The goal of the study is to assess if learning one's Lewy Body Dementia (LBD) biomarker test result impacts longitudinal psychosocial and behavioral responses and to identify factors that moderate and mediate these outcomes.

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.

Participants who have preclinical (early stage) or symptomatic Lewy Bodies Dementia.