Introduction

Increasing demands in the nature and amount of material to be learned, decreased frequency of bedside teaching experiences, and the need for authentic learning experiences have resulted in new and innovative uses of educational technologies in medical education [1,2,3]. Educational technologies offer the potential for facilitating safer, more suitable, and cost-effective learning experiences through which authentic education and training tasks can be simulated [2]. Simulation, in particular, has become an important cornerstone in medical education and, while an invaluable tool, manikin-based simulators are often located in urban centers and not easily accessible due to geographic barriers, equipment costs, time constraints, human resources, and space limitations [4]. Manikin-based simulations are also often limited to infrequent opportunities that require preparation, personnel, and scheduling, making it difficult to run at the time when the knowledge and skills are needed [5].

With increasing pressures on budgets and standardization, extended reality (XR) has emerged as a new method of creating simulated experiences in a more cost-effective way than traditional simulation modalities [6,7,8,9,10]. XR is an umbrella term referring to all immersive technologies including virtual reality (VR), augmented reality (AR), mixed reality (MR), and other computer-generated realities using head-mounted displays (HMDs) [11,12,13]. XR technologies offer greater portability with no heavy manikin parts to transport, repair, or safeguard, and no consumable parts that require replacing [5]. XR may also provide greater standardization, replicability in experience, and accessibility. It can be distributed widely and does not necessarily require the presence of a live instructor [5, 14]. Immersive XR also has the potential to have a broader impact through increased learner engagement and improved spatial representation and learning contextualization [3, 15].

Wearable technologies such as HMDs (e.g., virtual headsets, smart glasses) are key devices in the presentation of XR simulations [16]. HMDs are devices worn on the head as part of a helmet that has an optical display, allowing the user to project images or see through it [13]. Smart glasses are wearable technologies, meaning that they are smart electronic devices that can be worn on the body without interfering with the user’s movement [13]. VR headsets allow for total immersion in a 3-dimensional (3D) space, providing stereoscopic views of a scene (i.e., a pair of images, one for each eye) [17]. Potential therapeutic and diagnostics applications of VR headsets have been demonstrated among patient populations, particularly in bio-psychosocial models of cognitive diseases, pain management, or psychological interventions [7, 18, 19].

VR, AR, and MR technologies have been described by numerous authors as disruptive technologies with significant potential uses in medical education and training. VR, AR, and MR-based HMDs introduce new immersive ways to learn complex medical content and may alleviate financial, ethical, and supervisory constraints on the use of traditional medical learning materials like cadavers and specialized lab equipment for skill development [15]. A number of potential uses of XR have been described, including use in anatomical learning and in training for practical skills and procedures across a number of medical and surgical specialties [20,21,22,23]. AR is increasingly used in emergency medicine education and training, and it may have greater relevance in emergency medicine applications because it displays information within an individual’s field of view, thus allowing information to be utilized in real time [24, 25]. Recent experiences with COVID-19 have also demonstrated how fragile health professions education can be with widespread cancelations of clinical and academic activities, yet XR technologies offer opportunities for continuing experiential learning, enabling progression, and developing clinical skills and knowledge remotely despite such disruptions [11, 26, 27].

The purpose of this integrative review of XR literature was to explore the nature of evidence, usage, and effectiveness of XR modalities across the medical education continuum. This review included English-language-only articles that described the use of XR with HMDs for training medical learners and/or physicians or interprofessional audiences that include at least medical learners and/or physicians.

Methods

We conducted an integrative review of studies and articles on XR research and literature published in the medical education field (undergraduate, postgraduate, and continuing professional development). An integrative review determines current knowledge about a specific topic as it is carried out to identify, analyze and synthesize results of independent studies on the same subject. Souza et al. (2010) describe an integrative review as one of the most comprehensive methodological approaches of reviews, as it allows including experimental and non-experimental studies to fully understand the phenomenon analyzed [28]. It can combine data from theoretical and empirical literature, and due to its methodological approach, the integrative review allows including diverse methods. It has been identified as a unique tool in healthcare for synthesizing investigations available on a given topic and for directing practice based on scientific knowledge [28]. According to Souza et al., the six phases of the integrative review process include:

  • 1st phase: preparing the guiding question

  • Defining the guiding question is the most important phase of the review as it determines which studies will be included.

