Assessing the validity of a Parkinson's care evaluation: the PRIME-NL study.

INTRODUCTION: The PRIME-NL study prospectively evaluates a new integrated and personalized care model for people with parkinsonism, including Parkinson's disease, in a selected region (PRIME) in the Netherlands. We address the generalizability and sources of selection and confounding bias of the PRIME-NL study by examining baseline and 1-year compliance data. METHODS: First, we assessed regional baseline differences between the PRIME and the usual care (UC) region using healthcare claims data of almost all people with Parkinson's disease in the Netherlands (the source population). Second, we compared our questionnaire sample to the source population to determine generalizability. Third, we investigated sources of bias by comparing the PRIME and UC questionnaire sample on baseline characteristics and 1-year compliance. RESULTS: Baseline characteristics were similar in the PRIME (n = 1430) and UC (n = 26,250) source populations. The combined questionnaire sample (n = 920) was somewhat younger and had a slightly longer disease duration than the combined source population. Compared to the questionnaire sample in the PRIME region, the UC questionnaire sample was slightly younger, had better cognition, had a longer disease duration, had a higher educational attainment and consumed more alcohol. 1-year compliance of the questionnaire sample was higher in the UC region (96%) than in the PRIME region (92%). CONCLUSION: The generalizability of the PRIME-NL study seems to be good, yet we found evidence of some selection bias. This selection bias necessitates the use of advanced statistical methods for the final evaluation of PRIME-NL, such as inverse probability weighting or propensity score matching. The PRIME-NL study provides a unique window into the validity of a large-scale care evaluation for people with a chronic disease, in this case parkinsonism.

How Lifetime Evolution of Parkinson's Disease Could Shape Clinical Trial Design: A Shared Patient-Clinician Viewpoint.

Parkinson's disease (PD) has a long, heterogeneous, pre-diagnostic phase, during which pathology insidiously accumulates. Increasing evidence suggests that environmental and lifestyle factors in early life contribute to disease risk and progression. Thanks to the extensive study of this pre-diagnostic phase, the first prevention trials of PD are being designed. However, the highly heterogenous evolution of the disease across the life course is not yet sufficiently taken into account. This could hamper clinical trial success in the advent of biological disease definitions. In an interdisciplinary patient-clinician study group, we discussed how an approach that incorporates the lifetime evolution of PD may benefit the design of disease-modifying trials by impacting population, target and outcome selection. We argue that the timepoint of exposure to risk and protective factors plays a critical role in PD subtypes, influencing population selection. In addition, recent developments in differential disease mechanisms, aided by biological disease definitions, could impact optimal treatment targets. Finally, multimodal biomarker panels using this lifetime approach will likely be most sensitive as progression markers for more personalized trials. We believe that the lifetime evolution of PD should be considered in the design of clinical trials, and that such initiatives could benefit from more patient-clinician partnerships.

[Hitting and yelling during sleep: diagnosis and implications of REM sleep behavior disorder]. / Slaan en schreeuwen in de slaap.

Rapid eye movement (REM) sleep behavior disorder is characterized by dream enactment during REM sleep. Due to different treatment requirements, it is important to distinguish REM sleep behavior disorder from other causes of nocturnal restlessness, including sleep apnea, non-REM parasomnia and sleep-related hypermotor epilepsy. In addition, a diagnosis of isolated REM sleep behavior disorder is impactful, because it carries a greatly increased risk for the later development of Parkinson's disease and related synucleinopathies. In this clinical lesson we describe three patients with abnormal nocturnal movements and vocalizations. The history can provide important clues towards the diagnosis, but a video-polysomnography is required before REM sleep behavior disorder can be diagnosed.

Age and gender differences in non-motor symptoms in people with Parkinson's disease.

