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Virtual reality applications for rehabilitation of COVID‐19 patients: A systematic review

Abstract Background and Aims The COVID‐19 pandemic has changed people's lifestyles as well as the way healthcare services are delivered. Undoubtedly, the difficulties associated with COVID‐19 infection and rehabilitation and those associated with quarantine and viral preventive efforts may exacerbate the need for virtual reality to be used as a part of a complete rehabilitation strategy for these individuals. Thus, the present research aimed to evaluate the potential uses of virtual reality for the rehabilitation of individuals suffering from COVID‐19. Methods From 2019 to March 1, 2022, a systematic search was conducted in PubMed, Cochran Library, Scopus, Science Direct, ProQuest, and Web of Science databases. The papers were selected based on search terms and those that discussed the use of virtual reality in the rehabilitation of COVID‐19 patients were reviewed. Each step of the study was reviewed by two authors. Results A total of 699 papers were found during the first search. Three papers were chosen for further investigation after a thorough evaluation of the publications' titles, abstracts, and full texts. Cross‐sectional studies, randomized controlled clinical trials, and case reports comprised 33%, 33%, and 33% of the publications, respectively. Based on the results, people suffering from COVID‐19 were the focus of two papers (66%) that employed immersion virtual reality for cognitive rehabilitation, whereas one study (33%) used non‐immersive virtual reality for physical rehabilitation. In two papers (66%), virtual reality was also offered to patients in the form of a game. Conclusion According to the results of the present research, virtual reality games may enhance functional and cognitive consequences, contentment levels among patients, and their ability to take charge of their own health care. In light of the obstacles faced by COVID‐19 patients, alterations in the delivery of healthcare, and the significance of rehabilitation in this group during quarantine, new techniques have been considered for these patients to maintain treatment, return to regular life, and enhance their standard of life.

pandemic has led to an economic crisis and a health emergency whose adverse effects are not equally distributed across sectors, regions, communities, and countries. [1][2][3][4][5][6][7] As defined by the WHO, rehabilitation refers to a combination of activities meant to improve individuals' performance and decrease their impairment. 8 Individuals experiencing COVID-19 need a combination of cognitive (like mindfulness and meditation techniques) and physical (like exercise therapy) rehabilitation, which can put public and private care systems under a burden and result in a lengthy hospitalization and a lack of sufficient access to healthcare. [1][2][3] Generally, rehabilitation is a difficult, unpredictable, lengthy, and tiresome domain that may limit patients' commitment to therapy, decline rehabilitation results, and alleviate quality enhancement. 9 Therefore, a worldwide reaction and readiness against COVID-19 are critical. Considering the short-and long-term consequences of the virus, 10 it is preferable to develop rehabilitation measures that assist patients in alleviating their manifestations and adapting to their new environment as well as the therapy. 1 In this context, many medical professionals have been obligated to employ virtual procedures and digital technologies instead of conventional ones because of the current situation. In fact, disease outbreaks and pandemics have changed people's behaviors, transformed societies, affected personal relationships, and changed global paradigms. 5,10 Telerehabilitation, active video games, augmented reality (AR), and virtual reality may all be regarded as potential strategies for preventing or responding to pandemics in this respect. [10][11][12] Telerehabilitation is an alternative method of providing everyday rehabilitation treatments to patients using information and communication technology. It allows patients to receive treatment at any time and any place. 12 The games that demand interactive physical activity in addition to passive control using typical manual controllers are classified as active video games. 11 Rather than providing entertainment, their mission is to assist recovery. Although these games may offer motivating, challenging, rewarding, and entertaining experiences while helping to improve learning, they are not specifically developed for rehabilitation applications in the traditional sense. Because these games need less computing time for 3D modeling, they are more inexpensive compared to virtual reality. Due to the lack of customization and models of rehabilitation hypothesis throughout the creation process, their distribution has been restricted. 12 In AR, real and virtual worlds are combined to allow the user to communicate with computer-generated information that has been added to the real world. 10 On the contrary to virtual reality settings, enhanced reality settings are not computerized and they are thus more inexpensive than virtual reality environments. 12 Using a computer to simulate the actual situation, virtual reality allows users to communicate with an artificial environment that looks and feels remarkably like reality. A wide range of applications is possible with this technology including therapy, surgery, education, pain management, and rehabilitation in the healthcare system. [13][14][15][16][17][18] Earlier investigations have underlined the necessity to employ various ways of delivering rehabilitation at home. 19,20 By giving feedback, extending the duration of workouts, enhancing the number of iterations, customizing activities, engagement, patients' pleasure and motivation, performance evaluation, decreasing discomfort, and increasing performance, virtual reality assists patients in doing exercise at home. 9 Additionally, virtual reality increases exercise participation by establishing sensory-motor contacts between the user and the virtual world, adapting to therapy, modifying the complexity level of workouts, following treatment, enhancing concentration and enthusiasm, assuring patient security, and managing patients.
This contributes to the improvement of patients' functioning. 12

