D5.1 is the initiation package of the dBM-DEV study. The dBM-DEV study is the first clinical study of the AI-PROGNOSIS project, conducted by four study sites [Technische Universität Dresden (TUD), Centre Hospitalier Universitaire de Toulouse (CHUT), Fundacion Iniciative para las Neurociencias (FIN), King’s College London (KCL)]. It aims to identify novel digital biomarkers for the detection of REM Sleep Behaviour Disorders (RBD) and daytime somnolence via a home-based assessment as its primary outcome. As secondary objectives, this study aims to validate already existing digital BioMarkers (dBMs) for motor and cognitive symptoms. The scope of this deliverable is to ensure study initiation is on track. The study initiation package includes the documents necessary for the enrolment of the first study participant, i.e. the study protocol, the information sheets for the study participants, and the informed consent form (ICF). Furthermore, it includes the clinical study registration number in a registry meeting WHO criteria, in this case clinicaltrials.gov (NCT06444789). Writing the study protocol included establishing the functioning of the study teams and details of the study procedures. The procedures pertaining to study preparation, study registration and data management are outlined in this document. The latest version of the approved study protocol, the English version of the ICF, the study approval letters from three IRBs (pending approval at KCL), and a snapshot of the listing of the study at clinicaltrials.gov are included as appendices.