Long-term neuropsychological outcomes of deep brain stimulation in early-stage Parkinson's disease.

INTRODUCTION: The pilot trial of deep brain stimulation (DBS) in early-stage Parkinson's disease (PD) randomized 30 patients (medication duration 0.5-4 years; without dyskinesia or motor fluctuations) to receive optimal drug therapy alone (early ODT) or subthalamic nucleus (STN) DBS plus ODT (early DBS + ODT). This study reports long-term neuropsychological outcomes from the early DBS pilot trial. METHODS: This is an extension of an earlier study that examined two-year neuropsychological outcomes in the pilot trial. The primary analysis was conducted on the five-year cohort (n = 28), and a secondary analysis was conducted on the 11-year cohort (n = 12). Linear mixed effects models for each analysis compared overall trend in outcomes for randomization groups. All subjects who completed the 11-year assessment were also pooled to evaluate long-term change from baseline. RESULTS: There were no significant differences between groups in either the five- or 11-year analyses. Across all PD patients who completed the 11-year visit, there was significant decline in Stroop Color and Color-Word and Purdue Pegboard from baseline to 11 years. CONCLUSIONS: Previous significant differences between the groups in phonemic verbal fluency and cognitive processing speed showing more decline for early DBS + ODT subjects one year after baseline diminished as PD progressed. No cognitive domains were worse for early DBS + ODT subjects compared to standard of care subjects. There were shared declines across all subjects on cognitive processing speed and motor control, likely reflecting disease progression. More study is needed to understand the long-term neuropsychological outcomes associated with early DBS in PD.

Levodopa Carbidopa Intestinal Gel in Advanced Parkinson's Disease: DUOGLOBE Final 3-Year Results.

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) improves motor and non-motor symptoms in patients with advanced Parkinson's disease (aPD). OBJECTIVE: To present the final 36-month efficacy and safety results from DUOGLOBE (DUOdopa/Duopa in Patients with Advanced Parkinson's Disease - a GLobal OBservational Study Evaluating Long-Term Effectiveness; NCT02611713). METHODS: DUOGLOBE was an international, prospective, long-term, real-world, observational study of patients with aPD initiating LCIG in routine clinical care. The primary endpoint was change in patient-reported "Off" time to Month 36. Safety was assessed by monitoring serious adverse events (SAEs). RESULTS: Significant improvements in "Off" time were maintained over 3 years (mean [SD]: -3.3 hours [3.7]; p < 0.001). There were significant improvements to Month 36 in total scores of the Unified Dyskinesia Rating Scale (-5.9 [23.7]; p = 0.044), Non-Motor Symptoms Scale (-14.3 [40.5]; p = 0.002), Parkinson's Disease Sleep Scale-2 (-5.8 [12.9]; p < 0.001), and Epworth Sleepiness Scale (-1.8 [6.0]; p = 0.008). Health-related quality of life and caregiver burden significantly improved through Months 24 and 30, respectively (Month 24, 8-item Parkinson's Disease Questionnaire Summary Index, -6.0 [22.5]; p = 0.006; Month 30, Modified Caregiver Strain Index, -2.3 [7.6]; p = 0.026). Safety was consistent with the well-established LCIG profile (SAEs: 54.9% of patients; discontinuations: 54.4%; discontinuations due to an adverse event: 27.2%). Of 106 study discontinuations, 32 patients (30.2%) continued LCIG outside the study. CONCLUSION: DUOGLOBE demonstrates real-world, long-term, reductions in motor and non-motor symptoms in patients with aPD treated with LCIG.

Connectivity Profile for Subthalamic Nucleus Deep Brain Stimulation in Early Stage Parkinson Disease.

