Research findings focus on people with a sleep disorder, but could have broader implications. For people with a certain sleep disorder, a simple blood test could help predict the development of dementia years before symptoms appear, a new study indicates.

Idiopathic REM sleep behaviour disorder (iRBD) causes people to physically act out their dreams while sleeping.

The disorder is also associated with a very high risk of Parkinson’s disease and a related condition called Dementia with Lewy Bodies.