Background: Non-motor symptoms of Parkinson's disease (PD) are highly prevalent and heterogenic. Previous studies aimed to gain more insight on this heterogeneity by investigating age and gender differences in non-motor symptom severity, but findings were inconsistent. Furthermore, besides examining the single effects of age and gender, the interaction between them in relation to non-motor functioning has -as far as we know- not been investigated before. Objectives: To investigate the association of age and gender identity -as well as the interaction between age and gender identity- with non-motor symptoms and their impact on quality of life. Methods: We combined three large and independent studies. This approach resulted in a total number of unique participants of 1,509. We used linear regression models to assess the association of age and gender identity, and their interaction, with non-motor symptoms and their impact on quality of life. Results: Older people with PD generally had worse cognitive functioning, worse autonomic functioning and worse quality of life. Women with PD generally experienced more anxiety, worse autonomic functioning and worse quality of life compared to men with PD, whereas men with PD generally had worse cognitive functioning. In interaction analyses by age and gender identity, depressive symptoms and anxiety were disproportionally worse with increasing age in women compared to men. Conclusion: Our findings indicate that both age and gender -as well as their interaction- are differentially associated with non-motor symptoms of PD. Both research and clinical practice should pay more attention to demographic subgroups differences and possible different treatment approaches with respect to age and gender. We showed how combining datasets is of added value in this kind of analyses and encourage others to use similar approaches.

Towards improved screening of toxins for Parkinson's risk.

Parkinson's disease (PD) is a chronic, progressive and disabling neurodegenerative disorder. The prevalence of PD has risen considerably over the past decades. A growing body of evidence suggest that exposure to environmental toxins, including pesticides, solvents and heavy metals (collectively called toxins), is at least in part responsible for this rapid growth. It is worrying that the current screening procedures being applied internationally to test for possible neurotoxicity of specific compounds offer inadequate insights into the risk of developing PD in humans. Improved screening procedures are therefore urgently needed. Our review first substantiates current evidence on the relation between exposure to environmental toxins and the risk of developing PD. We subsequently propose to replace the current standard toxin screening by a well-controlled multi-tier toxin screening involving the following steps: in silico studies (tier 1) followed by in vitro tests (tier 2), aiming to prioritize agents with human relevant routes of exposure. More in depth studies can be undertaken in tier 3, with whole-organism (in)vertebrate models. Tier 4 has a dedicated focus on cell loss in the substantia nigra and on the presumed mechanisms of neurotoxicity in rodent models, which are required to confirm or refute the possible neurotoxicity of any individual compound. This improved screening procedure should not only evaluate new pesticides that seek access to the market, but also critically assess all pesticides that are being used today, acknowledging that none of these has ever been proven to be safe from a perspective of PD. Importantly, the improved screening procedures should not just assess the neurotoxic risk of isolated compounds, but should also specifically look at the cumulative risk conveyed by exposure to commonly used combinations of pesticides (cocktails). The worldwide implementation of such an improved screening procedure, would be an essential step for policy makers and governments to recognize PD-related environmental risk factors.

Gender-aware Parkinson's care: a design-based study of patient perspectives on gender norms and gender-sensitive care.

Background: Gender dimensions are progressively recognised as a relevant social determinant of health in people with Parkinson's disease (PD). However, little is known about the impact of gender norms and stereotypes on illness experiences of men and women with PD and what they consider important focal points for gender-sensitive PD care. Methods: We conducted two equity-centred design (ECD) sessions on December 7, 2022 and December 8, 2022, at the Radboud University Medical Centre in the Netherlands. This participatory multi-method approach includes patients in the research and design process and was used to explore the impact of gender norms and stereotypes in illness experiences and generate patient-driven recommendations for gender-aware Parkinson's care. Quantitative survey data and design-based data were descriptively analysed, and qualitative focus group discussions were thematically analysed. Findings: This study included thirteen men and fifteen women with PD in the Netherlands. All participants were of Dutch descent, with a median age of 65.5 years and a median clinical disease duration of 4.2 years. The gendered stereotype that "people with PD are old men" affected both men's and women's perception of living with the disease and the perceptions of their social environment. Men described masculine stereotypes related to physical strength and provider roles, while women expressed those related to feminine physical appearance and caregiver roles, influencing their illness experiences. For some, these norms influenced personal behaviours, while for others, they affected experiences through societal attitudes. Interpretation: Our findings suggested that several gender norms and stereotypes influence the illness experiences of men and women with PD, manifesting at ideological, interpersonal, and internalised levels. Some participants internalised these norms, affecting their coping behaviours, while others encountered them in broader ideological contexts that shaped societal attitudes and interpersonal relationships. To advance gender sensitive PD care, it's essential to explore the impact of gender roles and norms, especially regarding how they might impede coping strategies, care access and utilisation for individuals of diverse gender identities. Funding: The Gatsby Foundation and co-funded by the PPP Allowance by Health∼Holland. Travel reimbursements for participants were made available through a Parkinson's Foundation grant (PF-FBS-2026).

