The prevalence of Parkinson disease (PD) is growing fast, amplifying the quest for disease-modifying therapies in early disease phases where pathology is still limited. Lifestyle interventions offer a promising avenue for preventing progression from prodromal to manifest PD. We illustrate this primarily for 1 specific lifestyle intervention, namely aerobic exercise because the case for the other main lifestyle factor (dietary interventions) to modify the course of prodromal PD is currently less persuasive. Various observations have hinted at the disease-modifying potential of exercise. First, studies in rodents with experimental parkinsonism showed that exercise elicits adaptive neuroplasticity in basal ganglia circuitries. Second, exercise is associated with a reduced risk of developing PD, suggesting a disease-modifying potential. Third, 2 large trials in persons with manifest PD indicate that exercise can help to stabilize motor parkinsonism, although this could also reflect a symptomatic effect. In addition, exercise seems to be a feasible intervention, given its minimal risk of side effects. Theoretical risks include an increase in fall incidents and cardiovascular complications, but these concerns seem to be acceptably low. Innovative approaches using gamification elements indicate that adequate long-term compliance with regular exercise programs can be achieved, although more work remains necessary to demonstrate enduring adherence for multiple years. Advances in digital technology can be used to deliver the exercise intervention in the participant9s own living environment and also to measure the outcomes remotely, which will help to further boost long-term compliance. When delivering exercise to prodromal participants, outcome measures should focus not just on phenoconversion to manifest PD (which may well take many years to occur) but also on measurable intermediate outcomes, such as physical fitness or prodromal nonmotor symptoms. Taken together, there seems to be sufficient evidence to advocate the first judicious attempt of investigating exercise as a disease-modifying treatment in prodromal PD.

Digital biomarkers that remotely monitor symptoms have the potential to revolutionize outcome assessments in future disease-modifying trials in Parkinson’s disease (PD), by allowing objective and recurrent measurement of symptoms and signs collected in the participant’s own living environment. This biomarker field is developing rapidly for assessing the motor features of PD, but the non-motor domain lags behind. Here, we systematically review and assess digital biomarkers under development for measuring non-motor symptoms of PD. We also consider relevant developments outside the PD field. We focus on technological readiness level and evaluate whether the identified digital non-motor biomarkers have potential for measuring disease progression, covering the spectrum from prodromal to advanced disease stages. Furthermore, we provide perspectives for future deployment of these biomarkers in trials. We found that various wearables show high promise for measuring autonomic function, constipation and sleep characteristics, including REM sleep behavior disorder. Biomarkers for neuropsychiatric symptoms are less well-developed, but show increasing accuracy in non-PD populations. Most biomarkers have not been validated for specific use in PD, and their sensitivity to capture disease progression remains untested for prodromal PD where the need for digital progression biomarkers is greatest. External validation in real-world environments and large longitudinal cohorts remains necessary for integrating non-motor biomarkers into research, and ultimately also into daily clinical practice.

Objective In this systematic review on drug price comparison studies, we report on recent determinants of drug prices in a national and international context to facilitate regulation of drug prices by purchasers and policymakers worldwide. Determinants of drug prices were divided into non-modifiable and modifiable and were categorised as pertaining to a country’s income level, pharmaceutical market system and its policies and government. Primary outcome Determinants of drug prices or price variance. Design We systematically searched PubMed, EMBASE, Web of Science and Cochrane Library for peer-reviewed articles published between 2004 and 22 July 2020 that reported an association of the primary outcome with one or more determinants. We performed a best-evidence synthesis of these associations for determinants covered in at least three studies. Results 31 publications were included. Only one publication described net drug prices and 30 described retail drug prices. Five modifiable determinants were associated with lower retail prices: generic market portion, discounts, tendering policies, central (governmental) purchasing and pricing regulation schemes. The originators market portion and a system in which mark-ups are common were associated with higher retail prices. Retail prices were highest in the USA, even compared with other high-income countries. A positive association between national income level and drug retail prices could not be established among middle-income and high-income countries. Retail prices were highest in low-income countries when adjusted for purchasing power parity. Conclusions Literature on determinants of net drug prices is extremely sparse. Various healthcare system interventions, market-specific and governmental regulations are consistently associated with lower retail prices. Some interventions are easily implementable in developing or middle-income countries, such as tendering, central purchasing and fixed pricing regulation schemes. Net drug price comparison studies are needed to overcome the lack of price transparency and to quantify the effectiveness of policy measures on net drug prices.

