Minor Phenomena in Parkinson's Disease-Prevalence, Associations, and Risk of Developing Psychosis.

BACKGROUND: Minor phenomena, including passage phenomena, feeling of presence, and illusions, are common and may represent a prodromal form of psychosis in Parkinson's disease (PD). We examined the prevalence and clinical correlates of minor phenomena, and their potential role as a risk factor for PD psychosis. METHODS: A novel questionnaire, the Psychosis and Mild Perceptual Disturbances Questionnaire for PD (PMPDQ), was completed by Fox Insight cohort participants with and without PD. Additional assessments included the Non-Motor Symptoms Questionnaire (NMSQuest), REM Sleep Behavior Disorder Single Question Screen (RBD1Q), Movement Disorder Society-Unified Parkinson Disease Rating Scale Part II, demographic features, and medication usage. For participants with PD, we used regression models to identify clinical associations and predictors of incident psychosis over one year of follow-up. RESULTS: Among participants with PD (n = 5950) and without PD (n = 1879), the prevalence of minor phenomena was 43.1% and 31.7% (P < .001). Of the 3760 participants with PD and no baseline psychosis, independent correlates of minor phenomena included positive responses on the NMSQuest apathy/attention/memory (OR 1.7, 95% CI 1.3-2.1, P < .001) or sexual function domain (OR 1.3, 95% CI 1.1-1.6, P = .01) and positive RBD1Q (OR 1.3, 95% CI 1.05-1.5, P = .01). Independent risk factors for incident PD psychosis included the presence of minor phenomena (HR 3.0, 95% CI 2.4-3.9, P < .001), positive response on the NMSQuest apathy/attention/memory domain (HR 1.8, 95% CI 1.3-2.6, P < .001), and positive RBD1Q (HR 1.5, 95% CI 1.1-1.9, P = .004). CONCLUSIONS: Minor phenomena are common, associated with specific non-motor symptoms, and an independent predictor of incident psychosis in PD.

Reward and Punishment Learning as Predictors of Cognitive Behavioral Therapy Response in Parkinson's Disease Comorbid with Clinical Depression.

Depression is highly comorbid among individuals with Parkinson's Disease (PD), who often experience unique challenges to accessing and benefitting from empirically supported interventions like Cognitive Behavioral Therapy (CBT). Given the role of reward processing in both depression and PD, this study analyzed a subset (N = 25) of participants who participated in a pilot telemedicine intervention of PD-informed CBT, and also completed a Reward- and Punishment-Learning Task (RPLT) at baseline. At the conclusion of CBT, participants were categorized into treatment responders (n = 14) and non-responders (n = 11). Responders learned more optimally from negative rather than positive feedback on the RPLT, while this pattern was reversed in non-responders. Computational modeling suggested group differences in learning rate to negative feedback may drive the observed differences. Overall, the results suggest that a within-subject bias for punishment-based learning might help to predict response to CBT intervention for depression in those with PD.Plain Language Summary Performance on a Computerized Task may predict which Parkinson's Disease Patients benefit from Cognitive Behavioral Treatment of Clinical DepressionWhy was the study done? Clinical depression regularly arises in individuals with Parkinson's Disease (PD) due to the neurobiological changes with the onset and progression of the disease as well as the unique psychosocial difficulties associated with living with a chronic condition. Nonetheless, psychiatric disorders among individuals with PD are often underdiagnosed and likewise undertreated for a variety of reasons. The results of our study have implications about how to improve the accuracy and specificity of mental health treatment recommendations in the future to maximize benefits for individuals with PD, who often face additional barriers to accessing quality mental health treatment.What did the researchers do? We explored whether performance on a computerized task called the Reward- and Punishment-Learning Task (RPLT) helped to predict response to Cognitive Behavioral Therapy (CBT) for depression better than other predictors identified in previous studies. Twenty-five individuals with PD and clinical depression that completed a 10-week telehealth CBT program were assessed for: Demographics (Age, gender, etc.); Clinical information (PD duration, mental health diagnoses, levels of anxiety/depression, etc.); Neurocognitive performance (Memory, processing speed, impulse control, etc.); and RPLT performance.What did the researchers find? A total of 14 participants significantly benefitted from CBT treatment while 11 did not significantly benefit from treatment.There were no differences before treatment in the demographics, clinical information, and neurocognitive performance of those participants who ended up benefitting from the treatment versus those who did not.There were, however, differences before treatment in RPLT performance so that those individuals that benefitted from CBT seemed to learn better from negative feedback.What do the findings mean? Our results suggest that the CBT program benefitted those PD patients with clinical depression that seemed to overall learn best from avoiding punishment rather than obtaining reward which was targeted in CBT by focusing on increasing engagement in rewarding activities. The Reward- and Punishment-Learning Task hence may be a useful tool to help predict treatment response and provide more individualized recommendations on how to best maximize the benefits of psychotherapy for individuals with PD that may struggle to connect to mental health care. Caution is recommended about interpretating these results beyond this study as the overall number of participants was small and the data for this study were collected as part of a previous study so there was no opportunity to include additional measurements of interest.

