The impact of moulage on learners’ experience in simulation-based education and training: systematic review

Background Moulage is a technique used to simulate injury, disease, aging and other physical characteristics specific to a scenario, often used in health and emergency worker training, predominantly for simulation-based learning activities. Its use in allied health fields is unclear. Previous work has explored moulage as an adjunct for authentic simulations, however there is opportunity for broadening its scope. Aim To explore the effects of moulage interventions in simulation-based education and training, for learner experience. A secondary aim was to understand which pedagogical frameworks were embedded in moulage interventions. Method Four electronic databases (PubMed, CINAHL, EmBase, Proquest Central) were systematically searched to December 2022 for studies utilising moulage in simulation-based education experiences. Outcomes were focused on learner satisfaction, confidence, immersion, engagement, performance, or knowledge. Study quality was assessed using the Mixed Methods Appraisal Tool. Results Twenty studies (n = 11,470) were included. Studies were primarily conducted in medicine (n = 9 studies) and nursing (n = 5 studies) and less frequently across other health disciplines. The findings demonstrated greater learner satisfaction, confidence, and immersion when moulage was used against a comparator group. Minimal improvements in knowledge and performance were identified. One study underpinned the intervention with a pedagogical theory. Conclusion Moulage improves learner experience in simulation-based education or training, but not knowledge or clinical performance. Further research utilising moulage across a broader range of professions is needed. Interventions using moulage should be underpinned by pedagogical theories. Supplementary Information The online version contains supplementary material available at 10.1186/s12909-023-04976-w.


Introduction
Simulation-based education (SBE) and training allows learners to practice skills, decision-making, and critical thinking in a safe, supervised environment [1].Thus, it improves preparedness for placement and develops empathetic behaviours [2].It aims to closely mimic real-life scenarios and offer learners the opportunity to refine skills, particularly those required for less common but crucial situations [3,4].The use of simulation-based education and training has been well-documented across nursing and medical curricula [1] and has been adopted in allied health professions such as speech pathology, physiotherapy, audiology, and dietetics [5][6][7].
The reported effectiveness of simulation-based education and training for learning can be understood through its basis in multiple learning theories and frameworks [2].For example, consider Kolb's Experiential Learning Cycle (Kolb, 1984).It encompasses four stages of the learning process: concrete experience, reflective observation, abstract conceptualization, and active experimentation.SBE and training can provide learners with all four stages, offering hands-on learning in safe environments, with or without peer observation, to deliver concrete experiences and experimentation in simulated sessions with guided reflection [8].
A feature increasingly utilised in simulation experience, known as moulage, attempts to increase the realism of cases used in learning activities through enhancing sensory properties, thus contributing to a believable simulation experience.Modern moulage techniques include special effects makeup techniques on simulated participants or manikins.Methods can include applying castings and moulded wounds; painting bruises, lacerations or rashes; creating an illusion of blood loss, or signs of illnesses on the skin, or any other clinical presentation [9].Moulage has been used extensively within the field of dermatology to provide an opportunity to educate individuals in various skin ailments including melanoma [10].
Several theories inform moulage use in simulation, including the theories of realism, authenticity, and fidelity [11][12][13].Realism describes how a participant perceives the reality of a simulated environment, while authenticity describes how close to reality something is [14].For this paper, we will discuss moulage in the context of realism and authenticity, but not fidelity, due to the contentious nature of the term fidelity [15][16][17].Moulage use is informed by Dieckmann's theory of realism (2007) in which realism comprises three elements: physical, semantic, and phenomenal [11].These three aspects contribute to how a participant might perceive reality.This is particularly important when it comes to moulage, as moulage can contribute to all three aspects of realism [14].That is, moulage provides physical prompts, conceptual prompts (e.g., bleeding means low blood pressure), and semantic prompts (e.g., moulage contributes to emotional engagement).The theory of authentic learning argues four key aspects are essential: "real worldness", open ended inquiry, discourse among learners, and choice [12].Moulage can contribute to authentic learning experiences by providing "real worldness" that narrows the gap between real and simulated worlds.
The Society of Simulation in Healthcare, defines moulage as: "A technique used to simulate injury, disease, aging and other physical characteristics specific to a scenario; moulage supports the sensory perceptions of participants and authenticity of the simulation scenario through the use of makeup, attachable artefacts (e.g.penetrating objects), and smells." [18].
Moulage use is emerging in paramedicine, radiography, medical education, rescue ambulance services, however largely exists in discipline silos [19].Military simulations utilise moulage techniques to aid in desensitisation, prepare for battle and provide opportunities to practice injury treatment [20].Recent advancements in moulage include the use of temporary tattoos to represent injuries during virtual reality training to increase the preparedness of healthcare students responding to mass casualty incidents [21].
Moulage has been shown to assist in content and face validity of simulated learning experiences, along with the transfer of clinical skills and knowledge retention [22].Comparative studies of moulage versus no moulage have shown that moulage demonstrated improvement in learners' performance and immersion in their clinical scenario [23].A previous systematic review exploring the role of moulage in simulation practice and the degree to which its authenticity impacts engagement, identified that further research into the use of moulage was warranted [24].What is yet to be understood is how moulage contributes to the learner's experience and the role that moulage plays in educational outcomes.Therefore, this systematic review aims to explore the effect of moulage in simulation-based education and training on learner experience.A secondary aim is to describe the pedagogical frameworks and/or learning theories that can aid in better simulation experiences.

