The rationale for using realist synthesis

DCM is a multi-component intervention dependent on those delivering and receiving care in care settings. Realist review is a theory-driven interpretive approach to evidence synthesis (Pawson, 2006). It helps build a programme theory by gathering various types of research, peer-reviewed and not, and information from stakeholders (Handley, Bunn, and Goodman, 2017; Handley, Bunn, and Goodman, 2015). It articulates how particular contexts (C) have prompted certain mechanisms (M) or responses to lead to the observed outcomes (O). Research suggests that patient and public involvement (PPI) as part of a research project helps build and maintain trust and relationships, sustain the successful involvement of people in research and foster positive working communications and relationships (Dawson et al., 2020). An advisory group was composed as part of a research project to help focus the scope of the review, identify potential programme theories, and provide clarity and explanatory strength of the mechanisms. Seven health and social care professionals, who are experienced mappers involved in delivering and training in DCM and research in care settings agreed to be involved in the advisory group.

Identifying relevant studies

A realist type of review acknowledges the limitation of restricted search protocols. It allows for an iterative and broader search of literature. It is refined throughout the process by the findings and how they fit into the overall research question (Pawson, 2006). We included empirical research of any study design or data type, whether quantitative (randomised or non-randomised), qualitative or mixed methods (Wong et al., 2013).

It is important to note that one of the areas of discussion around realist reviews is the use, or not, of critical appraisal tools to assess the trustworthiness of the studies included. In this paper, critical appraisal tools were not employed. This decision is based on the argument that these tools do not align with the goals of realist reviews. Realist reviews aim to consider vital and specific information for assessing studies, emphasising their contribution to theory building rather than focussing on methodological quality (Dada et al., 2023).

Studies were included if:

• The domain studied was dementia, of any sub-type, and/or cognitive impairment and PCC.
• Participants were adults 18 years and over living with dementia, of any sub-type, and/or cognitive impairment and care staff working with people with dementia.
• They were published between 2000 and 2022 (the development of the PCC approach is widely attributed to the work of Professor Thomas Kitwood in his book published in, 1997, ‘Dementia Reconsidered’).
• They were focussed on a psychosocial intervention, defined here as any non-pharmacological intervention that is delivered to professional caregivers, or people with dementia, and aims to improve the PCC behaviour of professional caregivers, for example, educational interventions, behaviour-oriented interventions, emotional-oriented and multisensory interventions. Studies had to explicitly state that they were person-centred or aimed to make care more person-centred (Barbosa et al., 2015), or if they were judged by the team to capture key features of person-centred care (PCC).
• They were conducted in any care setting for people living with dementia as recognised by the American Psychosocial Association (2007) as reflecting a need to improve PCC with the use of, for example, educational interventions, physical activities, behaviour-oriented interventions, emotional-oriented and multisensory interventions aiming to improve PCC.
• Included psychosocial interventions should be based on a theoretical understanding of psychosocial interventions that promote PCC as reflecting the rationale of Tom Kitwood’s work on PCC dementia care.

Studies were excluded if:

• They did not examine the implementation nor the barriers and facilitators of implementing psychosocial PCC interventions and did not contribute to creating the programme theory.
• They did not include people with dementia and/or cognitive impairment as explicitly stated.
• They were not written in the English Language.

Search strategy

A search of previous literature reviews was analysed to identify the most appropriate keywords for the database searches; related to dementia and/or cognitive impairment. The advisory group, as well as subject librarians, gave suggestions for relevant search terms.

Five electronic databases – SCOPUS, Web of Science, CINAHL, APA Psych INFO and Medline – were searched to identify studies published in English from 2000 to 2022. Truncations and wildcards were used appropriately by the database when required, and key terms were also adapted when needed. In supplementary material, you can find a list of the search terms used and a figure with an example for a database search.

Study selection process

Figure 1 shows the PRISMA flow (Page et al., 2021) diagram of the search and selection process. Records obtained through the searches were downloaded into Endnote™, and duplicates were deleted. One author (AFP) independently reviewed the titles and abstracts of selected studies using initial inclusion and exclusion criteria. AB and LC examined a sample of 10 per cent of abstracts each to ensure that the same selection criteria were used. The first author (AFP) obtained and reviewed the full texts of the studies identified as relevant to answering the research question. Disagreements were discussed between the team, and a consensus was achieved for all included studies.

Data retrieval and analysis

Data from the included studies were extracted using an extraction table by the first author and reviewed by the remaining authors. Data extracted were related to authors and study information, intervention type, context, participants, country, methodology used, and barriers and facilitators of psychosocial PCC interventions. The results in this paper are summarised in narrative form to integrate information from the advisory group, which is a critical component of realist reviews. Rigour in realist synthesis is a topic discussed in the research, and there are factors for evaluating research rigour, such as sample size, data collection methods, analysis techniques and research claims (Hunter et al., 2022).

