Immersive virtual reality methods in cognitive neuroscience and neuropsychology: the Virtual Reality Everyday Assessment Lab (VR-EAL), an immersive neuropsychological test battery of everyday cognitive functions
Authors: Kourtesis Panagiotis 
Published: February 2022

In this PhD, a technological systematic literature review of the reasons for adverse symptomatology was conducted and suggestions and technological knowledge for the implementation of virtual reality HMD systems in cognitive neuroscience provided. Another aim of this PhD was to devise a brief tool to appraise and report both the quality of software features and VRISE intensity quantitatively; such a tool does not currently exist. The Virtual Reality Neuroscience Questionnaire (VRNQ; Kourtesis et al., 2019) was developed to assess the quality of virtual reality software in terms of user experience, game mechanics, in-game assistance, and VRISE. The results demonstrated that VRNQ is a valid tool for assessing virtual reality software as it has good convergent, discriminant, and construct validity. The maximum duration of virtual reality sessions should be between 55 and 70 min when the virtual reality software meets or exceeds the parsimonious cut-offs of the VRNQ, and the users are familiarized with the virtual reality system. The VRNQ facilitates the brief assessment and reporting of the quality of virtual reality software features and/or the intensity of VRISE, while its minimum and parsimonious cut-offs may appraise the suitability of virtual reality software for implementation in research and clinical settings. However, the development of virtual reality software is predominantly dependent on third parties (e.g., freelancers or companies) with programming and software development skills. In Chapter 4, guidelines are offered for the development of virtual reality software in cognitive neuroscience and neuropsychology, by describing and discussing the stages of the development of Virtual Reality Everyday Assessment Lab (VR-EAL), the first neuropsychological battery in immersive virtual reality. Techniques for evaluating cognitive functions within a realistic storyline are discussed. The utility of various assets in Unity, software development kits, and other software are described so that cognitive scientists can overcome challenges pertinent to VRISE and the quality of the virtual reality software. The virtual reality neuroscience questionnaire (VRNQ) was implemented to appraise the quality of the three versions of VR-EAL in terms of user experience, game mechanics, in-game assistance, and VRISE. The final version of VR-EAL achieved high scores in every sub-score of the VRNQ and exceeded its parsimonious cut-offs. The results substantially support the feasibility of the development of effective virtual reality research and clinical software without the presence of VRISE during a 60-min virtual reality session. In Chapter 5, validation of VR-EAL as an assessment of prospective memory, episodic memory, attention, and executive functions using an ecologically valid approach is examined. Performance on the VR-EAL, an immersive virtual reality neuropsychological battery, is examined against an extensive paper-and-pencil neuropsychological battery. VR-EAL scores were significantly correlated with their equivalent scores on the paper-and-pencil tests. The participants' reports indicated that the VR-EAL tasks were considered significantly more ecologically valid and pleasant than the paper-and-pencil neuropsychological battery. The VR-EAL battery also had a shorter administration time. The VR-EAL appears to be an effective neuropsychological tool for the assessment of everyday cognitive functions, and has enhanced ecological validity, a highly pleasant testing experience, and does not induce cybersickness. In the final part of this thesis, the preparatory attentional and memory (PAM) and the multiprocess theories of prospective memory are examined by attempting to identify the cognitive functions which may predict the individual's performance on ecologically valid prospective memory tasks in the same group of participants described in Chapter 5. The results revealed that the type of prospective memory task does not play a significant role in everyday prospective memory functioning, but instead the length of delay between encoding and retrieving the prospective memory intention plays a central role. Support for the PAM and MP frameworks was found in non-focal and focal event-based tasks respectively. However, the findings, inferring a dynamic interplay between automatic and intentional monitoring and retrieval processes, agree with the inclusive approach of the multiprocess framework. Also, the role of executive functions appears crucial in everyday PM. Finally, everyday PM is predominantly facilitated by episodic memory, visuospatial attention, auditory attention, and executive functions. In conclusion, this PhD thesis attempted to show how immersive virtual reality research methods may be implemented efficiently without the confounding effect of cybersickness symptomatology in order to enhance the ecological validity of neuropsychological testing and contribute to our understanding of everyday cognitive ability.