A new European study suggests individuals suffering from REM sleep behavior disorders have an increased risk of developing Parkinson’s disease (PD).

REM sleep behavior disorders are characterized by dream nightmares in which a person is attacked and pursued leading an individual to scream, cry, punch and kick while sleeping.

The current study is the third work on the topic within the last five years to be published by Lancet Neurology.

The first work showed in 2006 that 45 percent of patients who suffer this sleep disorder develop Parkinson’s disease and other neurodegenerative diseases caused by a lack of dopamine in the brain.

The second article discovered that neuroimaging tests that measure dopamine in the brain, such as the brain SPECT scan (single-photon emission computed tomography), are useful to identify patients with REM sleep disorders with increased risk of developing a neurodegenerative diseases such as Parkinson’s disease.

In the current study, researchers used SPECT to conclude that the levels of dopamine in the brain are quickly lowering over the years in patients with REM sleep behavior disorder.

SPECT is the first neuroimaging technique to detect the disease progression at an early stage. The study involved comparing for three years the evolution of brain SPECT in 20 patients with REM disorder and 20 healthy controls.

The neuroimaging technique measures the presence of dopamine in the substantia nigra, a part of the brain associated with learning and harmony of body movements. In Parkinson’s disease, a deficiency of dopamine in the substantia nigra causes tremor, stiffness and movement slowness in patients.

Results showed that after three years of monitoring the production of dopamine in the control group was reduced by 8 percent due to age, while the group of REM sleep disorder patients experienced a reduction of 20 percent.

Once the three-year follow-up ended, three of 20 patients in the REM sleep disorder group had developed Parkinson’s disease and their dopamine reduction was around 30 percent.

Researchers conclude that more efforts are needed to create neuroprotective drugs that prevent the progression from REM sleep behavior disorders to Parkinson’s disease.

Authors of the study suggest that, to be considered effective, a neuroprotective drug should significantly prevent the dopamine concentration from dropping in these patients.

Source: IDIBAPS – Institut d’Investigacions Biomèdiques August Pi i Sunyer