According to Pawson (2006) in realist reviews all sources of evidence are of equal standing provided they contribute to the development of mechanism-based explanatory theories. As such, the screening of studies was based on relevance and this was applied in two ways: the article (i) is relevant to the content/topic of interest, and (ii) provides evidence relevant to theory development, refinement or testing. We looked at the validity and reliability of the data contained in each article – we have not assessed the rigour of a study or intervention as a whole. For each article we asked – are the methods appropriate? Is the source credible? We drew on our research training and judgement to determine if the data was trustworthy and the source credible. All data was considered trustworthy. We finally reflected on the coherence of the CMOCs which was done through multiple discussions with the research team and advisory group and presentations at conferences to see if inferences were logical (Pawson, 2006).

Characteristics of the included studies

Geographically, the scope of the papers was varied. Most studies were conducted in Europe. The most significant number of studies was conducted in the UK (n = 9). Two studies were conducted in Germany; two in the Netherlands, one in Italy and the Netherlands, and one in three countries – Italy, Poland, and the UK; three in Norway and one in Portugal. One study was conducted in the United States, two in Canada, and three in Australia. Three studies were review studies, so no country is specified, as is the case with three other studies where the country of origin is not specified.

Regarding the methodology, three studies used quantitative data (e.g., questionnaires and surveys), and most used qualitative data drawn from interviews (n = 20). Nine publications focussed on DCM use ADD citations (Table 3), and the rest of the studies focussed on other psychosocial interventions, including… (add citations) (Table A in the supplementary material). Eight of the nine publications that specifically focussed on DCM, reported on studies that were conducted in care homes settings. Although the eligibility criteria for the studies were broad enough to include various types of care settings, the majority of the studies that were ultimately included in the review were conducted specifically in care home settings.

a) Individual level

Five publications focused on DCM were conducted in the UK and were related to a large, cluster-randomised control trial: Enhancing Person-Centred Care in Care Homes (EPIC) (Surr et al., 2016). In a paper by Griffiths and colleagues (Griffiths et al., 2019), the authors found several reasons why individual mappers were not able to complete repeat cycles of DCM, which were necessary for the trial:

• Lack of IT skills and fluency in English which, in turn, impacted their ability to feedback on data obtained from their mapping observations.
• Mappers failed to view DCM as a priority to improve care and questioned DCM validity to enhance the quality of care.
• Mappers could not understand the expectations for implementing DCM and completing the trial.

The same barriers were found in another study (Quasdorf et al., 2017), as individual mappers lacked knowledge about what the intervention meant and had negative attitudes towards the implementation of DCM. This translated into mappers failing to translate data from cycles of mapping into action plans for daily care practice.

When implementing DCM, the choice of mappers acted as a barrier to implementation (Griffiths et al., 2019; Kelley et al., 2020; Quasdorf et al., 2017; Surr et al., 2021). This was seen as an obvious problem when mappers still failed to understand the process and expected role after the trial ended, mentioning that they felt unprepared and unskilled to implement a complex DCM intervention (Kelley et al., 2020).

The care home managers’ individual qualities (leadership and managerial skills) were also identified as barriers to implementation of DCM (Bartholomeyczik and Quasdorf, 2019; Karrer et al., 2020; Kelley et al., 2020). If the manager was passive (meaning avoiding taking responsibility for the implementation) or if the manager presented as authoritative or demanding (and failing in the delegation of tasks), then this acted as a barrier (Bartholomeyczik and Quasdorf, 2019; Griffiths et al., 2021; Kelley et al., 2020). Managers who lacked vision or failed to show or articulate their vision of care to their staff were also unable to implement DCM (Bartholomeyczik and Quasdorf, 2019) and failed to engage staff in the implementation process (Kelley et al., 2020).

A scoping review (Karrer et al., 2020) on nurse-led PCC interventions also reported on lack of engagement from the managers as a barrier to implementation of these interventions. In a recent study conducted in 2022, Backman and colleagues (Backman et al., 2023) when interviewing nursing home managers, found that individual barriers to promoting PCC were staff and family considerations prioritized over residents’ choices.