Search strategy
The search strategy was developed using the PICO tool (population, intervention/exposure, comparison and outcome) with assistance from a specialist librarian and based on the review aim.Four key databases (Medline, CINAHL, Embase and ProQuest) were searched from inception until the 9th of December 2022, using the Boolean combination AND and OR for "moulage" and "simulation-based training" with relevant MeSH terms and adaptations to suit each database (supplementary material 1).No date or language limitations were applied; however, the ProQuest Central database was restricted to peer-review journals only.A further snowball search of included article reference lists and hand-searching of key simulation journals (Advances in Simulation, Simulation in Healthcare, Clinical Simulation in Nursing INACSL, The British Medical Journal: simulation, International Journal of Healthcare Simulation) was conducted.The systematic review was registered with the International Prospective Register of Systematic Review (PROSPERO) (CRD42021292052).Ethical approval was not required.

Inclusion and exclusion criteria
Studies were eligible for inclusion if they (1) reported on adult learners (18+ years), including students or workers across all professions; (2) utilised moulage in a simulation-based education or training experience; (3) reported on at least one primary outcome of interest (experience, engagement, satisfaction, preference, preparedness or confidence) with or without a secondary outcome (clinical competency or performance); and (4) employed an empirical research design.Studies were excluded if they reported only on secondary outcomes; were not peer reviewed or were single case studies, editorials, commentary articles or reported only as conference abstracts.

Study selection and quality appraisal
Search results were exported into a single EndNote 20 library and deduplicated.The results were then uploaded to Covidence© software for title and abstract screening against the inclusion criteria, completed independently by two reviewers (GZ, SD).Papers not excluded during title and abstract screening were retrieved for further independent full-text screening by two reviewers (GZ, SD).Conflicts were resolved either through consensus or discussion with other reviewers (JSP, DR).Included studies were critically appraised independently by two reviewers (GZ, SD) using the Mixed-Methods Appraisal (MMAT) tool [25], with disagreements resolved by consensus or third reviewer (DR).The MMAT is a tool for critically appraising qualitative and quantitative methodology studies using a single tool.

Data extraction
A data extraction tool was developed to capture key characteristics of included studies.Data extracted for each study included participant type and number, study design, intervention and reported pedagogical theory, comparator, and reported findings.Qualitative studies were tabulated by method of data collection, analysis, identified themes, and supporting quotes.Data extraction was conducted independently by one reviewer (GZ) with all studies checked for accuracy by a second reviewer (SD).

Study selection
Seventeen thousand twenty articles were identified in the database search.Following deduplication, 11,470 articles were screened based on title and abstract.Of these, 111 articles were retrieved for full text review resulting in 16 included studies from the database search (Fig. 1).An additional four studies were identified through snowball and hand searching, resulting in a total of 20 final included studies for quality appraisal.The most common reason for exclusion was not describing or utilising 'moulage' within their intervention.Of the included papers within the study, three were duplicated from the previously cited review [24].The remaining 17 were either studies that were conducted after its review date or not included in the review based on their search strategy and inclusion criteria.

