Comparison of the effect of zopiclone and brotizolam on sleep EEG by quantitative evaluation in healthy young women

Abstract

We studied the effect of brotizolam (BRO) (0.25 mg) and zopiclone (ZPC) (7.5 mg) on the sleep electroencephalograms (EEG) of seven healthy young women (ages 20-21 years). In addition to conventional sleep scoring, we performed spectral analysis of EEG wave forms using the Fast Fourier Transformation (FFT) method. Four weeks following two consecutive polysomnographic recordings with placebo administration (for baseline data), polysomnography with BRO or ZPC administration was performed on the subjects who were then crossed over to polysomnography with ZPC or BRO, respectively, 1 week later. Total rapid eye movement (REM) time was decreased on the ZPC and BRO nights and REM latency was prolonged on the ZPC night compared with baseline (BL) night. Other parameters, however, were not significantly different between the drug nights and the BL night. There were also no differences in standard scoring results between both drug nights. FFT analysis revealed significant differences in total power density percentage and mean power density percentage in both nonrapid eye movement (NREM) and REM sleep between ZPC and BRO nights and between both drug nights compared to the BL night. Total power density and mean power density per epoch showed significant decreases in the theta band (6.0-8.0 Hz) and sigma band (12.0- 14.0 Hz) on the ZPC night versus the BRO night or BL night during specific NREM periods. The results of this study corroborate previous reports that suggest computer-aided quantitative electroencephalography aids in differentiating specific effects of hypnotics and other central-nervous- system-acting agents on the sleep EEG. Specifically, this study suggests that ZPC and BRO differ significantly in their effects on the EEG activity of both NREM and REM sleep. Such differences are likely to be of clinical importance.