Excessive daytime sleepiness or lower enthusiasm to get things done due to sleep problems can significantly increase the risk of predementia or motoric cognitive risk syndrome, as it is formally known, in older adults compared to individuals without such sleep-related issues, according to a study published Nov. 6, 2024 in the journal Neurology.1
Motoric cognitive risk is characterized by the presence of subjective cognitive complaints along with slow gait speed in older individuals without dementia or mobility disability. It is a potential precursor to dementia.2
The objectives of the study were to examine if overall sleep disturbances are associated with an increased risk of developing incident MCR and investigate the relationship between sleep disturbances and prevalent MCR in older adults. The study also evaluated the association of specific subtypes of sleep disturbances with MCR. Subjects who had data available for MCR and Pittsburgh Sleep Quality Index (PSQI) were included in the study.
The PSQI scale encompasses seven components to measure sleep disturbances, each scored from 0 to 3, with higher scores indicating greater dysfunction. These include: sleep duration, sleep disturbance, sleep latency, daytime dysfunction due to sleepiness, sleep efficiency, overall sleep quality, and sleep medication use.
MCR was identified based on the self-reported cognitive complaints on standardized questionnaires and slow gait speed measured objectively using an electronic treadmill. A total of 268 participants with PSQI cut score of ≤5 were categorized as “good†sleepers, while 177 with a score of >5 were classified as “poor†sleepers.
A total of 445 participants, mean age of ~76 years, who did not have dementia, were included in the study with women comprising ~57% of the study group. At the start of the study, there were 403 participants who did not have MCR. After a follow-up period of 2.9 years (mean), 36 participants developed incident MCR. Poor sleepers had a nearly three-times higher likelihood of developing incident MCR with hazard ratio (HR) of 2.7. However, this association lost statistical significance after adjustment for depressive symptoms with adjusted HR of 1.6.
Among the seven components of the PSQI, sleep-related daytime dysfunction (excessive sleepiness and lower enthusiasm) had more than three times higher risk of developing MCR compared to those who did not have those sleep-related problems, even after controlling for confounders such as age, depression and other health conditions (aHR 3.3). No significant association was observed between poor overall sleep quality and prevalent MCR (OR 1.1).
This study has shown a clear association between poor sleep quality and incident MCR, though no significant link was observed with prevalent MCR. Hence, there is a need to also focus on daytime consequences of poor sleep in older adults, in addition to nighttime sleep patterns. Early interventions in these patients may support better cognitive health outcomes and reduce the onset of MCR in the older population.
References
1. Leroy V, et al. Association of sleep disturbances with prevalent and incident motoric cognitive risk syndrome in community-residing older adults. Neurology. 2024 Dec 10;103(11):e210054. doi: 10.1212/WNL.0000000000210054.
2. Verghese J, et al. Motoric cognitive risk syndrome Multicenter incidence study. Neurology. 2014 Dec 9;83(24):2278–2284. doi: 10.1212/WNL.0000000000001084.