[Risk factors for Parkinson's disease: possibilities for prevention and intervention]. / Risicofactoren voor de ziekte van Parkinson.

Considering age to be the primary risk factor for developing Parkinson's disease and the observation that the Dutch population is rapidly aging, the parkinson prevalence is expected to increase over the coming years, as there is still no cure available for the disease. This has been confirmed by epidemiological data, which show a steady increase of the disease prevalence in the Netherlands for the period 2010-2021. Genetic risk factors only partially explain the disease pathogenesis. Environmental factors, such as exposure to pesticides and trichloroethylene are associated with a higher risk for developing Parkinson's disease. Lifestyle factors such as exercise, caffeine intake and the Mediterranean diet are associated with a lower risk for developing the disease and possibly delay the disease progression. Policy makers and healthcare providers should employ stricter regulations for pesticide use and should stimulate a healthy lifestyle to slow down the increasing prevalence.

Exploring the levodopa-paradox of freezing of gait in dopaminergic medication-naïve Parkinson's disease populations.

The relationship between dopaminergic treatment and freezing of gait (FOG) in Parkinson's disease (PD) is complex: levodopa is the most effective symptomatic treatment for FOG, but long-term pulsatile levodopa treatment has also been linked to an increase in the occurrence of FOG. This concept, however, continues to be debated. Here, we compared the occurrence of FOG between a levodopa-naive PD cohort and a levodopa-treated cohort. Forty-nine treatment-naive patients and 150 levodopa-treated patients were included. The time since first motor symptoms was at least 5 years. Disease severity was assessed using the MDS-UPDRS part III. Occurrence of FOG was assessed subjectively (new freezing-of-gait-questionnaire) and objectively (rapid turns test and Timed Up-and-Go test). The presence of FOG was compared between the levodopa-treated and levodopa-naive groups using a chi-square test of homogeneity. We also performed a binomial Firth logistic regression with disease duration, disease severity, country of inclusion, location of measurement, and executive function as covariates. Subjective FOG was more common in the levodopa-treated cohort (n = 41, 27%) compared to the levodopa-naive cohort (n = 2, 4%, p < 0.001). The association between FOG and levodopa treatment remained after adjustment for covariates (OR = 6.04, 95%Cl [1.60, 33.44], p = 0.006). Objectively verified FOG was more common in the levodopa-treated cohort (n = 21, 14%) compared to the levodopa-naive cohort (n = 1, 2%, p = 0.02). We found an association between long-term pulsatile levodopa treatment and an increased occurrence of FOG. Future studies should further explore the role of nonphysiological stimulation of dopamine receptors in generating FOG, as a basis for possible prevention studies.

Caregiver burden in Parkinson's disease: a mixed-methods study.