Quality assessment
The 20 included studies were assessed as variable in quality based on MMAT, against relevant questions according to study design.Nine publications were assessed against the 'Mixed-Methods' questions (Domain 5.0); three were assessed against the 'Quantitative Randomised Controlled Trials' questions (Domain 2.0) and the remaining eight were assessed against the 'Quantitative Descriptive' questions (Domain 4.0).For randomised controlled trials, there was unclear or no blinding of allocation for all studies, and the criterion on appropriate randomisation was rated as no or unclear for 2 of the 3 studies.For quantitative descriptive studies, the most common area that was rated as unclear was the criterion for sampling strategy used (n = 3 out of 8 studies), with one of those studies also being rated unclear for the criterion on nonresponse bias [26].Mixed methods studies were most frequently rated down for failing to address inconsistencies between quantitative and qualitative findings (n = 5 out of 9 studies).

Study characteristics
The full characteristics of included studies can be seen in Table 1.Most studies were from medical disciplines (n = 9), were with undergraduate learners (n = 15) and situated at a university setting (n = 15).Moulage was utilized to simulate a variety of scenarios.Table 2 outlines the use of moulage in each study and the mediums used to create it.

Impact of moulage on learner experience
For this review, learner experience was captured across several outcome categories including, satisfaction, confidence, immersion, engagement, preparedness, and overall experience.Qualitative results from the nine mixed-methods studies provide further details about how moulage impacted learner experience (Table 3).

Satisfaction
A total of 11 studies reported on participant satisfaction (Table 1).Most studies (n = 6) utilised post-survey design and found higher learners' satisfaction with the use of moulage.Of the other five studies that utilised moulage during simulation and compared the findings to a comparator scenario, three in total reported statistically significant higher satisfaction with the moulage intervention versus the comparator.

Confidence
A total of 8 studies reported on participants' improvement in confidence regarding clinical management of the relevant medical presentation, however only three [27][28][29] were statistically significant.

Immersion and engagement
Four studies in total reported on participants' level of immersion and engagement with the simulation experience.In two studies, participants highly rated the inclusion of moulage as an important and strong contributor to the level of immersion or engagement they felt with the experience [30,31].

Preparedness and experience
A total of nine studies reported on the level of preparedness for practice and overall experience as part of their quantitative findings.Overall, moulage contributed positively to learners' experience by improving self-reported preparedness for practice.One study [32] reported that although moulage improved participant experience, feelings of distraction increased after seeing an open wound.

Rules of simulation:
• Aware they were in a simulation yet mentally processing the conditions of simulation vs. reality.Believability: • Background awareness of simulation depending on authenticity presented.

Consistency of presentation:
• Consistency of presentation of visual cues.

Personal knowledge:
•  Thematic analysis using six-phase coding process.
Concordance check between two researchers.

Patient centredness:
• What others see • Non-verbal cues/reactions Learning: • Experiential learning had improved their memory recall for their exam Realism: • Wounds appeared realistic • Thought it was an actual burns patient.
"I saw some people' s faces and they looked pretty scared." "During the OSCE I thought back and its kinda helped." "The makeup was really realistic looking I couldn't tell it was makeup at first." "To be honest, you couldn't really hide it was intense." "For me it felt like definitely one of the topics I was most prepared for as I'm a visual learner."

Santomauro., 2020
Anecdotal comments from the simulation staff.
N/A • Participants are taken aback when they first see the manikin.
• Participants display caution and apprehension when examining.

Impact of moulage on knowledge and clinical performance Knowledge
Five studies reported on level of knowledge using a prepost-test assessment design.Results varied between studies, however the majority saw improvement in knowledge scores.

Performance
Of the six studies that reported on the performance and clinical competency of participants, three studies [10,29,33] found the intervention group to have higher mean scores compared to the control group.. Two studies measured time-to-action, however, had mixed results [21,31].

