Using Virtual Technology for Fear of Medical Procedures: A Systematic Review of the Effectiveness of Virtual Reality-Based Interventions

Abstract Background Innovations in virtual reality (VR) technologies have improved the adaptability of its use in therapeutic settings, and VR has shown to be a promising treatment for fear of medical procedures, with research increasing in this area in recent years. Purpose This review aims to collate evidence for the impact of VR on fear of medical procedures. Methods CENTRAL (Cochrane), MEDLINE, EMBASE, and PsychINFO databases were searched up to October 2020. A mix of experimental and case–control studies were included for review, which evaluated the effectiveness of VR for fear, anxiety, and pain of medical procedures for people with needle phobia, dental phobia, claustrophobia of medical scans, and burn wound care anxiety. Risk of bias (RoB) was assessed by Cochrane and ROBINS-I tools. Results Twenty-eight studies were selected. Some studies included mixed participant groups of young people adults. The interventions varied, with VR used for distraction, hypnosis, or exposure. These were shown to be effective for reducing fear of medical procedures. However, effectiveness for blood-injection-injury phobias and burn wound care patients was unclear. Conclusions Evidence on the effectiveness of VR suggests that it does decrease fear of medical procedures in some situations. However, the RoB assessment illustrated a poor quality of studies across those included in this review, limiting the ability to draw firm general conclusions from the study findings. There is a need for further research exploring the use of VR technologies in the management of anxiety in physical health care settings.

Fear of medical procedures is a significant problem for patients and health care professionals. Indeed, many patients experience such fear of medical, dental, or surgical procedures and refuse to participate in procedures or avoid appointments entirely as a result [3]. Procedural anxiety is frequently recognized in people who need to take part in medical procedures regularly (e.g., Byers et al. [4]). Due to their constant exposure to these procedures, patients may attend their treatments with a recurrent experience of significant anxiety, sometimes associated with previous negative experiences [5].
Research recommends several techniques for patients with a fear of medical procedures. These include distraction techniques, such as listening to music or using imagery, relaxation techniques, and exposure therapy with patients who experience this fear [6]. In addition to these techniques, there is a growing interest in the application of VRT.

Description of Intervention
VR is a form of computer technology (including a headmounted display devices with headphones, screens, and monitor-tracking devices) that recreates life-like settings in a digitalized world and provides an opportunity for people to actively interact with this new environment [1]. Studies of VR for fear of medical procedures, broadly speaking, use it in one of two ways: (a) as a form of distraction or (b) as a type of exposure method. The first type of intervention aims to connect individuals' attention to a different environment, thereby decreasing possible thought processes regarding the medical procedure. This could also be achieved by providing hypnosis via VR. On the other hand, VR interventions for the use of exposure, often referred to as virtual reality exposure therapy, aim to gradually expose people to the feared stimulus so as to decrease their anxiety toward the medical procedure. Essentially, both approaches are meant to reduce fear and anxiety, the first by blocking contact with the provoking situation, and second by reducing the capacity of situations to generate these feelings.

How the Intervention Might Help VRTs for Dental Phobia
Dental phobia, also known as dentophobia or odontophobia, is the persistent and unreasonable fear of dental objects and situations, which is estimated to affect 11% of the UK population whilst nearly half of the adult population expressed feeling moderate to high levels of anxiety from dental treatments [6][7][8][9][10] also suggest that dental phobia is the most prevalent subtype of specific phobia.
Individuals with dental phobia avoid common dental treatment procedures, which negatively impacts their oral and general health by reducing dental attendance and uptake of dental care [11]. Effective management of dental phobia is crucial to improving oral health and quality of life. While researchers focused on the usage of VR to distract the patients' attention away from the dental procedures to reduce the fear [12,13], some researchers have recently started to work on using exposure therapy through VR [14].

VTRs for BII Types of Phobias
It is estimated that approximately 3% of the population experience needle or injection phobia (also named trypanophobia). BII phobia is another specific phobia characterized by extreme anxiety in relation to treatments involving one or all of these elements [15]. Due to the intense fear experienced, individuals avoid seeking medical or dental care, following recommended treatment, or providing blood for needed blood tests [16]. Because these are necessary for health and can even be lifesaving, treating needle phobia to improve patients' adherence to appropriate health behaviors and recommendations for medical treatments is crucial.

