Virtual reality (VR) is a rapidly developing technology that contains significant potential for medical application. The ability to develop and deliver sufficiently realistic visuals augmented by auditory and tactile enhancements has been successfully utilized in a number of medical interventions. The areas of VR implementation include treatment of eating disorders, phobias, post-traumatic stress disorder, and a variety of physical rehabilitation programs. However, despite a number of advantages, the use of VR in the field of healthcare remains limited. This inconsistency can be partially attributed to the lack of universally accepted medical standards, high cost of equipment, and its operational complexity. More importantly, a number of human factor-related limitations can be identified in the field. These limitations include physical properties of hardware, adverse physiological effects associated with its use, and a number of undesirable psychological outcomes. These solutions need to be addressed in order to broaden the medical applications of VR.
The technology of virtual reality (VR) provides numerous opportunities for application in healthcare. However, in its current state, the technology has a number of limitations regarding human factors and ergonomics that restrict and discourage its widespread adoption. The following paper aims to identify both physical and psychological aspects of VR and determine their impact on the medical applicability of the technology.
Physical and Psychological Aspects
The technology behind VR allows for a wide variety of applications in healthcare. These applications can be described as pertinent to two broad categories. The first category includes psychological aspects of VR. The variety and flexibility of options offered by the technology can create a number of psychological effects that can enhance the effectiveness of medical interventions.
The development of eating disorders is partially attributed to social and psychological factors and the distorted perception of body image. By extension, physiological recovery from the condition requires a respective psychological adaptation. These body image distortions can be addressed by a VR-based intervention. One example of such a tool is a 3D model of a physical body incorporated into an immersive system that creates a perceived sense of physical presence. This approach has several advantages in terms of flexibility and adjustability. For instance, it permits the use of different environments to diversify the effect. Next, the 3D model can be adjusted to different scenarios (e.g. the depiction of a body before and after food intake). Finally, it allows for the manual modification of the whole model or its parts, thus further broadening the application of treatment.
Post-Traumatic Stress Disorder
Currently, exposure is among the most feasible evidence-based approaches to treatment of post-traumatic stress disorder (PTSD). However, in most cases, exposure is limited to the retelling of a traumatizing experience to the therapist. VR technology has the potential to enhance the procedure by introducing additional visual, auditory, and tactile sensations. Importantly, it also permits invoking a persuasive feeling of immersion by employing high-end computer graphics. As a result, the intensity of exposure can be amplified, leading to habituation to specific environments and scenarios. Recent studies suggest a noticeable reduction in PTSD-related symptoms resulting from the incorporation of VR technology in exposure-based interventions (Rizzo et al. 54).
Currently, the most effective approach to the treatment of phobias is cognitive behavioral therapy, which assists the patients in determining the cause of negative feelings and replacing them with positive ones. Understandably, in some cases, the setting pertinent to a specific phobia can enhance the effectiveness of treatment. However, in some cases, this can constitute a limitation due to the limited access to certain settings and scenarios. This issue can be addressed via VR technology. For instance, an individual with aerophobia (fear of flying) can benefit from a VR-simulated environment that convincingly recreates the interior of a plane, sounds characteristic of the environment (e.g. flight attendant announcements), and vibrations occurring during takeoff and landing. Such a degree of realism is able to generate emotional feedback sufficient for effective therapy. At the same time, the patient acknowledges the safety of their position, thus reducing anxiety and stress.
The second category includes potential applications for treatment of physiological conditions. This category is noticeably smaller, primarily due to the fact that VR works on the level of perception. Thus, physical applications are limited to motor rehabilitation practices.
The goal of rehabilitation is to provide qualitative and quantitative improvements in the quality of life of the patient and enable their autonomous functioning. On the other hand, it necessitates the establishment of reliable monitoring practices for patient recovery progression. In this light, the effect of VR inclusion is twofold. On the one hand, it allows generating environments that are both safe and aesthetically pleasing, thus creating a suitable setting for rehabilitation. On the other hand, it does not interfere with measurement procedures, providing reliable data in a timely manner. The latter is especially relevant as the monitoring and evaluation procedures can be improved through the use of a VR set.
