Periodic Limb Movements in Sleep are Associated with Greater Cognitive Decline in Older Men without Dementia

Abstract

Study objectives: To examine the association between periodic limb movements in sleep (PLMS) and change in selected aspects of cognition in community-dwelling older men.

Methods: We studied 2,636 older men without dementia who underwent in-home polysomnography with measurement of the periodic limb movement index (PLMI) and periodic limb movement arousal index (PLMAI) using piezoelectric sensors. Random-effects models and logistic regression were used to examine the association between PLMI, PLMAI, and 3- to 4-y change in cognition.

Results: After multivariable adjustment, men with a high PLMI had greater decline on the Trail Making Test - Part B (P trend = 0.02); those with a PLMI ≥ 30 were 48% more likely (odds ratio = 1.48, 95% confidence interval = 1.05-2.07) to experience the development of significant cognitive impairment (≥ 1 SD above mean change). Further adjustment for sleep efficiency, nocturnal hypoxemia, or dopaminergic medication use and analysis among men without Parkinson disease (n = 2,607) showed similar findings. No significant association was found for PLMAI or for Modified Mini-Mental State Examination scores.

Conclusions: Among older men without dementia, higher PLMS frequency was associated with greater decline in cognition, particularly in executive function.

Keywords: PLMS; cognition; cognitive decline; periodic limb movements; polysomnography.

Figure 1

Multivariable-adjusted* association of periodic limb movements index and clinically significant cognitive impairment as measured by the Trail Making Test – Part B (completion time increased by 58 sec), odds ratio, and 95% confidence interval (CI) (n = 2,343). *Models adjusted by age, site, race (white vs. nonwhite), education level, physical activity level, history of diabetes mellitus, history of hypertension, history of coronary heart disease.