Implicit fear-based virtual reality exposure therapy paradigm for use in low income environments

Thesis (MEng)--Stellenbosch University, 2022.ENGLISH SUMMARY: The presence of Post-Traumatic Stress Disorder (PTSD) in South Africa is an issue that only continues to grow in both severity and prevalence. The disorder affects people of all demographics and all income brackets. Often, the trauma goes untreated and develops into PTSD, causing rapid deterioration of both the victim’s mental health and those that care for them. The presence of PTSD can give rise to other anxiety related disorders, often exacerbating the situation. Each case is different to the next, with unique symptoms complicating treatment. In the South African context, the prevalence of PTSD is extremely high, with the history and social context providing a unique environment for this disorder. The frequency and severity of traumatic experiences is significantly higher in low-income areas and post-migration communities than those in safer, higher-income areas. The underlying issue stems from the disparity between the presence of trauma and the accessibility of treatment. This project focuses on the validation of a potential form of treatment for PTSD, utilizing virtual reality (VR) and the methodology of Exposure Therapy. The VR paradigm to be validated was tested on a sample population of 22 healthy participants. The paradigm itself was designed and created to be compatible with current VR technologies and meet all the necessary criteria to be used as a facilitation tool for Virtual Reality Exposure Therapy (VRET). Each participant was put through a VR simulation that was designed to consistently induce stress/anxiety while monitoring the physiological feedback of the participants. Additionally, each participant was asked a number of questions pertaining to their experience – both in the context of their sense of presence and how they were feeling at certain points in the simulation. The design of the simulation focused heavily on optimization and efficiency, hoping to reduce the risk of motion sickness and improve the overall efficacy of the paradigm. The simulation showed encouraging performance results, with the average frame time kept below 11 ms (ensuring the device maintains a refresh rate of 90 Hz). Nausea (a measurement for the onset of motion sickness) was well-controlled and almost entirely mitigated – with the largest mean for self-reported nausea being only 0.65 out of 10. Additionally, dizziness (another measurement for onset of motion sickness) had a peak mean of 1.45 out of 10. The value representative of physiological stress (the Continuous Decomposition Analysis (CDA) scores) supported the success of the paradigm. The CDA means across all participants consistently peaked at the same points in the simulation and showed meaningful significance when compared to the stimuli and their corresponding events. Furthermore, the self-reported stress and anxiety levels of all the participants support the findings from the physiological data. Unfortunately, there was no significant correlation between the Presence Score metric and any of the other variables. This study supports the efficacy and validity of the simulation as a VRET paradigm for use in the treatment of PTSD.AFRIKAANS OPSOMMING: Die teenwoordigheid van Post-traumatiese stresversteuring (PTSV) in Suid-Afrika groei tans in beide erns en voorkoms. Die versteuring raak mense van alle demografiese herkoms en inkomstegroepe. Trauma word dikwels onbehandeld en ontwikkel in PTSV, wat vinnige agteruitgang van beide die slagoffer se geestesgesondheid en dié van versorgers veroorsaak. Die teenwoordigheid van PTSV kan aanleiding gee tot ander angsverwante versteurings, wat dikwels die situasie vererger. Elke geval is anders as die volgende, met unieke simptome wat behandeling bemoeilik. In die Suid-Afrikaanse konteks is die voorkoms van PTSV uiters hoog, met die geskiedenis en sosiale konteks wat 'n unieke omgewing vir hierdie versteuring bied. Die frekwensie en erns van traumatiese ervarings is aansienlik hoër in lae-inkomstegebiede en postmigrasie gemeenskappe as dié in veiliger, hoër-inkomste gebiede. Die onderliggende kwessie spruit uit die verskil tussen die teenwoordigheid van trauma en die toeganklikheid van behandeling. Hierdie projek fokus op die validering van 'n potensiële vorm van behandeling vir PTSV, deur gebruik te maak van virtuele realiteit (VR) en die metodologie van blootstellingsterapie. Die VR-paradigma word ondersoek in 'nsteekproefpopulasie van 22 gesonde deelnemers. Die paradigma self is ontwerp en geskep om versoenbaar te wees met huidige VR-tegnologieë en voldoen aan al die nodige kriteria om as 'n fasiliteringsinstrument vir Virtual Reality Exposure Therapy (VRET) gebruik te word. Elke deelnemer is deur 'n VRsimulasie gesit wat ontwerp is om konsekwent stres/angs te veroorsaak terwyl die fisiologiese terugvoer van die deelnemers gemonitor word. Daarbenewens is elke deelnemer 'n aantal vrae gevra oor hul ervaring – beide in die konteks van hul gevoel van teenwoordigheid en hoe hulle op sekere punte in die simulasie voel. Die ontwerp van die simulasie het sterk gefokus op optimalisering en doeltreffendheid, met die hoop om die risiko van simulasie siekte te verminder en die algehele doeltreffendheid van die paradigma te verbeter. Die optimaliseringspogings was suksesvol in terme van beide die ervaring en die prestasie van die simulasie. Naarheid ('n meting vir die aanvang van simulasie-siekte) was goed beheer – met die grootste gemiddelde vir selfgerapporteerde naarheid slegs 0,65 uit 10. Boonop het duiseligheid (nog 'n meting vir die aanvang van bewegingsiekte) 'n piekgemiddelde van 1,45 uit 10. Die waarde verteenwoordigend van fisiologiese stres (die CDAtellings) het die sukses van die paradigma ondersteun. Die CDA-betekenis oor alle deelnemers bereik konsekwent op dieselfde punte in die simulasie en toon betekenisvolle betekenis in vergelyking met die stimuli en hul ooreenstemmende gebeure. Verder ondersteun die selfgerapporteerde stres- en angsvlakke van al die deelnemers die bevindinge van die fisiologiese data. Daar was geen beduidende korrelasie tussen die Presence telling en enige van die ander veranderlikes nie. Hierdie studie ondersteun die doeltreffendheid en geldigheid van die simulasie as 'n VRETparadigma vir gebruik in die behandeling van PTSV.Master