Poor sleep quality is observed in mild cognitive impairment and is largely unrelated to depression and anxiety

Background: Individuals with mild cognitive impairment (MCI) commonly experience a number of sleep quality related issues. However, it remains unclear if these issues are specific to MCI or are simply attributed to the elevated levels depression and anxiety symptoms frequently observed among those with MCI. The present study sought to examine group differences between participants with MCI and matched controls on self-reported measures of sleep quality while controlling for depression and anxiety levels.

Methods: Participants with MCI (N = 48) and demographically matched controls (N = 48) were administered with self-reported measures of anxiety, depression and sleep quality. Sleep quality between both groups were first analyzed using a Multivariate Analysis of Variance, and then subsequently a Multivariate Analysis of Covariance incorporating depression and anxiety scores as covariates.

Results: The MCI group had significantly higher levels of depression and anxiety than the controls. On the sleep-related measures, the MCI group had significantly worse outcomes in sleep duration, disturbances, latency, efficiency, quality and daytime dysfunction. After controlling for depression and anxiety levels, with the exception of daytime dysfunction, all other differences remain significant, and are also associated with moderate to large effect sizes.

Conclusion: The results suggest that sleep quality issues are present in MCI and are largely independent of depression and anxiety.