Social Control and Health Behaviors Among Individuals Living with Parkinson's Disease: A Pilot Study.

BACKGROUND: Positive health behaviors (e.g., exercise, healthy eating habits, good sleep hygiene, treatment adherence) are important in ensuring optimal symptom management and health outcomes among individuals living with Parkinson's disease (PD). While multiple factors may influence engagement in health behaviors, little is known about the occurrence of social control, or relationship partners' attempts to influence and regulate another's behavior, and its potential role in the adoption of health behaviors among individuals with PD. METHODS: To better understand the types of social control attempts employed and begin to explore the association between social control attempts and behavioral responses (e.g., engage in the targeted health behavior, hide the behavior) to those attempts, survey data were drawn from a cross-sectional, pilot study of married/partnered Veterans diagnosed with idiopathic PD (n = 25). Participants completed self-reported measures of sociodemographics, physical and mental well-being, relationship functioning, and both the frequency of and behavioral responses to positive and negative social control attempts. RESULTS: Although the majority of individuals reported their partners engaged in positive social control attempts, half also reported negative attempts. Bivariate analyses revealed more frequent positive social control attempts from one's partner were related to both positive and negative behavioral responses, and negative social control attempts were related to negative behavioral responses. However, when adjusting for covariates, positive social control attempts were related to positive behavioral responses, while negative social exchanges with one's partner (e.g., general conflict), rather than exposure to negative social control attempts, were related to negative behavioral responses. CONCLUSIONS: Findings lend preliminary evidence of the relationship between social control and exchanges and health behavior that may inform future, adequately powered observational and intervention studies that target interpersonal processes and health behaviors among individuals living with PD and their relationship partners.

Impact of the Dopamine System on Long-Term Cognitive Impairment in Parkinson Disease: An Exploratory Study.

Background: Little is known about the impact of the dopamine system on development of cognitive impairment (CI) in Parkinson disease (PD). Objectives: We used data from a multi-site, international, prospective cohort study to explore the impact of dopamine system-related biomarkers on CI in PD. Methods: PD participants were assessed annually from disease onset out to 7 years, and CI determined by applying cut-offs to four measures: (1) Montreal Cognitive Assessment; (2) detailed neuropsychological test battery; (3) Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) cognition score; and (4) site investigator diagnosis of CI (mild cognitive impairment or dementia). The dopamine system was assessed by serial Iodine-123 Ioflupane dopamine transporter (DAT) imaging, genotyping, and levodopa equivalent daily dose (LEDD) recorded at each assessment. Multivariate longitudinal analyses, with adjustment for multiple comparisons, determined the association between dopamine system-related biomarkers and CI, including persistent impairment. Results: Demographic and clinical variables associated with CI were higher age, male sex, lower education, non-White race, higher depression and anxiety scores and higher MDS-UPDRS motor score. For the dopamine system, lower baseline mean striatum dopamine transporter values (P range 0.003-0.005) and higher LEDD over time (P range <0.001-0.01) were significantly associated with increased risk for CI. Conclusions: Our results provide preliminary evidence that alterations in the dopamine system predict development of clinically-relevant, cognitive impairment in Parkinson's disease. If replicated and determined to be causative, they demonstrate that the dopamine system is instrumental to cognitive health status throughout the disease course. TRIAL REGISTRATION: Parkinson's Progression Markers Initiative is registered with ClinicalTrials.gov (NCT01141023).

A Pilot Study of Telehealth Mindfulness-Based Cognitive Therapy for Depression in Parkinson's Disease.