Background: Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a widely applied therapy in Parkinson’s disease (PD). Occasionally, postoperative worsening of gait or balance occurs, even in the face of a persistently gratifying appendicular symptom improvement. The characteristics vary considerably, and the risk factors for this postoperative gait or balance worsening are largely unknown. We systematically investigated the literature for all cases of gait or balance worsening after STN-DBS in PD and explored its characteristics and determinants. In consecutive populations with best medical treatment as the control group, we also explored its incidence. Methods: We searched PubMed, Embase and Cochrane. We considered all cases occurring between 1 month after surgery (to exclude immediate postoperative complications as most likely cause) and 12 months after surgery (to exclude disease progression). Results: From 2719 entries, we included 20 studies (n=1010 operated patients). Freezing of gait and falls were the most commonly reported symptoms. The first worsening of symptoms occurred between 3 and 6 months after surgery. Modulation of pedunculopontine afferents was more likely associated with worsening of gait and balance. In controlled trials with consecutive patients, 24 cases (15.9%) were reported, compared with 5.8% with best medical treatment (p=0.0013). Conclusions: Gait or balance worsening after STN-DBS is a complex phenomenon that cannot readily be explained by mere disease progression. The multifactorial nature warrants further study in gait labs and through advanced imaging techniques. Future studies should also estimate the actual incidence, which we could not establish as we excluded cohorts without any reported cases.

Background: The Movement Disorders Society Unified Parkinson Disease Rating Scale (MDS‐UPDRS), Part III, is the gold standard for assessing motor symptoms in Parkinson's disease (PD). However, motor symptoms fluctuate significantly from day to day, potentially limiting the sensitivity of this scale for trials with short duration and crossover designs. This study investigated whether day‐to‐day variability in motor symptoms exceeds the minimal clinically important difference (MCID) in the MDS‐UPDRS, Part III.Methods: Twenty PD participants (Hoehn & Yahr stages 1.5–3) underwent 10 weekly off‐medication assessments by one assessor on the same morning. Several determinants of day‐to‐day variability were explored.Results: Symptom variability often exceeded the MCID for worsening and improvement. Current mental stress and fatigue did not correlate with worse scores, nor did physical activity and sleep quality in the previous week.Conclusions: These findings suggest that day‐to‐day symptom variability impacts MDS‐UPDRS scores in smaller and shorter‐duration trials of symptomatic interventions. Continuous monitoring using wearable sensors may offer more accurate and reliable measures for evaluating PD motor symptoms in clinical studies. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Interest has risen in identifying individuals at high risk of incident Parkinson's disease (PD) to facilitate inclusion in neuroprotective treatment trials. Current risk estimates of prodromal markers are based on aggregated data of an entire population, but this approach disregards differences in risk estimates by subgroups of a population. In this proof of concept, we determine subgroup-specific risk estimates of olfactory dysfunction for incident PD. PubMed, EMBASE and Cochrane were searched for prospective studies investigating the association between olfactory dysfunction and incident PD. Random-effects meta-analysis, subgroup analyses and meta-regression were performed to investigate general and subgroup risk estimates. Individuals with odor identification dysfunction seemed to be at greater risk of incident PD compared to controls without olfactory dysfunction (OR = 4.18; 95%CI [2.47-7.07]). Risk estimates were higher in studies that included higher percentages of women (regression slope β = 0.053 increase in log odds ratio per 1% increase 1%, p = 0.0006), increased with mean study age (β = 0.21 per one year increase; p = 0.005) and in REM-sleep behavior disorder cohorts (β = 1.95; p = 0.03). Furthermore, the association between olfactory dysfunction and incident PD was most distinct in studies with shorter follow-up duration (ß = -0.56; p = 0.0047). The presence of olfactory dysfunction conveys a considerably elevated risk of incident PD, likely more in studies with a higher proportion of women, older individuals or short follow-up duration. Individual patient data are warranted to confirm these findings and to yield subgroup-specific risk estimates of other common markers to refine prodromal PD criteria.