The Key Determinants to Quality of Life in Parkinson's Disease Patients: Results from the Parkinson's Disease Biomarker Program (PDBP)

Motor improvement in Parkinson's disease patients receiving caffeine adjuvants: A double-blind randomized controlled trial in Indonesia

Parkinson's disease (PD) manifests as a movement and brain function disorder characterized by symptoms such as resting tremors, rigidity, bradykinesia, and postural instability, leading to disability among patients. The use of psychostimulants such as caffeine has been associated with the improvement of motor symptoms in PD patients; however, studies regarding the effect of caffeine adjuvant therapy on motor function among PD patients in the Indonesian population are lacking. The aim of this study was to evaluate motor improvement as measured by the change in scores of the Movement Disorder Society - Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS-III) among PD patients receiving caffeine adjuvant. A double-blind randomized controlled trial (RCT) was conducted among PD patients at Dr. Soetomo General Academic Hospital and Universitas Airlangga Hospital, Surabaya, Indonesia, from April to August 2023. A total of 27 patients were enrolled and randomly assigned to an intervention (receiving caffeine adjuvant, n=15) and control group (receiving placebo, n=12). Motor improvement was measured using the UPDRS III score prior to intervention and three weeks after. The Chi-squared test was used to analyze the difference in UPDRS III scores between the two groups. Motor improvement, as demonstrated by a reduction in the UPDRS III score, was observed in patients receiving caffeine adjuvant compared to those receiving placebo (80.0% vs 16.7%; p=0.004). Regarding the safety profile, only four out of 15 (26.6%) patients treated with caffeine reported minor adverse events. These conditions improved over time during the intervention. None of the 12 patients in the placebo reported adverse events. This study provides valuable insights into the initial dosage of caffeine that improves motor function in PD patients with minimum adverse effects.

Correlation Between Depression and Quality of Life Among Patients With Parkinson's Disease: An Analytical Cross-Sectional Study

Introduction Parkinson's disease (PD) is a progressive complex degenerative disorder characterised by several motor and non-motor symptoms that result in disability and deterioration of the patient's quality of life (QOL). Depression is the most common non-motor symptom that may severely alter the QOL. The objective of this study was to examine the correlation between depression and QOL among patients with PD who received treatment from a movement disorder clinic of a tertiary care teaching hospital in South India. Methods This was an analytical cross-sectional study conducted among 220 PD patients who received treatment from a movement disorder clinic of a tertiary care teaching hospital in South India. The participants aged between 40 and 80 years, who can comprehend Malayalam or English and were clinically diagnosed with PD according to United Kingdom PD Society Brain Bank criteria were included in the study. Depression was assessed using the Hospital Anxiety and Depression Scale, motor function using the Movement Disorder Society Unified Parkinson's Disease Rating Scale Part III, and the quality of life was assessed using the Parkinson's Disease Questionnaire 39. Results The results of this study showed that there was a significant positive correlation between depression and QOL (r=0.699, p<0.01) among patients with PD who received treatment from a tertiary care teaching hospital. The correlation with domains of QOL also identified that depression was significantly correlated with all domains of QOL and more to the emotional domain of QOL (r=0.799, p<0.01). Conclusion Depression is the most common neuropsychiatric condition in PD and the most important determinant of QOL. Depression may occur at any stage of PD and can significantly impact the QOL of patients and their caregivers. Hence it should be recognized early and managed by pharmacological and nonpharmacological measures to improve the QOL.

Parkinson's Disease, Impulsive-Compulsive Behaviors, and Health-Related Quality of Life

OBJECTIVE

A large body of literature has examined the links between the use of dopamine replacement therapy (DRT) in Parkinson's disease (PD) and the development of "impulsive-compulsive behaviors (ICBs)." Little is known regarding the link between the development of ICBs and health-related quality of life (HRQOL). We aimed to explore the factors that are associated with poorer HRQOL, especially in relation to DRT-induced ICBs, in a sample of PD patients.

