Can virtual reality boost brain power in movement disorders?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patient capable of understanding, signing and dating the written informed consent at baseline visit prior to randomization. * Patient diagnosed with Parkinson's disease (Movement Disorder Society PD Criteria) or Huntington's disease. * Patient with Hoehn and Yahr stage I-III for PD, and Shoulson and Fahn stage I-II for HD. * Patient with a score on the Parkinson's Disease Cognitive Rating Scale (PD-CRS) \>83, who present subjective memory complaints will be included in "group I: subjective memory complaints". * Patient with a score on the Parkinson's Disease Cognitive Rating Scale (PD-CRS) between 64 and 83, both inclusive, will be included in "group II: mild cognitive impairment". * Patient diagnosed with Parkinson's disease with stable dopaminergic treatment in the last 4 weeks. * Patient capable and willing to comply with study visits as detailed in the protocol. Exclusion Criteria: * Illiterate patients. * Patients with severe vision or hearing impairment. * History of deep brain stimulation surgery. * Patients diagnosed with severe dementia (possible or probable) associated with Parkinson's disease, according to the Clinical Diagnostic Criteria for Dementia Associated with PD with a score of \>2 on the CRD or with Huntington's disease. * Patients with active psychosis in the form of incapacitating delusional ideation. * Patients who were under experimental treatment in the 2 months prior to the selection period. * Patients with any of the following conditions: * Life expectancy of less than 6 months. * Any severe or uncontrolled medical condition. * Patients with a history of poor treatment compliance or drug/alcohol abuse that may interfere with the patient's ability to comply with the study protocol or give informed consent. * Pregnancy or breastfeeding. * Contraindications for MRI\*. * Except for patients with Parkinson's disease (PD), since MRI is optional for these patients. Therefore, if there are contraindications for MRI, they can still participate without undergoing MRI.