  • 2nd phase: searching or sampling the literature

  • The search in databases should be broad and diverse, with the ideal procedure to include all the studies found, or if this is not feasible due to the amount of works, the inclusion and exclusion criteria adopted for the articles must be clearly explained and discussed.

  • 3rd phase: data collection

  • To extract data from the articles selected, a data extraction instrument should be constructed and used to assure collection of all relevant data.

  • 4th phase: critical analysis of the studies included

  • Similar to data analysis in conventional research, this phase demands an organized approach to weigh the rigor and characteristics of each study. We adapted an evidence classification system based on Harden et al.’s [29] work for grading evidence in medical education research, which is characterized by the methodological approach and/or design of the research:

    • Evidence based on professional judgment: the beliefs and values of experienced teachers

    • Evidence based on educational principles

    • Evidence based on professional experience

    • Evidence based on a quantitative approach

    • Evidence based on a qualitative approach

    • Other

  • 5th phase: discussion of results

  • In this stage, interpretation and synthesis of results are described.

  • 6th phase: presentation of the integrative review

  • The presentation of the review must contain relevant and detailed pieces of information based on contextualized methodologies. Identification of patterns and differences and redistribution of topics may be included as part of the general discussion.

The purpose of the integrative review of XR literature was to explore the nature of the evidence, usage, and effectiveness of XR modalities across the medical education continuum. The search was limited to English-language, peer-reviewed literature published between January 2000 and August 2021. The inclusion criteria for this review were as follows: (1) English-language-only articles; (2) articles that focused on XR using HMDs; (3) both empirical research and commentary-type papers; and (4) articles that described the use of XR for training medical learners and/or physicians or interprofessional audiences that include at least medical learners and/or physicians. The exclusion criteria were as follows: (1) articles about desktop-based virtual patient systems; (2) articles about XR that did not involve HMDs; and (3) non-medical education literature. The inclusion and exclusion criteria were applied in both the abstract and full-text reviews.

Ovid MEDLINE, Cochrane, CINAHL, ERIC, Embase, Scopus, ACM Digital Library, and IEEE Xplore were identified as the most pertinent literature databases to search. The search terms used in the databases were slightly different due to the database capabilities. The Boolean operator “OR” was used to connect the alternative terms for XR, the alternative terms for HMDs, and the alternative terms for medical education, respectively. The Boolean operator “AND” was used to narrow down the results to the articles that focused solely on the use of XR with HMDs in medical education. The search was conducted in each database separately, and then all duplicates among the databases were removed. Given the rapid evolution in this field, the start date of January 2000 was selected because the literature published since that time would be more reflective of the current changes in technologies and applications in the field. The search identified 1239 articles published from January 2000 to August 2021.

The initial round of the review involved assessing the abstracts to ensure that the focus of the articles was specifically on XR systems and medical education. We included evaluation studies, descriptive articles, and commentary articles that focused on recommendations, guidelines, best practices, and evidence-based implementation. In the second round of the review, 133 full articles that fit the criteria for inclusion were obtained and analyzed by members of the review team using a data extraction tool to chart key items of information from each article. Charting has been described as a technique for synthesizing and interpreting qualitative data by sifting, charting, and sorting material according to key themes. In a systematic review, this is also called data extraction. We adopted an approach similar to Arskey and O’Malley that involved charting the type of study design (e.g., quantitative or qualitative), the target audience and level of the learner (e.g., undergraduate, postgraduate, continuing professional development), and key outcomes and/or results [30]. These data were stored in an Excel file.

Findings

Figure 1 summarizes the methodological approaches represented across the papers included in this integrative review based on an adaptation of Harden et al.’s evidence classification system for grading evidence in medical education research [29]. A majority of the studies (N = 89, 59.33%) reflected research based on evidence involving a quantitative approach, 5.33% (N = 8) of the papers represented evidence based on a qualitative approach, and 13.33% (N = 20) were papers that presented evidence based on professional experience. Papers classified as “Other” included mainly systematic reviews and/or scoping review articles.

