P018 The effects of zopiclone on sleep spindles in obstructive sleep apnea: A randomized placebo-controlled trial

Abstract

Abstract Purpose This study aimed to determine the effects of a standard dose of zopiclone (7.5mg) on sleep spindle activity and to assess if potential changes in sleep spindles correlate with improvements in next-day measures of sleepiness and simulated driving performance in people with obstructive sleep apnoea (OSA). Methods Thirty-one people with OSA completed polysomnography (PSG) at baseline followed by 1-month nightly treatment with 7.5mg zopiclone or placebo according to a double-blind, parallel design (ANZCTRN12613001106729). Participants completed two further PSGs on the first (night1) and final (night30) night of treatment. A 30-min AusEd driving simulator task and a subjective sleepiness questionnaire (Karolinska sleepiness scale, KSS) on each visit were also performed in the morning. Sleep spindle events and spindle frequency activity (SFA, sigma EEG power) were quantified during N2 sleep from all-night EEG recordings. Results Sleep spindle events were consistently higher in both frontal and central EEG sites on night1 and night30 treatment nights in the zopiclone group compared to placebo (e.g. F4 night30 = 346[SEM±28] vs. 239[SEM±27] total # of sleep spindles respectively, p=0.009). Additionally, greater sleep spindle density in the zopiclone group correlated with better next-day simulated driving performance on night1 and night30. No correlations were observed between sleep spindle activity and the KSS. Conclusions Zopiclone is associated with greater sleep spindle activity in OSA compared to placebo, and sleep spindle increases are associated with better driving simulator performance. Thus, hypnotic-induced increases in sleep spindles may help alleviate certain cognitive performance decrements in people with OSA.