A little-understood sleep disorder affects millions and has clear links to dementia – 4 questions answered

Past age 50, men are much more likely to have REM sleep behavior disorder than women. Jose Luis Pelaez/Stone via Getty Images

A little-known and poorly understood sleep disorder that occurs during the rapid eye movement, or REM, stage of sleep has been garnering attention for its role in foreshadowing neurodegenerative brain diseases such as Parkinson’s disease and dementia with Lewy bodies. The disorder, known as REM sleep behavior disorder, or RBD in the medical field, affects around 1% of the general population worldwide and about 2% of adults over 65.

The Conversation talked with Anelyssa D'Abreu, a neurologist who specializes in geriatric neurology, to explain what researchers know about the condition’s links to dementia.