Introduction: Parkinson's disease (PD) is characterized by high-rates of depression with limited evidence-based treatment options to improve mood. Objective: To expand therapeutic options, we evaluated the feasibility and effect of a telehealth mindfulness-based cognitive therapy intervention adapted for PD (MBCT-PD) in a sample of participants with DSM-5 depressive disorders. Methods: Fifteen participants with PD and clinically-significant depression completed 9 sessions of MBCT-PD. Depression, anxiety, and quality of life were evaluated at baseline, endpoint, and 1-month follow-up. Results: Telehealth MBCT-PD was feasible and beneficial. Completion rates exceeded 85% and treatment satisfaction rates were high. Notable improvements were observed for depression, anxiety, and quality of life over the course of the trial. Conclusion: Telehealth MBCT-PD shows promise and warrants further evaluation via randomized clinical trial with more diverse participants. Such research holds the potential to expand the range of therapeutic options for depression in PD, thereby setting the stage for personalized care.

Management of psychiatric and cognitive complications in Parkinson's disease.

Neuropsychiatric symptoms (NPSs) such as affective disorders, psychosis, behavioral changes, and cognitive impairment are common in Parkinson's disease (PD). However, NPSs remain under-recognized and under-treated, often leading to adverse outcomes. Their epidemiology, presentation, risk factors, neural substrate, and management strategies are incompletely understood. While psychological and psychosocial factors may contribute, hallmark PD neuropathophysiological changes, plus the associations between exposure to dopaminergic medications and occurrence of some symptoms, suggest a neurobiological basis for many NPSs. A range of psychotropic medications, psychotherapeutic techniques, stimulation therapies, and other non-pharmacological treatments have been studied, are used clinically, and are beneficial for managing NPSs in PD. Appropriate management of NPSs is critical for comprehensive PD care, from recognizing their presentations and timing throughout the disease course, to the incorporation of different therapeutic strategies (ie, pharmacological and non-pharmacological) that utilize a multidisciplinary approach.

A Systematic Review of Psychotherapy Approaches for Anxiety in Parkinson's Disease.

OBJECTIVES: Anxiety is common in Parkinson's disease (PD), negatively impacting daily functioning and quality of life in PD patients and their families. This systematic review evaluates the effectiveness of different psychotherapeutic approaches for reducing anxiety in PD and provides recommendations for clinical practise. METHODS: Following PRISMA guidelines, 36 studies were included and risk of bias was evaluated. RESULTS: We identified cognitive behavioral therapy (CBT), mindfulness-based therapies, acceptance and commitment therapy, and psychodrama psychotherapies. There is good evidence-base for anxiety reduction using CBT approaches, but with mixed results for mindfulness-based therapies. Other therapeutic approaches were under researched. Most randomized control trials examined anxiety as a secondary measure. There was a paucity of interventions for anxiety subtypes. Secondarily, studies revealed the consistent exclusion of PD patients with cognitive concerns, an importance of care partner involvement, and a growing interest in remote delivery of psychotherapy interventions. CONCLUSIONS: Person-centered anxiety interventions tailored for PD patients, including those with cognitive concerns, and trials exploring modalities other than CBT, warrant future investigations. CLINICAL IMPLICATIONS: Practitioners should consider PD-specific anxiety symptoms and cognitive concerns when treating anxiety. Key distinctions between therapeutic modalities, therapy settings and delivery methods should guide treatment planning.

Phenomenology of Atypical Anxiety Disorders in Parkinson's Disease: A Systematic Review.

OBJECTIVE: Anxiety is a prominent concern in Parkinson's disease (PD) that negatively impacts quality of life, increases functional disability, and complicates clinical management. Atypical presentations of anxiety are under-recognized and inadequately treated in patients with PD, compromising global PD care. METHODS: This systematic review focuses on the prevalence, symptomology and clinical correlates of atypical presentations of PD-related anxiety following PRISMA guidelines. RESULTS: Of the 60 studies meeting inclusion criteria, 14 focused on 'Anxiety Not Otherwise Specified (NOS)' or equivalent, 31 reported on fluctuating anxiety symptoms, and 22 reported on 'Fear of Falling (FOF)'. Anxiety NOS accounted for a weighted mean prevalence of 14.9%, fluctuating anxiety for 34.19%, and FOF for 51.5%. These latter two exceeded the average reported overall prevalence rate of 31% for anxiety disorders in PD. We identified a diverse array of anxiety symptoms related to motor and non-motor symptoms of PD, to complications of PD medication (such as "on" and "off" fluctuations, or both), and, to a lesser extent, to cognitive symptoms. CONCLUSION: Atypical anxiety is common, clinically relevant, and heterogeneous in nature. A better understanding of the phenomenology, clinical course, and pathophysiology of varied forms of atypical anxiety in PD is needed to improve recognition, advance therapeutic development and ultimately optimize quality of life in PD.

