Alpha-synuclein Education and Disclosure in Individuals With Preclinical and Symptomatic Lewy Body Disease

Inclusion Criteria All Participants * Able to provide 1) written, informed consent or 2) assent if a care partner can provide consent. * Access to a primary care or neurology provider for ongoing care. * 1\) willing to undergo skin biopsy or lumbar puncture for alpha-synuclein testing or 2) has access to as-yet undisclosed skin biopsy or lumbar puncture alpha-synuclein testing results. Healthy/Asymptomatic Arm * Undergoing testing for defined reason (e.g., research study) * Mini-Mental State Examination score between 26 and 30 (or MoCA between 25 and 30) * General good health (no diseases expected to interfere with the study) Symptomatic Arm \[Concern for dementia with Lewy bodies (DLB), Parkinson's disease (PD), or multiple system atrophy (MSA)\] * Referred by a neurologist or movement disorder specialist * Adults with any of the following: symptomatic LBD, mild cognitive impairment with Lewy body (MCI-LB), Parkinson's disease dementia (PDD), MCI in Parkinson's disease (PD-MCI), or criteria for multiple system atrophy (MSA). Exclusion criteria: All Participants * Clinician judgment that disclosure poses unacceptable psychological risk. * Concurrent enrollment in a trial with conflicting disclosure protocols. Healthy/Asymptomatic Arm • Neurological diagnosis at the time of biomarker assessment (e.g., Alzheimer's disease, Parkinson's disease, normal pressure hydrocephalus, brain tumor, progressive supranuclear palsy, seizure disorder, subdural hematoma, etc.) Symptomatic Arm • Absence of a caregiver who can complete assessments.