EEG Sleep Test Research for Dementia Identification

Understanding Dementia and Its Impact

Researchers are exploring the potential of an EEG sleep test to identify individuals with dementia or those at risk of developing this condition. Dementia is a progressive brain disease that leads to a decline in memory, cognitive function, behavior, and daily activities. This condition primarily affects older adults, causing significant challenges not only for patients but also for their families. Traditional diagnostic methods, such as brain scans, tend to be costly, limited in availability, and require hospital visits. Therefore, a simple and affordable test for early detection of dementia would be highly beneficial.

Investigation by Massachusetts General Hospital

A team at Massachusetts General Hospital in the USA is examining the use of electroencephalography (EEG) to measure electrical activity in the brain via electrodes placed on the scalp. Their most recent study, published in JAMA Network Open, focuses on how EEG could help identify individuals with dementia or those at risk.

Changes in EEG Patterns with Aging

Brain electrical activity patterns vary during daily activities and sleep, with aging leading to fragmented sleep reflected in EEG recordings. Individuals with dementia experience even more significant sleep fragmentation, making sleep EEG recordings a potentially valuable tool for identifying brain changes associated with the condition. The researchers have developed a Brain Age Index (BAI) that uses artificial intelligence and a comprehensive dataset of sleep EEGs to ascertain the difference between the brain age indicated by an individual’s EEG pattern and their actual chronological age. A higher BAI signifies a deviation from normal brain aging, suggesting the possible presence or risk of dementia.

Study Methodology and Findings

To evaluate the effectiveness of sleep EEG BAI measurements in diagnosing dementia, the researchers analyzed over 5,000 sleep EEGs from more than 4,000 participants. These were categorized into four groups: 81 dementia patients, 44 individuals with mild cognitive impairment, 1,075 individuals with some symptoms but no diagnosis, and 3,024 individuals without dementia. The team computed BAI values based on the sleep EEG recordings and compared the averages across the groups. The results showed that BAI values increased in tandem with cognitive impairment and dementia symptoms. Patients diagnosed with dementia had an average BAI value approximately four years older than those without the condition.

Potential of BAI as a Diagnostic Tool

The study’s findings indicate that BAI values derived from sleep EEG recordings hold promise as a diagnostic tool for dementia. The BAI could serve both as a screening mechanism and a method for monitoring the progression of the disease.

“This is an important advance because previously, measuring brain age was only feasible through magnetic resonance imaging (MRI), which is expensive, not easily repeatable, and cannot be performed at home,” stated Elissa Ye, MSc, the study’s lead author. With the rise of affordable technologies, such as EEG headbands, sleep EEG tests may soon be conducted in primary care or even at home settings.

Dr. Alice Lam, the co-author of the study, added, “Given the feasibility of obtaining multiple nights of EEG data, we anticipate that measuring BAI will one day become a routine aspect of primary care, as essential as measuring blood pressure.”

References

1. Ye E, Sun H, Leone M, et al. Association of sleep electroencephalography-based brain age index with dementia. JAMA Network Open 2020;3(9):e2017777357, doi:10.1001/jamanetworkopen.2020.17357.
2. Massachusetts General Hospital, Press release Sept 28, 2020. Noninvasive sleep test may help diagnose and predict dementia in older adults. https://www.eurekalert.org/pub_releases/2020-09/mgh-nst092420.php