METHODS

This PARKADD (PARK: PARKinson's disease; ADD: behavioral ADDictions) study was a prospective case‒control study initially designed to assess the factors associated with ICBs in PD patients. A prospective clinical follow-up was added, aiming to capture the long-term evolution of HRQOL in relation to ICBs occurring or worsening after the beginning of PD. We focused on sociodemographic and PD characteristics and the history or presence of ICBs. HRQOL was measured using the Parkinson's Disease Questionnaire-8. A multivariate linear regression was performed to identify factors related to poorer HRQOL.

RESULTS

A total of 169 patients were eligible for the follow-up study. The presence of an ICB, a higher levodopa equivalent daily dose (LEDD) and a longer PD duration were significantly associated with poorer HRQOL, with an interaction between LEDD and PD duration.

CONCLUSION

The presence of an ICB was related to poorer HRQOL and should be considered a crucial factor for the management of PD patients. Several studies were recently published that provide guidelines for the management of these patients, with recommendations based on two key principles: prevention and specific treatment.

Pain Fluctuations in Parkinson's Disease and Their Association with Motor and Non-Motor Fluctuations

Background

Pain fluctuations are a characteristic phenomenon in advanced Parkinson's disease (PD), but their temporal association with motor and non-motor symptom (NMS) fluctuations remains largely enigmatic. Moreover, data on their importance for disease severity perception and health-related quality-of-life (hr-QoL) is limited.

Objective

To dissect pain fluctuations with respect to pain type and frequency patterns, and their association with motor and non-motor fluctuations.

Methods

Prospective observational cohort study in advanced PD assessing symptom fluctuations by simultaneous hourly ratings using the PD Home diary (Off, On, Dyskinetic state), a pain diary (assessing 9 pain types) and a non-motor diary (10 key NMS) based on validated instruments.

Results

Forty-seven out of 55 eligible participants with fluctuating PD (51% men, median age 65, median disease duration 10 years) had sufficient datasets (>95% of hours) from 2 consecutive days. Pain was reported in 35% of waking hours with clear circadian rhythm peaking in early morning Off periods and clustering during motor Off state (49% of Off state hours with pain). Main NMS co-fluctuating with pain were "Fatigue" and "Inner Restlessness". Simultaneous assessment of global disease severity by participants revealed that pain was associated with worse disease severity only in motor On and Dyskinetic state but not in Off state, which translated into significant correlations of daily pain times with hr-QoL only during motor On and Dyskinetic state.

Conclusions

Aside from treating motor Off periods, specific recognition of pain particularly during motor On and Dyskinetic state comprises an important aspect for disease management in advanced PD.

The Effect of Frailty Syndrome on the Quality of Life of Individuals with Parkinson's Disease: A Pilot Observational and Multicenter Study on the Polish Population

Parkinson's disease (PD) is a neurodegenerative disorder involving decreased dopamine release and atrophy of dopaminergic neurons of the substantia nigra. Frailty syndrome (FS) is common in older adults, which, in combination with PD symptoms, can substantially affect the quality of life (QOL). This study aimed to assess the prevalence of FS among PD patients and to identify variables affecting their QOL with particular attention to FS. The study included 296 patients (n = 173 women) with a mean age of 70.3 ± 5.7 years suffering from PD for an average of 8.2 ± 5.6 years. Patients were classified as at least stage II according to the Hoehn and Yahr scale. The following standardized questionnaires were used in the study: Schwab and England Activities of Daily Living (SE-ADL), Parkinson's Disease Questionnaire (PDQ-39), Beck Depression Inventory (BDI), Unified Parkinson's Disease Rating Scale (UPDRS), and Tilburg Frailty Indicator (TFI). FS was found in 96% (n = 283) of the PD patients studied. No depression occurred in 30% (n = 89) of subjects, moderate depression in 48% (n = 141) of subjects, and severe depression in 22% (n = 66) of subjects. The mean score of the PDQ-39 questionnaire in PD subjects with FS was 41.6 pts (min-max: 5.2-81.5 pts; SD = 17.4 pts), which was statistically significantly higher than in subjects without FS (p < 0.05). FS has been shown to be present in most of the subjects with PD. FS occurs more frequently with a longer PD period, which is associated with reduced physical capacity and QOL. Physical activity improves QOL and reduces disease progression. FS, similar to PD, is a common cause of disability in older adults and their dependency. Predictors such as depression, advanced stage of the disease, higher education, and low professional and economic status significantly affect the QOL level of PD patients. However, the results obtained among the Polish population of PD patients do not confirm the impact of FS on the QOL, so there is a need to conduct further research on this subject.

