Effect of zopiclone and temazepam on sleep EEG parameters, psychomotor andmemory functions in healthy elderly volunteers

Rationale: The increased prevalence of sleep disturbance in old age is acco mpanied by a higher prescription rate of hypnotics, predominantly benzodiaz epines in the elderly. In young volunteers zopiclone exerts a beneficial ef fect on sleep continuity without suppression of SWS and REM sleep; psychomo tor performance and vigilance seemed to be less impaired than under classic al benzoediazepines. Objective: The present study investigates the effects of zopiclone on sleep EEG and cognitive performance in comparison to temaze pam and placebo in the elderly population. Methods: Single oral doses of zo piclone (7.5 mg), temazepam (20 mg) and placebo were administered in a rand omized double-blind, completely counterbalanced cross-over design to 12 hea lthy elderly men and women (65.9+/-3.6 years, range 60-70 years). On each o f the 3 study nights a sleep EEG was registered from 10 p.m. to 6.30 a.m. a nd cognitive performance tests were applied at 8 p.m., 2 a.m. (when subject s were awake for 30 min), 7 a.m. and 9 a.In. Results: After zopiclone treat ment, sleep continuity had significantly improved and sleep stage 4 was inc reased compared to temazepam and placebo. In addition, both active substanc es significantly reduced REM density. Neither active compound substantially altered psychomotor and memory performance. Conclusions: Zopiclone and tem azepam can be considered as effective hypnotics in elderly subjects when ad ministered in that dosage. The superiority of zopiclone on sleep architectu re may be related to a more specific action of zopiclone at the GABA-A benz odiazepine receptor complex. The suppression of REM density by both compoun ds and their subtle effects on cognition may reflect a GABAergic mediated r eduction of cholinergic neurotransmission.