A noninvasive dementia sleep test may help with predicting and diagnosing neurodegenerative diseases in older adults.
Sleep has been an increasing focus of study when it comes to learning what causes dementia, how to predict it and how to diagnose it: Deep sleep has been linked to the clearing of harmful brain toxins that may cause Alzheimer’s and related dementias. Previous research has examined average amount of sleep, quality of sleep, breathing patterns in sleep, the impact of “all-nighters” on the brain, the impact of sleep medications, snoring, napping, daytime drowsiness, and many other facets of sleep as they pertain to risk, symptoms or biomarkers of dementia. Now, scientists have developed a dementia sleep test.
Researchers at Massachusetts General Hospital and Beth Israel Deaconess Medical Center recently developed a sleep-related data model called the Brain Age Index (BAI) — an artificial intelligence-powered model that leverages a huge amount of data to estimate the difference between a person’s chronological age and the biological age of their brain as measured through electrical measurements (with an electroencephalogram, or EEG) while they sleep.
A higher BAI could be a sign that the brain is not aging typically. Thus, researchers believe it could be leveraged as a marker of dementia.
In a new study published by JAMA Network Open, the researchers investigated whether high BAI values could indicate dementia. To do this, they studied the sleep of 88 individuals with dementia, 44 with mild cognitive impairment, 1,075 with cognitive symptoms but no diagnosis of impairment, and 2,336 without dementia, and computed values for a cumulative 5,144 EEG sleep tests.
“The model computes the difference between a person’s chronological age and how old their brain activity during sleep ‘looks,’ to provide an indication of whether a person’s brain is aging faster than is normal,” senior author Dr. M. Brandon Westover, director of Data Science at the MGH McCance Center for Brain Health, said in a news release.
Across the different study groups, Westover and his colleagues found that BAI values increased as cognitive impairment increased, and that the model said people living with dementia had brains that biologically appeared to be an average value of about four years older than those without dementia.
They backed up these BAI values with neuropsychiatric scores from standard cognitive assessments conducted by clinicians alongside the sleep study.
An estimated 50 million people around the world are living with dementia, a neurodegenerative condition characterized by memory impairment and cognitive decline. According to the World Health Organization, there are nearly 10 million new cases annually. It is also fatal. In fact, it is one of the leading causes of death in the U.S. and that rate, worldwide, keeps going up.
If, with further research, BAI proves an effective way to determine the presence and progression of dementia long before obvious cognitive symptoms appear, it could make diagnosis much easier, more accessible, and more affordable, which would allow those living with early-stage Alzheimer’s and related dementias to engage in preventive lifestyle changes and treatments with the goal of staving off the onset of symptoms.
Traditionally, dementia diagnoses follow a battery of cognitive screening tests and often a PET scan, which can be expensive and hard to access. Sometimes, first diagnoses can be inaccurate so it is wise to get a second opinion. Some patients have told Being Patient they needed to get fourth, fifth and sixth opinions.
According to first author Elissa Ye at MGH, “This is an important advance because, before now, it has only been possible to measure brain age using brain imaging with magnetic resonance imaging, which is much more expensive, not easy to repeat, and impossible to measure at home,” nothing that sleep EEG tests are increasingly geographically accessible to the general public and that they rely on inexpensive technologies, like headbands and dry EEG electrodes.
Co-senior author Dr. Alice D. Lam, in the Department of Neurology at MGH added, “Because quite feasible to obtain multiple nights of EEG, even at home, we expect that measuring BAI will one day become a routine part of primary care, as important as measuring blood pressure.”
“BAI has potential as a screening tool for the presence of underlying neurodegenerative disease and monitoring of disease progression.”