The effect of infective exacerbations on sleep and neurobehavioral function in cystic fibrosis

Adults with cystic fibrosis (CF) are susceptible to hypoxemia, hypercapnia, arousal from sleep, and neurobehavioral impairment.

We hypothesized that pulmonary exacerbations would adversely affect sleep and neurobehavioral performance.

Patients with exacerbations (cases) had sleep studies and neurobehavioral testing before and after inpatient intravenous therapy. Adults with stable CF underwent the same testing procedures (control subjects).

When clinically stable, cases and control subjects had similar lung function, intelligence, and body mass index. Among cases, treatment of an exacerbation improved lung function, quality of life, mood, sleepiness, and activation. Cases spent more time awake after sleep onset (p = 0.02), less time in REM sleep (p = 0.03), and were more hypoxemic than control subjects when unwell. The severity of hypoxemia correlated with lung function. On admission, cases had slower throughput than control subjects in the serial addition and subtraction task (cases, 16 +/- 4, vs. control subjects, 17 +/- 3; F[1, 36] = 5.15, p = 0.03) and a slower response time on the digit symbol substitution task (F[1, 36] = 11.91, p = 0.001), which persisted after treatment (F[1, 36] = 8.48, p = 0.006). Cases experienced significant improvements in sleep efficiency, amount of REM sleep, and hypoxia with treatment. Their performance in the serial addition and subtraction task, psychomotor vigilance task, and simulated driving task also improved with treatment. Sex modified the effect of an exacerbation on some aspects of performance.

Exacerbations of lung disease in adults with CF adversely affect sleep and tests of neurobehavioral performance regardless of underlying disease severity. The implications for performance in daily life need further evaluation because patients often delay admission to hospital to fulfill study or work commitments.