Mobilise-D: Extension Study

Control Cohort: Inclusion Criteria: * Aged 50 years or over * Able to walk 4 meters independently without walking aids * Anticipated availability for 12 months. * Ability to consent and comply with any study specific procedures. * Willingness to wear a wearable sensor for mobility monitoring * Able to read and write in first language in the respective country Exclusion Criteria: * Occurrence of any of the following within 3 months prior to informed consent: myocardial infarction, hospitalization for unstable angina, stroke, coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), implantation of a cardiac resynchronization therapy device (CRTD), active treatment for cancer or other malignant disease, uncontrolled congestive heart disease (NYHA class \>3), acute psychosis or major psychiatric disorders or continued substance abuse, other neurological or orthopaedic impairment that significantly impacts on gait * Patients with a clinical diagnosis of PD, COPD, proximal hip fracture or MS * History of dementia/significant cognitive impairment, or movement disorder (including essential tremor) PD Cohort Inclusion Criteria: * Participant in the Mobilise-D Clinical Validation Study (CVS) PD Cohort - see below. CVS PD Cohort: Inclusion criteria: * Aged 18 or over * Patients with the clinical diagnosis of PD according to the recent criteria of the Movement Disorder Society * Hoehn \& Yahr stage I-III Exclusion Criteria: * History consistent with Dementia with Lewy Bodies (DLB), atypical parkinsonian syndromes (including multiple system atrophy or progressive supranuclear palsy, diagnosed according to accepted criteria) * Repeated strokes or stepwise progression of symptoms, leading to a diagnosis of 'vascular parkinsonism' * Drug-induced Parkinsonism