Long hours in bed tied to impaired thinking in post-stroke patients

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6 days ago

ST. PAUL, Minn., May 28 (UPI) -- The suspected connection between lack of proper sleep and stroke got stronger Wednesday with the publication of a study associating brain tissue damage and impaired thinking with long in-bed time among post-stroke patients.
The study found that people who spent the most time in bed either sleeping or trying to sleep after suffering mild strokes or transient ischemic attacks were more likely to have areas of damage to the white matter and in their brains known as "hyperintensities," which are visible in magnetic resonance imaging or computed tomography scans.
Areas of hyperintensity in white matter are possible indicators of stress or damage to the brain's many small blood vessels, a condition known as cerebral small vessel disease, or SVD. They are associated with cognitive impairment, triple the risk of stroke and double the risk of dementia.
Stroke patients who spent the most time in bed also scored slightly lower in cognition tests of thinking and memory skills, according to researchers in Scotland and Hong Kong in a study published in the online version of the U.S. medical journal Neurology.
In that study, some 420 people from Edinburgh and Hong Kong with an average age of 66 who had a mild stroke or a transient ischemic attack, also known as a "mini stroke," underwent brain scans, filled out sleep questionnaires and took cognitive tests within one to three months after the stroke.
Those who spent a longer time in bed were more likely to have signs of damage to small blood vessels in the brain, such as white matter hyperintensities, and also were more likely to have "slightly lower" scores on the test of thinking and memory skills.
The results provide the latest piece in the mosaic of evidence pointing to poor or disturbed sleep as a risk factor for both initial and recurrent stroke or TIAs.
Stroke is the fifth-leading cause of death and a top culprit in long-term disability in the United States, with nearly 800,000 Americans each year experiencing one. Given the tremendous health burden stroke imposes, identifying new ways to reduce secondary episodes and risk of death in stroke survivors is a major priority for the global health community.
In probing sleep as a possible means of intervention, researchers have generally found that its relationship with stroke is complex -- sleep disturbances are likely both a contributor to, and consequence of, stroke, they have found.
A 2023 review of the relatively limited number of studies available concluded that insomnia symptoms and/or poor sleep quality, as well as long sleep duration, were probably associated with increased risk of stroke. Sleep, "a modifiable behavior," was deemed a promising "secondary prevention target" to reduce the risk of recurrent event and death after a stroke.
The new study strengthens the case that sleep patterns are an important marker for preventing further strokes and TIAs, according to one of the authors.
Dillys Xiaodi Liu, a postdoctoral scholar in the Department of Psychiatry and Behavioral Sciences at the University of California-San Francisco, told UPI in emailed comments the findings yielded some important new insights about stroke patients who spend long periods of time in bed.
"Most of the previous studies have focused on sleep duration, [while] in-bed time is less investigated," she said. "One longitudinal study has reported long in-bed time is associated with higher risk of dementia and cognitive decline in older adults.
"We found it particularly interesting that longer in-bed time was associated with greater white matter hyperintensity burden, a marker of cerebral small vessel disease, or SVD, which causes 'slow' thinking and movement.
"This indicates the associations may be bidirectional -- patients with higher white matter hyperintensity burden may have longer in-bed time), which requires further validation in longitudinal study," she said.
Liu added she'd like to see future research focus on whether the association found between sleep patterns and small vessel disease burden remains in place over time.
"For example, do stroke patients with longer time in bed or longer sleep duration at the time of stroke onset exhibit greater SVD burden after one year or more? It will offer valuable insights into the role of sleep health in the management of SVD," she said, noting that another of the study's co-authors, the prominent neurologist Dr. Joanna Wardlaw of the University of Edinburgh, is currently leading a longitudinal stroke cohort study.
"I hope more interesting findings will emerge from it in the future," Liu said.
More evidence is emerging that links disturbed sleep patterns and stroke, according to Dr. Joyce K. Lee-Iannotti, a professor of neurology at Barrow Neurological Institute in Phoenix and the inaugural director of its Sleep Division.
Lee-Iannotti, who was not connected to the new study, told UPI there is "growing and compelling evidence linking insufficient sleep to increased stroke risk.
"From my perspective as both a sleep medicine and vascular neurology specialist, this relationship is multifactorial. Chronic sleep deprivation promotes systemic inflammation, endothelial dysfunction and autonomic dysregulation -- all of which are known contributors to cerebrovascular disease," she said.
Short sleep duration also is associated with traditional stroke risk factors such as hypertension, diabetes and atrial fibrillation, Lee-Iannotti said, adding, "Clinically, I have also observed that patients with sleep disorders like obstructive sleep apnea -- which fragment sleep and reduce sleep efficiency -- often present with more severe strokes and slower recovery trajectories.
"This underscores that sleep is not a passive state, but a critical pillar of brain and vascular health."
Lee-Iannotti, who serves as the chair of American Academy of Neurology's Sleep Section, said future research should aim to clarify the mechanisms that link sleep quality and architecture with both ischemic and hemorrhagic stroke subtypes.
"There's also a need to integrate wearable technology and home-based diagnostics into large, longitudinal studies that can capture real-world sleep patterns over time," she said.
"Biomarker discovery, including inflammatory and neurovascular markers influenced by sleep, could offer predictive insights."