Plasma MIA, CRP, and Albumin Predict Cognitive Decline in Parkinson's Disease

OBJECTIVE

Using a multi-cohort, discovery-replication-validation design, we sought new plasma biomarkers that predict which individuals with Parkinson's disease (PD) will experience cognitive decline.

METHODS

In 108 discovery cohort PD individuals and 83 replication cohort PD individuals, we measured 940 plasma proteins on an aptamer-based platform. Using proteins associated with subsequent cognitive decline in both cohorts, we trained a logistic regression model to predict which patients with PD showed fast (> = 1 point drop/year on Montreal Cognitive Assessment [MoCA]) versus slow (< 1 point drop/year on MoCA) cognitive decline in the discovery cohort, testing it in the replication cohort. We developed alternate assays for the top 3 proteins and confirmed their ability to predict cognitive decline - defined by change in MoCA or development of incident mild cognitive impairment (MCI) or dementia - in a validation cohort of 118 individuals with PD. We investigated the top plasma biomarker for causal influence by Mendelian randomization (MR).

RESULTS

A model with only 3 proteins (melanoma inhibitory activity protein [MIA], C-reactive protein [CRP], and albumin) separated fast versus slow cognitive decline subgroups with an area under the curve (AUC) of 0.80 in the validation cohort. The individuals with PD in the validation cohort in the top quartile of risk for cognitive decline based on this model were 4.4 times more likely to develop incident MCI or dementia than those in the lowest quartile. Genotypes at MIA single nucleotide polymorphism (SNP) rs2233154 associated with MIA levels and cognitive decline, providing evidence for MIA's causal influence.

CONCLUSIONS

An easily obtained plasma-based predictor identifies individuals with PD at risk for cognitive decline. MIA may participate causally in development of cognitive decline. ANN NEUROL 2022.

Association of Motor and Nonmotor Symptoms With Health-Related Quality of Life in a Large Online Cohort of People With Parkinson Disease

Background and Objectives

There is growing interest in health-related quality of life (HRQOL) as a comprehensive view of the patient's well-being, guiding concept for the treating clinician, and therapeutic trial outcome measure for patients with Parkinson disease (PwPD). The key determinants of HRQOL have not been investigated in large populations of PwPD. Our objective was to evaluate correlates of HRQOL in a large, online cohort of PwPD.

Methods

As part of an ongoing online cohort study, we performed a cross-sectional analysis at enrollment of 23,058 PwPD. We conducted univariate and stepwise multivariate linear regression analyses of HRQOL as measured by the EQ-5D-5L tool. In addition, we performed an interaction analysis to evaluate heterogeneity of the effect of motor symptoms on HRQOL and Spearman correlation analysis to evaluate the association of nonmotor symptoms with HRQOL.

Results

In the multivariate linear regression model, participants with moderate or severe depression, more severe motor symptoms, and a higher burden of medical comorbidities had the most substantially decreased HRQOL as measured by the EQ index (β −0.11, −0.18, −0.02, −0.01, respectively; p < 0.001 for all). An interaction analysis showed that more severe motor symptoms had a higher effect on individuals with female sex, lower educational level, lower income, more severe depression, or more severe cognitive impairment (p ≤ 0.01 for interaction terms). Neuropsychiatric symptoms and falls had the most negative associations with HRQOL (ρ −0.31 to 0.37; p < 0.0001).