OBJECTIVE: This study was undertaken to describe relationships between electrode localization and motor outcomes from the subthalamic nucleus (STN) deep brain stimulation (DBS) in early stage Parkinson disease (PD) pilot clinical trial. METHODS: To determine anatomical and network correlates associated with motor outcomes for subjects randomized to early DBS (n = 14), voxelwise sweet spot mapping and structural connectivity analyses were carried out using outcomes of motor progression (Unified Parkinson Disease Rating Scale Part III [UPDRS-III] 7-day OFF scores [∆baseline➔24 months, MedOFF/StimOFF]) and symptomatic motor improvement (UPDRS-III ON scores [%∆baseline➔24 months, MedON/StimON]). RESULTS: Sweet spot mapping revealed a location associated with slower motor progression in the dorsolateral STN (anterior/posterior commissure coordinates: 11.07 ± 0.82mm lateral, 1.83 ± 0.61mm posterior, 3.53 ± 0.38mm inferior to the midcommissural point; Montreal Neurological Institute coordinates: +11.25, -13.56, -7.44mm). Modulating fiber tracts from supplementary motor area (SMA) and primary motor cortex (M1) to the STN correlated with slower motor progression across STN DBS subjects, whereas fiber tracts originating from pre-SMA and cerebellum were negatively associated with motor progression. Robustness of the fiber tract model was demonstrated in leave-one-patient-out (R = 0.56, p = 0.02), 5-fold (R = 0.50, p = 0.03), and 10-fold (R = 0.53, p = 0.03) cross-validation paradigms. The sweet spot and fiber tracts associated with motor progression revealed strong similarities to symptomatic motor improvement sweet spot and connectivity in this early stage PD cohort. INTERPRETATION: These results suggest that stimulating the dorsolateral region of the STN receiving input from M1 and SMA (but not pre-SMA) is associated with slower motor progression across subjects receiving STN DBS in early stage PD. This finding is hypothesis-generating and must be prospectively tested in a larger study. ANN NEUROL 2023;94:271-284.

Racial and Ethnic Differences in Health-Related Quality of Life for Individuals With Parkinson Disease Across Centers of Excellence.

BACKGROUND AND OBJECTIVES: Racial and ethnic minorities have been underrepresented in Parkinson disease (PD) research, limiting our understanding of treatments and outcomes across all non-White groups. The goal of this research is to investigate variability in health-related quality of life (HRQoL) and other outcomes in patients with PD across different races and ethnicities. METHODS: This was a retrospective, cross-sectional and longitudinal, cohort study of individuals evaluated at PD Centers of Excellence. A multivariable regression analysis adjusted for sex, age, disease duration, Hoehn and Yahr (H&Y) stage, comorbidities, and cognitive score was used to investigate differences between racial and ethnic groups. A multivariable regression with skewed-t errors was performed to assess the individual contribution of each variable to the association of 39-item PD Questionnaire (PDQ-39) with race and ethnicity. RESULTS: A total of 8,514 participants had at least 1 recorded visit. Most of them (90.2%) self-identified as White (n = 7,687), followed by 5.81% Hispanic (n = 495), 2% Asians (n = 170), and 1.9% African American (n = 162). After adjustment, total PDQ-39 scores were significantly higher (worse) in African Americans (28.56), Hispanics (26.62), and Asians (25.43) when compared with those in White patients (22.73, p < 0.001). This difference was also significant in most PDQ-39 subscales. In the longitudinal analysis, the inclusion of cognitive scores significantly decreased the strength of association of the PDQ-39 and race/ethnicity for minority groups. A mediation analysis demonstrated that cognition partially mediated the association between race/ethnicity and PDQ-39 scores (proportion mediated 0.251, p < 0.001). DISCUSSION: There were differences in PD outcomes across racial and ethnic groups, even after adjustment for sex, disease duration, HY stage, age, and some comorbid conditions. Most notably, there was worse HRQoL among non-White patients when compared with White patients, which was partially explained by cognitive scores. The underlying reason for these differences needs to be a focus of future research.

Eleven-Year Outcomes of Deep Brain Stimulation in Early-Stage Parkinson Disease.

