Researchers at Boston University Medical Center have just made a remarkable discovery, and one that could change how we diagnose dementia in its early stages. They’ve found that sleep habits could predict whether or not you are likely to develop the degenerative brain disease, and specifically that people who sleep more than nine hours per night are at a very high risk of dementia.

Scientists examined 2,400 people who self-reported their sleep duration over a decade and compared their likelihoods of getting dementia based on how much they slept. They found that people who spend nine hours or more asleep were twice as likely to develop dementia over 10 years than those who did not sleep as long.

Scientists say that changes in sleep patterns are one of the big indicators of brain damage, and this finding could open up a whole new way to catch dementia early, potentially allowing doctors to treat it more successfully. Also, it could help scientists understand how dementia works better, possibly leading to new treatments down the road.

“Participants without a high school degree who sleep for more than 9 hours each night had six times the risk of developing dementia in 10 years as compared to participants who slept for less. These results suggest that being highly educated may protect against dementia in the presence of long sleep duration,” explained co-corresponding author Sudha Seshadri, MD, professor of neurology at BUSM and FHS senior investigator.

“Self-reported sleep duration may be a useful clinical tool to help predict persons at risk of progressing to clinical dementia within 10 years. Persons reporting long sleep time may warrant assessment and monitoring for problems with thinking and memory,” added co-corresponding author Matthew Pase, PhD, fellow in the department of neurology at BUSM and investigator at the FHS.