Cognitive performance and sleep quality in the elderly suffering from chronic insomnia -: Relationship between objective and subjective measures

Objective: The objective of the present study was to evaluate the relationship between objective and subjective sleep quality and objective and subjective evaluation of cognitive performance in older adults suffering of chronic insomnia (using or not benzodiazepines, BZs) or self-reported good sleepers. Methods: Three groups of participants 55 years and older were evaluated: 20 insomnia sufferers using BZs chronically, 20 drug-free insomnia sufferers and 20 good sleepers. Objective sleep (PSG) and subjective sleep (sleep diaries, SD) were measured. Objective measures of cognitive performance (attention/concentration, verbal/visual memory, executive function and psychomotor speed) and subjective perception of daily performance were evaluated. Results: Correlational analysis revealed that objective and subjective measures of daytime performance are differentially related to sleep quality for the three groups. An objective good night of sleep is associated with better cognitive performance in good sleepers and drug-free individuals. On the other hand, the impression of having slept well is related to better cognitive performance in good sleepers and chronic insomnia sufferers using BZs. Conclusion: Daytime performance and sleep quality are related, but differently so for a good sleeper, an insomnia sufferer without treatment, or one using BZs to alleviate sleep difficulties. (C) 2003 Elsevier Science Inc. All rights reserved.