Psychomotor performance deficits and their relation to prior nights' sleep among individuals with primary insomnia.
OBJECTIVE
To examine psychomotor (reaction time) performance deficits and their relation to subjective and objective sleep measures among individuals with primary insomnia (PI).


METHODS
This study was conducted at affiliated VA and academic medical centers using a matched-groups, cross-sectional research design.


METHODS
Seventy-nine (43 women) individuals with PI (MAge = 50.0 +/- 17.1 y) and 84 (41 women) well-screened normal sleepers (MAge = 48.6 +/- 16.8 y).


METHODS
Participants underwent 3 nights of polysomnography (PSG) followed by daytime testing with a 4-trial multiple sleep latency test (MSLT). Before each MSLT nap, they rated their sleepiness and completed a performance battery that included simple reaction time (SRT), continuous performance (CPT), and 4 switching attention (SAT) tests. Performance measures included the mean response latency and the standard deviation of each subject's within-test response latencies.


RESULTS
PI sufferers reported greater (P = 0.001) daytime sleepiness, but were significantly (P = 0.02), more alert than normal sleepers on the MSLT. Multivariate analyses showed the PI group had significantly longer response latencies and greater response variability across many of the subtests than did the controls. Regression analyses showed that both PSG- and diary-based sleep measures contributed to the prediction of daytime performance indices, although objective wake time after sleep onset appeared the best single predictor of the daytime measures.


CONCLUSIONS
Results confirm that PI sufferers do show relative psychomotor performance deficits when responding to challenging reaction time tasks, and these deficits appear related to both objective and subjective sleep deficits. Findings support PI patients' diurnal complaints and suggest the usefulness of complex reaction time tasks for assessing them.
VA Medical Center, Durham, NC 27705, USA. jack.edinger@duke.edu
Jack D
JD
Edinger
Melanie K
MK
Means
Colleen E
CE
Carney
Andrew D
AD
Krystal
D000328:Adult; D000368:Aged; D001143:Arousal; D001288:Attention; D001294:Attitude to Health; D003072:Cognition Disorders / Q000175:diagnosis / Q000523:psychology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003469:Culture; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017286:Polysomnography; D011597:Psychomotor Performance; D011930:Reaction Time; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications / Q000523:psychology*; D014851:Wakefulness