Criticism in the Parkinson's Caregiving Relationship: A Key Target for Intervention.

INTRODUCTION: Caregiver distress is prevalent in Parkinson's disease (PD) and predictive of negative health outcomes for both people with PD and caregivers. To identify future intervention targets, it is important to better elucidate the specific processes, such as criticism, that perpetuate burden. OBJECTIVE: Evaluate the frequency and impact of criticism and reactivity to criticism in PD caregiving dyads. METHODS: Eighty-three people with PD and their caregivers independently completed measures of criticism and physical and emotional health. RESULTS: Criticism in the caregiving relationship was reported by 71.1% (n = 59) of people with PD and 80.7% (n = 67) of caregivers. Both perceived criticism and emotional reactivity to criticism were significant predictors of caregiver distress, adjusting for PD motor and non-motor symptom severity. In contrast, criticism was not related to PD depression. CONCLUSION: Criticism in the PD caregiving relationship is a clear target for psychotherapeutic intervention and may improve caregiver health and quality of life.

The neuropsychiatry of Parkinson's disease: advances and challenges.

In people with Parkinson's disease, neuropsychiatric signs and symptoms are common throughout the disease course. These symptoms can be disabling and as clinically relevant as motor symptoms, and their presentation can be similar to, or distinct from, their counterparts in the general population. Correlates and risk factors for developing neuropsychiatric signs and symptoms include demographic, clinical, and psychosocial characteristics. The underlying neurobiology of these presentations is complex and not well understood, with the strongest evidence for neuropathological changes associated with Parkinson's disease, mechanisms linked to dopaminergic therapy, and effects not specific to Parkinson's disease. Assessment instruments and formal diagnostic criteria exist, but there is little routine screening of these signs and symptoms in clinical practice. Mounting evidence supports a range of pharmacological and non-pharmacological interventions, but relatively few efficacious treatment options exist. Optimising the management of neuropsychiatric presentations in people with Parkinson's disease will require additional research, raised awareness, specialised training, and development of innovative models of care.

Innovating Parkinson's Care: A Randomized Controlled Trial of Telemedicine Depression Treatment.

BACKGROUND: For several decades, a myriad of factors have contributed to the inadequate diagnosis and management of depression in Parkinson's disease (PD), leaving up to 60% of significantly symptomatic patients untreated. Poor access to evidence-based neuropsychiatric care is one major barrier to achieving optimal Parkinson's outcomes. OBJECTIVE: The goal of this study was to compare the efficacy of individual Parkinson's-informed, video-to-home cognitive-behavioral therapy (experimental group), to clinic-based treatment as usual (control group), for depression in PD. METHOD: Ninety United States military veterans with clinical diagnoses of both depression and PD were computer-randomized (1:1) to either the experimental or control group; randomization was stratified by baseline antidepressant use and blind to all other baseline data. The acute treatment period spanned 10 weeks and was followed by a 6-month extension phase. The Hamilton Depression Rating Scale was the a priori primary outcome. Depression treatment response was defined as a score ≤2 on the Clinical Global Impression Improvement Scale. All statistical analyses were intent to treat. RESULTS: Video-to-home cognitive-behavioral therapy outperformed clinic-based treatment as usual across three separate depression measures (P < 0.001). Effects were observed at the end of acute treatment and maintained through 6-month follow-up. Number needed to treat (based on treatment response classification) was 2.5 with an absolute risk reduction of 40%. CONCLUSION: Video-to-home cognitive-behavioral therapy may be an effective intervention to bypass access barriers to specialized, evidence-based depression care in PD and to address the unmet neuropsychiatric treatment needs of the Parkinson's community. © 2021 International Parkinson and Movement Disorder Society.