VRTs for Claustrophobia in Magnetic Resonance Imaging Screening
It is estimated that approximately 3% of the population experience anxiety when in a confined space, such as small rooms, lifts, tunnels, or public toilets [17]. Claustrophobic individuals may also experience restriction and suffocation fear as well as some characteristics of panic disorder or agoraphobia [18]. Many magnetic resonance imaging (MRI) devices include entering a small tunnel-like chamber, which can cause phobic responses in claustrophobic individuals. Due to this fear, participants may experience significant fear and anxiety whilst undertaking a scan or they may refuse to complete their MRI screening, posing potential threats to diagnostic ability of the medical team [19]. Many patients with a fear of MRIs control their anxiety by taking sedatives or using distraction techniques, such as listening to music or trying relaxation exercises. VR provides another mechanism to help patients manage anxiety during MRI scans. In a case study conducted by Garcia-Palacios et al. [19], the use of VR to distract individuals was found to be more effective than listening to music as a distraction method. Furthermore, individual's anxiety levels significantly decreased compared to no distraction and the music distraction.
It is known that the experience of pain is strongly affected by psychological factors [20,21]. It is common for burn patients to feel anxious and fearful about their daily wound care (cleaning and removing of the dead tissue) as wound care is associated with significant pain. Therefore, many patients have found it beneficial to use distraction techniques during their daily wound care in order to focus less on the pain and reduce related discomfort and distress [22]. The interactive and immersive nature of VR is recognized to decrease conscious attention to the medical procedure, thereby reducing the experienced pain by burn patients [23]. Indeed, Hoffman et al. [24] demonstrated that burn patients who participated in a virtual game using VR reported a decline in their perceived pain compared to patients who played Nintendo (e.g., a 2D game) while staples were removed from their tissues.

Why This Review is Important
As demonstrated through the aforementioned literature, fear of medical procedures may cause individuals to avoid medical procedures due to the experience of anxiety and distress. Preliminary empirical studies show that VRTs may provide an effective treatment method to help patients with these negative experiences. Previous systematic reviews and meta-analyses [25][26][27][28] also support this claim. As VR technologies and published studies for medical procedures using VR have dramatically increased in recent years, an update is needed. Therefore, this review aims to explore the use of VR techniques and their effectiveness for reducing or managing the fear of medical procedures. Due to significant heterogeneity expected among the included studies, a meta-analyses was not performed.

Objectives
This review aims to summarize the effectiveness of VR in therapeutic settings for reducing the fear of medical procedures in the general population, specifically among: dental fear (dentophobia), fear of needle (trypanophobia), claustrophobia for magnetic resonance imagining (MRI), and burn wound care anxiety. These procedures were chosen due to representing the most common fears of medical procedures.

Protocol and Registration
This review is based on the guidelines set out by the Cochrane Handbook for Systematic Reviews of Interventions [29] and the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement [30]. This study is registered to the PROSPERO system (www.crd.york.ac.uk/prospero/; registration number CRD42019152327) and can be found online.

Types of studies
This review collected evidence from experimental and case-control studies on fear of needles and claustrophobia related to MRIs. Only experimental designs were included for the studies on dental fear and burn wound care anxiety (see Supplementary Appendix A). Studies without a full-text report (e.g., only having a conference abstract) were excluded from the review.

Types of participants
This review included people who were reported to experience fear, anxiety, or pain during medical procedures. There were no age, gender, or country restrictions for the included studies. Some of the studies had heterogeneous age groups, which included children and young people (0-18 years old) and adults (over 18 years old) together. Thus, while interpreting the study findings, age groups were not separated.

