Inclusion Criteria: 

• Male or female (non-childbearing potential) age 50 years or older at Screening Visit.
• Use English as their primary language.
• Be willing to undergo health and cognitive assessments, brain MRI, and biofluid/tissue collection (blood, skin biopsy, +/- cerebrospinal fluid collection)
• Has a prior clinical diagnosis made by a board-certified neurologist of PD for at least 2 years at Screening Visit.
• Patients must have at least two of the following: resting tremor, bradykinesia, rigidity (must have either resting tremor or bradykinesia); OR either asymmetric resting tremor or asymmetric bradykinesia.
• Gradual decline, in the context of established PD, in cognitive ability reported by either the patient or informant, observed by the clinician, and/or demonstrated on formal .
• neuropsychological testing – such that patient has clinical diagnosis made by a board-certified neurologist of Mild Cognitive Impairment (MCI) in PD25 or PD dementia26
• Will need to have an available study partner (also called a “co-participant”) who is familiar with the participant’s daily functioning.

Exclusion Criteria:

• Received surgical treatment(s) for PD (e.g., deep brain stimulation or focused ultrasound)
• Atypical parkinsonian syndromes due to either drugs (e.g., metoclopramide, flunarizine, neuroleptics) or metabolic disorders (e.g., Wilson’s disease), encephalitis, or other primary degenerative diseases (e.g., progressive supranuclear palsy, corticobasal syndrome, multiple system atrophy, Huntington’s disease, dystonia)
• Current treatment with anticoagulants (e.g., coumadin, heparin, oral thrombin inhibitors) that might preclude safe completion of the lumbar puncture (applicable only in the context of participants who are willing to undergo lumbar puncture).
• Condition that precludes the safe performance of routine lumbar puncture, such as prohibitive lumbar spinal disease, bleeding diathesis, or clinically significant coagulopathy or thrombocytopenia (applicable only in the context of participants who are willing to undergo lumbar puncture).
• Any other medical, neurologic or psychiatric condition or lab abnormality, which in the opinion of the investigator might preclude participation. Examples include stroke, epilepsy, meningitis/encephalitis, metabolic or toxic encephalopathy, penetrating or severe closed head injury, brain tumor/other structural lesion.
• In addition, as necessitated by the risks of Magnetic Resonance Imaging (MRI), patients who have any type of implanted electrical device (such as a cardiac pacemaker or other neurostimulator including deep brain stimulation), or a certain type of metallic clip in their body (i.e., an aneurysm clip in the brain), are not eligible for participation.
• Individuals who experience severe claustrophobic anxiety (e.g., which would normally require general anesthesia for sedation to tolerate MRI) will also be excluded from participation.
• Any other reason that, in the opinion of the investigator, would render the participant unsuitable for study enrollment.

Dementia with Lewy bodies

Inclusion Criteria:

• Male or female (non-childbearing potential) age 50 years or older at Screening Visit.
• Use English as their primary language.
• Be willing to undergo health and cognitive assessments, brain MRI, and biofluid/tissue collection (blood, skin biopsy, +/- cerebrospinal fluid collection)
• Has a clinical diagnosis made by a board-certified neurologist of probable DLB by 4th Consensus4, or research criteria of prodromal DLB27.
• Will need to have an available study partner (also called a “co-participant”) who is familiar with the participant’s daily functioning.

Exclusion Criteria:

• Atypical parkinsonian syndromes due to either drugs (e.g., metoclopramide, flunarizine, neuroleptics) or metabolic disorders (e.g., Wilson’s disease), encephalitis, or other primary degenerative diseases (e.g., progressive supranuclear palsy, corticobasal syndrome, multiple system atrophy, Huntington’s disease, dystonia)
• Current treatment with anticoagulants (e.g., coumadin, heparin, oral thrombin inhibitors) that might preclude safe completion of the lumbar puncture (applicable only in the context of participants who are willing to undergo lumbar puncture).
• Condition that precludes the safe performance of routine lumbar puncture, such as prohibitive lumbar spinal disease, bleeding diathesis, or clinically significant coagulopathy or thrombocytopenia (applicable only in the context of participants who are willing to undergo lumbar puncture).
• Any other medical, neurologic or psychiatric condition or lab abnormality, which in the opinion of the investigator might preclude participation. Examples include stroke, epilepsy, meningitis/encephalitis, metabolic or toxic encephalopathy, penetrating or severe closed head injury, brain tumor/other structural lesion.
• In addition, as necessitated by the risks of MRI, patients who have any type of implanted electrical device (such as a cardiac pacemaker or other neurostimulator including deep brain stimulation), or a certain type of metallic clip in their body (i.e., an aneurysm clip in the brain), are not eligible for participation.
• Individuals who experience severe claustrophobic anxiety (e.g., which would normally require general anesthesia for sedation to tolerate MRI) will also be excluded from participation
• Any other reason that, in the opinion of the investigator, would render the participant unsuitable for study enrollment.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 3/19/2025. Questions regarding updates should be directed to the study team contact.