One important finding was the role of an external facilitator (person) in implementing interventions. Griffiths and colleagues (Griffiths et al., 2019) and Surr and colleagues (C. A. Surr et al., 2019b) found that, when implementing DCM after the EPIC trial, a more experienced external mapper can help facilitate the implementation by supporting less confident junior mappers to find the skills necessary to undertake and complete the DCM process, including not only observation but also data analysis, report writing and action planning. Quasdorf and colleagues (Quasdorf et al., 2017) also found that individual characteristics that act as facilitators for implementing DCM were positive knowledge and beliefs about the intervention and a positive attitude towards DCM. The authors stated that it is vital for staff to reflect critically on the value of DCM in practice. This becomes compromised if managers also lack an understanding of how DCM and the overall intervention study worked and do not view DCM as a priority or allow time for mapping (Bartholomeyczik and Quasdorf, 2019; Griffiths et al., 2021; Rokstad et al., 2015; C. A. Surr et al., 2019b; Surr, Griffiths, and Kelley, 2018). Another study (Van Mierlo, 2018) also reported on the importance of qualified, motivated, and professional staff to guide the implementation of a PCC intervention. Argyle and Kelly (Argyle and Kelly, 2015) also pointed out that, for better implementation of a music intervention, the right leadership, and a clear rationale for selecting appropriate staff to be involved in the intervention and provision of more staff and support acts as a facilitator.

Leaders and managers of the care setting act as facilitators for the implementation when they show confidence, pragmatism, and academic abilities, such as computer literacy, report writing and sufficient academic competence to engage in the more complex components of the implementation. The right skills can drive individuals and influence practice change (Griffiths et al., 2019).

b) Interpersonal level

Four studies focused on DCM found that managers could not provide appropriate support to their staff during the implementation period due to a lack of effective leadership skills (Griffiths et al., 2019; Kelley et al., 2020; Quasdorf et al., 2017; Rokstad et al., 2015). These findings were transversal to other studies not limited to DCM; one of the main barriers was the lack of support from managers to the wider staff, including the lack of education opportunities during the implementation of the interventions (Barbosa et al., 2017; Boersma et al., 2017, 2015; Chenoweth et al., 2018, , 2015; Griffiths et al., 2021, , 2019; Karrer et al., 2020; Kelley et al., 2020; C. A. Surr et al., 2019a; C.A. Surr et al., 2019b; Van Mierlo, 2018). Managers could not provide appropriate support to their staff during the implementation period due to a lack of effective leadership skills. This was particularly noticed in studies focused on DCM (Barbosa et al., 2016a; Griffiths et al., 2019; Kelley et al., 2020; Quasdorf et al., 2017; Rokstad et al., 2015).

When implementing DCM, several barriers found in the EPIC trial study were the attrition of mappers (Griffiths et al., 2019), a lack of communication between staff (Quasdorf et al., 2017), and team conflicts (Surr et al., 2021). This is also seen in a study by Kolanowski and colleagues (Kolanowski et al., 2015) looking at communication breakdown and the influence of PCC. The authors stated that communication breakdown within a facility, between staff and residents, staff and families and staff to staff, was a critical barrier to implementing a behavioural health toolkit for nursing staff in nursing homes. A study evaluating the impact of PCC psychosocial interventions in Portuguese care homes found that care assistants felt undervalued and unsupported by their line managers (Barbosa et al., 2017). Staff stated that managers lacked an understanding of the ‘floor work’ and lacked interpersonal skills to communicate with staff.

When thinking about the implementation of complex interventions such as DCM in care settings, it is vital to engage the wider staff team and have open and effective channels of communication to facilitate the implementation and adoption of the intervention in care practice (Surr et al., 2019a; C.A. Surr et al., 2019b). According to Griffiths and colleagues (Griffiths et al., 2021), this can be facilitated using interactive group-based training to assist staff discussions and reflections and support psychosocial interventions’ implementation. This facilitator also played a role in implementing other PCC interventions in a hospital setting, where the whole staff must communicate, be engaged, and support each other (Skingley et al., 2021).

Effective leadership in the nursing staff facilitates good role-modelling between staff and promotes a bigger focus on residents’ needs and preferences (Kolanowski et al., 2015).

To improve good communication skills among staff, one study (Mariani et al., 2017), implemented a shared decision-making (SDM) intervention using role-playing methods. Communication skills training was provided for the healthcare professionals ahead of the intervention. The authors stated that training staff in communication skills was crucial for implementing the SDM intervention. The authors also found that mutual support between colleagues in carrying out the project tasks favoured the accomplishment of the implementation steps and made them feel more secure. The authors argued that the main facilitators for the implementation were the communication and collaboration between staff and the management team’s commitment.

c) Institutional setting

A main barrier identified in most studies was high staff turnover rates and low staffing levels. This, however, is not only related to DCM, where time constraints and competing priorities take precedence over PCC interventions (Boersma et al., 2017; Doyle and Rubinstein, 2014; McGilton et al., 2021; Moyle et al., 2013; Skingley et al., 2021; Van Haeften-Van Dijk et al., 2015). According to Argyle and Kelly (2015), time pressure and conflicting demands during intervention are significant barriers to implementation. The authors argued that, even if staff are enthusiastic about starting the intervention, the enthusiasm decreases after initial implementation due to the pressure of limited time and resources (Barbosa et al., 2017).

