Conventional and power spectrum analysis of the effects of zolpidem on sleep EEG in patients with chronic primary insomnia.
OBJECTIVE
The purpose of this study was 1) to assess the effect of zolpidem or a placebo on sleep in two groups of insomniac patients with a diagnosis of moderate-to-severe chronic primary insomnia and 2) to determine the effect of zolpidem on sleep structure using spectral analysis.


METHODS
A randomized, double-blind, placebo-controlled trial.


METHODS
Sleep laboratory of the Department of Pharmacology and Therapeutics at the Clinics Hospital.


METHODS
12 female outpatients with chronic primary insomnia.


METHODS
Zolpidem was given at a daily dose of 10 mg for 15 nights.


RESULTS
The hypnotic drug reduced sleep latency and waking time after sleep onset, and increased total sleep time and sleep efficiency. Values corresponding to visually scored slow wave sleep (stage 3 and 4) showed no significant changes. All-night spectral analysis of the EEG revealed that power density in NREM sleep was significantly increased in the low frequency band (0.25-1.0 Hz) in the zolpidem group during the first 2-h interval.


CONCLUSIONS
In agreement with previous findings obtained in patients with chronic primary insomnia, zolpidem significantly improved sleep induction and maintenance. Moreover, zolpidem increased power density in the 0.25-1.0 Hz band during short-term and intermediate-term treatment. Nevertheless, other frequency bands in the delta range showed a relative decrease which was not statistically significant.
Monti
J M
JM
Department of Pharmacology and Therapeutics, Clinics Hospital, Montevideo, Uruguay. jmonti@mednet.org.uy
Alvariño
F
F
Monti
D
D
D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000187:drug effects / Q000503:physiopathology; D004311:Double-Blind Method; D004569:Electroencephalography; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D011725:Pyridines / Q000627:therapeutic use*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012890:Sleep / Q000187:drug effects* / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy* / Q000503:physiopathology*; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology; D000077334:Zolpidem
D006993:Hypnotics and Sedatives; D011725:Pyridines; D000077334:Zolpidem