Fig. 1
figure 1

Summary of levels of evidence presented in reviewed studies and articles

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Figure 2 describes the levels of evaluation reflected across the studies using a levels of evaluation categorization recommended by Barr et al. (2005) for characterizing levels of evaluation evidence described in health professions education research [31]. Level 1—“Learner reaction” and level 2b—“Acquisition of knowledge/skills” were the levels of evaluation evidence reported in the highest proportion of studies reviewed. A minimal number of studies reported evaluation evidence that reflected level 4b—“Benefits to patients/clients” or level 4a—“Change in organizational practice; change in professional practice.”

Fig. 2
figure 2

Levels of evaluation evidence reported in studies and articles

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Types of XR Technologies

Computer-Generated VR (CGVR)

CGVR is an interactive 3-D simulation that allows complete real-time interaction and immersion in computer-generated virtual environments that can stimulate multiple sensory modalities, including visual auditory, or haptic experiences simulating sights, sounds, orientation, and motion [25, 32,33,34]. This virtual environment is visualized by looking into an HMD which allows the user to block out surroundings and interact with the virtual objects in the simulated environment [35]. This artificial world can mimic and simulate the real world or can be a totally imaginary world [12, 13]. In some VR environments, learners may also be able to interact with graphical characters called avatars [36].

360° Virtual Reality Video

360° VR video encompasses video recordings of real-world scenes that enables a totally immersive, 3D experience using a virtual headset [33, 37]. These 360° cinematic images can change in real time as the person moves around, and by looking in front, up, down, or behind them, they can see the entire environment picked up by the 360° camera [20]. Studies comparing two-dimensional (2D) and 3D movies have demonstrated improvement in learning, and similar to other XR modalities, a 360° video allows users to experience an immersive environment [17]. However, unlike VR and AR, users are unable to move within or interact directly with objects in the virtual environment [38].

Augmented Reality

Augmented reality is an enhanced version of reality created by using technology to overlay digital information (texts, graphic images, or 3D contents) into the user’s direct vision of the real world [12, 38,39,40,41]. AR allows a person to see the real world, but it is overlaid with this layer of digital content in real time [25, 33, 42, 43]. AR headsets use transparent screens and reflective lenses to enable the digital information to be overlaid on the real world in the wearer’s field of vision [44]. This seamless augmentation allows the user to see and interact normally with the physical world while still engaging with displayed digital objects [45]. AR differs from VR in that the user interaction provides a more realistic environment compared to a virtual one, resulting from the fact that some of the viewed objects are real and some are virtual, allowing the user to interact with virtual information in the context of their real-world surroundings [34, 43, 46].

Mixed Reality

MR refers to a merging of real and virtual worlds combining the best features of both AR and VR such that physical and digital objects co-exist and interact in real time, and the user is able to interact with both virtual and real-world environments using an HMD [33, 47,48,49]. MR has also been described as a broader class of technologies that includes the display environment of AR and augmented virtuality (AV). With AR, virtual information augments the real-world view, whereas in AV, real-world information augments the virtual scene. The ability to enhance interaction between the physical and virtual content, while preserving a feeling of presence, explains the growing expectations that MR may be best suited for healthcare education in various contexts [49].

Smart Glasses and the HoloLens

Smart glasses are a type of HMD and wearable technology that can display a variety of information and incorporates a video camera that records what the wearer is viewing [50]. Google Glass is one example of an optical HMD that can capture and display audio and video images in real time while interacting with the surrounding environment [39, 51]. Smart glasses have been proposed for use in video recording, skills training, and teleproctoring with video-based evaluation of resident performance found to be equally as reliable as in-person, real-time evaluation for various medical and procedural skills assessments [39, 52]. Some models have been shown to have considerable potential in furthering the development of telemedicine and as a tool to share time-sensitive medical expertise to areas that are physically difficult to reach [51]. Careera et al. (2019) also reports that Google Glass could be used as a telementoring device, allowing trainees to broadcast their point of view to supervising physicians and vice versa [53]. Other uses of Smart Glasses include taking photographs/recording videos/live broadcasting for learning, teaching, and training; connecting with physicians, nurses, and surgeons outside the operative field for hands-free teleconsultation during surgery; and reviewing patients’ medical records and images (e.g., CT scan, MRI, ultrasound, X-ray) [39, 53]. One of the latest and most advanced implementations of smart glasses are Microsoft’s HoloLens. The Hololens is an advanced form of smart glasses that features all the properties of previous generations, plus the capacity to overlay stereoscopic 3D graphics of a Hologram style on top of the real word, which is modeled as a 3-dimensional mesh reconstructed in real time [54].