Low staffing levels restrict PCC interventions in a complex care setting (Lawrence et al., 2012). Care professionals debated using such interventions because lower staff-to-resident ratios mean that staff needed to take on heavier workloads. Some residents have more complex care needs that are a barrier to PCC culture change (Lawrence et al., 2012).

The structural culture of the inner setting also played a crucial role in enabling implementation. According to Damschroder and colleagues (2009), the inner setting consists of features related to structural, political, and cultural domains that are part of where the intervention will take place and targeted for users and other individuals (patients, staff, leadership, networks and communication, culture, and engagement).

When implementing DCM, nursing units that presented more barriers to implementation exhibited a more functional understanding of care, for example, solely focussing on functional aspects of care such as serving food and drinks, personal care and hygiene and getting people dressed (Quasdorf et al., 2017). Functional nursing is task-focussed instead of person-focussed and consists of efficiency and distribution of work based on tasks and procedures where performance and target of actions are the main goals (Parreira et al., 2021). While implementing a PCC music intervention, one study found that the manager in a dementia specialist care home lacked an understanding of PCC culture and prevailed task-focussed care setting (Argyle and Kelly, 2015). The authors also found that the manager did not have the necessary skills to implement the intervention. A lack of a clear vision of culture and no PCC ethos (ideology) was a barrier identified in a third of the studies (Argyle and Kelly, 2015; Boersma et al., 2015; Chenoweth et al., 2015; Doyle and Rubinstein, 2014; Jacobsen et al., 2017; Karrer et al., 2020; Quasdorf et al., 2017; Skingley et al., 2021; Stein-Parbury et al., 2012; C. A. Surr et al., 2019a; C.A. Surr et al., 2019b; Surr, Griffiths, and Kelley, 2018).

The primary facilitator relates to the size and capacity of care settings. The implementation of DCM was facilitated when conducted in larger nursing homes or dementia-specific nursing homes (Griffiths et al., 2019; C.A. Surr et al., 2019b). According to the findings of the EPIC study, these settings tend to have more qualified staff working with people living with dementia, while smaller nursing homes lack capacity. Nursing units that successfully implemented DCM were also more dementia-friendly, with staff displaying positive attitudes towards people living with dementia and having more flexible organisational structures. An already established care climate centred around PCC culture within the care home was one of the leading facilitators in studies using DCM. A ‘whole home’ approach, centred around PCC and the ethos behind DCM, is seen as a significant facilitator of the implementation of DCM. When staff are aware of the PCC culture inside the care home, they are more open to change (Chenoweth et al., 2018; Griffiths et al., 2021; Griffiths et al.,et al. 2019; C.A. Surr et al., 2019b; Surr et al., 2021). Communication is facilitated and supported for briefing and feedback sessions after mapping (Griffiths et al., 2019; C.A. Surr et al., 2019b), thus promoting a good team culture, with engaged staff and routine systems that support mechanisms for practice change and reflections. This is an important mechanism to facilitate adopting practice change into daily practice. A ‘whole team approach’ also helps promote the successful implementation of DCM when managers can present a clear vision and mission statement of care practices (Bartholomeyczik and Quasdorf, 2019; Stein-Parbury et al., 2012). This can be facilitated when leaders of the care homes can actively make decisions in cooperation with team members across all hierarchical levels, provided open channels of communication and positive leadership occur across all hierarchical levels (Quasdorf et al., 2017). Organisational facilitators support the involvement of the wider staff in intervention development and delivery across wider teams (Karrer et al., 2020). Backman and colleagues (Backman et al., 2023) also found that barriers at the team level hindered the implementation of PCC. Specifically, the authors found that divergent care values, processes, and priorities within the team, staff turnover rates, and low foundational knowledge affect team performance. The study also found that functional building designs and group-level rostering issues impact the coordination and PCC care delivery.

d) (wider) Infra-structural setting

The hierarchical nature of care settings, was the main domain that acted as a barrier to implementing PCC interventions in care settings, and indeed any intervention. Distinctive hierarchical structures and inadequate organisational regulations and communication are barriers to implementation success (Griffiths et al., 2019; Karrer et al., 2020; Quasdorf et al., 2017). Policy, financial issues and lack of structural funding were also considered barriers to implementation (Ducak et al., 2018; Karrer et al., 2020; Kelley et al., 2020; Mariani et al., 2017; Van Haeften-Van Dijk et al., 2015; Van Mierlo, 2018). Lack of structural funding was also found in Backman and colleagues (2023) when interviewing managers of nursing homes. The authors stated that lack of resources and funding acted as overall barriers to delivered PCC, pointing out that ‘providing little extras for each resident and that extra glimmer in their everyday life’ (Backman et al., 2023, p. 5) can sometimes be an issue.

