Parkinson’s disease (PD) is one of the most common neurological disorders, with a prevalence of almost 12 million people worldwide (1). People with PD often experience both motor and non-motor symptoms, which greatly impact their quality of life (QoL) (2, 3). Currently, there is no cure for PD. Medical management, including medication or deep brain surgery, can provide symptomatic relief, but this is often insufficient to alleviate all symptoms (4). In addition, the responsiveness to dopaminergic medication differs between individuals and across symptoms, and the effects wear off over time (5). Therefore, lifestyle interventions are increasingly recognized as a valuable additional way to support people with PD (6).

Lifestyle includes six pillars: physical activity, nutrition, stress management, restorative sleep, social connection and risky substance avoidance (7). Among these, physical activity, optimal nutrition, stress management and sleep have received most attention in research and clinical practice. Exercise attenuates motor- and non-motor symptoms and increases QoL, and may perhaps affect disease progression (8–10). There is also growing excitement about the potential role of other lifestyle interventions. Dietary interventions can have multiple benefits. For example, optimal fluid and fiber intake may reduce constipation and thereby increase medication effectiveness (11). In addition, a well-balanced intake of proteins and dopaminergic medication is important: proteins can compete with dopaminergic medication by causing malabsorption in the gut and brain, thus limiting its efficacy (12). At the same time, proteins are essential for body composition and muscle preservation. A lack of protein consumption may cause malnutrition and underweight (13). Underweight is a well-known indicator of negative health outcomes and also increases the risk of mortality (14). Another important factor related to nutrition is the gut microbiome, which plays a role in the pathophysiology of PD by impacting on, e.g., mitochondrial functioning, inflammation and immune responses (13). Although the evidence from robust clinical trials remains limited, there is enough reason to motivate people with PD to adhere to a healthy diet with adequate intake of macronutrients as suggested by organizations such as the World Health Organization (WHO) (15). The other lifestyle domains have been studied less well. However, emerging evidence shows that stress-reducing interventions, such as mind–body exercises and mindfulness-based interventions (MBIs), can reduce, e.g., anxiety and depression for people with PD, thus improving QoL (16–19). Moreover, positive effects of sleep hygiene education in people with PD with sleep disturbances have been found (20, 21).

So far, no studies have investigated the effects of interventions including multiple lifestyle domains in people with PD. While all domains are expected to have positive effects in isolation, they may even have a larger, additive and perhaps even synergistic effect when delivered in combination (6). Moreover, no studies have evaluated the cost-effectiveness of offering lifestyle interventions in PD.

In the absence of robust studies on effectiveness and cost-effectiveness, lifestyle interventions are currently not routinely offered as part of standard medical care. Consequently, people with PD receive hardly any guidance related to lifestyle changes. Based on interviews and our own clinical experience, we identified that many healthcare professionals in the Netherlands are not trained to provide lifestyle information or to offer personalized coaching (22, 23). Lifestyle coaches have the potential to play a role as a central coordinator of lifestyle interventions with expertise on all lifestyle domains and capable of coaching toward behavioral change (24, 25). The potential of lifestyle coaches has been shown in other chronic conditions (24, 25). Of note, changing lifestyle behavior is an enormous challenge for people with PD, especially when one needs to sustainably change multiple lifestyle aspects (26, 27). Therefore, a personalized approach, taking into account potential barriers related to lifestyle behavior is needed.

Motivated by these considerations, we here propose to combine different lifestyle domains into one approach as part of a personalized and stepped care lifestyle intervention. This approach, called the SENSS approach (stress, exercise, nutrition, sleep and self-management), is based on a combination of previous pilot initiatives (22, 28–32). A stepped care approach, with limited guidance when possible but with access to more intensive treatment when necessary, will deliver personalized care without further straining an already overburdened healthcare system. We expect that such a stepped care approach minimizes the extra costs for providing lifestyle guidance, yet lead to benefits of a healthy lifestyle. We expect this approach to be associated with a reduction of (long-term) healthcare costs, an increased productivity of people with PD and their caregivers and an improved QoL.

Our primary objective is to evaluate the effect of the SENSS approach on QoL in people with PD. Our secondary objective is to evaluate the effects of SENSS on PD motor- and non-motor symptoms, self-management, overall health and attaining personal lifestyle goals. A third objective is to analyze the costs and (socio-)economic impact of SENSS compared to current usual care. Our fourth objective is to evaluate the experiences of participants, lifestyle coaches and healthcare professionals with the SENSS approach.

Figure 1 provides an overview of the key elements of the SENSS intervention and the expected outcomes.

