Parkinson’s disease is a progressive disease of the brain caused by the death of special nerve cells. The disease is characterized by movement disorders such as slowing movements, stiffness of the muscles, tremors or specific changes in the gait pattern. Often there can be many years before these typical symptoms permit a diagnosis of Parkinson’s disease. These can include, for example, constipation, dream sleep disorders (REM sleep behavior disorder), disorders of smell perception or depression. “These are already signs of the typical nerve cell damage in Parkinson’s disease. However, this has not yet reached the relevant area in the brain to the extent that the typical movement disorders arise, “explains Parkinson expert Daniela Berg. Director of the Clinic for Neurology at the University Medical Center Schleswig-Holstein (UKSH), Campus Kiel, and professor at the Medical Faculty of the Christian-Albrechts-Universität zu Kiel (CAU). Together with colleagues from Denmark, Canada and Sweden, she and her team summarize in the renowned specialist magazineNature Reviews Neurology summarizes the current state of the art on these early symptoms in terms of the course of the disease.