Discussion

Potentially treatable motor and nonmotor symptoms, particularly neuropsychiatric symptoms, account for a large amount of the variation in HRQOL in PwPD. Motor symptoms may have differential effects on HRQOL in different demographic and clinical subpopulations, highlighting important areas for future health disparities research. Our findings provide targets for clinician intervention and future research on symptom management to optimize HRQOL in PD.

Classification of Evidence

This study provides Class II evidence that motor and neuropsychiatric symptoms are associated with HRQOL in PwPD.

Effects of rasagiline on Parkinson’s Disease Questionnaire (PDQ-39) emotional well-being domain in patients with Parkinson’s disease: A post-hoc analysis of clinical trials in Japan

Background

Identifying the factors that influence health-related quality of life (HRQoL) is of great scientific interest, but a potential causal relationship between treatment and HRQoL has yet to be fully elucidated. Japanese patients reported better HRQoL outcomes on the Parkinson’s Disease Questionnaire (PDQ-39) emotional well-being domain, a 6-question subset of the PDQ-39 which is considered to reflect the emotional aspects of the disease-specific HRQoL, when treated with rasagiline, than placebo, in both a monotherapy clinical trial (NCT02337725) and an adjunctive therapy clinical trial in patients with wearing-off phenomena (NCT02337738).

Objective

To investigate how rasagiline exerts its effect on the PDQ-39 emotional well-being domain in Japanese patients with Parkinson’s disease.

Methods

A path analysis was performed to assess the direct treatment effects of rasagiline on the PDQ-39 emotional well-being domain and the effects mediated indirectly through the influence on items related to motor symptoms by a post-hoc analysis of two clinical trials in Japan.

Results

In the monotherapy trial, the PDQ-39 emotional well-being domain was mainly affected indirectly through items related to motor symptoms (80.7%) composed of the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part II (67.2%) and Part III (13.5%). In the adjunctive therapy trial, the PDQ-39 emotional well-being domain was also mainly influenced indirectly through effects on items related to motor symptoms (1 mg/day: 54.7%, 0.5 mg/day: 57.6%) composed of MDS-UPDRS Part II (1 mg/day: 35.6%, 0.5 mg/day: 40.9%), Part III (1 mg/day: 8.0%, 0.5 mg/day: 8.3%) and mean daily OFF-time (1 mg/day: 11.1%, 0.5 mg/day: 8.4%).

Conclusions

The effects of rasagiline on the PDQ-39 emotional well-being domain were mediated primarily by influence on the subjective aspects of motor experiences of daily living.

The Mediating Effect of Spiritual Well-Being and Quality of Life for Persons with Parkinson's Disease in Northern Taiwan

BACKGROUND

Parkinson's disease (PD), a degenerative disease with irreversible motor dysfunction, impacts patients' quality of life (QoL). Spirituality can provide a sense of hope and meaning when individuals are faced with adverse life events, such as a diagnosis of PD. However, few studies have examined the relationship between spiritual well-being and QoL for persons with PD.

OBJECTIVE

To explore the relationships between the disease characteristics, spirituality and QoL for persons with PD, and verify the mediating effects of spirituality on the relationship.

METHODS

This cross-sectional study recruited patients with PD (n = 110) by convenience sampling from a neurological clinic in northern Taiwan. Variables were measured using the Spirituality Index of Well-Being Chinese version (SIWB-C) and the 39-item Parkinson's disease Quality of Life Questionnaire Chinese version (PDQ-39-C) self-report questionnaires. Descriptive analysis and linear hierarchical regression were conducted to examine the studied variables and explore the mediating effect of spiritual wellbeing.

RESULTS

Those whose scores were significantly better in PDQ-39 were younger, employed, with shorter disease duration and less severe condition with better functioning on their early stages and lower LEDD; additionally, those who had better quality of life also experienced better spiritual wellbeing than the counterparts. The regression model demonstrated spiritual self-efficacy had mediating effects between disease characteristics and QoL, explaining 69.8%of the variance (adjusted R2 = 65.3%).

CONCLUSION

The results can be the references for future strategies and interventions, focusing on increasing spiritual self-efficacy and reducing the impact of disease severity to improve QoL for persons with PD.

