Spontaneous K-complexes in chronic psychophysiological insomnia.
OBJECTIVE
Spontaneous K-complexes are electroencephalographic features unique to non-rapid eye movement sleep. It has been suggested that this phasic event is a sleep-protective mechanism. Because insomnia sufferers report poor sleep quantity and quality, the objective of this study was to document the occurrence of spontaneous K-complexes in Stage 2 sleep of individuals with chronic insomnia. Specifically, the number and density of spontaneous K-complexes were studied in psychophysiological insomnia sufferers.


METHODS
This study took place in a sleep and event-related potentials laboratory.


METHODS
Spontaneous K-complexes were scored during Stage 2 sleep on the second and third nights of a four-consecutive-nights protocol of polysomnographic recordings.


METHODS
The sample included 14 participants suffering from psychophysiological insomnia (INS group; mean age=44.1 years) and 14 good sleepers (mean age=38.1 years). Participants underwent sleep and psychological evaluations. INS group participants met the diagnostic criteria for primary psychophysiological insomnia (mean duration of insomnia=9.6 years).


METHODS
Not applicable.


RESULTS
The total number of spontaneous K-complexes and the density according to the total time spent in Stage 2 sleep (spontaneous K-complexes per minute) were compiled. Repeated-measures analyses of variance showed no significant difference in the number and density of spontaneous K-complexes between the INS group (313.98 and 2.66) and the GS group (361.10 and 2.88), respectively.


CONCLUSIONS
These results suggest no deficiency in the sleep-protective mechanism of psychophysiological insomnia sufferers in comparison with good sleepers, as measured by the spontaneous K-complexes' number and density.
Bastien
Célyne H
CH
Ecole de Psychologie, Université Laval, Québec, Canada. celyne.bastien@psy.ulaval.ca
St-Jean
Geneviève
G
Turcotte
Isabelle
I
Morin
Charles M
CM
Lavallée
Mélanie
M
Carrier
Julie
J
Forget
Daniel
D
D000328:Adult; D002908:Chronic Disease; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D012720:Severity of Illness Index; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D012894:Sleep Stages / Q000502:physiology*; D011795:Surveys and Questionnaires