Reviews of Extended Reality in Medical Education

A number of systematic reviews emerged and were included in this integrative review (see Appendix A Supplementary for a summary and description of these reviews). Generally, the key findings from the systematic reviews suggest that particular forms of XR technologies (e.g., VR and AR) are as effective, if not better in some respects, in generating more positive learning outcomes when compared to traditional teaching methods. Although some reviews did note limitations and weaknesses in the quality of evidence reported in studies on VR and AR use in medical education, the growing body of evidence and research in this area does suggests that XR technologies do appear to promote more engaging, experiential learning and may, in some instances, actually lead to cost savings to institutions in curriculum delivery. Some studies described the disadvantages of HMDs, such as motion sickness and nausea, technical problems, and stress.

Barsom et al.’s (2016) systematic review found AR enabled trainees to understand spatial relationships and concepts, and provided substantial, contextual and situated learning experiences. Barsom et al. reported that AR increases trainees’ subjective attractiveness and enhances learning retention and performance [55]. Barteit et al. (2021) also reported on a systematic review that examined the effectiveness of HMDs using AR, MR, and VR for medical education [15]. AR and VR implemented with HMDs were most often used for training in the fields of surgery and anatomy, and training with AR- and VR-based HMDs was perceived as salient, motivating, and engaging. In the majority of studies, HMD-based interventions were found to be effective with results showing that HMDs were at least comparable to traditional methods of medical education and beneficial in terms of increasing students’ motivation for learning.

Tang et al.’s (2020) systematic review investigated the use of AR as teaching tools in medical education and reported inconsistencies in both focus and quality of the published studies; however, despite these shortcomings, many studies demonstrated positive responses toward AR and a desire by both trainees and experts to see the technology implemented in training programs [56]. Williams et al. (2020) conducted a systematic review on AR use in surgical education and found studies demonstrated either no difference or improved performance when using AR compared with traditional techniques [34]. Munzer et al.’s (2019) systematic review of the use of AR in emergency medicine training found that the use of AR for care delivery over distances was feasible, suggesting a role in telehealth and for providing instruction from a remote location [25]. Carrera et al. (2019) also undertook a systematic review on the use of Google Glass in graduate medical education in the clinical learning environment and its use for resident supervision and education [53]. GG was predominantly used for video teleconferencing, photo and video capture, and telementoring—allowing trainees to broadcast their point of view to supervising physicians and vice versa.

Uses of Extended Reality for Telesimulation and Telementoring

Telesimulation

Telesimulation is a process by which telecommunication and immersive technologies such as HMDs are used to provide education, training, and/or assessment to learners at remote locations [4, 57]. Careera et al. (2019) suggests that the ability to transmit the user’s point-of-view (POV) video using HMDs such as Smart Glasses offers great potential as a tool for procedural skills acquisition, remote supervision, and assessment [53]. Wang et al. (2017) reported the development of a new telepresence application using an augmented reality (AR) system that used the Microsoft HoloLens to undertake remote medical training [54]. HoloLens was used to capture the first-person view of a simulated rural emergency room through mixed reality capture (MRC) and enabled a telemedicine platform for remote training. Munzer (2019) also found that the use of AR for care delivery over distances was feasible and held great potential as a tool in telemedicine [25].

