Healthy young:  Inclusion criteria:  -18 to 50 years  Exclusion criteria:  Disease or condition that affects cognition, gait or balance. Severe hearing or visual impairments that affects participation in the assessments  Healthy elderly:  Inclusion criteria:  ≥60 years of age, 23 or more on the Montreal Cognitive Assessment (MoCA)  Exclusion criteria:  Disease or condition that affects gait or balance. Severe hearing or visual impairments that affects participation in the assessments  Parkinson cohort:  Inclusion criteria:  ≥60 years of age a clinical diagnosis of PD≤6 months prior to enrollment with the ability to walk without a mobility device for ≤5 minutes continuously.  Exclusion criteria:  People with speech difficulties (e.g. aphasia) cognitive difficulties affecting the ability to understand and/or follow verbal/written - instructions severe freezing of gait Severe hearing or visual impairments that affects participation in the assessments Other neurological diseases Other disease that can affect gait or balance.