Parkinson disease (PD) is a chronic and progressive, neurodegenerative condition which is characterized by motor symptoms such as tremor, bradykinesia, and rigidity. In addition to the motor symptoms, many patients experience nonmotor symptoms, such as sleep disturbances, depression, and constipation [1]. It was estimated that in 2016, 6.1 million people had PD globally [2]. People with PD typically start developing symptoms in their 60s; however, it can also occur at a younger age [3]. In 2018, in the United Kingdom, >145,000 people were living with PD, of whom 19,690 were younger than 65 years [4].

PD significantly impacts the lives of people with the diagnosis and their families [5,6]. Owing to its chronic and neurodegenerative nature, people with PD need ongoing care and support [6]. In addition to the physical symptoms associated with PD, receiving the diagnosis and living with the condition also has an emotional impact. This includes anxiety for the future, difficulties in managing the condition in daily life, and the impact on the family [7]. PD can affect people’s social lives and how they are involved in different roles, such as their role within the family, social circles, or at work. Receiving a diagnosis of PD and living with the condition can result in withdrawal from such social roles, increasing the risk of social isolation and loneliness [8].

The psychosocial impact of PD can be discussed within the social health framework [9,10]. In this framework, health is viewed in the social domain and includes three dimensions: (1) being able to fulfill potential and obligations, (2) managing life with some level of independence despite living with a health condition, and (3) being able to participate in social activities and work. When focusing on coping strategies and finding a balance between limitations and one’s abilities, people can successfully adapt to living with a chronic condition and still live meaningful and satisfying lives [10]. Dröes et al [9] discussed how the concept of social health relates to people living with dementia, suggesting that it is possible for people with dementia to still participate in the 3 dimensions of social health and perceive a good quality of life. Within the PD context, Vescovelli et al [11] touch upon the social health framework by emphasizing the importance of social support for the well-being of people with PD. Social support is a term used to describe receiving care and help from others. It is often linked to social connectedness and being part of a social network [12]. In their systematic reviews, Vescovelli et al [11] found that for people with PD, social support is associated with greater social inclusion and opportunities to remain involved with work, supporting people to keep living meaningful and satisfying lives despite their PD. Thus, social support could improve the social health of people with PD [11]. However, despite these findings, Hellqvist et al [8] and Vescovelli et al [11] conclude that the psychosocial impact of PD is still underresearched.

One way in which people can stay socially connected and thus improve their social health is through peer support [13]. Peer support can be defined as the exchange of support between those (also referred to as peers) who share a similar health condition or life experience [14,15]. Peers can provide one another with social support; more specifically, there is reciprocity of support, meaning that people can develop a relationship in which they can both receive and provide support. This can increase feelings of empowerment [16,17]. Furthermore, peers can share experiential knowledge, which includes information and perspectives that people have because of their personal experiences of living with a certain condition [17]. These elements are unique to peer support and cannot be provided by health care professionals or others who are not living with PD [14,15].

Peer support can be provided in different ways, including web-based settings. The internet is an important source of health-related information and provides a platform for the creation and spread of web-based patient communities [16]. Since the 1990s, the number of web-based patient communities for a variety of health conditions has been increasing [18,19]. Such communities can function as self-help groups in which members share experiences and emotions and provide mutual support and empathy [16,20,21]. Some of the advantages of online peer support compared with in-person support groups include that it overcomes geographical barriers [19,22]; provides a form of anonymity, which can be particularly suitable for people with stigmatized conditions [22,23]; and online peer support can be readily available at any time of the day when needed [19,22]. Research has been conducted on online peer support communities for a variety of health conditions, including chronic conditions such as multiple sclerosis (MS) [24,25], HIV or AIDS [26,27], and amyotrophic lateral sclerosis (ALS) [28,29]. The review by Kingod et al [13] shows that online peer support communities can offer people with chronic conditions emotional, social, and practical support in managing their condition in their daily lives. Chronic conditions covered by this review include type 1 diabetes, HIV or AIDS, and chronic pain [13].

Web-based health communities and peer support in web-based settings is a rapidly growing field [16,18,19]. Especially during the COVID-19 pandemic and national lockdowns, connecting with others on the web has become increasingly important. However, knowledge of the long-term effects of online peer support, how it impacts users’ health and self-management, and what particular elements make it useful and meaningful need further research [19,30]. Research into online peer support for people affected by PD is also growing [31,32]; however, to the best of our knowledge, there is no systematic synthesis of this research yet.

This narrative synthesis systematic review aimed to (1) explore the benefits and challenges of online peer support and (2) identify successful elements of online peer support for people with PD. In this review, the challenges cover things that make it more difficult for a person with PD to use online peer support. This can include aspects related to technology as well as PD-related challenges. Understanding the successful elements can be helpful in improving existing and developing new online peer support opportunities for people with PD as well as other conditions. Elements of online peer support were deemed successful if studies identified positive outcomes for the people with PD engaging in online peer support.