The SENSS study is a 12-month single-blind, randomized controlled trial (RCT). The intervention group receives a combined lifestyle intervention (SENSS approach) after a personalized intake and with continuous monitoring by a lifestyle coach. The control group only receives the personalized intake with a lifestyle coach, but continues with usual care. A total of 256 individuals with PD will be included, equally randomized into the control and intervention group. Participants complete three remote assessments: at baseline, 6 months, and 12 months follow-up. An overview of the study design is provided in Figure 2.

The study will be performed by the Radboud University Medical Center (Radboudumc), Nijmegen, the Netherlands. The assessments and interventions of the study will be provided remotely. The study will be conducted in the Netherlands. People with PD will be recruited through a number of open recruitment strategies (see the section on recruitment strategies).

Inclusion criteria are: a confirmed diagnosis of PD by a neurologist according to established diagnostic criteria, and being able to read and understand the Dutch language. The exclusion criteria are: cognitive impairments that do not allow to complete the questionnaire, as judged by the researcher during the screening call; not in possession of or no access to an electronic device that allows for (video) calls with a lifestyle coach and to complete the questionnaires; planned surgery or an expected major change in treatment plan; participation in other intervention trials during the participation of the SENSS study.

If a potential participant shows interest in the study, an assessor from the research team sends an information letter and informed consent through mail. After 2 weeks the assessor will contact the participant to answer questions, to check for eligibility and to discuss consent. When the participant is eligible and willing to participate, written informed consent will be obtained by signing the consent form and sending it to the research team by post. If an informal caregiver is available who is willing to fill out questionnaires, (s)he will receive an information letter and sign an informed consent as well. Participation of the informal caregiver is not mandatory for the participant to be included and does not influence the intervention in any way.

The intervention is a personalized and stepped care lifestyle intervention (SENSS) that combines five different and complementary lifestyle domains (stress, exercise, nutrition, sleep and self-management). In this intervention, self-management complements four important lifestyle domains, as it plays an overarching role in lifestyle behavior.

In the SENSS approach, participants receive guidance by a trained lifestyle coach. The title of lifestyle coach is not legally protected in the Netherlands. To ensure intervention quality, lifestyle coaches delivering the intervention are required to be affiliated with the Dutch professional association for lifestyle coaches (Beroepsvereniging Leefstijlcoaches Nederland; BLCN). BLCN affiliation requires compliance to strict admission standards and ongoing professional development. This includes holding at least a bachelor’s degree at a university of applied sciences level and having completed a BLCN-accredited postgraduate lifestyle coaching program, or having successfully completed an individual accreditation pathway (33). For this trial, two certified and dedicated lifestyle coaches will provide the intervention. Participants are divided pragmatically between the two lifestyle coaches, based on coach availability at the time of enrolment.

The SENSS approach starts with goal setting using a lifestyle decision aid, previously developed by our group in accordance with the International Patient Decision Aid Standards (22, 34). The Parkinson lifestyle decision aid (35) is a web-based tool. The tool includes information and questions that support people with PD to identify their needs in relation to lifestyle, set goals, make a plan, and determine the type of support they may need. The questions range from mapping the current situation in relation to their lifestyle, to clarifying their values, preferences and goals for all five lifestyle domains and identifying the needs for support to reach sustainable changes in lifestyle. The decision aid concludes with a summary of the answers given. This summary serves as a starting point for the consultation with the lifestyle coach, during which shared decision making is used to determine which lifestyle domain(s) to prioritize and what level of support is appropriate. For the participants in the intervention group, this level of support is further specified in a stepped care model (Figure 3).

The stepped care model is used to provide just the right amount of guidance. By following the steps in the model, people with PD are encouraged to work on their lifestyle goals independently, supported by technological tools when possible (self-management). Professional support is provided when needed, based on participant reported needs and the lifestyle coach’s professional judgment. The approach is highly personalized, meaning participants do not have to follow a fixed sequence of steps. They can move between steps in either direction throughout the intervention. Importantly, a lifestyle coach will continuously monitor adherence and progress, and discusses with the participant whether changes are needed in either the lifestyle domain they are working on or in the level of support. The frequency of monitoring is decided through shared decision making by the lifestyle coach and participant, within a range of once every month to once every 3 months. In the following paragraphs the different steps will be described in more detail.

