Slow Days, Restless Nights: Wrist Sensor Helps Predict Dementia

How older people move during the day and sleep at night says something about their later dementia risk. Those with little brisk activity and restless sleep developed dementia more often. A wrist sensor worn for one week made dementia prediction a little more accurate.

Researchers used data from 53,448 people aged 60 or older in the UK Biobank. Each wore a movement sensor for seven days, and were then followed for nearly eight years on average. A computer method picked two patterns out of 36 measurements. The first: short, rare bouts of brisk movement, lots of light activity and quick switches to rest. People who showed this pattern clearly more than average had a 43 percent higher dementia risk. The second pattern, very short or very long sleep, long wake periods and early waking, came with a 10 percent higher risk. A second group of 3,965 people confirmed the results.

Compared with predicting by age alone, the patterns improved accuracy about as much as testing for the known risk gene APOE. The gain was modest, though. The study cannot say whether movement and sleep help cause dementia or are early signs of it. Only one week was measured, and participants were healthier than the general population.