OBJECTIVE: The deep brain stimulation (DBS) in early-stage Parkinson's disease (PD) pilot clinical trial randomized 30 patients (Hoehn & Yahr II off; medication duration 0.5-4 years; without dyskinesia/motor fluctuations) to optimal drug therapy (ODT) (early ODT) or bilateral subthalamic nucleus (STN) DBS plus ODT (early DBS+ODT). This study aims to report the 11-year outcomes of patients who completed the DBS in early-stage PD pilot clinical trial. MATERIALS AND METHODS: Attempts were made to contact all 29 subjects who completed the two-year trial to participate in an 11-year follow-up study. Mixed-effects models compared overall trend in outcomes for randomization groups (fixed-effects: assigned treatment, year, their interaction; random-effect: subject) to account for repeated measures. RESULTS: Twelve subjects participated in this 11-year follow-up study (n = 8 early ODT, n = 4 early DBS+ODT). Participating subjects were 70.0 ± 4.8 years old with a PD medication duration of 13.7 ± 1.7 years (early DBS duration 11.5 ± 1.3 years, n = 4). Three early ODT subjects received STN-DBS as standard of care (DBS duration 6.5 ± 2.0 years). Early ODT subjects had worse motor complications (Unified Parkinson's Disease Rating Scale [UPDRS]-IV) than early DBS+ODT subjects over the 11-year follow-up period (between-group difference = 3.5 points; pinteraction = 0.03). Early DBS+ODT was well-tolerated after 11 years and showed comparable outcomes to early ODT for other UPDRS domains, Parkinson Disease Questionnaire-39 (PDQ-39), and levodopa equivalent daily dose (LEDD). CONCLUSIONS: Eleven years after randomization, early DBS+ODT subjects had fewer motor complications than early ODT subjects. These results should be interpreted with caution because only 40% of pilot trial subjects participated in this 11-year follow-up study. The Food and Drug Administration has approved the conduct of a pivotal clinical trial evaluating DBS in early-stage PD (IDEG050016). CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number for the study is NCT00282152.

Outcomes Impacting Quality of Life in Advanced Parkinson's Disease Patients Treated with Levodopa-Carbidopa Intestinal Gel.

BACKGROUND: It is believed that motor symptoms, including dyskinesia, and non-motor symptoms impact health-related quality of life (HRQoL) in patients with Parkinson's disease (PD), and that improvements in these metrics are correlated. OBJECTIVE: Investigate the relationship between HRQoL and measures of PD severity and treatment efficacy, including motor and non-motor symptoms. METHODS: This was a planned investigation of an international, prospective, single-arm, post-marketing observational study of the long-term effectiveness of levodopa-carbidopa intestinal gel (LCIG) in patients with advanced PD. Pearson correlation coefficients (PCC) were calculated for baseline and change from baseline at 12 months between HRQoL and motor and non-motor symptoms. RESULTS: A total of 195 patients were included. At baseline, HRQoL was moderately positively correlated with Activities of Daily Living (UPDRS II, PCC = 0.44), non-motor symptoms (0.48), and measures of sleep (0.50 and 0.40); all p < 0.001. After 12 months of treatment with LCIG, improvements in HRQoL were moderately positively correlated with improvement from baseline in non-motor symptoms (PCC = 0.42), sleep (0.54), and daytime sleepiness (0.40; all p < 0.001), and weakly correlated with improvement in dyskinesia signs and symptoms (PCC = 0.23; p = 0.011). Improvement in HRQoL was not correlated with improvements in OFF time or dyskinesia time. CONCLUSION: Both at baseline and for change from baseline at 12 months, HRQoL was correlated with baseline and change from baseline in dyskinesia, Activities of Daily Living, and non-motor symptoms, including sleep; but not with baseline or change in OFF time.

BDNF rs6265 Genotype Influences Outcomes of Pharmacotherapy and Subthalamic Nucleus Deep Brain Stimulation in Early-Stage Parkinson's Disease.

INTRODUCTION: The efficacy of pharmacotherapy and deep brain stimulation of the subthalamic nucleus in treating Parkinson's disease motor symptoms is highly variable and may be influenced by patient genotype. The relatively common (prevalence about one in three) and protein-altering rs6265 single nucleotide polymorphism (C > T) in the gene BDNF has been associated with different clinical outcomes with levodopa. OBJECTIVE: We sought to replicate this reported association in early-stage Parkinson's disease subjects and to examine whether a difference in clinical outcomes was present with subthalamic nucleus deep brain stimulation. MATERIALS AND METHODS: Fifteen deep brain stimulation and 13 medical therapy subjects were followed for 24 months as part of the Vanderbilt DBS in Early Stage PD clinical trial (NCT00282152, FDA IDE #G050016). Primary outcome measures were the Unified Parkinson's Disease Rating Scale (UPDRS) and Parkinson's Disease Questionnaire-39. RESULTS: Outcomes with drug therapy in subjects carrying the rs6265 T allele were significantly worse following 12 months of treatment compared to C/C subjects (UPDRS: +20 points, p = 0.019; PDQ-39: +16 points, p = 0.018). In contrast, rs6265 genotype had no effect on overall motor response to subthalamic nucleus deep brain stimulation at any time point; further, rs6265 C/C subjects treated with stimulation were associated with worse UPDRS part II scores at 24 months compared to medical therapy. CONCLUSIONS: Genotyping for the rs6265 polymorphism may be useful for predicting long-term response to drug therapy and counseling Parkinson's disease patients regarding whether to consider earlier subthalamic nucleus deep brain stimulation. Validation in a larger cohort of early-stage Parkinson's disease subjects is warranted.

