RBD is extremely difficult to diagnose because its symptoms can go unnoticed or be confused with other diseases. A definitive diagnosis requires a sleep study, known as a video-polysomnogram ...

there is a phase that may last for decades in which brain changes are taking place but the patient either remains ...

Nonmotor symptoms may appear during the course of ... Rapid eye movements-sleep behavior disorder (RBD) is associated with PD and can be a preclinical marker of an evolving Parkinsonian disorder.