| Literature review
Several studies have been conducted on the design and development of virtual reality in rehabilitation. In research performed by Triandafilou et al. on the establishment of a 3D virtual reality setting and multi-user network for home treatment following a stroke, more than 85% of the participants believed that virtual reality was an efficient way of encouraging repeated arm workouts and expressed a strong willingness to carry out the exercises. 21 To provide upper extremity activities for stroke patients, Qiu et al. created a virtual rehabilitation system that could be used at home. Patients who were able to use the system correctly with little help had much better function in their upper limbs. 22   Gray literature, such as books, websites, and conference articles, were searched, as well. Using the "AND" operator allowed the researchers to compare sets of words that were treated as distinct concepts.
Additionally, the "OR" operator was employed between synonymous words. The titles, abstracts, and keywords of the articles were searched.
Mesh terms were utilized in the PubMed database to search for papers.
The search strategy has been presented in Table 1. C or the identical comparison group was not included in PICO since there was no comparison group in this study.
The terms for the search were selected by the researcher. Then, the factors were retrieved from the papers chosen for analysis.
Subsequently, a comprehensive list of all the publications' references was compiled, after which the titles of the papers were reviewed.
The papers that were found to be irrelevant to the study goals were excluded. As a precautionary measure, all search processes were carried out twice. The management of the resources was carried out using END NOTE version X9 software.

| Inclusion criteria
The papers with virtual reality rehabilitation applications in the title, keywords, or abstract were chosen initially. Next, the abstracts were assessed and full texts were evaluated using assessment techniques.
The extracted papers from 2019 to March 1, 2022 included systematic reviews. Unreleased studies (gray literature), procedures, conference articles, guidelines, instructions, and reports from respected institutions were also reviewed. Quantitative and qualitative criteria were used to choose the best papers for inclusion in the reviews. Search terms might be found in the documents' titles, abstracts, or keywords. The papers had to be directly relevant to the study subject. Peer-reviewed articles were also included in the selection process.

| Exclusion criteria
The articles that included irrelevant parameters to the study objective were excluded.

| Screening
Initially, the titles of all the papers in the database were verified to ensure that they were relevant. Articles were chosen in case they met the inclusion criteria and were relevant to the study objective.
Subsequently, the abstracts of the chosen papers were reviewed.
In the next step, the papers that were totally in accordance with the study goal and the inclusion criteria were chosen, and their full texts were reviewed and assessed by the author. Ultimately, the publications discussing the use of virtual reality in the rehabilitation of COVID-19 individuals were selected. The papers were assessed according to the PRISMA guidelines. Citation and print bias were also considered, and the papers featuring high citations were meticulously assessed. All the abovementioned stages were repeated twice.

| Data collection
Based on the summary and collection forms created using Microsoft Word 2016 software, the necessary data were retrieved from the articles after they were carefully read and discussed. This form included parts for the title, corresponding author, research aims, study population, study sample, country, year, study design, tools, methods, results, and conclusion. The summary forms were completed for each of the selected papers. Once the two authors finished evaluating all the papers, all the forms were evaluated and shown in a table. In case of disagreements, other authors were asked to give their opinions.

| Ethical consideration
The informed consent form is not applicable in this study. Ethical considerations, including logical and scientific analysis of the articles, were also done without any bias.

| RESULTS
After extensive searching, 699 papers were extracted from the databases. Nevertheless, 68 papers were excluded due to their duplication in many databases. Additionally, 436 articles were excluded because their titles were irrelevant to the study objective. Following a thorough evaluation of the remaining 195 abstracts from the previous stage, 147 papers were deemed unsuitable for inclusion in the investigation. In the end, 10 full-text articles were selected for the research. Among these 10 publications, only 3 met the research objectives. The paper selection process has been shown in a flow diagram in Figure 1.
An overview of the types of the extracted papers has been presented in Table 2. Accordingly, one paper was a cross-sectional study (33%), one paper was a Randomized Controlled Trial (RCT; 33%), and one paper was a case report (33%).
The uses of virtual reality in the rehabilitation setting and the most often employed types of virtual reality (immersed, semi-immersed, and non-immersed) and virtual reality products (games and video clips) amongst COVID-19 patients have been highlighted in Table 3. Based on the results, people suffering from COVID-19 were the focus of two papers (66%) that employed immersion virtual reality for cognitive rehabilitation, whereas one study (33%) used non-immersive virtual reality for physical rehabilitation. Virtual reality was also offered to patients in form of a game in two papers (66%).
The three papers' full texts have been summarized in Table 4. The data include titles, corresponding authors, research aims, study populations, study samples, countries, years, study designs, tools, methods, results, and conclusions.

| DISCUSSION
Using virtual reality for the rehabilitation of COVID-19 patients has increased functional and cognitive results and has led to a higher level of contentment. [1][2][3] Recently, virtual reality has been used more commonly by doctors and investigators as an improved instrument for rehabilitation in response to healthcare expenses and patient contact. [28][29][30][31] More time and additional research are required to determine how this technology may be used during the pandemic.
In addition to organ malfunction, COVID-19 has been characterized by neurological impairments, apnea, undernourishment, and   developing cost-effective AI and AR products; providing sufficient infrastructure; improving computer literacy and educating the use of AI; and developing evidence-based educational content for AI.
To the best of our knowledge, this was the initial investigation on the use of virtual reality for the rehabilitation of individuals suffering from COVID-19.

| Limitations
The major drawbacks with the research were not being able to use the Embase database and only using papers written in English.

| Implications and suggestions for future study
To better understand how virtual reality may be used to help