Poor sleep quality impairs cognitive performance in older adults

The prevalence of insomnia increases with age. Short sleep duration is associated with deficits in cognitive performance. We hypothesized that short sleep duration and sleep quality influence cognitive performance in older adults. The study included 78 adults aged 60years and over (72.2 +/- 5.9years). Total sleep time and sleep efficiency (total sleep time/time in bedx100) were calculated using actigraphy. We evaluated cognitive performance with the continuous performance test-identical pairs and the number-back test. Sleep apnea was evaluated overnight with a portable home monitoring system. The accuracy of the 0-back test significantly decreased in participants with total sleep time less than 5h compared with those with total sleep time greater than 7h, but there was no significant difference in continuous performance test-identical pairs between the two groups. Participants with sleep efficiency <85% showed a significant decrease in 0- and 1-back test accuracy compared with those with sleep efficiency 85%. There were no significant differences in the accuracy of number-back tests and continuous performance test-identical pairs between apnea-hypopnea index 15h(-1) and apnea-hypopnea index <15h(-1) groups, or among lowest SpO(2)90%, lowest 80-90%, and lowest SpO(2)<80% groups. Age, total sleep time and sleep efficiency were significantly correlated with accuracy on the 0-back test. Age and sleep efficiency were significantly correlated with accuracy on the 1-back test. Multiple regression analysis revealed that total sleep time was independently correlated with accuracy on the 0-back test, while age was independently correlated with accuracy on the 1-back test. Our findings suggest that sleep duration and sleep quality may play a role in cognitive performance in older adults.