Types of interventions
Studies that mentioned the use of VR or immersive VR were included in the review. VR or immersive VR used for distraction, hypnosis, or exposure to the distressing stimulus/situation was included in this review. There were no differentiations for the types of VR settings, such as playing a game or observing a virtual environment. The intervention needed to be assessed in one or more sessions in order to meet inclusion criteria. Studies with other type of technologies (such as computer games without any kind of VR goggles etc., or telehealth) and traditional therapies (e.g., cognitive behavioral therapy) without the use of VR were excluded. Furthermore, there were no restrictions for who delivered the interventions (e.g., researchers, nurses, psychologists, dentists, and/or others).

Types of comparators
All studies required a comparison to baseline outcome measures (e.g., anxiety), to demonstrate change pre-use/ postuse of VR. Studies for fear of needles and claustrophobia for MRI did not require a control group; however, this was stipulated for case-control studies on dental fear and burn wound care, typically comparing against usual care for procedural anxiety management (e.g., distraction techniques, reassurance, and challenging negative thoughts, using imagery, using relaxation techniques, sedatives, and exposure therapy).

Types of outcomes
The main outcomes of this review were: experience of fear during a medical procedure, experience of anxiety during a medical procedure, and experience of pain during a medical procedure. These outcome measures were chosen due to being the most commonly reported outcome measures in studies from preliminary literature searches. Anxiety and fear were included as separate outcomes due to reporting approach of included studies (e.g., usage of different scales to measure anxiety and fear). Any study with at least one or more of these outcomes were included. The study outcomes were expected to be measured by validated questionnaires, such as Visual Analogue Scale [31] for anxiety. Studies using only interviews or qualitative assessments to measure the study outcomes were excluded from this review.

Setting
Included studies were conducted within settings that required individuals to receive a medical procedure.

Language
Included papers were restricted to those written in the English language or had full English translations; papers with English abstracts without full English texts were excluded.

Electronic searches
This review searched Cochrane Central Register of Controlled Trials (Central) and OVID databases, which are MEDLINE, EMBASE, and PsycINFO. Medical Subheadings (MeSH terms) were used to determine proper search terms; after peer review, the search terms outlined in Supplementary Appendix B were used for the database search.

Selection of studies
All study selection procedures were conducted by two independent reviewers (A.K. and A.B.). The studies searched through CENTRAL, EMBASE, MEDLINE, and PsycINFO up to October 2020 and merged into the reference management software, EndNote X8 (Clarivate Analytics, 2017). After data collection, the duplicates were first detected and removed by EndNote before manual deduplication. After screening for duplicates, eligibility criteria were assessed by title and abstract. The articles that did not include VR or target medical procedures were rejected and were not included in the full-text screening. Only papers that were identified as eligible for the full-text assessment were assessed for selection, and suitable studies were included in the review.

Data extraction and management
A data extraction table, which was informed by Cochrane [29] and PRISMA guidelines [30], was used to extract information from the selected studies. The main characteristics of the studies were tabulated to summarize the data Table 1.

Assessment of risk of bias in included studies
The possibility of having risk of bias (RoB) in the review was acknowledged and assessed using the "RoB" tool for randomized studies by the Cochrane Collaboration [29] and ROBINS-I for nonrandomized studies [32] (see Supplementary Appendix D).

Data synthesis
The studies were mainly grouped according to the relevant medical procedure (dental anxiety or pain, claustrophobia during MRI, burn wound care, and BII/needle phobia). Within these categories, the studies are summarized for their effectiveness on decreasing fear, anxiety, and pain in relation to the procedure. SWiM guidelines [33] were followed, and Cohen's d effect sizes [34] and 95% confidence intervals were calculated for providing a narrative synthesis (see Table 1 and Supplementary Appendix E). A meta-analysis was not carried out due to the heterogeneous nature of the included studies in line with study protocol. Figure 1 illustrates relevant studies identified through the database search performed independently by A.K. and A.B. Cohen's Kappa agreement [35] between the independent reviewers was substantially high (0.85). In total, 28 studies included for qualitative synthesis.