Pedagogical theories informing moulage practice
Five studies mentioned a pedagogical framework or learning theory.Two studies used Kirkpatrick's fourlevel approach in the evaluation of their interventions [34].The remaining three mentioned one of the following theories or frameworks; Bloom's Taxonomy Educational Learning [35]; Promoting Excellence and Reflective Learning in Simulation [36]; and Empiricism [37].One study [38] referenced the pedagogical theory as underpinning their intervention, one utilised it for guiding the reflection phase of the simulation [32] and the remaining three referenced a theory either to interpret [39] or evaluate their results [33,40].

Discussion
This systematic review explored the effects of moulage in SBE on learner experiences and described the pedagogical theories underpinning the simulation experience.
The results suggest that the use of moulage does impact learner experience, by improving learner satisfaction, confidence, and immersion within the task.However, moulage did not improve knowledge attainment and performance, although overall evidence was weak.The use of moulage within included studies was limited to a small range of health professions (predominantly medical and nursing disciplines).Only a handful of papers (n = 5) identified pedagogical theories as informing the research design.
Our findings of improved participant satisfaction and confidence regarding clinical skills, supports simulation as an effective learning technique to increase self-efficacy.Self-efficacy is an individual's perception of their ability to achieve a goal, and while it is not a reflection of their actual capabilities, it can affect performance and achievement [27,41,42].
Moulage contributes to a realistic simulation experience and consequently, improves learner engagement [24].Engagement in simulation has been described as "the state in which the participant is observed to be actively interacting with the simulation as if it were real" [31] [31] Our review supports this, as studies consistently reported that moulage contributed to the perceived engagement of participants A proposed reason for this is that moulage provides visual cues for learners to guide their actions, without disrupting the flow of the experience [21,31].Participants have previously noted that the benefit of the moulage was that they did not need to "switch out" of simulation mode to gather cues from other sources [31].
A similar, but separate concept of engagement is immersion which is the "subjective impression that one is participating in a comprehensive, realistic experience" [43].An interesting simulation modality that emerged from our review, was virtual and augmented realities [44].In the included study, simulated participants with applied moulage, were filmed in 360-degree, virtual reality compatible footage to simulate a live mass-causality scenario [44].Paramedic students wore a virtual reality headset that immersed them in the footage and allowed them to gather basic clinical information and allocate a triage position.While no difference in satisfaction between the live or virtual reality simulation experience was found, participants noted the lack of human interaction and emotional immersion as a limitation of virtual reality technology.However, virtual reality may be a viable option for improving immersion given its minimal maintenance costs and ability to expose learners to situations difficult to replicate with traditional techniques, such as those that are dangerous or rare (Mills et al., 2020).Augmented reality (whereby virtual objects appear to coexist in the same space as the real world), may present an interesting approach for moulage to include human interaction whilst retaining the desirable traits of virtual reality simulations, such as immersion and cost-effectiveness.
Simulations have been found to improve empathy and communication skills in healthcare learners [45,46].Empathetic encounters with healthcare professionals have been shown positive results for patient care [47], whilst, conversely, a lack of empathy can result in increased risk of harm to patients [48,49].Our findings suggest moulage may aid in developing participants' empathy by preparing them for potentially distressing scenarios with simulated wounds and illnesses [32,39].One reason for this may be its ability to develop learned psychological responses to uncomfortable imagery without causing them to lose comprehension of the patient's feelings and emotions [50], which is what occurred in the Shiner & Howard (2019) study.The simulation with moulage prepared them emotionally and assisted in maintaining person-centredness [39].Notably, none of the included studies did incorporated smell, which may be a topic for consideration when it comes to preparedness.There is some contention on whether smell can be considered a component of moulage, however, experts could not agree that smell was moulage in a 2017 consensus study [14].Despite this, smell could create an additional stimulus for experience or emotion.SBE with moulage may assist learners to better display empathy to patients and in situations reflecting more confronting cases prior to practice, as well as emotionally preparing them in a psychologically safe environment.
