Researchers from the University of Colorado Anschutz Medical Campus and Washington University in St. Louis have identified a way to assess brain activity in sleep that occurs in the earliest stages of Alzheimer’s disease, typically many years prior to developing symptoms of dementia.

The digital biomarker uses electroencephalography (EEG) that can be recorded from simple headband devices to detect brain wave patterns related to memory reactivation in sleep, which are part of a system that processes memories in deep sleep. Study results published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association identify a relationship between EEG readings and levels of specific molecular changes indicative of pre-symptomatic Alzheimer’s disease. 

Additional findings further demonstrate that early stages of mild cognitive impairment due to Alzheimer’s disease can be detected in the EEG signals.  The longitudinal EEG recordings were obtained from participants at home up to six nights using Advanced Brain Monitoring’s Sleep Profiler, a single-channel EEG device worn on the forehead (with sensors at approximately AF7, AF8, and Fpz) and with a sampling rate of 256 samples per second.

“This digital biomarker essentially enables any simple EEG headband device to be used as a fitness tracker for brain health,” says Brice McConnell, MD, PhD, assistant professor of neurology at the University of Colorado School of Medicine and study senior author, in a release. “Demonstrating how we can assess digital biomarkers for early indications of disease using accessible and scalable headband devices in a home setting is a huge advancement in catching and mitigating Alzheimer’s disease at the earliest stages.” 

Researchers analyzed data from 205 aging adults, identifying measurable problems with memory reactivation in association with levels of proteins such as amyloid and tau that build up in Alzheimer’s Disease.

“What we found is these abnormal levels of proteins are related to sleep memory reactivations, which we could identify in people’s brain wave patterns before they experienced any symptoms,” says McConnell in the release. “Identifying these early biomarkers for Alzheimer’s disease in asymptomatic adults can help patients develop preventative or mitigation strategies before the disease advances.”

Researchers say this is an exciting step toward using wearables as digital biomarkers for disease detection. “We are just scratching the surface with this work, paving the way for affordable and easy-to-use devices to monitor brain health,” says McConnell in the release. “This is proof of principle that brain waves during sleep can be turned into a digital biomarker, and our next steps involve perfecting the process.” 

Photo caption: Researchers analyzed 205 adults using a single-channel sleep EEG headband device.

Photo credit: University of Colorado Anschutz Medical Campus