BACKGROUND: Providing informal care for a person with Parkinson's disease (PD) can be a demanding process affecting several dimensions of a caregiver's life and potentially causing caregiver burden. Despite the emerging literature on caregiver burden in people with PD, little is known about the inter-relationship between quantitative and qualitative findings. Filling this knowledge gap will provide a more holistic approach to develop and design innovations aiming at reducing or even preventing caregiver burden. This study aimed to characterize the determinants of caregiver burden among informal caregivers of persons with PD, in order to facilitate the development of tailored interventions that reduce caregiver burden. METHODS: We conducted a cross-sectional study in The Netherlands using a sequential mixed methods approach, entailing a quantitative study of 504 persons with PD and their informal caregivers as well as a qualitative study in a representative subsample of 17 informal caregivers. The quantitative study included a standardized questionnaire of caregiver burden (Zarit Burden Inventory) and patient-related (Beck Depression Inventory, State-Trait Anxiety Inventory, Acceptance of Illness Scale, MDS-Unified Parkinson's Disease Rating Scale part II on motor functions in daily life, Self-assessment Parkinson's Disease Disability Score), caregiver-related (Brief Coping Orientation to Problems Experience Inventory, Caregiver Activation Measurement, Multidimensional Scale of Perceived Social Support) and interpersonal determinants (sociodemographic variables including among others gender, age, education, marital status and working status). The qualitative study consisted of semi-structured interviews. Multivariable regression and thematic analysis were used to analyse quantitative and qualitative data, respectively. RESULTS: A total of 337 caregivers were women (66.9%), and the majority of people with PD were men (N = 321, 63.7%). The mean age of persons with PD was 69.9 (standard deviation [SD] 8.1) years, and the mean disease duration was 7.2 (SD 5.2) years. A total of 366 (72.6%) persons with PD had no active employment. The mean age of informal caregivers was 67.5 (SD 9.2) years. Most informal caregivers were female (66.9%), had no active employment (65.9%) and were the spouse of the person with PD (90.7%). The mean Zarit Burden Inventory score was 15.9 (SD 11.7). The quantitative study showed that a lack of active employment of the person affected by PD was associated with a higher caregiver burden. The qualitative study revealed cognitive decline and psychological or emotional deficits of the person with PD as additional patient-related determinants of higher caregiver burden. The following caregiver-related and interpersonal determinants were associated with higher caregiver burden: low social support (quantitative study), concerns about the future (qualitative study), the caregiving-induced requirement of restrictions in everyday life (qualitative study), changes in the relationship with the person with PD (qualitative study) and a problem-focused or avoidant coping style (both studies). Integration of both data strands revealed that qualitative findings expanded quantitative findings by (1) distinguishing between the impact of the relationship with the person with PD and the relationship with others on perceived social support, (2) revealing the impact of non-motor symptoms next to motor symptoms and (3) revealing the following additional factors impacting caregiver burden: concern about the future, perceived restrictions and limitations in performing daily activities due to the disease, and negative feelings and emotional well-being. Qualitative findings were discordant with the quantitative finding demonstrating that problem-focused was associated with a higher caregiver burden. Factor analyses showed three sub-dimensions of the Zarit Burden Inventory: (i) role intensity and resource strain, (2) social restriction and anger and (3) self-criticism. Quantitative analysis showed that avoidant coping was a determinant for all three subscales, whereas problem-solved coping and perceived social support were significant predictors on two subscales, role intensity and resource strain and self-criticism. CONCLUSIONS: The burden experienced by informal caregivers of persons with PD is determined by a complex interplay of patient-related, caregiver-related and interpersonal characteristics. Our study highlights the utility of a mixed-methods approach to unravel the multidimensional burden experienced by informal caregivers of persons with chronic disease. We also offer starting points for the development of a tailored supportive approach for caregivers.

Lipopolysaccharide-binding protein and future Parkinson's disease risk: a European prospective cohort.

INTRODUCTION: Lipopolysaccharide (LPS) is the outer membrane component of Gram-negative bacteria. LPS-binding protein (LBP) is an acute-phase reactant that mediates immune responses triggered by LPS and has been used as a blood marker for LPS. LBP has recently been indicated to be associated with Parkinson's disease (PD) in small-scale retrospective case-control studies. We aimed to investigate the association between LBP blood levels with PD risk in a nested case-control study within a large European prospective cohort. METHODS: A total of 352 incident PD cases (55% males) were identified and one control per case was selected, matched by age at recruitment, sex and study center. LBP levels in plasma collected at recruitment, which was on average 7.8 years before diagnosis of the cases, were analyzed by enzyme linked immunosorbent assay. Odds ratios (ORs) were estimated for one unit increase of the natural log of LBP levels and PD incidence by conditional logistic regression. RESULTS: Plasma LBP levels were higher in prospective PD cases compared to controls (median (interquartile range) 26.9 (18.1-41.0) vs. 24.7 (16.6-38.4) µg/ml). The OR for PD incidence per one unit increase of log LBP was elevated (1.46, 95% CI 0.98-2.19). This association was more pronounced among women (OR 2.68, 95% CI 1.40-5.13) and overweight/obese subjects (OR 1.54, 95% CI 1.09-2.18). CONCLUSION: The findings suggest that higher plasma LBP levels may be associated with an increased risk of PD and may thus pinpoint to a potential role of endotoxemia in the pathogenesis of PD, particularly in women and overweight/obese individuals.