Included studies
This systematic review only shared 25% or less of similarity for the included papers with previously mentioned reviews. Included studies were conducted in the following countries: the USA (n = 8), Australia (n = 4), Canada (n = 3), India (n = 3), Netherlands (n = 2), Turkey (n =2), Finland (n = 1), Iran (n =1), Malaysia (n =1), Syria (n =1), Taiwan (n =1), and the UK (n =1). Of the included studies, a total of 1,652 people participated. The mean sample size of these 28 studies was 59 participants (range 2-255 participants per study). No age restrictions were imposed within the inclusion/exclusion criteria; therefore, this review illustrated a heterogeneous age group, ranging between 2 months to 80 years old. The main outcomes of the included studies were anxiety (n = 15), fear (n = 5), and pain (n = 23). Furthermore, the guiding theoretical framework of the included studies was mostly based on distraction (n = 25), followed by hypnosis (n = 2) and exposure (n = 2). The included studies used a wide variety of devices for creating a virtual world for the study participants (see Supplementary Appendix C). Studies involved various kinds of VR environments, including computer games (n = 14), natural environments (n = 5), cartoons (n = 4), adventure rides (n = 2), or outpatient clinics (n = 2).

RoB in included studies
The overall quality of included studies was low for randomized and nonrandomized studies (see Supplementary Appendix D for further information).

Dental phobia
Eight studies including 771 participants investigated the use of VR for distraction for dental phobia, whilst only one study used VR for exposure. Young people (n = 3) and adult (n = 5) samples were used in included studies and no differences were seen between them. The main study outcomes of these studies were pain (n = 6) and anxiety (n = 7; see Table 1). Studies used VR during dental procedures (e.g., periodontal scaling or root planning; n = 7) or to treat dental anxiety (n = 1).
All studies used the VR distraction method for the pain outcome. Nearly all these studies showed a significant decrease in experienced pain during VR, with only one study indicating no significant difference (p = .54). It seems that the use of VR as a distraction during a dental procedure may decrease experienced pain.
The outcome of anxiety was assessed by VR studies for both distraction and exposure, all of which demonstrated statistically significant decreases in the experience of anxiety for VR groups. Studies showed that VR used as a distraction, as well as for exposure, were both effective in decreasing the experienced anxiety relating a dental procedure.

The BII types of phobia
There were seven studies including 542 participants that investigated the use of VR for distraction (n = 6) or exposure (n = 1) for BII phobia. None of the studies reported the use of VR for hypnosis. Nearly all studies included child samples, whilst only one study included an adult group ranging between 18 and 48 and a mixed age group ranging between 10 and 21 years. The main study outcomes were pain (n = 6), fear (n = 4), and anxiety (n = 4). The VR distraction was used for various injection-related procedures (e.g., blood withdrawal or immunization).
Conflicting findings emerged. While some studies with a non-VR or usual care control (n = 4) reported statistically significant decreases for pain, studies with an active control (e.g., watching television, the Child Life program, and standard care distraction; n = 2) did not find any statistical differences between the groups. Similar trends were also seen in fear and anxiety outcomes. The use of VR as a distraction was an effective method to decrease the experience of pain, fear, and anxiety among participants for the fear of injection phobia. However, these improvements were no better than other active distraction techniques.

Claustrophobia in MRI screening
There was only one study [19] that investigated the use of VR for claustrophobia during an MRI scan. The main study outcomes were fear and anxiety using an anxiety rating scale and a behavioral avoidance test to measure outcomes. Two participants who were 25 and 49 years old were included as participants. VR or listening to music were used as distraction methods. Results illustrated that VR used as a distraction reduced the claustrophobic fear during the mock MRI, but music distraction alone did not.

Burn wound care
There were 11 studies with 334 participants that investigated the use of VR for distraction (n = 10) and hypnosis (n = 1) during the treatment of burn wound care. The use of VR for exposure was not applicable as a technique for the burn wound care population. Young people (n = 6), adult (n = 3), and mixed (n = 2) samples were used in the included studies. The main study outcomes were pain (n = 11) and anxiety (n = 4); fear was not separately reported in any of the studies. VR was used as a distraction method during the changes of dressing or the removal of dead skin tissue.
Nearly all studies (n = 9) reported that the VR distraction group demonstrated statistically significant decreases in the experience of pain. Only two studies indicated that VR did not result in any change on the experience of pain. Additionally, one study reported that, even though VR decreased the experience of pain, this decrease in pain was not significantly different from watching television as a form of distraction. Moreover, none of the studies reported statistically significant decreases in the experience of anxiety. Overall, the effectiveness of VR used for the application of distraction among burn wound care type of medical procedures consistently demonstrates improved pain outcomes, though results are mixed in its ability to reduce anxiety.

Effectiveness of VR in Overall Study Outcomes and its Comparison to the Degrees Field of View of the VR Goggles
Standardized mean differences by using Cohen's d [34] were calculated for posttest scores of fear, pain, and anxiety outcomes. Studies are grouped under four categories [34,63]: small (0.2), medium (0.5), large (0.8), and very large (1.30).
Overall outcomes mostly demonstrated small effect sizes, followed by large, very large, and medium effect sizes. It is important to note that some of these small effect sizes were found in the comparison of control to distraction techniques (e.g., TV vs. treatment as usual; see Table 1 and Supplementary Appendix E). VR usage showed larger effect sizes for decreasing fear, pain, and anxiety outcomes in comparison to usual care or other distraction techniques.
No trend was found between the field of degree and effect sizes. However, careful consideration is needed for this finding as not all studies provide detailed information about the VR equipment used.

Discussion
The main purpose of this systematic review was to investigate the current evidence on the effectiveness of VR-based interventions for reducing fear, pain, or anxiety of medical procedures. This review specifically focused on VR used for dental phobia, BII phobias, claustrophobia during MRI scans, and burn wound care. Twenty-eight research papers were selected based on the inclusion/exclusion criteria developed. Although the number of the studies was limited within each setting or condition, most of the studies showed significant reduction for the experience of fear, anxiety, or pain among participants. However, although the reduction in pain was clear for burn wound care studies comparing VR versus standard care, this reduction was not clear for the BII phobias and burn wound care when compared to active control.
The selected studies were heterogeneous with respect to patient groups, age, the study outcomes, and the study designs. Also, the RoB assessment exhibited significant risks across included studies in this review additionally limiting the ability to draw firm general conclusions.
Dental phobia has been associated with psychosocial impairment as a consequence of avoidance of dental care, resulting in deteriorating oral health [64,65]. Berggren and Meynert [66] described the vicious cycle of dental anxiety: dental fear (often compounded by feelings of embarrassment) leads to the avoidance of dental care, which results in poor oral health, and poor oral health results in the need for more invasive (and typically more painful) dental care. Therefore, it is necessary to find a solution on how to best treat dental anxiety and phobia to prevent poor oral health in the future. As the literature points out, the complexity of the multifactorial etiology of dental anxiety, compensation for these factors seems to be a more efficient strategy to tackling the root cause (i.e., distraction works to increase better coping without necessarily overcoming the underlying fear). In this way, VR provides the tools to not only distract the patients' attention from the procedure but also decreases the vividness of procedural memories especially in highly anxious people [44].
Clear negative cognitive impacts in the cycles of care can also be seen in procedural phobias (BBI phobias and claustrophobia during MRIs). Studies show that, after the hereditary factors, early traumatic experiences are thought to be the second highest reason for the acquisition of procedural phobias, which is also in line with conditioning theory [67,68]. Similarly, this vicious cycle can be seen in the wound care: an early bad experience during a dressing change may lead individuals to experience increased pain and anxiety, which may then lead to the experience of increased anticipated anxiety [69] and higher pain perception. Increased anticipation of pain and anxiety may increase the chronic stress levels and this recurring theme would demonstrate itself in subsequent further pain and anxiety [70]. Upton [71] also shows that increased anxiety can decrease the tolerance and pain threshold, which would eventually make people more prone to experiencing greater pain. Therefore, VR may be an effective tool for its application to health care settings in order to decrease the chance of developing a vicious cycle of care and help decrease fear of medical procedures, ultimately increasing the quality of life.
Various methodologies, such as traditional distraction or exposure, have been used for the treatment of fear of medical procedures, and the effects of these methods, such as watching a movie, on pain, anxiety, and fear outcomes may be limited. In contrast, the use of VR from the earliest session may provide more immersive distraction possibly through emotional, cognitive and attentional processes (see Li et al. [72] for further discussion), which may lead to decreased pain and anxiety, along with the reduction of the chances of entering the negative cycle of medical phobias described above. Although the use of VR for the fear of medical procedures seems promising [73,74], some studies show inconsistent results. Therefore, it is important for future research to invest in the application of VR to health care settings to better understand it's potential role.
This systematic review followed the Cochrane and PRISMA guidelines for conducting a systematic review and published a protocol before conducting the systematic review, which increased the transparency of the study findings. Cohen's Kappa agreement [35] between the independent reviewers indicated a high reliability for the inclusion of studies. However, this review provides only a narrative synthesis of the included studies and included case-control studies for some medical procedures (e.g., claustrophobia for MRI); therefore, some caution is needed when making interpretations or generalizations from these findings. Unfortunately, due to the limited research in the area and, therefore, the consequential heterogeneity of the included studies, meta-analyses could not be performed. Therefore, firm recommendations for clinical protocols are not possible at the present time.
VR-based interventions may reduce the anxiety and distress patients experience during medical procedures. Therefore, investigating its effectiveness is important for improving methods within the health care system. This systematic review revealed that VR-based interventions used distraction, hypnosis, or exposure, with the majority of studies utilizing VR for the purposes of distraction. Future research might usefully focus on its use for exposure and hypnosis techniques. Moreover, the most investigated medical procedure treated with VR was burn wound care. One may conclude that the use of VR for distraction as pain relief is more applicable to wound care over other procedures that are not necessarily associated with pain (e.g., MRI scans). Therefore, it is evident to say that there is a need for investigating other types of medical procedures, such as VR usage, for claustrophobia in MRI. Furthermore, VR research is closely affected by the technological innovations, which may increase patients' involvement with the virtual world. In 2020, the VR market was forecasted to grow about 19 million dollars [75]. Accordingly, the worlds' largest technology companies increased their shares spent on research and development expenditures of VR technologies [75]. Thus, it is expected that VR will become more immersive and cost-effective in the future due to this competitive mass marketing, which may increase analgesic effectiveness [76,77]. Consequently, researchers need to follow technological innovations closely and implement these techniques in a clinical setting in order to use the most up-to-date and effective technologic innovations.
The use of VR technologies for the fear of medical procedures may influence clinical practice in future. If future studies support the findings of this systematic review, the application of VR systems to health care policies or within the NHS could improve patients' satisfaction and decrease the amount of money spent on other traditional methods (such as cognitive behavioral therapy for reducing fear). Moreover, further application of VR technologies to the health care settings could improve adherence to medical procedures and health-related quality of life by allowing visits to a hospital or a health center to be a less fearful and more desirable experience.
In conclusion, the use of VR-based interventions appear effective to reduce the fear of medical procedures in some situations. However, the number of studies for different types of medical procedures were limited. Heterogeneity across studies was high, and methodological quality relatively low, meaning there is considerable RoB. Funding studies that can test the effectiveness of the new, more distracting VR systems in larger randomized controlled trials may lead to interventions that improve procedure acceptability, reduce negative patient outcomes (e.g., fear, anxiety, and pain), and reduce service costs. Thus, findings outlined in this review are clearly encouraging and point to future question to address.

Supplementary Material
Supplementary material is available at Annals of Behavioral Medicine online.

Compliance With Ethical Standards
Authors' Statement of Conflict of Interest and Adherence to Ethical Standards We have no known conflict of interest to disclose. We the undernamed declare that this manuscript is original, has not been published before and is not currently being considered for publication elsewhere. We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome. We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us. We confirm that we have given due consideration to the protection of intellectual property associated with this work and that there are no impediments to publication, including the timing of publication, with respect to intellectual property. In so doing, we confirm that we have followed the regulations of our institutions concerning intellectual property. We understand that the corresponding author is the sole contact for the editorial process (including editorial manager and direct communications with the office). She is responsible for communicating with the other authors about progress, submissions of revisions and final approval of proofs. We confirm that we have provided a current, correct email address which is accessible by the corresponding author.