Subjects and Methods
Patients and Centers
Details of recruitment of participants and centers in the baseline
study have been previously described.10 Briefly, 13 centers
from the IRBDSG recruited patients with idiopathic RBD
(according to standard criteria11). All cases had neurologic
examination confirming that dementia and parkinsonism were
absent. Patients with mild cognitive impairment (MCI) could
be included (although the Barcelona and Innsbruck centers did
not include MCI patients). All participants provided written
informed consent to participate, and the research ethics boards
of each center gave approval for the study.