A Novel Measurement Concept to Objectively Quantify Severity of Vocal and Speech Related Symptoms Associated With Parkinson's Disease

Inclusion Criteria: PD: 1. Male or female age 30 years or older at Screening Visit. 2. Diagnosis of PD as defined by MDS PD diagnostic criteria \[1\] 3. PD severity at Screening Visit of either: * PD Hoehn and Yahr Stage 1-2, inclusive (PD Cohort I) * PD Hoehn and Yahr Stages 3-4, inclusive (PD Cohort II) 4. Able and willing to complete all aspects of the study, including at home smartphone app and Zoom telehealth assessments. 5. Able to provide informed consent. Prodromal PD: 1. Confirmation that participant is eligible based on clinician determined predictive criteria of known risk of PD including 1. Rapid eye movement sleep behavior disorder (RBD), possible, probable or definite, OR 2. Hyposmia defined as less than 10th percentile on University of Pennsylvania Smell Identification Test (UPSIT), age and gender adjusted, OR 3. Known genetic variants associated with PD risk, AND Confirmed eligible DAT scan. 2. Male or female age 30 or older at Screening Visit. 3. Able and willing to complete all aspects of the study, including at home smartphone app and Zoom telehealth assessments 4. Able to provide informed consent. Age \& Sex Matched Healthy Control: 1. Male or female age 30 years or older at Screening visit. 2. Able and willing to complete all aspects of the study, including at home smartphone app and Zoom telehealth assessments 3. Able to provide informed consent. Exclusion Criteria: PD: 1. Late-stage PD diagnosis (i.e., Hoehn \& Yahr Stage 5) at Screening Visit 2. Symptomatic or atypical PD syndromes due to either drugs (e.g., metoclopramide, flunarizine, neuroleptics) or metabolic disorders (e.g., Wilson's disease), encephalitis, or degenerative diseases (e.g., progressive supranuclear palsy). 3. Current or active clinically significant neurological disorder other than PD (in the opinion of the Investigator). 4. Significant cognitive impairment or clinical dementia at Screening that, in the opinion of the Investigator, would interfere with study evaluation. 5. History of drug and/or alcohol abuse within the past year prior to Screening Visit. 6. Inability or unwillingness to complete all aspects of the study - including use of a provisioned smartphone for study assessments; completion of telehealth assessments. 7. Any other medical or psychiatric condition, which in the opinion of the investigator might preclude participation. Prodromal PD: 1. Clinical diagnosis of PD, other parkinsonism, or dementia. 2. Any current or active clinically significant neurological disorder (in the opinion of the Investigator). 3. Previously obtained MRI scan with evidence of clinically significant neurological disorder (in the opinion of the Investigator). 4. Significant cognitive impairment or clinical dementia at Screening that, in the opinion of the Investigator, would interfere with study evaluation. 5. History of drug and/or alcohol abuse within the past year prior to Screening Visit. 6. Inability or unwillingness to complete all aspects of the study - including use of a provisioned smartphone for study assessments; completion of telehealth assessments. 7. Any other medical or psychiatric condition, which in the opinion of the investigator might preclude participation. Age \& Sex Matched Healthy Control: 1. First degree relative with PD (i.e., biologic parent, sibling, child). 2. Any current or active clinically significant neurological disorder (in the opinion of the Investigator). 3. Previously obtained MRI scan with evidence of clinically significant neurological disorder (in the opinion of the Investigator). 4. Significant cognitive impairment or clinical dementia at Screening that, in the opinion of the Investigator, would interfere with study evaluation. 5. History of drug and/or alcohol abuse within the past year prior to Screening Visit. 6. Inability or unwillingness to complete all aspects of the study - including use of a provisioned smartphone for study assessments; completion of telehealth assessments. 7. Any other medical or psychiatric condition, which in the opinion of the investigator might preclude participation