Figures & data
Figure 1. Hypnogram of three individuals: upper panel: healthy: 7.5 hours sleep with regular NonREM-REM cycles and sigma spindles predominantly in NREM sleep 2; medium panel: patient with insomnia using daily zolpidem (5 -10 mg) for 18 years; note more or less ‘healthy’ hypnogram; lower panel: patient with insomnia using daily diazepam (5 -10 mg) or brotizolam (0.25 mg) for 15 years; note absence of stage 3 (deep sleep, SWS), marked reduction in REM sleep and frequent sigma spindles during all sleep stages. W = stage awake, R = stage REM, 1/2 = stage NonREM 1/2 (light sleep), 3 = stage NonREM 3 (deep or slow-wave sleep), Sigma = sigma spindle frequency.
Figure 2. 30 second epochs of NonREM 2; upper panel: patient with insomnia using daily zolpidem (5–10 mg) for 18 years; note more or less ‘healthy’ EEG; low voltage, mixed frequency; alpha/theta range, with diffuse activity in the sigma range, though without pronounced spindles; lower panel: patient with insomnia using daily diazepam (5–10 mg) or brotizolam (0.25 mg) for 15 years; note additional ‘finger-print like’ excessive occurrence of spindle activity; often still to be detected months after benzodiazepine withdrawal
Table 1. Hypnotics in chronic insomnia