Neuropsychological effects of one-week continuous positive airway pressure treatment in patients with obstructive sleep apnea: a placebo-controlled study.
OBJECTIVE
To determine whether 1-week continuous positive airway pressure (CPAP) treatment, compared with placebo CPAP, improves cognitive functioning in patients with obstructive sleep apnea (OSA).


METHODS
36 OSA patients (aged 32-60 years, respiratory disturbance index [RDI] > 15) were monitored 2 nights with polysomnography, then randomized for 1-week treatment to CPAP or placebo (CPAP at 2 cm H2O with holes in mask). Participants completed Wechsler Adult Intelligence Scale-Revised Digit Symbol and Digit Span, Trailmaking A/B, Digit Vigilance, Stroop Color-Word, Digit Ordering, and Word Fluency tests pre- and posttreatment. These produced 22 scores per participant, which were analyzed by use of repeated-measures analysis of variance (ANOVA) and a rank-sum test.


RESULTS
In ANOVA, only 1 of the 22 scores showed significant changes specific to CPAP treatment, a number that could be expected by chance alone: Digit Vigilance-Time (p = .035). The CPAP group improved their time (from 7.5 to 6.9 minutes. p = .013). The rank-sum test revealed that the CPAP group had significantly better overall cognitive functioning posttreatment than the placebo group (mean ranks of 17.8 vs. 20.2, respectively; p = .022).


CONCLUSIONS
Although results suggest overall cognitive improvement due to CPAP, no beneficial effects in any specific cognitive domain were found. Future studies of neuropsychological effects of CPAP treatment should include a placebo CPAP control group. Placebo studies that use longer-term treatment might demonstrate additional effects. It is also possible that, even at 2 cm H2O, CPAP conveys some beneficial neuropsychological effects.
Bardwell
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University of California, San Diego, Department of Psychiatry, and Veterans Affairs San Diego Healthcare System, La Jolla 92093-0804, USA. wabardwell@ucsd.edu
Ancoli-Israel
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Berry
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Dimsdale
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JE
D000328:Adult; D001288:Attention / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology; D011175:Positive-Pressure Respiration; D011340:Problem Solving / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D012691:Serial Learning / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D012894:Sleep Stages / Q000502:physiology; D016896:Treatment Outcome
D010100:Oxygen