Flash Electroretinography Parameters and Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is known to affect retinal structure and activity. As such, retinal evaluations may be used to develop objective and possibly early PD diagnostic tools. OBJECTIVE: The aim of this study was to investigate the effects of Parkinson's disease (PD) manifestation and treatment on retinal activity. METHODS: Data were collected on 21 participants diagnosed with PD, including the number of medications taken, clinical scales and flash electroretinography (fERG) measurements, under light-adapted and dark-adapted conditions. The fERG parameters measured included a-wave and b-wave amplitude and implicit time (i.e., latency). First, we investigated correlations between symptom measure scores and the fERG parameters. Next, we divided participants into two groups based on their antiparkinsonian medication load and analyzed differences between these groups' fERG parameters. RESULTS: fERG parameters were strongly correlated with a number of clinical variables, including motor and non-motor symptoms and age at PD onset. Photoreceptor cell implicit time was longer among participants taking one or less antiparkinsonian medication as compared to those taking two or more. However, overall there was not strong evidence of a relationship between the number of antiparkinsonian medications taken and the fERG parameters. CONCLUSION: Findings suggest that fERG may be a useful, non-intrusive measure of retinal, and, perhaps overall CNS function, in PD. However, additional studies in larger samples are needed to clarify this association.

Erratum: Author Correction: Report from a multidisciplinary meeting on anxiety as a non-motor manifestation of Parkinson's disease.

[This corrects the article DOI: 10.1038/s41531-019-0102-8.].

Telephone-based cognitive behavioral therapy for depression in Parkinson disease: A randomized controlled trial.

OBJECTIVE: To determine whether, for patients with depression and Parkinson disease (PD), telephone-based cognitive-behavioral treatment (T-CBT) alleviates depressive symptoms significantly more than treatment as usual (TAU), we conducted a randomized controlled trial to evaluate the efficacy of a 10-session T-CBT intervention for depression in PD, compared to TAU. METHODS: Seventy-two people with PD (PWP) were randomized to T-CBT + TAU or TAU only. T-CBT tailored to PWPs' unique needs was provided weekly for 3 months, then monthly during 6-month follow-up. CBT targeted negative thoughts (e.g., "I have no control"; "I am helpless") and behaviors (e.g., social withdrawal, excessive worry). It also trained care partners to help PWP practice healthy habits. Blind raters assessed outcomes at baseline, midtreatment, treatment end, and 1 and 6 months post-treatment. Analyses were intent to treat. RESULTS: T-CBT outperformed TAU on all depression, anxiety, and quality of life measures. The primary outcome (Hamilton Depression Rating Scale score) improved significantly in T-CBT compared to TAU by treatment end. Mean improvement from baseline was 6.53 points for T-CBT and -0.27 points for TAU (p < 0.0001); gains persisted over 6-month follow-up (p < 0.0001). Improvements were moderated by a reduction in negative thoughts in the T-CBT group only, reflecting treatment target engagement. CONCLUSIONS: T-CBT may be an effective depression intervention that addresses a significant unmet PD treatment need and bypasses access barriers to multidisciplinary, evidence-based care. CLINICALTRIALSGOV IDENTIFIER: NCT02505737. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with depression and PD, T-CBT significantly alleviated depressive symptoms compared to usual care.

Innovative Recruitment Strategies to Increase Diversity of Participation in Parkinson's Disease Research: The Fox Insight Cohort Experience.

BACKGROUND: Clinical research in Parkinson's disease (PD) faces practical and ethical challenges due to two interrelated problems: participant under-recruitment and lack of diversity. Fox Insight (FI) is a web-based longitudinal study collecting patient-reported outcomes and genetic data worldwide to inform therapeutic studies. FI's online platform provides an opportunity to evaluate online strategies for recruiting large, diverse research cohorts. OBJECTIVE: This project aimed to determine 1) whether FI's digital marketing was associated with increased enrollment overall and from under-represented patient groups, compared to traditional recruitment methods; 2) the clinical and demographic characteristics of samples recruited online, and 3) the cost of this online recruitment. METHOD: FI recruitment during a 6-week baseline period without digital promotion was compared to recruitment during several periods of digital outreach. Separate online recruiting intervals included general online study promotion and unique Facebook and Google ad campaigns targeting under-represented subgroups: early PD, late/advanced PD, and residents of underrepresented/rural geographic areas. RESULTS: Early PD, late PD, and geotargeting campaigns enrolled more individuals in their respective cohorts compared to baseline. All online campaigns also yielded greater total FI enrollment, attracting more participants who were non-White, Hispanic, older, female, and had lower educational attainment and income, and more medical comorbidities. Cost per new participant ranged from $21 (Facebook) to $108 (Google). CONCLUSION: Digital marketing may allow researchers to increase, accelerate, and diversify recruitment for PD clinical studies, by tailoring digital ads to target PD cohort characteristics.