There was limited used of pedagogical theory in the development of moulage interventions, reported by only one of our included studies [38].However another four described a pedagogical theory in the manuscripts, or provided other evidence of considering learning approaches such as Bloom's Taxonomy [35].When a theory was utilised to evaluate the simulation-based experience, student performance was greater despite no difference in knowledge to a control group [33].Previous researchers have suggested that the use of a learning theory within simulation-based education and training provides a more structured experience that integrates effective learning attributes and skills [51].Greater use of learning theories in the development of moulage interventions may improve outcomes for learners beyond experience.
Several theories could inform moulage practice in simulation, as described earlier.Relevant theories include realism and authentic learning [11,52].Another theory that might have application is the theory of visual attention, whereby the eyes constantly scan the visual field to determine areas of priority [53].This may have relevance when it comes to moulage, due to its focus on visual cues.For example, in the virtual reality study described earlier (Mills et al. (2018), the theory of visual attention would have been to the use of eye tracking methodology to determine paramedicine student engagement with moulage [21].Similarly, authentic learning theory could have been applied to Flores & Hess' (2018) work, in which they utilised moulage to improve pharmacy students' ability to assess skin disorders instead of pictures [27].
We found that moulage in SBE is rarely utilised with participants from allied health professions, with only one included-study evaluating the use of moulage to improve podiatrists' confidence in foot ulcer management [40].Notably, we did find published work in non-health fields, such as emergency services and military fields, however these studies did not meet our inclusion criteria [20,54,55].For this reason, the use of moulage may be broader than what is reported in the literature.The lack of use in allied health may be attributable to the costs associated with high quality moulage techniques and the constraints of time.However, given the findings of this review which suggest that communication skills may be impeded in confronting situations and the importance of communication and emotional intelligence for allied health professions, such as dietetics [5], there is cause for more robust research in this area.
Considering the direction for future research, it may be useful to steer focus away from objective outcomes such as knowledge or clinical skill performance, as our findings suggest that moulage has minimal impact on these.Instead, we recommend to further explore: 1) what contributes to a beneficial learning experience using qualitative enquiry methods, 2) the role of emotional preparedness and moulage, 3) moulage and the return on investment, 4) the role of moulage in empathy development, 5) the barriers to disciplines embedding moulage in practice, and 6) the impact the level of the learner has on moulage importance in simulation.
The strengths of this review include the comprehensive search strategy across both databases and relevant journals, with no restriction on profession, language or date, thus maximising the studies captured.Independent researcher screening, data extraction and appraisal of studies provided confidence in the robustness of the methods.Inclusion of a broad range of primary outcomes and study designs captured a breadth of learners' experiences relating to the use of moulage.However, there are limitations that need to be considered.Firstly, there were large discrepancies in quality of study design; notably the high number of included studies following a single-site, one-test point design.12 of the 20 studies had no control group or comparator arm, resulting in difficulties measuring the effectiveness of the outcome change.In addition, four of the 20 studies did not provide sufficient justification of which statistical tests were used to analyse the data, thus reducing the confidence in the results provided.Although three studies utilised a validated tool to evaluate study outcomes, the data was presented using different statistical analysis, which limits comparisons between studies.Additionally, most of the studies utilised self-reported surveys to collect data, which is not a valid method to evaluate performance.

Conclusion
The use of moulage within SBE and training can play an important role in the experience of the learner.Moulage contributes to improved learner satisfaction, immersion, confidence, and may contribute to empathy development, but not necessarily knowledge improvement.The opportunities for future research are immense, spanning pragmatic considerations and pedagogical enquiries.There is a continued need for higher quality evidence with robust study designs that are based on pedagogical theories and learning frameworks, evaluating the use of moulage against designated comparator interventions or controls.We recommend that researchers resist the temptation to focus on knowledge and focus on emerging areas of moulage, such as empathy and emotional preparedness.

Table 1
Characteristics of studies included in systematic review of moulage interventions n * None identifiedGarg et al., 2010

Table 1 (
continued) a Mann Whitney U Test statistical significance set at p < 0.05 b One-way multivariate analysis significance set at α = 0.05 c Paired sample t-test significance set at p ≤ 0.05 d Linear fixed-effects model e One-way ANOVA statistical significance set at p = 0.05 f independent t-test * No between post-group results were reported ** No a priori theory used but Empiricism used to interpret *** Used to evaluate the effectiveness of the intervention

Table 2
Summary of moulage interventions in n = 20 studies

Table 3
Summary of qualitative findings from n = 9 studies reporting the impact of moulage on student experience