Influence of motor impairment on exercise capacity and quality of life in patients with Parkinson disease

This study evaluated the impact of motor impairment (MI) on exercise capacity and quality of life in patients with Parkinson disease (PD). One hundred ninety-two patients (≥50 years old) were divided according to the Hoehn and Yahr stages in: mild (stage I), mild to moderate (stage II), moderate (stage III), and advanced MI (stage IV). Exercise capacity (6-min walk test [6MWT]) and quality of life (Parkinson's Disease Questionnaire [PDQ-39]) were obtained. In this context, 6MWT was progressively worse with increasing the severity of MI (P<0.01). Patients with advanced MI achieved 39% of predicted 6MWT of healthy subject, while subjects with mild MI achieved 83% of healthy subject (P<0.01). In addition, patients with advanced MI presented higher (i.e., worse) PDQ-39 scores in summary index, cognition, mobility and activities of daily live domains compared to other groups (P<0.01). Patients with moderate MI also presented worse scores in PDQ-39 summary index, mobility and activities of daily live domains in comparison with mild MI patients (P<0.01). Higher MI was correlated with worse exercise capacity (6MWT: r=-0.46, P<0.01), with worse PDQ-39 summary index and the mobility and activities of daily live domains scores (r=0.38, r=0.46, and r=0.43, P<0.01). In conclusion, MI is related to lower exercise capacity and quality of life (i.e., PDQ-39 summary index and mobility and activities of daily live domains) in patients with PD.

Effects of depression and exercise on health-related quality of life in patients with Parkinson's disease

OBJECTIVES

There is limited literature describing the effect exercise may have on depression and an individual's health-related quality of life (HRQoL) in Parkinson's Disease (PD). We aim to quantify this effect.

METHODS

A cross-sectional questionnaire was administered to 60 PD subjects. The Parkinson's Disease Questionnaire-39 (PDQ-39) summary index and the Geriatric Depression Scale-30 were used to quantify HRQoL and depression, respectively. Data were obtained on exercise habits. ANOVA and multivariate linear regression analysis were used to calculate mean differences in HRQoL.

RESULTS

Depression was consistently related to HRQoL (p < 0.05). Of those who exercised as an adult before PD diagnosis, 49.02% (n = 25) reported depression as compared to 88.89% (n = 8) of those who did not report adult exercise (p = 0.03). Those who exercised frequently as an adult prior to PD diagnosis had a better PDQ-39 Cognitive Index (p = 0.03). Those who were not depressed and were currently exercising had a significantly higher HRQoL than those who were depressed and did not exercise (p < 0.01).

DISCUSSION

Exercising and depression may interact to affect HRQoL. Thus, coordination of mental health evaluation and exercise regimens in persons with PD may improve HRQoL.

"Does the Response to Morning Medication Predict the ADL-Level of the Day in Parkinson's Disease?"

Background

Individuals with Parkinson's Disease (PD) have bradykinesia during mobility tasks in the morning before intake of dopaminergic treatment and have difficulties managing Activities of Daily Living (ADLs). Early morning off (EMO) refers to off-states in the morning where the severity of bradykinesia is increased and causes a decrease in mobility related to wearing off of effects of medication. Measurements from devices capable of continuously recording motor symptoms may provide insight into the patient's response to medication and possible impact on ADLs.

Objectives

To test whether poor or slow response to medication in the morning predicts the overall ADL-level and to assess the association between change in bradykinesia score (BKS) and the risk of having disabilities within three selected ADL-items.

Methods

In this cross-sectional study, the sample consists of 34 patients with light to moderate PD. Data collection encompasses measurements from the Parkinson KinetiGraph, and the ADL-limitations are assessed by the Movement Disorder Society Unified Parkinson Disease Rating Scale (MDS-UPDRS) Part II.

Results

The association between UPDRS- II and BKS from the algorithm was -0.082 (p < 0.01), 95% CL:-0.113; -0.042). The individuals experienced disabilities in performing "Speech" (p=0.004) and "Doing hobbies" (p=0.038) when being slow or poor responders to dopaminergic therapy. The PD patients' L-dopa equivalent dose seems to be a strong predictor of the ADL-level in the morning.