DUOGLOBE: One-Year Outcomes in a Real-World Study of Levodopa Carbidopa Intestinal Gel for Parkinson's Disease.

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) is an established treatment for improving motor and some non-motor symptoms (NMS) in patients with advanced Parkinson's disease (PD). Prospective long-term data in routine clinical practice are limited. OBJECTIVE: Assess LCIG effectiveness and safety in patients with advanced PD after 12 months during real-world routine clinical practice. METHODS: Duodopa/Duopa in patients with advanced Parkinson's disease-a global observational study evaluating long-term effectiveness (DUOGLOBE) (NCT02611713) is an ongoing, prospective, multinational, observational study of LCIG-naïve patients treated as part of routine clinical practice; 3 years of follow-up are planned. The primary outcome is the change in patient-reported off time. Other assessments include the Unified Dyskinesia Rating Scale (UDysRS), Non-Motor Symptoms Scale (NMSS), Parkinson's Disease Sleep scale (PDSS-2), Epworth Sleepiness Scale (ESS), health-related quality of life (HR-QoL), caregiver burden, and serious adverse events (SAEs). Outcomes from baseline to month (M) 12 are presented. RESULTS: In this 12-month follow-up, patients (N = 195) had baseline characteristics similar to other LCIG studies. Significant improvements (mean change to M12) were observed in off time (-3.9 ± 3.6 hr/day, P < 0.001), dyskinesia assessed using the UDysRS (-9.6 ± 22.5, P < 0.001), NMSS (-23.1 ± 41.4, P < 0.001), sleep and sleepiness symptoms on the PDSS-2 (-6.5 ± 12.2, P < 0.001) and ESS (-1.0 ± 5.7, P < 0.05), HR-QoL (-9.0 ± 21.6, P < 0.001), and caregiver burden (-1.9 ± 6.7, P = 0.008). Overall, 40.5% (n = 79) of patients experienced SAEs; fall (n = 6; 3.1%) and urinary tract infection (n = 6; 3.1%) were SAEs reported in ≥3% of patients. CONCLUSIONS: These 12-month outcome data show sustained, long-term improvements and support the real-world effectiveness of LCIG in patients with advanced PD. Safety was consistent with previous studies.

Application of the '5-2-1' screening criteria in advanced Parkinson's disease: interim analysis of DUOGLOBE.

Aim: A Delphi expert consensus panel proposed that fulfilling ≥1 of the '5-2-1 criteria' (≥five-times daily oral levodopa use, ≥two daily hours with 'Off' symptoms or ≥one daily hour with troublesome dyskinesia) suggests advanced Parkinson's disease (PD). Patients & methods: DUOdopa/Duopa in Patients with Advanced PD - a GLobal OBservational Study Evaluating Long-Term Effectiveness (DUOGLOBE) - is a single-arm, postmarketing, observational, long-term effectiveness study of levodopa-carbidopa intestinal gel (LCIG) for advanced PD. Results: This 6-month interim analysis (n = 139) affirms that most (98%) enrolled patients fulfill ≥1 of the 5-2-1 criteria. These patients responded favorably to LCIG treatment. Safety was consistent with other LCIG studies. Conclusion: In advanced PD patients, the 5-2-1 criteria generally aligns with clinician assessment. Clinical Trial Registration: NCT02611713 (ClinicalTrials.gov).

Deep brain stimulation in early-stage Parkinson disease: Five-year outcomes.