Determinants of coping styles of people with Parkinson's Disease.

Little is known about how people with Parkinson's disease (PD) cope with stressful life events. We examined the determinants of specific coping strategies and whether specific choices have any impact on quality of life (QoL). We recruited patients with PD who had been seen at a neurology outpatient clinic at least once during the past year as part of the PRIME-NL cohort study. Coping was measured using the Ways of Coping Questionnaire (WCQ) and QoL was measured using the Parkinson's Disease Questionnaire (PDQ-39). 977 out of 988 participants completed the questionnaires and 935 participants were diagnosed with PD. Factor analysis was undertaken to test if ways of coping were similar or different to previous findings in a PD population. We used linear regression analyses to examine predictors of coping styles. We then used multivariable linear regression to test how coping style was associated with the domains of QoL conditional on potential confounders. The five coping styles identified by the factor analysis were: "taking action and emphasizing the positive", "distancing and fantasizing", "goal oriented and planful problem solving", "seeking social support" and "avoidance and acceptance". Age, gender, education and anxiety were associated with the type of coping strategy. For example, higher education was associated with more active coping strategies (e.g. ß = 4.39, p < 0.001 for goal oriented). Conditional on other confounders, most coping strategies had little effect on QoL domains. These findings demonstrate that coping behavior of people with PD is influenced by psychological status and personal traits. However, there was only a modest effect of coping behavior on QoL. Future research needs to test whether the enhancement or discouragement of certain coping strategies is feasible and can enhance QoL.

Case management interventions in chronic disease reduce anxiety and depressive symptoms: A systematic review and meta-analysis.

BACKGROUND: There is no systematic insight into the effect of case management on common complications of chronic diseases, including depressive symptoms and symptoms of anxiety. This is a significant knowledge gap, given that people with a chronic disease such as Parkinson Disease or Alzheimer's Disease have identified care coordination as one of their highest priorities. Furthermore, it remains unclear whether the putative beneficial effects of case management would vary by crucial patient characteristics, such as their age, gender, or disease characteristics. Such insights would shift from "one size fits all" healthcare resource allocation to personalized medicine. OBJECTIVE: We systematically examined the effectiveness of case management interventions on two common complications associated PD and other chronic health conditions: Depressive symptoms and symptoms of anxiety. METHODS: We identified studies published until November 2022 from PubMed and Embase databases using predefined inclusion criteria. For each study, data were extracted independently by two researchers. First, descriptive and qualitative analyses of all included studies were performed, followed by random-effects meta-analyses to assess the impact of case management interventions on anxiety and depressive symptoms. Second, meta-regression was performed to analyze potential modifying effects of demographic characteristics, disease characteristics and case management components. RESULTS: 23 randomized controlled trials and four non-randomized studies reported data on the effect of case management on symptoms of anxiety (8 studies) or depressive symptoms (26 studies). Across meta-analyses, we observed a statistically significant effect of case management on reducing symptoms of anxiety (Standardized Mean Difference [SMD] = - 0.47; 95% confidence interval [CI]: -0.69, -0.32) and depressive symptoms (SMD = - 0.48; CI: -0.71, -0.25). We found large heterogeneity in effect estimates across studies, but this was not explained by patient population or intervention characteristics. CONCLUSIONS: Among people with chronic health conditions, case management has beneficial effects on symptoms of depressive symptoms and symptoms of anxiety. Currently, research on case management interventions are rare. Future studies should assess the utility of case management for potentially preventative and common complications, focusing on the optimal content, frequency, and intensity of case management.

The salience of gender in the illness experiences and care preferences of people with Parkinson's disease.

