Smartwatch Study Suggests Older Adults Can Sense Their Own Mental Decline in Daily Life

Four times a day for a week, a smartwatch on the wrist of an older adult buzzed with the same request: how sharp do you 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, repeated across 62 participants, is the core of a University of California, Davis study that suggests older adults may be better judges of their own mental sharpness than scientists once assumed.

The finding was simple. When a person rated their sharpness below their own personal average, their results on the objective tasks also tended to be lower. The work appears in Neuropsychology, a journal of the American Psychological Association. All 62 participants had performed within normal ranges on standard cognitive tests before the study began. The researchers accounted for age, mood and time of day, and found that both perceived sharpness and measured performance tended to decline later in the day.

The design is what sets the study apart. Doctors and researchers usually ask people to look back over the past year and judge how their thinking has held up, said Sarah Tomaszewski Farias, a study author and professor of neurology at UC Davis. Those retrospective judgments are vulnerable to recall bias. When patients bring up cognitive problems in a clinic, doctors also rely on the patient's memory of those episodes, and the screening may happen on a day the person feels better. Brandon Gavett, the study's first author, put it plainly: measuring change in a person's cognitive functioning is really hard. Asking repeatedly how someone feels in the moment may get around some of those limits.

There is also a history of skepticism that people can judge their own cognition at all. Mood is the usual complication, because depression can color how people rate their memory and thinking. Farias said previous research has tied subjective cognitive concerns to depression. That is why she found one result so encouraging: the link between perceived sharpness and objective performance did not appear to be explained by mood. It was, she said, one of the aspects of the study that surprised her the most.

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

The appeal is the setting. A traditional assessment captures performance at one moment, often in a quiet, controlled room. A wearable could in theory collect many observations while someone cooks dinner, runs errands or goes about the rest of the day.

The limits are real, though. Gavett noted that some older adults may not want to wear the devices or be continuously prompted, and that users must tolerate interruptions and remember to charge them. He also cautioned that a week of smartwatch data cannot tell anyone whether they are developing dementia. Scientists still have to learn whether patterns gathered over months or years can predict later cognitive impairment, and Gavett said that may require following people for that long. Farias called it one of the biggest questions facing the team.

The researchers say the next step is more testing of this kind of approach in clinical trials, before expanding to larger populations and measuring how reliably it detects meaningful change. Gavett described the goal as moving in the right direction to get people help for dementia as early as possible.