Telementoring

Telementoring is another area where AR and HMDs show much promise. Video learning and video coaching POV video captured by HMDs reduces logistical barriers presented by third-person cameras and can be used for remote consultation among colleagues [41, 58]. Using AR in surgical telementoring overcomes the limitation of traditional video-based systems by enabling users to see both the surgical field and virtual instructions in one field of view [59]. Using AR, remote mentees can view expert-authored operative instructions directly in their field of view [58]. Rojas-Munoz (2020) describes “STAR” as a surgical telementoring platform that uses an AR HMD to display operative instructions directly into the field of view of a mentee [60]. At the mentee site, a camera captures a real-time video feed of the operative field that is sent to the remote mentor. This video is displayed on a large interactive display on which the remote mentor may then add annotations to be seen by the mentee in their field of view.

Uses in Anatomical Education

Anatomy has traditionally been taught via human cadaveric dissection, lectures, and the use of textbooks [21, 47, 61]. There are challenges associated with anatomy teaching due to the limited availability of dissection specimens and the increasing number of educational topics but less curricular time [7, 23, 62]. XR technologies have been explored as innovative ways for anatomical education. The effectiveness of XR technologies to enhance anatomy learning was extensively evaluated by comparison with traditional anatomy teaching methods, and XR technologies demonstrated generally positive outcomes [7, 23, 38, 45, 47, 63,64,65]. The papers by Kurul et al. (2020) and Weeks et al. (2020) demonstrated that VR and AR led to significant anatomy knowledge improvement when compared with conventional training methods [7, 45]. Moro et al. (2017) suggested that VR, AR, and 3D tablet devices were equally effective in anatomy teaching, but VR and AR showed intrinsic benefits, such as enhanced student engagement and immersion [64]. Similarly, Stepan et al. (2017) found no significant differences in knowledge improvement between unitizing VR and web-based textbooks, but medical students found the VR experience of learning neuroanatomy to be more engaging and enjoyable and demonstrated higher motivation [65]. By comparing a group of medical students viewing 360° videos using the Oculus Go Headset with a group of students viewing 2D videos on a laptop, Chan et al. (2021) found that the average engagement of the 360° video group remained higher than the engagement rated by the 2D group [38].

As some AR systems were limited to only one active user, Bork et al. (2020) explored the use of a collaborative AR system that allowed medical students to learn anatomy in a collaborative learning setting [63]. The study suggested that the multi-user collaboration had a positive impact on students’ 3D understanding of topographic anatomy, engagement, and motivation. Le Van et al. (2021) also developed an AR system for anatomy training that enabled multiple users to interact with 3D models in the same environment and suggested that the multi-user AR system provided a robust interactive experience for learners [66]. Some other advantages of using XR technologies include more opportunities for students to study on their own time and learn instances more frequently, more opportunities for students to interact with models and specimens which are rare in practice, clear visualization of anatomical structures, and reduced anatomy training costs [62, 65, 67, 68]. Adverse effects associated with VR, such as blurred vision, dizziness, difficulty concentrating, and eye fatigue, were reported in the literature [63, 64].

It is debatable whether XR technologies could replace the traditional cadaveric dissection in anatomical education. Stojanovska et al. (2020) suggested that MR was an effective learning modality as cadaveric dissection for medical students to learn musculoskeletal anatomy, and thus MR could be used as an alternative learning tool, particularly when students lack access to cadaveric dissection facilities [23]. However, Uruthiralingam and Rea (2020) and Romand et al. (2020) suggested that AR and MR could be used to supplement anatomy teaching, but not to replace traditional teaching methods [21, 62]. As many studies appear to favour the use of XR technologies in anatomical education, there is value in developing XR technologies on a broader scale and accommodating a wider range of learning styles [62]. Appendix B Supplementary provides a summary and description of studies and articles using XR in anatomical education.

Uses in Surgical Education

The potential of using XR technologies in surgical education has been widely explored to increase resident exposure to surgical procedures given the time pressures of the operating room [69,70,71]. The validity and usability of VR, AR, and MR applications have been examined across various surgical specialties. Appendix C Supplementary provides a summary and description of studies and articles using XR in surgical education.

Neurosurgery

Bernard et al. (2019) developed 3D video tutorials, which enabled neurosurgery residents to view 3D anatomic structures via HMDs and learn operative techniques and nuances from the surgeon’s intraoperative point of view [72]. The majority of the neurosurgery residents indicated that the 3D VR technology enhanced their understanding of the surgical approach. Roh et al. (2021) integrated photographic 3D models into VR for neurosurgery education and reported that the residents found this technique of neurosurgical simulation helpful for improving their surgical skills and developing new surgical approaches [73]. Sahyouni et al. (2017) reported that residents found that using Google Glass for postoperative surgical debriefing in neurosurgical residency training enhanced their educational experience [74].

Otolaryngology Surgery

Mitani et al. (2021) developed 3D holograms in otolaryngological tumor resection with a mixed reality technique for attending and resident otolaryngologists to view on HMDs [75]. The use of the 3D holograms on HMDs was reported to be more beneficial than the radiological images displayed on a computer screen. Moshtaghi et al. (2015) suggested that the use of Google Glass in the context of otolaryngology has enormous benefits, such as enabling surgeons to stream the video in real time, providing an immersive learning experience for learners, and enabling learners to record their actions for self-monitoring and instant feedback. However, Google Glass has limitations in otolaryngology, including the difficulty of clearly visualizing the small anatomical structures of the head and neck on film and the challenge of wearing Google Glass in addition to loupes and surgical headlights that many otolaryngology procedures require [76].

Urological Surgery

Borgmann et al. (2017) suggested that AR headsets enable urological surgeons to record first-person videos and offer a new method for surgical education [39]. Dickey et al. (2016) examined the use of Google Glass to train urology residents. The study reported that 81% of the residents and faculty recommended implementing the AR technology in their residency program. The educational usefulness, ease of navigation, and likelihood of using the application were rated as 8.6, 7.6, and 7.4, respectively, using a 10‑point scale. There is a need for further development and validation of the AR technology for urologic surgical training [77].

Orthopedic Surgery

Cecil et al. (2018) compared the effectiveness of a haptic-based simulator and an immersive simulator for training medical students and residents in an orthopedic surgical procedure. The results showed a significant improvement in both the haptic-based simulator group and the immersive simulator group in the post-test compared to the control group, while the survey results indicated that the immersive VR-based simulator was more effective and user friendly than the haptic simulator [78]. Lohre et al. (2021) examined the validity and efficacy of using immersive VR compared to a traditional learning modality in orthopedic education. The study showed that immersive VR led to substantial increased learning improvement than traditional training [79].

Applications of XR technologies have been explored as an educational and training resource in other surgical specialties, such as ophthalmic surgery and vascular surgery [13, 80]. XR technologies have also been developed for laparoscopic surgery training [19, 81,82,83,84,85,86], and the educational effect of XR technologies has been evaluated in comparison with conventional teaching approaches [87]. In the study by Brewer et al. (2016), Google Glass was used to stream video from the learner’s system in real time to the trainer’s system when the learner was performing a simulated needle placement. The results showed that usage of Google Glass improved the accuracy of needle placement in surgical training although it did not help reduce task completion time [69]. Yoganathan et al. (2018) conducted a randomized controlled study to explore the effectiveness of using 360° VR video technology in training knot-tying skills compared to 2D video teaching. The study showed that a 360° VR video was more effective than a 2D video, both as an independent teaching tool and when supplemented with traditional teaching approaches [37]. A partially blinded randomized control trial conducted by Dickerson et al. (2019) found no significant difference between the intervention group using intraprocedural videos captured by Google Glass in immediate postprocedural resident coaching and the control group receiving only verbal coaching in terms of skill improvement. However, the interview conducted by the researchers showed that the majority of residents found point-of-view video coaching beneficial and wanted to see more integration of video coaching in surgical education [58]. Some limitations of XR technologies reported in this specific body of literature are associated with battery life, image quality, head-mounted display comfort, compatibility with surgeon loupes, and cost of development [26, 52, 74, 81].