Conclusion

Slow response to the medication dosages in the morning is correlated with disabilities in the overall ADL-level in PD. The combination of PD-drugs and precise, timely dosages must be considered in the improvement of the ADL-level in PD patients.

Systematic Review Looking at the Use of Technology to Measure Free-Living Symptom and Activity Outcomes in Parkinson's Disease in the Home or a Home-like Environment

BACKGROUND

The emergence of new technologies measuring outcomes in Parkinson's disease (PD) to complement the existing clinical rating scales has introduced the possibility of measurement occurring in patients' own homes whilst they freely live and carry out normal day-to-day activities.

OBJECTIVE

This systematic review seeks to provide an overview of what technology is being used to test which outcomes in PD from free-living participant activity in the setting of the home environment. Additionally, this review seeks to form an impression of the nature of validation and clinimetric testing carried out on the technological device(s) being used.

METHODS

Five databases (Medline, Embase, PsycInfo, Cochrane and Web of Science) were systematically searched for papers dating from 2000. Study eligibility criteria included: adults with a PD diagnosis; the use of technology; the setting of a home or home-like environment; outcomes measuring any motor and non-motor aspect relevant to PD, as well as activities of daily living; unrestricted/unscripted activities undertaken by participants.

RESULTS

65 studies were selected for data extraction. There were wide varieties of participant sample sizes (<10 up to hundreds) and study durations (<2 weeks up to a year). The metrics evaluated by technology, largely using inertial measurement units in wearable devices, included gait, tremor, physical activity, bradykinesia, dyskinesia and motor fluctuations, posture, falls, typing, sleep and activities of daily living.

CONCLUSIONS

Home-based free-living testing in PD is being conducted by multiple groups with diverse approaches, focussing mainly on motor symptoms and sleep.

Predictors of health-related quality of life in Parkinson's disease

BACKGROUND

Health-related quality of life in Parkinson's disease may be affected by a wide range of motor and non-motor symptoms. Identifying which symptoms are significant predictors of health-related quality of life in Parkinson's disease prioritizes symptoms for treatment, therapeutic development, and clinical outcomes.

OBJECTIVES

To determine predictors of health-related quality of life in patients with Parkinson's disease.

METHODS

We recruited 102 subjects into a prospective study to investigate neuropsychiatric symptoms in Parkinson's disease. Health-related quality of life was measured with the 39-item Parkinson's Disease Questionnaire. Subjects completed the Movement Disorder Society Unified Parkinson's Disease Rating Scale Parts I-IV as well as validated scales to assess anxiety, depression, apathy, cognition, psychosis, impulsive-compulsive disorder, autonomic dysfunction, sleep quality, excessive daytime sleepiness, and rapid eye movement sleep behavior disorder. We used univariate analyses to select clinical predictors to construct a multivariate regression model to determine which predictors were independently associated with worse health-related quality of life.

RESULTS

In a multivariate linear regression model adjusted for age and gender, higher scores for the International Parkinson and Movement Disorder Society Unified Parkinson's Disease Rating Scale part II as well more severe symptoms of depression, anxiety, apathy, and excessive daytime sleepiness were associated with worse health-related quality of life. The model explained 78% of the variance of health-related quality of life, and the non-motor symptoms explained 49% of the variance.

CONCLUSIONS

Anxiety, depression, excessive daytime sleepiness, apathy, and impairment in activities of daily living related to motor symptoms were independently associated with worse health-related quality of life.

Susceptibility MRI captures nigral pathology in patients with parkinsonian syndromes

BACKGROUND

Parkinsonisms are neurodegenerative disorders characterized pathologically by α-synuclein-positive (e.g., PD, diffuse Lewy body disease, and MSA) and/or tau-positive (e.g., PSP, cortical basal degeneration) pathology. Using R2* and quantitative susceptibility mapping, susceptibility changes have been reported in the midbrain of living parkinsonian patients, although the exact underlying pathology of these alterations is unknown.

