A new study from researchers at a Danish University linked restless sleep and neurological diseases such as Parkinson’s and Dementia.

The study conducted at Aarhaus University found that people who have trouble sleeping during the rapid eye movement (REM) phase of sleep have lower levels of dopamine in their brain. The lower levels of dopamine in the brain can be a warning sign for diseases such as Parkinson’s. Restless sleep during this phase is called REM behavior disorder (RBD.) REM is when healthy people lie perfectly still and dream. RBD sufferers can sometimes physically act out their dreams by kicking and moving.

Parkinson’s disease causes nerve cell damage which causes a drop in dopamine. The drop in dopamine level leads to Parkinson’s symptoms which include impaired motor function and can eventually lead to dementia.

“These [RBD] patients have an inflammation of the brain in the area where the dopamine-producing nerve cells are found,” said Morten Gersel Stokholm from Aarhus University and the PET Centre at Aarhus University Hospital.

The new research published in the neurological journal The Lancet Neurology is the first to identify RBD brain inflammation as a precursor to Parkinson’s.

“With this study, we have gained new knowledge about the disease processes in the brain in the early initial stages of the disease development. The idea is for this knowledge to be used to determine which patients with the sleep disorder will later develop Parkinson's disease. At the same time, this is also knowledge that can help to develop drugs which can stop or slow the development of the diseases,” said Stokholm.

According to the Parkinson’s Foundation, around 1 million Americans live with Parkinson’s disease and approximately 60,000 people are diagnosed with the disease each year. The disease typically affects older people with symptoms setting in around 50. Men are 1.5 times more likely to have the disease than women.