The data obtained from the session can be logged and processed using the VR software and excerpts from it can be fed directly to the patient’s headset. At the same time, computer-generated imagery can be utilized to depict otherwise unrealistic scenarios suitable for a specific condition. As a result, VR provides a motivating, functional, and purposeful setting and introduces a range of otherwise unavailable tools and strategies.
In addition to the challenges described in the previous sections, stroke rehabilitation introduces a further challenge of disrupted neural functioning. Patients recovering from this condition commonly require specific, low-impact activities in order to form new neural connections. In many cases, these activities are limited to manipulation of small objects. Traditionally, such an object is manipulated on a screen using human interface devices (HID). However, this approach limits the interactions to a two-dimensional plane, significantly reducing the effectiveness of the approach. Virtual reality addresses this limitation by providing the opportunity to manipulate the on-screen items in all directions using respective motor responses. In some cases, the effect can be enhanced by increasing the sensitivity of the equipment. Additional confidence gained from observing the amplified result (e.g. extended limb movement) will increase the likelihood of spontaneous use of the affected limb, leading to a complete recovery.
As can be seen, the technology behind VR offers a wide variety of opportunities for improvement of medical interventions. However, despite the commercial availability of solutions, the number of real-world use cases remains low. To a certain degree, this gap can be attributed to financial restraints faced by healthcare providers. Due to specificities of funding schemes, the level of competition among medical organizations remains prohibitively high, limiting the use of expensive VR equipment. At the same time, patient populations tend to seek cost-effective solutions, discouraging the clinicians from incorporating VR into treatment programs. It should also be pointed out that the technology used for medical purposes needs to comply with certain standards of safety and quality. While VR is compliant with these standards in some areas, its full compliance with all medical standards would require further modifications. Understandably, these enhancements will inevitably increase the complexity of the solution and, by extension, slow down the adoption.
In addition to the generalizable issues identified above, the use of VR presents several clusters of technology-specific limitations pertinent to the field of ergonomics and human factors. The first group includes limitations posed by physical properties of the equipment. The second group covers physiological reactions of patients to certain effects of the technology. Finally, psychological factors involve behavioral and cognitive issues resulting from VR usage.
The first limitation of medical VR use is the physical discomfort induced by the use of VR equipment. The delivery of the visual aspect of a program is done with the help of a headset mounted on the patient’s head, which involves a certain amount of effort to maintain the correct posture. Admittedly, modern VR headsets are relatively lightweight, making the issue negligible for the majority of patients. However, in some scenarios (e.g. as a part of a stroke rehabilitation program) patients may experience discomfort from excessive muscular strain.
A similar effect can be produced by human interface devices such as haptic manipulators. As with VR headsets, several prototypes of relatively unrestrictive haptic devices are available on the market. Nevertheless, some interventions require specific equipment that can be restrictive to the patient. Some of the instances of discomfort are created as a result of posture demands required by the intervention. For instance, manipulating objects may require specific arm positioning, which can be challenging for certain individuals, thus diminishing the effectiveness of therapy.
It is also necessary to recognize the limitations of equipment fit. Certain parts of VR can be adjusted to accommodate for different individual parameters. However, in some cases, engineering requirements introduce limitations, rendering the equipment unusable for wider audiences. Currently, this limitation can be circumvented by purchasing several sets of hardware, which introduces additional expense.
Next, the use of VR equipment is associated with hygiene concerns. In order to interact with the program, the user needs to come into physical contact with the hardware. As a result, the surface of the equipment can become the source of bacterial, viral, or fungal infection. While the equipment can be sterilized, the procedure is complicated by the complexity of the construction and properties of surfaces. The medical use of VR requires its use by multiple patients within a short time span, further aggravating the issue.
