Boston University School of Medicine
This study, conducted by a team from Boston University School of Medicine, was published in the journal Neurology. They determined that even a small loss of the dreaming phase of sleep, called REM or rapid eye movement sleep, can increase the risk of Alzheimer’s.
The Boston team studied 321 people over age 60 who volunteered for a sleep study in the 1990s. Over the next 12 years, 32 developed dementia and of those, 24 were diagnosed with Alzheimer’s. Those who had just a little less REM sleep during the sleep test were more likely to be in the dementia group later. The difference in REM sleep was indeed slight—those who later developed dementia had only 3% less REM sleep than those who did not develop dementia. Most did not even notice the difference in their sleep.
It is not clear if the disordered sleep is a cause or an early effect of the dementia process. One of the leaders of the study, Matthew Pace, commented that, “Sleep disturbances are common in dementia but little is known about the various stages of sleep and whether they play a role in dementia risk. Our findings point to REM sleep as a predictor of dementia. The next step will be to determine why lower REM sleep predicts a greater risk of dementia.”