NREM sleep EEG frequency spectral correlates of sleep complaints in primary insomnia subtypes.
OBJECTIVE
To determine whether the frequency spectrum of the sleep EEG is a physiologic correlate of 1) the degree to which individuals with persistent primary insomnia (PPI) underestimate their sleep time compared with the traditionally scored polysomnogram (PSG) and 2) the sleep complaints in PPI subjects who have relatively long traditionally scored PSG sleep times and relatively greater underestimation of sleep time.


METHODS
We compared EEG frequency spectra from REM and NREM sleep in PPI subjects subtyped as subjective insomnia sufferers (those with relatively long total sleep time and relative underestimation of sleep time compared with PSG), and objective insomnia sufferers (those with relatively short PSG total sleep time) with EEG frequency spectra in normals. We also studied the correlation between these indices and the degree of underestimation of sleep. Further, we determined the degree to which sleep EEG indexes related to sleep complaints.


METHODS
Duke University Medical Center Sleep Laboratory.


METHODS
Normal (N=20), subjective insomnia (N=12), and objective insomnia (N=18) subjects.


METHODS
N/A.


RESULTS
Lower delta and greater alpha, sigma, and beta NREM EEG activity were found in the patients with subjective insomnia but not those with objective insomnia, compared with the normal subjects. These results were robust to changes in the subtyping criteria. No effects were found for REM spectral indexes. Less delta non- REM EEG activity predicted greater deviation between subjective and PSG estimates of sleep time across all subjects. For the subjective insomnia subjects, diminished low-frequency and elevated higher frequency non- REM EEG activity was associated with their sleep complaints.


CONCLUSIONS
NREM EEG frequency spectral indexes appear to be physiologic correlates of sleep complaints in patients with subjective insomnia and may reflect heightened arousal during sleep.
Krystal
Andrew D
AD
krystal@phy.duke.edu
Edinger
Jack D
JD
Wohlgemuth
William K
WK
Marsh
Gail R
GR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D004311:Double-Blind Method; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology*