## 1 Introduction
### Treatment  
Previous research has suggested that acute stress can decrease tolerance to sound in some individuals [21]; therefore, reducing phobic anxiety could feasibly improve both the emotional reaction to the feared sound and its perceived loudness. Current recommendations pertaining to the treatment of phobia call upon cognitive behavioural therapy (CBT) techniques, such as systematic desensitisation (a procedure that reduces pathological fear and its related emotions by exposing the patient to the feared stimulus in the presence of relaxation or play activity) to target the emotional responses surrounding phobia. These techniques do not alter existing pathological structures; rather, they form new and competing structures that aim to remove pathological associations [22]. There is extensive literature that supports the use of CBT as an effective intervention to reduce anxiety in autistic individuals. However, there are arguments based on the delivery of these traditional CBT techniques that suggest that they may not be appropriate for this neurotype. Firstly, CBT sessions often involve face-to-face verbal exchanges, which autistic individuals frequently report finding uncomfortable and anxiety-provoking [23]. Secondly, they typically use imagined exposure, which is, therefore, not contextualised and may not fully characterise the specific way in which the individual experiences their anxiety [24]. Another important consideration of current CBT is a lack of accessibility. A recent systematic review by [PERSON] et al. [25] has noted that the rates of implementation for cognitive behavioural therapy are below the recommended levels for the United Kingdom. This gap in delivering successful mental health interventions has stemmed from a number of influences, including lack of resources, limited dedicated therapy time, and a lack of specialist training [26]. Therefore, to address these challenges for providing behavioural interventions, new and accessible approaches are needed. One possible solution is to exploit consumer gaming technology to deliver low-cost digital interventions at home; this will allow for flexible usage with minimal training required [27]. There is evidence to suggest higher involvement in video games among the autistic population compared to their neurotypical peers [28]. These systems are capable of incorporating CBT protocols into the core game mechanics and gameplay loops, thus delivering a safe, controllable, and engaging environment in which players can achieve meaningful therapeutic outcomes. Furthermore, the use of game-based digital interventions can provide a cost-effective and accessible method of remediation for autistic children. An example of one such game that targets auditory hypersensitivity is Sinbad and the Magic Cure [29], which motivates players to voluntarily expose themselves to problematic sounds in order to progress through the gameplay narrative. With the development of low-cost consumer virtual reality (VR) devices over recent years, the development of digital interventions deployed to this platform has become more popular. The technology is capable of rendering realistic and immersive three-dimensional audio and visual environments whilst simultaneously providing novel and engaging methods for serious game interactions. VR environments have played a key role in reducing specific phobias in autistic children in a study conducted by [PERSON] et al. [30,31]. Participants were exposed to hierarchical levels of virtual representations of their feared stimuli, such as animals and open spaces. Following multiple sessions, one-third of the participants displayed improvements in their response to real-world phobias. In order to simulate realistic auditory environments, VR applications often utilise binaural-based spatial audio [32]. This audio reproduction technology is capable of moving virtual sound sources that rotate and transform depending upon the dynamic movement and rotation of the listener's head within the virtual environment.