEFICITS - A POPULATION-BASED STUDY

The relationship of sleep-disordered breathing (SDB) to neuropsycholog ical deficits was investigated with cross-sectional data from the Wisc onsin Sleep Cohort Study, a population-based study of the natural hist ory of SDB. A sample of 841 employed men and women ages 30 to 60 yr wa s studied by overnight polysomnography to assess the frequency of apne as and hypopneas per hour of sleep (apnea-hypopnea index, AHI). Prior to overnight polysomnography, the participants were given a battery of neuropsychological tests for functionally important capacities includ ing motor skills, attention, concentration, information processing, an d memory. Principal factor analysis of all the neuropsychological test data revealed a psychomotor efficiency and a memory factor. Multiple regression analysis showed a significant negative association between logarithmically transformed AHI (LogAHI) and psychomotor efficiency sc ore independent of age, gender, and educational status (p = 0.017). Th e relationship was not explained by self-reported sleepiness. No signi ficant relationship was seen between LogAHI and memory score. In asses sing the clinical significance of mild SDB, we estimate that an AHI of 15 is equivalent to the decrement in psychomotor efficiency associate d with 5 additional yr of age, or to 50% of the decrement associated w ith hypnosedative use.