Elderly people who are excessively sleepy during the day or lack motivation to go about their daily activities may be more likely to develop a pre-dementia syndrome called motoric cognitive risk (MCR) – that can progress to dementia.
Those are the findings of a new study by researchers from the Albert Einstein College of Medicine in New York, which cross-referenced sleepiness in the day with certain signs of MCR: occasional memory issues and a slower walking gait.
This could help healthcare professionals spot signs of dementia risk at the earliest opportunity – potentially at a point where mitigations can be put in place to prevent it from developing.
"Our findings emphasize the need for screening for sleep issues," says lead author and geriatrician Victoire Leroy.
"There's potential that people could get help with their sleep issues and prevent cognitive decline later in life."
Leroy and colleagues recruited 445 adults without dementia aged over 65, with an average age of 76.
Once a year for an average of three years, the participants completed questionnaires about their recall abilities, sleep patterns, and daily activities, while their walking speed was tracked on treadmills for an average period of three years.
Over the study period, 35.5 percent of the participants categorized as having excessive daytime sleepiness and a lack of enthusiasm for day-to-day activities developed MCR. In the participants outside that group, 6.7 percent developed the syndrome.
While the study doesn't prove a direct relationship, it does suggest that in some people, being overly sleepy and feeling sluggish during the day could be early signs of MCR. The condition was three times more likely in people with those symptoms, after accounting for age, sex, and several health issues – including depression.
"Our findings also emphasize the need for an early screening of sleep disturbances as a potential preventive intervention for cognitive decline," write the researchers in their published paper.
It's well established that earlier is better when it comes to a diagnosis of dementia – or pre-dementia – and we're seeing more and more evidence that the condition can be prevented in a large number of cases, if it's spotted earlier on.
Based on previous research, those who have MCR are around three times more likely to go on to develop dementia than the general population. Vascular dementia is particularly likely, caused by a reduced blood flow to the brain.
Add all this together and we've got what might be an early warning of increased dementia risk in certain people – though more information needs to be collected about the how and the why behind this association.
"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," says Leroy.
"We also need studies to explain the mechanisms that link these sleep disturbances to motoric cognitive risk syndrome and cognitive decline."
The research has been published in Neurology, the medical journal of the American Academy of Neurology.