Initially, an assessor from the research team sends an information letter and informed consent to potential participants. Two weeks later, a phone call is planned with the participants, during which they have the opportunity to ask questions. If they are still willing to participate, participants undergo a brief cognitive assessment over the phone to determine eligibility and informed consent will be obtained. Upon signing the informed consent, participants will receive multiple questionnaires for the baseline assessment which they can complete at home, at their own pace within two weeks. Reminder emails will be sent after two and four weeks, followed by telephone contact after six weeks if questionnaires remain incomplete. After the baseline questionnaires have been returned, participants will be randomly allocated into the control or intervention group. Within two weeks after completing the questionnaires participants will receive a package. Some participants will receive a package containing a wrist monitor. The monitor will be worn one week at the start of the study and one week at the end. The package also includes a “part 2.” After the week in which the participant has worn the monitor, part 2 of the package can be opened. It contains the randomization result and login details for the lifestyle decision aid. Participants can contact a helpdesk during office hours for additional information or guidance on how to use the wrist monitor or decision aid if needed. Participants who receive a package without wrist monitor can open the randomization results and login details for the lifestyle decision aid immediately.

The lifestyle coach will schedule an intake meeting with participants two weeks after the package delivery. The participants are required to complete the lifestyle decision aid before the meeting. Participants in the intervention group schedule a follow-up meeting with the lifestyle coach during the intake, typically one to three months later, based on personal goals and needs. The control group receives no further coaching after the intake.

All participants will receive a set of questionnaires at T1 and T2. Importantly, participants will not be required to visit the research location at Radboudumc. All research procedures can be performed from their own home.

Based on a recent systematic review on self-management interventions in people with PD (71) we identified two RCT’s (72, 73) that have studied a self-management intervention including lifestyle advice for people with PD using the PDQ-39 as an outcome. While the present intervention is much more comprehensive and personalized and includes more coaching and guidance when needed, we decided to conservatively use the results of those studies for our sample size calculation. Both studies found a mean between group difference of 4.15 on the PDQ-39, with a mean standard deviation of 10.55. With a significance level of 0.05 and 80%, we need 102 participants per group. Assuming 20% dropouts, we will include 128 participants per group (256 in total).

We will apply a series of previously successful recruitment strategies. First, we will send an invitation to a panel of people with PD interested in research, who are subscribed to a mailing list of our research group. They have either shown interest in research by subscribing to the mailing list or by participating in one of our previous research projects. Second, we will exploit other options to reach potential participants, including advertising and blogging on social media (LinkedIn, Facebook, X, Instagram) and the online platforms of the Parkinson Vereniging (Dutch association for people with PD), giving presentations at local and regional patient support groups, recruiting patients at our outpatient clinic at the Center of Expertise for Parkinson & Movement Disorders at the Radboudumc, and using the regional PD professional network (i.e., the Dutch ParkinsonNet with national coverage). Furthermore, word-of-mouth recruitment is encouraged via current participants and community contacts. We aim to recruit a representative study population by using multiple complementary recruitment strategies, balancing targeted approaches to reach individuals with greater lifestyle-related needs with broader recruitment efforts to ensure sufficient statistical power within the limited timeframe of the trial (74).

The researcher performing the analyses is fully blinded from allocation. In addition, we aim to partially blind the participants by informing them that they are either in a guided lifestyle group or an independent lifestyle group, instead of naming them the intervention and control group. At the end of the study, participants will be asked to indicate which group they believe they were allocated to, in order to assess the impact. We do not foresee any reasons to unblind the participants for the coordinating researcher (TG).

Questionnaire data in this study is securely stored using CastorEDC, a certified data management system with a built-in audit trail. Data from the wrist monitor will be stored and made accessible through Empatica’s Carelab cloud environment, which is also certified and complies with relevant data protection (67). Within the Empatica environment, pseudonyms will be used for all participants, and no directly identifiable data will be collected or stored. Log data generated using the lifestyle decision aid is stored within the secure environment of Zorgkeuzelab (35), a member of the study consortium. This data is pseudonymized and Zorgkeuzelab does not have access to any personal information of the participants.

Personal information will be stored in the participant management software Salesforce (Salesforce, San Francisco, CA, United States). Access to this system is restricted to the research team and protected by secure password authentication. The participants receive a pseudonym that will be stored in PIMS, a local system in the Radboudumc to manage pseudonyms and identifiers in a secured and central way, separate from the research data. The informed consents and diagnosis confirmation will be collected and stored on paper in a fireproof and locked cabinet at the Radboudumc. The data collected in this study will be archived for 15 years after the study.

Descriptive statistics will be used to summarize baseline characteristics. Means, standard deviations, medians, ranges, counts, and percentages will be reported as appropriate, depending on the distribution and scale of the variable.

All study participants will be informed about the study results through email. In addition, we will use communication channels of ParkinsonNet, The Dutch Parkinson Patient Association and ParkinsonNL, targeting people with PD, their caregivers and healthcare professionals. We will further promote the results at (patient) conferences, Parkinson support groups and via social media. All non-identifiable data collected during this study will be shared with the international research community via the RDR, and will be available upon reasonable request. The publications arising from this study will be made available Open Access.