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Sleep microstructure around sleep onset differentiates major depressive insomnia from primary insomnia
Author(s) -
Staner Luc,
Cornette Françoise,
Maurice Damien,
Viardot Geoffrey,
Bon Olivier Le,
Haba José,
Staner Corinne,
Luthringer Rémy,
Muzet Alain,
Macher JeanPaul
Publication year - 2003
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1046/j.0962-1105.2003.00370.x
Subject(s) - insomnia , primary insomnia , sleep (system call) , sleep onset , psychology , electroencephalography , audiology , sleep disorder , psychiatry , medicine , computer science , operating system
Summary In the present study we investigate whether alterations of sleep propensity or of wake propensity are implicated in sleep initiation disturbances encountered in major depressive insomnia and in primary insomnia. For this purpose, the time course of electroencephalogram (EEG) power density during the period preceding sleep onset and during the first non‐rapid eye movement (REM) period was examined in three age and gender matched groups of 10 women and 11 men (healthy controls, primary insomniacs and depressive insomniacs). In contrast to healthy controls and depressive insomniacs, patients with primary insomnia did not experience a gradual decrease of their alpha and beta1 power during the sleep onset period and had a lower delta activity in the 5 min preceding sleep onset. Compared with the two other groups, depressive patients exhibit less dynamic changes in slow wave activity during the first non‐REM period. The present results suggest that hyperarousal (high ‘Process W’) may mainly be implicated in the sleep initiation difficulties of primary insomniacs whereas the homeostatic sleep regulation process seems to be partially maintained. In our major depressed patients, the sleep initiation disturbances appeared to relate to a lower sleep pressure (low ‘Process S’) rather than to hyperarousal. This study supports the idea that different mechanisms are implicated in sleep disturbances experienced by primary insomniacs and major depressive insomniacs.