Daytime Sleepiness Linked With Predementia Syndrome in Older Adults
Older adults with sleep-related daytime dysfunction, consisting of excessive sleepiness and lower enthusiasm, are at increased risk of developing a predementia syndrome called motoric cognitive risk syndrome, according to a study published in Neurology.
“Our findings emphasize the need for screening for sleep issues,” said study corresponding author Victoire Leroy, MD, PhD, of Albert Einstein College of Medicine in the Bronx, New York. “There’s potential that people could get help with their sleep issues and prevent cognitive decline later in life.”
The study looked at associations between sleep disturbances in older adults and motoric cognitive risk syndrome, a condition characterized by slow gait speed and cognitive complaints.
Some 445 community-residing adults aged 65 years and older without dementia were included in the analysis. At the start of the study and annually for an average 3 years afterward, participants answered questions about memory issues and had their walking speed tested on a treadmill. Their sleep was assessed using the Pittsburgh Sleep Quality Index.
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Among participants, 56.9% were women and the mean age was 75.9 years. Some 42 participants had motoric cognitive risk syndrome at the start of the study, and 36 developed incident motoric cognitive risk syndrome over the 3-year follow-up.
Poor sleepers, identified by Pittsburgh Sleep Quality Index scores above 5, had an increased risk of developing the syndrome, according to the study. Compared with participants with scores of 5 or lower, which identified them as “good” sleepers, poor sleepers had a hazard ratio of 2.7 for incident motoric cognitive risk syndrome. After adjustment for depressive symptoms, however, the hazard ratio dropped to a nonsignificant 1.6.
When researchers investigated the 7 components of the Pittsburgh Sleep Quality Index, they found sleep-related daytime dysfunction was significantly associated with an increased risk of the syndrome. Specifically, 35.5% of older adults with sleep-related daytime dysfunction developed motoric cognitive risk syndrome compared with 6.7% of the people without sleep-related daytime dysfunction. In models fully adjusted for components including age, depression, and other health conditions, participants with sleep-related daytime dysfunction were more than 3 times as likely to develop the syndrome than participants without it.
Meanwhile, prevalent motoric cognitive risk syndrome at baseline was not associated with overall poor sleep quality in the study.
“More research needs to be done to look at the relationship between sleep issues and cognitive decline and the role played by motoric cognitive risk syndrome,” Dr Leroy said. “We also need studies to explain the mechanisms that link these sleep disturbances to motoric cognitive risk syndrome and cognitive decline."
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