OBJECTIVE: To report 5-year outcomes from the subthalamic nucleus (STN) deep brain stimulation (DBS) in early-stage Parkinson disease (PD) pilot clinical trial. METHODS: The pilot was a prospective, single-blind clinical trial that randomized patients with early-stage PD (Hoehn & Yahr II off medications) to receive bilateral STN DBS plus optimal drug therapy (ODT) vs ODT alone (IDEG050016, NCT0282152, IRB040797). Participants who completed the 2-year trial participated in this observational follow-up study, which included annual outpatient visits through 5 years. This analysis includes 28 patients who were taking PD medications for 6 months to 4 years at enrollment. Outcomes were analyzed using both proportional odds logistic regression and linear mixed effects models. RESULTS: Early STN DBS + ODT participants required lower levodopa equivalent daily doses (p = 0.04, ß = -240 mg, 95% confidence interval [CI] -471 to -8) and had 0.06 times the odds of requiring polypharmacy at 5 years compared to early ODT participants (p = 0.01, odds ratio [OR] 0.06, 95% CI 0.00 to 0.65). The odds of having worse rest tremor for early STN DBS + ODT participants were 0.21 times those of early ODT participants (p < 0.001, OR 0.21, 95% CI 0.09 to 0.45). The safety profile was similar between groups. CONCLUSIONS: These results suggest that early DBS reduces the need for and complexity of PD medications while providing long-term motor benefit over standard medical therapy. Further investigation is warranted, and the Food and Drug Administration has approved the conduct of a prospective, multicenter, pivotal clinical trial of DBS in early-stage PD (IDEG050016). CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that DBS implanted in early-stage PD decreases the risk of disease progression and polypharmacy compared to optimal medical therapy alone.

Current Practices for Outpatient Initiation of Levodopa-Carbidopa Intestinal Gel for Management of Advanced Parkinson's Disease in the United States.

In 2015, the US Food and Drug Administration approved levodopa-carbidopa intestinal gel (LCIG; also known as carbidopa-levodopa enteral suspension in the US) for the treatment of motor fluctuations in patients with advanced Parkinson's disease. LCIG provides a continuous infusion of levodopa and carbidopa by means of a portable pump and percutaneous endoscopic gastrojejunostomy tube. The delivery system has a two-fold pharmacokinetic advantage over orally administered carbidopa/levodopa. First, levodopa is delivered in a continuous rather than intermittent, pulsatile fashion. Second, delivery to levodopa's site of absorption in the jejunum bypasses the stomach, thereby avoiding issues with erratic gastric emptying. In blinded prospective clinical trials and observational studies, LCIG has been shown to significantly decrease "off" time, increase "on" time without troublesome dyskinesia, and reduce dyskinesia. Consistent with procedures in previous studies, LCIG initiation and titration in the pivotal US clinical trial were performed in the inpatient setting and followed a standardized protocol. In clinical practice, however, initiation and titration of LCIG have a great degree of flexibility and, in the US, almost always take place in the outpatient setting. Nonetheless, there remains a significant amount of clinician uncertainty regarding titration in outpatient clinical practice. This review aims to shed light on and provide guidance as to the current methods of titration in the outpatient setting, as informed by the medical literature and the authors' experiences. FUNDING: AbbVie, Inc. Plain language summary available for this article.

Results from recent studies have shown that continuous infusion of levodopa-carbidopa intestinal gel (LCIG) into the jejunum (a part of the small intestine) effectively manages the motor and nonmotor complications (e.g., tremor, extreme stiffness in arms and legs, difficulty walking, and impaired balance) experienced by patients with advanced Parkinson's disease (PD). LCIG is administered by a portable pump directly into the patient's jejunum by a permanent tube that is inserted surgically. LCIG therapy is beneficial to advanced PD patients over orally administered carbidopa/levodopa for two reasons. First, oral carbidopa/levodopa moves from the stomach to the small intestine where it is intermittently absorbed into the blood stream. LCIG is administered continuously and offers better symptom control for longer. Results from clinical trials and observational studies have shown that LCIG significantly decreases "off" time (poor motor control) and increases "on" time (good motor control) in advanced PD patients without troublesome dyskinesia, which results from the higher doses of oral levodopa required to treat the symptoms. Second, LCIG is absorbed in the jejunum, thereby bypassing the stomach where problems can occur because of inconsistent stomach emptying. In the US, titration of LCIG is performed mostly in an outpatient setting. Some clinicians may view titration of LCIG to be too complex and variable, so they avoid using LCIG therapy for their PD patients. Fortunately, emerging data and clinicians' expanding experience with LCIG have shown that titration can be easily managed in an outpatient setting, allowing for more customized therapeutic regimens for patients.