RATIONALE: In recent years, interest in sex characteristics and gender dimensions of Parkinson's disease (PD) has increased. Yet, much remains to be understood about how gender-related aspects specifically impact the illness and experiences of care in persons living with PD. OBJECTIVE: The purpose of this study was to explore the salience of gender-related aspects in the illness experiences and care provision preferences of people with PD. METHODS: A descriptive qualitative study including semi-structured life story interviews was conducted with men and women living with PD in the Netherlands. Between September 2020 and February 2021, forty people with PD (20 men and 20 women) participated in digital interviews of which thirty-one (18 men and 13 women) were included in the thematic analyses for this specific study. RESULTS: Overall, most participants did not consider gender-related aspects salient towards their illness experiences. However, when prompted, a number of participants described several stereotypical views about gender as related to the visibility of PD, emotional experiences, help seeking, role patterns and physical appearance. While most men and women with PD did not express specific gender-related preferences for their healthcare providers, those that did, all preferred women as healthcare providers. These preferences were generally related to attributed feminine traits which are considered relevant in routine, particularly sensitive, physical examinations of people with PD. CONCLUSION: This study demonstrates that although every person has a gender identity, the salience attributed to gender varies with illness experiences and in care provision preferences between people with PD. These findings highlight the need for precise and personalized methodologies to capture more nuanced insights into the impact of gender dimensions on PD. Furthermore, drivers behind gender-related preferences in care provision are multifactorial and warrant further investigation among people with PD.

Proactive and Integrated Management and Empowerment in Parkinson's Disease protocol for a randomised controlled trial (PRIME-UK) to evaluate a new model of care.

BACKGROUND: People living with Parkinson's disease experience progressive motor and non-motor symptoms, which negatively impact on health-related quality of life and can lead to an increased risk of hospitalisation. It is increasingly recognised that the current care models are not suitable for the needs of people with parkinsonism whose care needs evolve and change as the disease progresses. This trial aims to evaluate whether a complex and innovative model of integrated care will increase an individual's ability to achieve their personal goals, have a positive impact on health and symptom burden and be more cost-effective when compared with usual care. METHODS: This is a single-centre, randomised controlled trial where people with parkinsonism and their informal caregivers are randomised into one of two groups: either PRIME Parkinson multi-component model of care or usual care. Adults ≥18 years with a diagnosis of parkinsonism, able to provide informed consent or the availability of a close friend or relative to act as a personal consultee if capacity to do so is absent and living in the trial geographical area are eligible. Up to three caregivers per patient can also take part, must be ≥18 years, provide informal, unpaid care and able to give informed consent. The primary outcome measure is goal attainment, as measured using the Bangor Goal Setting Interview. The duration of enrolment is 24 months. The total recruitment target is n=214, and the main analyses will be intention to treat. DISCUSSION: This trial tests whether a novel model of care improves health and disease-related metrics including goal attainment and decreases hospitalisations whilst being more cost-effective than the current usual care. Subject to successful implementation of this intervention within one centre, the PRIME Parkinson model of care could then be evaluated within a cluster-randomised trial at multiple centres.

Time trends in demographic characteristics of participants and outcome measures in Parkinson's disease research: A 19-year single-center experience.

Background: Females, people with young-onset PD and older individuals, and non-white populations are historically underrepresented in clinical Parkinson's disease (PD) research. Furthermore, research traditionally focused predominantly on motor symptoms of PD. Including a representative and diverse group of people with PD and also studying non-motor symptoms is warranted to better understand heterogeneity in PD and to generalize research findings. Objective: This project aimed to determine whether, within a consecutive series of PD studies performed within a single center in the Netherlands: (1) the proportion of included females, mean age and proportion of native Dutch people changed over time; and 2) reports of the ethnicity of participants and the proportion of studies with non-motor outcomes changed over time. Methods: Characteristics of participants and non-motor outcomes were analyzed using a unique dataset of summary statistics of studies with a large number of participants conducted at a single center during a 19-year period (2003-2021). Results: Results indicate no relationship between calendar time and proportion of females (mean 39 %), mean age (66 years), proportion of studies that reported ethnicity, and proportion of native Dutch people in studies (range 97-100 %). The proportion of participants in whom non-motor symptoms were assessed increased, but this difference was consistent with chance. Conclusion: Study participants in this center reflect the PD population in the Netherlands in terms of sex, but older individuals and non-native Dutch individuals are under-represented. We have still a lot to do in ensuring adequate representation and diversity in PD patients within our research.