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

Four times a day, for one 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 ran a short test of processing speed and attention. That routine, repeated across 62 participants, is the core of a UC Davis study that suggests older adults may be better judges of their own mental sharpness than scientists have long assumed.

The finding is simple to state. When a person rated their sharpness below their own average, their results on the objective tasks also tended to be lower. The researchers accounted for age, mood and time of day. Both perceived sharpness and measured performance tended to slide later in the day. The work was published in Neuropsychology, a journal of the American Psychological Association.

All 62 participants had scored within normal ranges on standard cognitive tests, so these were not people with a diagnosis. That matters for how the result is read: the self-ratings seemed to capture small, ordinary swings in function among healthy older adults.

The method is what sets the study apart. Doctors who hear a patient's cognitive complaint usually depend on that person's memory of events, and they often see the patient on a day when they feel better. Sarah Tomaszewski Farias, a study author and professor of neurology at UC Davis, said traditional assessments ask people to look back over the past year, which invites recall bias. Asking repeatedly about the present moment sidesteps some of that. "Measuring change in a person's cognitive functioning is really hard," said Brandon Gavett, the study's first author. He said the results offer a new way to bring people's own sense of whether they are above or below their norm into the measurement.

Mood was the complication Farias was watching. Scientists have been sceptical of self-judgment partly because depression can make people feel their memory is worse than it is, and earlier research has tied subjective cognitive concerns to depression. Yet in this study the link between perceived sharpness and actual performance did not appear to be explained by mood. "That's one of the aspects of the study that surprised me the most," Farias said.

Heather Snyder, senior vice president of medical and scientific relations at the Alzheimer's Association, was not involved in the research. She called it an interesting step toward learning whether people's perceptions could add information about cognitive health. "Our perceptions are sometimes the first indicator," she said. She placed the study within a growing body of work using everyday technology to detect subtle cognitive change, including wearables that track speech and activity patterns.

The appeal is the setting. A clinic test captures one moment, often in a quiet, controlled room, while a wearable could in theory gather many observations as someone cooks dinner or runs errands. But the approach has costs. Gavett noted that some older adults may not want to wear the devices or be prompted continuously, and that users must tolerate interruptions and remember to charge them.

He was also clear about limits. A week of smartwatch data 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 say anything about the risk of larger decline, and Farias called that one of the biggest open questions. The next step is more testing in clinical trials, then larger populations, to see how reliably such methods detect meaningful change. "Moving in the right direction to get people help for dementia as early as possible is the goal," Gavett said.