We have not found any information on facilitators regarding the wider infra-structural setting. While the study did not identify specific facilitators in the wider infrastructural setting, the advisory group suggested that addressing issues related to funding and improving policy management and support could contribute to a more successful uptake of PCC interventions in care homes, further reinforcing the potential for enhanced care quality and resident well-being. In the scoping review study by Karrer and colleagues (Karrer et al., 2020), the authors found that policy facilitators could be, for example, if health insurance companies would encourage the cooperation of dementia care networks and enable reimbursement for the delivery of psychosocial PCC interventions.

Assimilation of both sources

This theory-driven evidence synthesis highlights factors that may affect the implementation of DCM. Some of the factors identified are transversal to other PCC interventions.

A common link between all four contextual factors and the discussions with the advisory group is the role of good managerial and leadership support and interpersonal relationships. Staff and team leaders need to have a good communication approach for a whole culture of PCC to develop and for staff to feel like their team leaders are supporting them when implementing DCM. A good communication approach between all staff teams provides a better environment for interventions to be fostered. When implementing DCM, good leaders include their staff members in the decision process, promoting a strong partnership focussing on improving care and building respect, and understanding, to better enable an organisational culture of change. The need for ‘top-down’ and ‘bottom-up’ approaches to implementing interventions in complex care settings plays a significant role.

According to one study by Bartholomeyczik and Quasdorf (2019), when implementing DCM in nursing homes in Germany, it was clear that implementation failed when there was no leadership support. Leaders at all levels failed to take responsibility, were authoritative towards staff, were not directly involved and failed to communicate and engage with staff. This suggests the need for integrating training for managers into the intervention to create a better environment for staff to feel more supported (Barbosa et al., 2017). This is in line with studies conducted with other PCC interventions that showed that the major barriers at organisational and interpersonal levels were the need for more communication, support and feedback between leader and staff teams (Argyle and Kelly, 2015). As with previous findings (Bartholomeyczik and Quasdorf, 2019), good implementation is found in settings where a vision of culture change is formed before the intervention.

It is important to note that the notion of leaders and/or managers is usually used interchangeably but the two concepts are distinct. This can influence the culture and organisational structures. According to Zaleznik (Zaleznik, 2004), organisational leadership needs to focus on elements of inspiration and vision, to drive organisational success. It is also important to note the differences between management (managers) and leadership (leaders) culture; managers seek stability and control to solve problems quickly, while leaders do not mind embracing chaos and lack of stability to wait and think, to understand the problem before acting. The author also argues that organisations need both types to succeed fully (Zaleznik, 2004). Still, as in most complex care settings, there is never only one manager or leader. In fact, hierarchical structures can support this theory in a ‘whole home’, ‘top-down, bottom-up’ approach.

The review highlights that implementing DCM and other PCC interventions often faces challenges related to sustainability and cultural change in care settings. However, these challenges are not unique to PCC but affect the implementation of many other interventions. Successful adoption requires mechanisms that help staff and care teams effectively engage with and sustain these approaches. For example, financial support plays a crucial role. Allan and Vadean (2023) found that higher pay is linked to better care quality in long-term care settings. This is particularly important given the low wages and high staff turnover common in the care sector. Fair compensation improves staff retention, enhances workforce quality, and ultimately leads to better outcomes for residents.

The findings suggest that a core value of DCM is the need to create a ‘whole home’ approach, a feature also shared by other PCC interventions. This is facilitated through the engagement of all staff and good leadership communication. According to the advisory group, some staff members working in care settings are intuitively empathic. Still, because they are not given feedback, they do not realise that they are being person-centred. Feedback on the positive attitudes of staff and emphasising positive interactions help build staff confidence and create an ethos around PCC.

The advisory group members also highlighted the impact of a collective approach to care. They stated that before implementing DCM, training courses are needed for staff to understand PCC, and practical leadership support, skills development, practice development and supportive feedback are essential. These aspects can flourish in environments where a whole home culture of care is focussed on supportive feedback, leadership, and supervision. The primary interest of every staff and team member is improving care practices and putting forwards their ideas for culture change while providing timely feedback.