OBJECTIVE

The current study investigated the pathological correlates of these susceptibility MRI measures.

METHODS

In vivo MRIs (T1- and T2-weighted, and T2*) and pathology were obtained from 14 subjects enrolled in an NINDS PD Biomarker Program (PDBP). We assessed R2* and quantitative susceptibility mapping values in the SN, semiquantitative α-synuclein, tau, and iron values, as well as neuronal and glial counts. Data were analyzed using age-adjusted Spearman correlations.

RESULTS

R2* was associated significantly with nigral α-synuclein (r = 0.746; P = 0.003). Quantitative susceptibility mapping correlated significantly with Perls' (r = 0.758; P = 0.003), but not with other pathological measurements. Neither measurement correlated with tau or glial cell counts (r ≤ 0.11; P ≥ 0.129).

CONCLUSIONS

Susceptibility MRI measurements capture nigral pathologies associated with parkinsonian syndromes. Whereas quantitative susceptibility mapping is more sensitive to iron, R2* may reflect pathological aspects of the disorders beyond iron such as α-synuclein. They may be invaluable tools in diagnosing differential parkinsonian syndromes, and tracking in living patients the dynamic changes associated with the pathological progression of these disorders. © 2018 International Parkinson and Movement Disorder Society.

Predicting the multi-domain progression of Parkinson's disease: a Bayesian multivariate generalized linear mixed-effect model

BACKGROUND

It is challenging for current statistical models to predict clinical progression of Parkinson's disease (PD) because of the involvement of multi-domains and longitudinal data.

METHODS

Past univariate longitudinal or multivariate analyses from cross-sectional trials have limited power to predict individual outcomes or a single moment. The multivariate generalized linear mixed-effect model (GLMM) under the Bayesian framework was proposed to study multi-domain longitudinal outcomes obtained at baseline, 18-, and 36-month. The outcomes included motor, non-motor, and postural instability scores from the MDS-UPDRS, and demographic and standardized clinical data were utilized as covariates. The dynamic prediction was performed for both internal and external subjects using the samples from the posterior distributions of the parameter estimates and random effects, and also the predictive accuracy was evaluated based on the root of mean square error (RMSE), absolute bias (AB) and the area under the receiver operating characteristic (ROC) curve.

RESULTS

First, our prediction model identified clinical data that were differentially associated with motor, non-motor, and postural stability scores. Second, the predictive accuracy of our model for the training data was assessed, and improved prediction was gained in particularly for non-motor (RMSE and AB: 2.89 and 2.20) compared to univariate analysis (RMSE and AB: 3.04 and 2.35). Third, the individual-level predictions of longitudinal trajectories for the testing data were performed, with ~80% observed values falling within the 95% credible intervals.

CONCLUSIONS

Multivariate general mixed models hold promise to predict clinical progression of individual outcomes in PD.

TRIAL REGISTRATION

The data was obtained from Dr. Xuemei Huang's NIH grant R01 NS060722 , part of NINDS PD Biomarker Program (PDBP). All data was entered within 24 h of collection to the Data Management Repository (DMR), which is publically available ( https://pdbp.ninds.nih.gov/data-management ).

Parkinson's disease biomarkers: perspective from the NINDS Parkinson's Disease Biomarkers Program

Biomarkers for Parkinson's disease (PD) diagnosis, prognostication and clinical trial cohort selection are an urgent need. While many promising markers have been discovered through the National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) and other mechanisms, no single PD marker or set of markers are ready for clinical use. Here we discuss the current state of biomarker discovery for platforms relevant to PDBP. We discuss the role of the PDBP in PD biomarker identification and present guidelines to facilitate their development. These guidelines include: harmonizing procedures for biofluid acquisition and clinical assessments, replication of the most promising biomarkers, support and encouragement of publications that report negative findings, longitudinal follow-up of current cohorts including the PDBP, testing of wearable technologies to capture readouts between study visits and development of recently diagnosed (de novo) cohorts to foster identification of the earliest markers of disease onset.