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 show that after 3 years of monitoring the production of dopamine in the control group was reduced by 8% due to age, while the group of REM sleep disorder patients experienced a reduction of 20%. Once the 3 year follow-up ended, 3 of 20 patients in the REM sleep disorder group had developed Parkinson's disease and their dopamine reduction was around 30%.
The three works led by the IDIBAPS - Hospital Clínic of Barcelona team conclude that more efforts are needed to create neuroprotective drugs that prevent the progression from REM sleep behavior disorders to Parkinson's disease. For the first time scientists have a technique, brain SPECT, to evaluate whether these drugs are effective. Authors of the study suggest that, to be considered effective, a neuroprotective drug should significantly prevent the dopamine concentration from dropping in these patients.