Finally, some of the core advantages of the technology can create additional difficulties. Specifically, the immersive nature of a simulation can distract patients to a degree where they become disoriented and lose track of their immediate physical environment. Such a scenario introduces the risk of immersion injuries resulting from collisions with the environment (Jerald 112). This limitation can be addressed by introducing physical restraints. However, such an approach also compromises the immersion effect, decreasing the effectiveness of the intervention.
One of the most recognized limitations of VR is its ability to induce the effect known as ‘virtual reality sickness’ (Diels and Howarth 595). The common effects of VR sickness are generally consistent with those of motion sickness and include fatigue, nausea, vomiting, disorientation, and drowsiness (Diels and Howarth 598). Importantly, VR sickness can be induced via self-motion based on visual perception. The discomfort caused by the condition may compromise any psychological benefits of the intervention.
It is also necessary to acknowledge the limitation associated with the use of stereoscopic displays in VR headsets. Specifically, focusing on a virtual object in a setting with a fixed viewing distance between the patient and the virtual object (accommodation) may conflict with the convergence of the eyes on an object. These processes are closely linked on a physiological level, leading to the dissociation of accommodation and convergence (Hua and Javidi 27). This phenomenon produces a range of undesirable effects, such as eyestrain, visual and binocular stress, and changes in points of convergence (Hua and Javidi 28). These effects compromise the quality of interventions and may create additional difficulties for patients.
Finally, a number of cognitive and behavioral limitations should be recognized. The most apparent one is the cognitive effect of distorted perceptual judgment. VR technology relies on perceptional specificities that create visual perceptions that correspond to physical positioning. However, the accuracy of the effect is limited by the current operational capacity of the technology. As a result, some of the perceptions developed during the session can become a significant distraction factor in the physical world. The effect can be especially prominent in programs that utilize amplification of motion or involve active movement sections (Coyle et al. 337). In most cases, the duration of the effect is relatively short. Nevertheless, its adverse effect on patient comfort should be acknowledged.
A number of behavioral effects also constitute a significant limitation. For instance, certain VR programs designed to induce pleasant sensations and experiences affect pleasure centers of the nervous system. In some cases, frequent usage can lead to the development of a psychological addiction (Berridge and Kringelbach 649). In addition, the immersive nature of VR can lead to mood changes, dissociative disorders, and perceived isolation. Finally, the overwhelming emotional, sensory, and cognitive response to VR-enhanced imagery may also result in perceptual shifts, thus contributing to stress.
As can be seen, current limitations are based largely on the state of technology. Thus, it is reasonable to expect an increase in adoption once some of these limitations are addressed by enhancements of existing tools or the introduction of new ones. For instance, it is possible to expect a wider use of VR in studies on human perception. Currently, the research in this area is restricted by the physical limitations of the environment, with associated technical and ethical issues. The perceptional basis of VR offers two advantages beneficial for the field. First, it provides a relatively inexpensive, safe, and accessible alternative to costly physical-based simulations. Second, it allows incorporating measurement and analysis of data in real time, opening up new possibilities for researchers.
Another viable area of application is in education and training of medical professionals. This option is an extension of existing approach that delivers simulated environments and scenarios using computer screens. The immersive effect of VR, coupled with the use of haptic interfaces, can greatly increase the applicability and efficiency of training and increase the variety of training programs.
Despite significant recent improvements, the adoption of VR in healthcare remains relatively low. Such scarcity can be partially attributed to human factor-related limitations of technology. At the same time, it is apparent that the technology contains massive potential for a diverse range of medical applications. Thus, it is necessary to address the identified limitations as quickly and effectively as possible in order to incorporate more VR into medical practices in the future.
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Diels, Cyriel, and Peter Howarth. “Frequency Characteristics of Visually Induced Motion Sickness.” Human Factors, vol. 55, no. 3, 2013, pp. 595-604.
Hua, Hong, and Bahram Javidi. “Augmented Reality: Easy on the Eyes.” Optics and Photonics News, vol. 26, no. 2, 2015, pp. 26-33.
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