Institute For Biomedical Engineering (IBE)

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Browsing Institute For Biomedical Engineering (IBE) by Author "Du Plessis, Stefan"

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    Utilizing virtual reality as a therapeutic tool psychiatry
    (Stellenbosch : Stellenbosch University, 2022-04) Du Plessis, Stefan; Van den Heever, D. J.; Schreve, K.; Rosenstein, D.; Stellenbosch University. Faculty of Engineering. Institute of Biomedical Engineering.
    ENGLISH ABSTRACT: The mass production of modern cellphone technology has resulted in a dra matic cost reduction of producing Virtual Reality (VR) head-mounted dis plays. Although VR has been effective in the treatment of phobias, uptake is still far from mainstream. Fear of heights (i.e. acrophobia) is one of the more common forms of phobias in the general population. Up to 28% of people have distress and anxiety when exposed to heights (i.e. visual heights intoler ance (VHI)), with up to 6% of people meeting clinical criteria for the specific phobia. Virtual Reality Exposure Therapy (VRET) for acrophobia has been shown to be effective as early as the 1990s. There are, however, still relatively few randomized controlled studies that have looked at its effectiveness . Even fewer studies look at physiological responses associated with fear cessation. Biofeedback is the process of presenting participants with their physiological responses allowing them to gain a measure of control over them. Biofeedback shows promise as a treatment adjunct for specific phobias. We therefore aim to create a VR height exposure platform, that offers a graduated exposure, is optimized to avoid excessive motion sickness, is cost-effective for widespread use, and is validated by participant reports collected during the exposure. Here we developed and tested a cost effective VR acrophobia environment with biofeedback in a sample of 22 participants, 4 of whom had clinically measurable acrophobia. We constructed an Electrodermal Activity (EDA) biofeedback prototype using two Arduino boards, one being electrically isolated (Nano) to reduce noise and increase safety. The second Arduino (UNO R3) was con nected via USB to a VR workstation running the Unreal Engine 4.24.2. USB connectivity was established via the UE4duino plugin. All participants un derwent clinical screening, excluding for confounding psychopathology except acrophobia. Acrophobia symptoms were evaluated using the Visual Height Intolerance Severity Scale (vHISS) questionnaire. Participants were placed on a VR platform which ascended to 28 meters. Subjective stress responses were recorded during the task as well as VR related motion sickness. Data was en tered into a repeated measures ANOVA to check for within-subject differences in levels of stress, comparing when the platform was on the ground as well as in the air. Afterwards participants experiences were evaluated via a brief questionnaire. Biofeedback based on the mean of the signal consistently informed participants that they were stressed while the platform was elevated. Participants showed a significant increase in mean skin conductance signal while the platform was elevated. Continuous decomposition analysis as well as subjective responses confirmed the accuracy of the biofeedback provided. All participants reported a positive experience using the biofeedback, most perceiving it to be accurate. The present work indicates that biofeedback in VRET is a promising treatment adjunct, which should be explored in further clinical trials.