Rapid eye movement sleep behavior disorder is associated with an increased risk of developing Parkinson's disease. For the first time, researchers demonstrate that inflammation may play a key role.

Rapid eye movement (REM) sleep behavior disorder (RBD) is connected with frightening dreams combined with nighttime motor activity. In other words people with these kind of dreams act out what they are dreaming.

Researchers have found that RBD is linked to an increased risk of developing Parkinson's disease later in life.

The condition can precede Parkinson's disease and other dementias by half a century. In fact, most people with RBD will go on to develop Parkinson's, Lewy body dementia, or multiple system atrophy.

Parkinson's disease is caused by death of dopamine-producing neurons in a part of the striatum called the substantia nigra. Dopamine levels are slowly reduced, the characteristic motor symptoms of Parkinson's disease appear, including rigid muscles, tremor, slow movement, and changes in speech.

In Parkinson's disease and similar conditions, inflammation in the brain has also been observed. In particular, there is an activation of microglia, which are a type of macrophage and a major player in the central nervous system's immune response. They are heavily involved in neuroinflammation.

Influencing this inflammatory response is currently being investigated as a potential route to treatment for Parkinson's disease.