The method that was selected for this systematic review was narrative synthesis, using the procedures outlined by Popay et al [33]. This entails including the following elements: (1) theory development, (2) development of a preliminary synthesis, (3) exploration of relationships in the data, and (4) assessment of robustness of the synthesis. With a narrative synthesis, the presentation of the findings is mainly words- and text-based, and it is a useful method to identify elements of best practice [33]. Furthermore, this review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines [34]. More details on the narrative synthesis methods can be found in Multimedia Appendix 1 [9,10,14,16,33,35].

A systematic database search was conducted in April 2020. The search strategy was developed with the help of 2 librarians and NC, who is an academic expert on online peer support. The initial search was part of a wider appraisal of the literature and included PD, MS, ALS, and Huntington disease. This paper will only present the results for patients with PD. A total of 6 databases were searched: CINAHL, Cochrane Library, EMBASE MEDLINE, PsycINFO, Scopus, and Web of Science. The keywords used for the searches are presented in Textbox 1. A search filter for the year of publication, 1989 to 2020, was applied. This was because the World Wide Web was introduced in 1989. No filters on the study design were applied. Finally, the reference lists of the included papers were searched manually. This did not result in any new papers being added.

Textbox 2 lists the inclusion and criteria followed while selecting papers for this review.

The search results were imported into EndNote (Clarivate), after which all duplicates were removed. The primary reviewer (EVG) reviewed each title and abstract against the eligibility criteria. The primary reviewer consulted a second reviewer (ARL) on the titles and abstracts that she was unsure about. The title and abstract screening was followed by a full-text analysis of the potentially relevant papers. The initial full-text analysis was conducted by the primary reviewer. The same procedures as used for the title and abstract screening were followed. At this stage, the main reason for labeling a paper as unsure was that although the paper met the inclusion and exclusion criteria, it mainly focused on other outcomes (eg, quality of life) rather than peer-to-peer interactions. Following a discussion with a third reviewer (OM), it was decided to refine the exclusion criteria and add the criterion that papers could be excluded if they did not report on peer-to-peer interactions. The papers that were included up to that point were reassessed against the newly added exclusion criterion.

Following the study selection, the primary reviewer (EVG) extracted the data using standardized data extraction forms. Data were extracted on (1) study information, (2) study characteristics, (3) population characteristics, (4) characteristics of the web- or app-based platform, (5) outcomes, and (6) implications for future research. ARL provided a second independent review of the completed data extraction forms.

In all, 2 quality assessment tools were used to assess the risk of bias in individual studies. EVG completed the initial quality assessment and ARL provided a second independent review. For the assessment of the risk of bias in qualitative studies, the Critical Appraisal Skills Programme (CASP) qualitative research checklist was used [36]. This checklist consists of 10 questions related to “rigour, credibility and relevance” [37]. For studies that could not be assessed using the CASP checklist, the Downs and Black quality checklist was used. This tool consists of 27 items and is suitable for both randomized and nonrandomized studies [38]. Both the CASP checklist and the Downs and Black quality checklist were recommended by the Centre for Reviews and Dissemination guidance for undertaking reviews in health care [37] and have been successfully used in previous systematic reviews [39,40].

For the CASP checklist, studies will be graded high, if they met or partially met 8 to 10 items; medium, if they met or partially met 5 to 7 items; and low, if they met or partially met 0 to 4 items [41]. For the Downs and Black quality checklist, papers are labeled excellent, if they have 24 to 28 points; good, if they have 19 to 23 points; fair, with 14 to 18 points; and poor, when they have less than 14 points [42].

The results section covers element 2 of a narrative synthesis: developing a preliminary synthesis. A web-based database search returned 10,987 unique titles and abstracts. After screening of the titles, abstracts, and full texts, of the 10,987 papers, 8 (0.07%) met the inclusion criteria for this review. An overview of the web-based database search and screening process can be found in Figure 1.

An overview of the study characteristics is presented in Table 1. This review includes a variety of methods. Of the 8 papers, 3 (38%) papers used a qualitative content analysis of posts on a discussion forum [31,32,43], 3 (38%) papers reported the findings of a pilot study [44-46], 1 (13%) paper conducted an ethnographic study in a virtual world [47], and 1 (13%) paper conducted a survey and interviews [48].

In all studies, the mode of communication between the participants was text-based. In 50% (4/8) of studies, communication was asynchronous [31,32,43,48], meaning that participants did not necessarily communicate with each other in real time. This is one of the characteristics of discussion forums, where people can post a message and others can respond at a time that is convenient for them. A total of 50% (4/8) of studies [44-47] used real-time communication (synchronous). Other than in a study [48], all online peer support communities analyzed in this review were moderated. This means that one or multiple people either guided the discussion or monitored posts. Although 75% (6/8) of studies only included people living with a PD diagnosis [31,43-47], 25% (2/8) of studies included both caregivers and people with a PD diagnosis [32,48].

