Tiagabine is associated with sustained attention during sleep restriction: evidence for the value of slow-wave sleep enhancement?

STUDY OBJECTIVES: To evaluate the impact of enhanced slow-wave sleep (SWS) on behavioral, psychological, and physiologic changes resulting from sleep restriction

DESIGN: A double-blind, parallel-group, placebo-controlled design was used to compare tiagabine, 8 mg, (a SWS-enhancing drug) to placebo during 4 nights of sleep restriction (time in bed = 5 hours per night). Behavioral, psychological, and physiologic measures of the impact of sleep restriction were compared between groups at baseline, during sleep restriction, and following recovery sleep.

SETTING: Two sleep research laboratories.

PARTICIPANTS: Thirty-eight healthy adults; 9 men and 10 women (mean age: 26.0 +/- 6.1 years) in the placebo group and 8 men and 11 women (mean age: 26.7 +/- 8.1 years) in the tiagabine 8 mg group

INTERVENTIONS: Both experimental groups underwent 4 nights of sleep restriction. Each group received either tiagabine 8 mg or placebo on all sleep-restriction nights, and both groups received placebo on baseline and recovery nights.

MEASUREMENTS AND RESULTS: Polysomnography documented a SWS-enhancing effect of tiagabine. The placebo group displayed the predicted deficits due to sleep restriction on the Psychomotor Vigilance Task and the Multiple Sleep Latency Test. Compared with placebo, the tiagabine group did not demonstrate impairment in sustained attention on the Psychomotor Vigilance Test, performed better on the Wisconsin Card Sorting Task, reported more restorative sleep, and had less of an increase in afternoon-evening salivary free cortisol. Multiple Sleep Latency Test, ratings of sleepiness, recovery sleep, and other measures did not differ between groups.

CONCLUSIONS: To our knowledge these findings are the first to be consistent with the hypothesis that pharmacologic SWS enhancement reduces selective aspects of the behavioral, psychological, and physiologic impact of sleep restriction.