Activity Trackers May Provide Signs of Early Alzheimer’s

Fitness trackers can help us keep an eye on several different health metrics, from our resting heart rate to how quality our sleep is. As the technology continues to expand, could it also help monitor activity that reflects early Alzheimer’s? Possibly, according to new research.

A team from Johns Hopkins Bloomberg School of Public Health recently used a wrist device to monitor whether there were sleep and waking activity differences between older people with beta-amyloid protein buildup and those without it. The protein is a hallmark of Alzheimer’s. The findings, published in the journal SLEEP, showed that at least during waking hours, the tracker data did show a difference, which backs up evidence from another recent study the team conducted.

Dr. Adam Spira, first author and professor in the Department of Mental Health at the Bloomberg School, says, “We need to replicate these findings in larger studies, but it is interesting that we’ve now seen a similar difference between amyloid-positive and amyloid-negative older adults in two independent studies.”

For this study, the team had 82 cognitively healthy participants from the Baltimore Longitudinal Study of Aging wear wrist devices nonstop for a week and get PET brain scans to determine whether or not they had detectable beta-amyloid buildup.

The team found that amyloid-positive participants had higher mean activity in the early afternoon (between 1 and 3:30 p.m.) than amyloid-negative participants, along with less variability in activity between 1:30 and 4 p.m. and 7:30 to 10:30 p.m.

With more conservative analysis, some of these differences weren’t quite as strong, but the team believes that the consistent higher activity in the afternoon and evening may have to do with circadian dysfunction. This issue is common in Alzheimer’s patients, as is sundowning, a behavior involving increased agitation in the afternoon and evening.

It’s thought that beta-amyloid buildup may begin causing such issues early on in the disease’s development, which suggests that abnormal sleep and waking activity behaviors may be an early sign of Alzheimer’s. If so, wearable devices may provide people with data that encourages them to get tested.

The researchers stress that further study is needed, however.

Dr. Spira explains, “It’s conceivable that the higher afternoon activity we observed is a signal of ‘preclinical sundowning,’ At the same time, it’s important to note that these findings represent averages among a small sample of older people over a short period of time. We can’t predict whether an individual will develop amyloid plaques based on the timing of their activity. So, it would be premature for older people to be concerned because their fitness trackers say they are particularly active in the afternoon, for example.”

The team plans to do a larger study, including examining whether these changes are also linked with cognitive decline, not just beta-amyloid buildup.