Comparison of an Online-Only Parkinson's Disease Research Cohort to Cohorts Assessed In Person.

BACKGROUND: Online tools for data collection could be of value in patient-oriented research. The Fox Insight (FI) study collects data online from individuals with self-reported Parkinson's disease (PD). Comparing the FI cohort to other cohorts assessed through more traditional (in-person) observational research studies would inform the representativeness and utility of FI data. OBJECTIVE: To compare self-reported demographic characteristics, symptoms, medical history, and PD medication use of the FI PD cohort to other recent observational research study cohorts assessed with in-person visits. METHODS: The FI PD cohort (n = 12,654) was compared to 3 other cohorts, selected based on data accessibility and breadth of assessments: Parkinson's Progression Markers Initiative (PPMI; PD n = 422), Parkinson's Disease Biomarker Program (PDBP; n = 700), and PD participants in the LRRK2 consortium without LRRK2 mutations (n = 508). Demographics, motor and non-motor assessments, and medications were compared across cohorts. Where available, identical items on surveys and assessments were compared; otherwise, expert opinion was used to determine comparable definitions for a given variable. RESULTS: The proportion of females was significantly higher in FI (45.56%) compared to PPMI (34.36%) and PDBP (35.71%). The FI cohort had greater educational attainment as compared to all other cohorts. Overall, prevalence of difficulties with motor experiences of daily living and non-motor symptoms in the FI cohort was similar to other cohorts, with only a few significant differences that were generally small in magnitude. Missing data were rare for the FI cohort, except on a few variables. DISCUSSION: Patterns of responses to patient-reported assessments obtained online on the PD cohort of the FI study were similar to PD cohorts assessed in-person.

Report from a multidisciplinary meeting on anxiety as a non-motor manifestation of Parkinson's disease.

Anxiety is a severe problem for at least one-third of people living with Parkinson's disease (PD). Anxiety appears to have a greater adverse impact on quality of life than motor impairment. Despite its high prevalence and impact on daily life, anxiety is often undiagnosed and untreated. To better address anxiety in PD, future research must improve knowledge about the mechanism of anxiety in PD and address the lack of empirical evidence from clinical trials. In response to these challenges, the Parkinson's Foundation sponsored an expert meeting on anxiety on June 13th and 14th 2018. This paper summarizes the findings from that meeting informed by a review of the existing literature and discussions among patients, caregivers, and an international, clinician-scientist, expert panel working group. The goal is to provide recommendations to improve our understanding and treatment of anxiety in PD.

Dynamic Digital Biomarkers of Motor and Cognitive Function in Parkinson's Disease.

As Parkinson's disease (PD) is a heterogeneous disorder, personalized medicine is truly required to optimize care. In their current form, standard scores from paper and pencil symptom- measures traditionally used to track disease progression are too coarse (discrete) to capture the granularity of the clinical phenomena under consideration, in the face of tremendous symptom diversity. For this reason, sensors, wearables, and mobile devices are increasingly incorporated into PD research and routine care. These digital measures, while more precise, yield data that are less standardized and interpretable than traditional measures, and consequently, the two types of data remain largely siloed. Both of these issues present barriers to the broad clinical application of the field's most precise assessment tools. This protocol addresses both problems. Using traditional tasks to measure cognition and motor control, we test the participant, while co-registering biophysical signals unobtrusively using wearables. We then integrate the scores from traditional paper-and-pencil methods with the digital data that we continuously register. We offer a new standardized data type and unifying statistical platform that enables the dynamic tracking of change in the person's stochastic signatures under different conditions that probe different functional levels of neuromotor control, ranging from voluntary to autonomic. The protocol and standardized statistical framework offer dynamic digital biomarkers of physical and cognitive function in PD that correspond to validated clinical scales, while significantly improving their precision.