Impact of Tremor on Patients With Early Stage Parkinson's Disease.

Tremor is one of the most visible features of Parkinson's disease (PD), and the majority of PD patients experience tremor during the course of the disease. However, the distress caused by this cardinal motor feature for patients early in the course of their PD is commonly underappreciated. People living with early stage PD often experience intense embarrassment and difficulties due to their tremor that limit social interactions, and tremor frequently interferes with the ability to perform activities of daily living and simple tasks at home and work. Although tremor is primarily managed with medications, both tremor response and satisfaction with medical therapy are highly variable. This review offers an overview of reports of the patient experience of tremor in early stage PD and current management options for this cardinal motor feature.

Effects of deep brain stimulation on rest tremor progression in early stage Parkinson disease.

OBJECTIVE: To evaluate whether the progression of individual motor features was influenced by early deep brain stimulation (DBS), a post hoc analysis of Unified Parkinson's Disease Rating Scale-III (UPDRS-III) score (after a 7-day washout) was conducted from the 2-year DBS in early Parkinson disease (PD) pilot trial dataset. METHODS: The prospective pilot trial enrolled patients with PD aged 50-75 years, treated with PD medications for 6 months-4 years, and no history of dyskinesia or other motor fluctuations, who were randomized to receive optimal drug therapy (ODT) or DBS plus ODT (DBS + ODT). At baseline and 6, 12, 18, and 24 months, all patients stopped all PD therapy for 1 week (medication and stimulation, if applicable). UPDRS-III "off" item scores were compared between the ODT and DBS + ODT groups (n = 28); items with significant between-group differences were analyzed further. RESULTS: UPDRS-III "off" rest tremor score change from baseline to 24 months was worse in patients receiving ODT vs DBS + ODT (p = 0.002). Rest tremor slopes from baseline to 24 months favored DBS + ODT both "off" and "on" therapy (p < 0.001, p = 0.003, respectively). More ODT patients developed new rest tremor in previously unaffected limbs than those receiving DBS + ODT (p = 0.001). CONCLUSIONS: These results suggest the possibility that DBS in early PD may slow rest tremor progression. Future investigation in a larger cohort is needed, and these findings will be tested in the Food and Drug Administration-approved, phase III, pivotal, multicenter clinical trial evaluating DBS in early PD. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for patients with early PD, DBS may slow the progression of rest tremor.

Regular Exercise, Quality of Life, and Mobility in Parkinson's Disease: A Longitudinal Analysis of National Parkinson Foundation Quality Improvement Initiative Data.

BACKGROUND: Research-based exercise interventions improve health-related quality of life (HRQL) and mobility in people with Parkinson's disease (PD). OBJECTIVE: To examine whether exercise habits were associated with changes in HRQL and mobility over two years. METHODS: We identified a cohort of National Parkinson Foundation Quality Improvement Initiative (NPF-QII) participants with three visits. HRQL and mobility were measured with the Parkinson's Disease Questionnaire (PDQ-39) and Timed Up and Go (TUG). We compared self-reported regular exercisers (≥2.5 hours/week) with people who did not exercise 2.5 hours/week. Then we quantified changes in HRQL and mobility associated with 30-minute increases in exercise, across PD severity, using mixed effects regression models. RESULTS: Participants with three observational study visits (n = 3408) were younger, with milder PD, than participants with fewer visits. After 2 years, consistent exercisers and people who started to exercise regularly after their baseline visit had smaller declines in HRQL and mobility than non-exercisers (p < 0.05). Non-exercisers worsened by 1.37 points on the PDQ-39 and a 0.47 seconds on the TUG per year. Increasing exercise by 30 minutes/week was associated with slower declines in HRQL (-0.16 points) and mobility (-0.04 sec). The benefit of exercise on HRQL was greater in advanced PD (-0.41 points) than mild PD (-0.14 points; p < 0.02). CONCLUSIONS: Consistently exercising and starting regular exercise after baseline were associated with small but significant positive effects on HRQL and mobility changes over two years. The greater association of exercise with HRQL in advanced PD supports improving encouragement and facilitation of exercise in advanced PD.