Smartwatch Study Finds Older Adults' Sense of Their Own Mental Sharpness Tracks Real Cognitive Performance

Four times a day for a week, a smartwatch on the wrist of an older adult buzzed with the same request: how sharp does your mind feel right now, and what is your mood? Once the answer was logged, the watch moved straight to a short test of processing speed and attention. That routine sits at the center of a University of California, Davis study that suggests older adults may be better judges of their own mental sharpness, moment to moment, than scientists once assumed.

The study gave smartwatches to 62 participants, all of whom had scored within normal ranges on standard cognitive tests. The researchers accounted for age, mood and time of day. When a person rated their sharpness below their own average, their performance on the objective tasks also tended to be lower. Both the ratings and the scores tended to slip later in the day. The work was published in Neuropsychology, a journal of the American Psychological Association.

What makes the approach unusual is where it captures cognition: in daily life, rather than through a person's memory of how things have been or a single test in an office. Brandon Gavett, the study's first author, put the difficulty plainly: measuring change in a person's cognitive functioning is really hard. Sarah Tomaszewski Farias, a study author and professor of neurology at UC Davis, noted that there are many open questions about how best to measure cognitive complaints.

The current practice has known weaknesses. When patients report cognitive problems, doctors typically rely on recollections of those episodes, and they screen patients at moments when the person may be feeling better. Researchers and clinicians also often ask people to assess how their thinking has gone over the past year, which Farias said is vulnerable to recall bias. Asking repeatedly how someone feels right now could sidestep some of that.

There has also been long-standing skepticism that people can judge their own cognition at all, and mood is a big part of it. Depression can color how people evaluate their memory and abilities, and earlier research has tied subjective cognitive concerns to depression. That is why Farias called one finding the most surprising: the relationship between perceived sharpness and objective performance did not appear to be explained by mood.

Heather Snyder, senior vice president of medical and scientific relations at the Alzheimer's Association, was not involved in the study. She called it an interesting step toward understanding whether people's perceptions could give researchers additional information about cognitive health. "Our perceptions are sometimes the first indicator," she said. She added that the study joins a growing body of work testing whether everyday technology can pick up subtle cognitive changes, including research using wearables to study speech and patterns of activity.

The appeal is that measurement can happen outside a clinic. A traditional assessment captures one point in time, often in a quiet, controlled room. A wearable could in theory collect many observations while a person cooks dinner or runs errands. But a watch that buzzes several times a day has costs. Gavett said some older adults may not want to wear the devices or be prompted continuously, and users must tolerate interruptions and remember to charge them.

He was also direct about what a week of data cannot do: it will not tell anyone whether they are developing dementia. Researchers may need to follow people for months or even years to learn whether changes in these measurements carry meaningful information about the risk of larger decline. Farias said that is now among the biggest questions facing the team. Next, the researchers plan to keep testing such approaches in clinical trials before moving to larger populations and judging how reliably they detect meaningful change. "Moving in the right direction to get people help for dementia as early as possible is the goal," Gavett said.