Of the 8 papers, 5 (63%) were of good or high quality, 2 (25%) were labeled medium or fair quality, and 1 (13%) paper was labeled as poor quality. In total, 63% (5/8) of papers were assessed using the CASP checklist. Of these5 papers, 3 (60%) were labeled as high quality [31,32,43], 1 (20%) as medium [47], and 1 (20%) was assessed to be of low quality [48]. The 38% (3/8) of remaining papers were assessed using the Downs and Black quality checklist. Of these 3 papers, 2 (67%) were labeled as good [45,46] and 1 (33%) was labeled as fair [44]. An overview of the CASP checklist, Downs and Black quality checklist, and the scores for each study can be found in Multimedia Appendix 2 [31,32,43-48].

This section presents the summary and interpretation of the findings, covering narrative synthesis element 3: exploring relationships within and between studies. To the best of our knowledge, this is the first review to systematically synthesize the literature on online peer support for people with PD. This review shows that online peer support can be a way for people with PD to stay socially connected, share experiences, and exchange support for managing daily life with PD. Furthermore, this review identified the successful elements of online peer support.

This section covers narrative synthesis element 4: assessing the robustness of the synthesis. This systematic review only included studies on written communication between people with PD on publicly available platforms. The database search did not identify any papers that included other platforms that can potentially be used for online peer support, such as videoconferencing platforms or social media platforms such as WhatsApp or Instagram. Therefore, the findings of this review are limited to the platforms covered in this review (discussion forums and Facebook groups) and cannot be generalized beyond these. Moreover, of the 8 studies, only 1 (13%) study has included findings on the potential challenges of online peer support [31]. As a result, this review may overrepresent the positive and beneficial aspects of online peer support and may not provide an accurate picture of the real-world experiences of people with PD who are part of such communities. In addition, within the studies, it was sometimes difficult to identify the contributions of technological, social, and individual elements to how people experienced online peer support. Finally, people have different preferences and needs, and online peer support may not be suitable for everyone living with PD. In addition, the physical symptoms of PD may be a barrier for people to use technology and to access online peer support communities. The views and experiences of people who are unable or do not want to engage in online peer support groups have not been presented in this review.

For this review, no papers were identified that covered videoconferencing platforms that can be used for peer support; for example, Zoom, Skype, or Microsoft Teams. As these platforms have become more widely used since the COVID-19 pandemic, future research could explore how widely they are used among people with PD, and if and how they are used for peer support. Furthermore, research could focus on how people experience this form of online peer support and how it impacts their lives, as it is different in nature than what has been discussed in this review. More specifically, videoconferencing platforms include synchronous and verbal communication, often where one sees the other members. This reduces anonymity and adds a face-to-face element, in which nonverbal communication can be more prevalent.

Future research could also focus on using different methodologies for analyzing online peer support for people with PD. Direct assessment of users’ personal experiences was also recommended by some of the studies included in this review [31,43,48]. Examples of these methods include individual interviews, focus groups, or surveys. It is necessary to learn how people with PD truly experience being part of an online peer support community and what the impact is on their daily lives. Furthermore, future research is needed to explore potential negative experiences people may have with online peer support, as these are currently underresearched. Qualitative methods, such as individual interviews and open-question surveys, can be used for this purpose. In addition, there is a group of people who are unable to access online peer support or use technology, for example, because of their PD symptoms. It is important to explore in more detail the barriers that people face and how they could overcome them. Some of the studies included in this review recommended investigating the use of voice assistive tools for people with PD [31,45]. Research into the use of such assistive tools for online peer support has already been conducted for people with ALS; for example, in the work of Caron and Light [53].

Peer support can be an extremely valuable source of social support for people with PD. More specifically, peer support can improve social health and support people with PD in living meaningful and satisfying lives, despite their condition. Sharing experiences with peers can improve feelings of empowerment and social connectedness and help people with PD develop new coping skills. Peer support is unique and cannot be replaced by family members, friends, or health care professionals who do not live with PD. The benefits of peer support are not limited to physical, in-person support groups but can be transferred via the internet. Online peer support is accessible to a wide range of people and is not limited by geographical barriers. This could make online peer support particularly suitable for those who do not have an in-person peer support group in their local area, or whose PD symptoms hinder them from traveling. However, research on the personal experiences of those who engage in online peer support and potential barriers to accessing online peer support remains limited. Future research could use qualitative methods, such as individual interviews, focus groups, and open-question surveys to explore these fields further.