Insights

We have reached the point where the audiovisual elements afforded by XR technologies have reached a very good level of fidelity, providing compelling experiences for most applications. The growing body of literature in this field suggests there is enormous potential for XR technologies in medical education [25]. Further studies comparing XR versus traditional delivery methods such as videos, or multimedia, will not yield much additional value to the body of knowledge in medical education, but explorations into what are the most pressing needs for medical training that can be best served with these solutions are still needed. The research question these days is not whether XR is comparable or even superior to traditional media for medical education, but where and how it should be deployed for maximum impact. For instance, Rizzetto et al. (2020) has suggested that randomized studies involving adequate cohorts are needed to assess not just the user’s satisfaction but the concrete benefits of XR systems in comparison with other novel tools [35]. The research question in the near and intermediate future is which particular tasks are best suited, and produce the most benefit, to the use of XR technologies. For example, procedural tasks that require prescribed sequences of steps with some variations in potential outcomes appear ideal for XR simulation. 

XR may be a game-changer in medical education, as it alleviates financial, ethical, and supervisory constraints on the use of traditional medical learning materials and equipment [15]. It offers an intermediate level of fidelity between manikin simulations, traditional media, such as books and videos, and in-person training. While XR lacks the tangible aspects of manikin-based simulations, and cannot replace manikin-based simulations, the technology still opens the possibility to include contextual information that may relate to the setting where manikins actuate, from transporting the medical trainee to an emergency room, to allowing for a virtual simulation of a surgical procedure in a health practitioner's office. According to Mäkinen et al., (2020), as emerging technologies, studies comparing the ‘user’ experiences of different XR technologies are relatively limited, but a very important contributor in the adoption of such technologies in medical education [84]. Moro et al. (2017) also suggests that as the degree of realism in these simulations increases, both visual and textual, so will the load on working memory [64]. A better understanding of the psychological and cognitive workloads that XR simulations can place on users will become more significant over time and this could be a direction for future research as well.

Nowadays, the development of interactive simulations in the medical field mediated through XR parallels to a great extent the development of computer games, where teams of artists and developers work together to produce a product. Moro et al. (2017) highlight the importance of educators’ attitudes towards the adoption and use of XR technology [64]. Zweifach and Triola (2019) suggests that faculty engagement is key and recommends that faculty ‘champions’ participate in the development process, from identifying learning objectives, through system design and implementation, to validation and integration of XR technologies into education and training. ‘Multidisciplinary’ approaches to the adoption of XR in medical education are recommended in which medical educators collaborate with engineers, educationists and students to test and pilot the use of XR [12]. Together with medical faculty champions, computer scientists, digital artists, and software developers can build effective teams to further research and develop interactive medical applications using this relatively new media. 

McKnight et al. (2020) reports that multiple studies have demonstrated that HMDs can cause side effects such as nausea, headaches, and vertigo. This situation has changed to the extent that the severe effects found in the past have become rarer nowadays, allowing XR users to spend much longer periods of time wearing HMDs than what was previously possible [41]. A main factor inducing simulator sickness (e.g., the delay between head motion and the corresponding visual update display) has been greatly reduced with state-of-the-art computer systems, graphics cards, and HMDs. However, the evaluation of the side effects related to the use of XR in medical education must still be considered to find out the percentage of the population still being affected and the extent to which these effects are still a relevant limitation for most users [35]. Additionally, concerns about battery life, line of sight, and secure network access have been raised [41], and these are being actively addressed by the developers of these technologies.

Conclusions

XR technology has emerged as an innovative form of simulation-based medical education with numerous potential applications in medical education. Usage has ranged from recording procedural demonstrations for teaching, recording 3D video and POV videos for supplementary instructional materials, live POV video transmissions for observing procedural or skills demonstrations and telesupervising or telementoring, and VR-simulated environments for experiential and interactive teaching and learning in medicine. The nature and extent of evaluative evidence is growing as well, as new opportunities for applying XR technologies in different medical disciplines arise. The emerging evidence does suggest that different forms of XR technology applications have potential in creating immersive learning experiences that are engaging and lead to learning outcomes that appear to be equivalent to, or in some areas potentially more effective than, traditional methods for teaching and learning in medicine. Opportunities for adopting and using XR technologies in diverse fields of medical education are numerous, and in some knowledge and skill training areas, XR platforms may offer more cost-effective means for curriculum delivery. Further research to explore the effectiveness of XR use in medical education is needed to support potential applications of this innovative technology, including more rigorous evaluation studies that compare different types of XR systems along with traditional teaching approaches.