Relationship between sleep, sleep apnea, and neuropsychological function in children with Down syndrome.

Purpose: To determine whether sleep and sleep disordered breathing (SDB) contribute to the neuropsychological deficits of patients with Down syndrome, and whether treatment of SDB results in improvement in cognitive function.

Methods: In this cohort study, 25 children with Down syndrome underwent overnight polysomnography (PSG), Multiple Sleep Latency Testing (MSLT), and a battery of neuropsychological tests. Patients with SDB underwent a follow up PSG after treatment. All patients repeated the neuropsychological tests 13 months later.

Results: At baseline, there was no relationship between SDB and performance on the neuropsychological tests. However, total sleep time and sleep latency were related to tests of cognitive ability (p < 0.05) and comprehension (p < 0.01). The amount of time in slow-wave sleep correlated with tests of achievement (p < 0.01), and adaptive behavior (p < 0.01). Ten patients had SDB confirmed on PSG. Five of these patients were treated successfully with adenotonsillectomy and/or continuous positive airway pressure. The five who did not tolerate treatment were deficient in tests of adaptive behavior (Vineland p < 0.05) visual-motor integration (Beery p < 0.01) and achievement (Woodcock-Johnson p < 0.05) compared to those successfully treated. After treatment the patients improved in ratings of attention (Conners p < 0.05).

Conclusions: Although SDB is common in children with Down syndrome, it is not a major contributor to their cognitive deficits. Cognitive function is related to the amount of sleep and particularly slow wave sleep. Successful treatment of SDB may improve their attention.