Virtual Reality Exposure Therapies
It is when we are interested in behavioral and cognitive therapies that we can discover that new technologies (virtual reality, video games, serious games ...) can become real tools in the service of therapy to treat certain types of disorders. The first experiences of exposure to virtual reality as part of a therapy took place in 1992 and focused on anxiety disorders. They were based on the theory of emotional treatment of Foa and Kozac (1986) , namely that if an Virtual Environment (VE) can generate anxiety and activate anxiety-causing structures, it can become an alternative exposure. As in the in vivo exposure, information that contradicts anxious beliefs can be experienced and modification of the anxiety-producing structure can occur. Consequently, the emotions aroused in an VE participate greatly in the virtual experience and this is even what is the basis of exposure therapies in psychiatry. In the context of phobias, the objective is most often to create anxiety-provoking situations. The realism of stimuli and the induction of emotions will be targeted. The same goes for addictions whose objective is to trigger craving. The main goal of this exhibition is to understand the cognitive and behavioral functioning of the individual and to reduce the effects of objects causing anxiety or craving by confronting the patient with these to help him set up thought and more adapted behaviors. In this way the exposure to these objects is progressive, controlled and adapted to the patient. These concepts are extremely important in therapy. VR interfaces are developed so that the patient performs a specific activity or is subjected to a specific exposure.
Therapeutic Path
Although most studies are only case studies ( Krijn, Emmelkamp, Olafsson & Biemond, 2004 ), clinical protocols have been able to emerge, making it possible to move towards a more scientific approach and to better grasp the cognitive and behavioral components at play in these therapies. CBTs with virtual reality generally represent around ten sessions during which the patient will first learn how anxiety or craving are generated, how they are maintained (consciously or unconsciously) and secondly how modify his cognitive patterns and replace his inappropriate behaviors to reduce his anxiety disorders and addictions and thus regain his formerly lost freedom . Over the sessions and depending on their progress, the patient will be offered to increase the difficulty of the exposure. The goal is to cause by the implementation and revision of the methods learned, a decrease in the level of anxiety or craving to take it to the next step, the exposure being done in a graduated manner. The therapist present throughout the process also intervenes to comment and analyze the elements of therapy. In addition, patients are invited to confront themselves as soon as possible (when the therapist feels they are ready, generally around the 6th or 7th session) with anxiety-provoking situations or causing craving in the real world .
In the same way as for learning a musical instrument or a sport, to be effective, the exposure in virtual reality must be: progressive , repeated and prolonged . In general, 15 to 20 minutes of exposure is enough once a week or a fortnight.
Target Patients
Since the beginning of the appearance of virtual reality within therapies, studies have multiplied, taking advantage of advances in technology. Most have focused on anxiety disorders , but research on eating disorders, sexual disorders , addictions , depression and even pain control is increasing. Depending on the patients' troubles and difficulties, the therapy is readapted .
The Benefits of Adding Virtual Reality
More suitable Therapy
Virtual reality can be used to overcome difficulties encountered in the traditional treatment of anxiety disorders and addictions. With this device the therapist can choose an exposure adapted to each patient by also modulating its intensity (also possible in real time). The use of virtual reality allows the patient to be able to repeat the different scenarios chosen and thus to better adapt to the situations. Difficult situations to set up in reality such as an assault, being several meters above the void, a cigarette break in a tropical beach bar or meeting certain types of objects can be simulated in virtual reality thanks to an almost unlimited panel of complex, dynamic and interactive stimuli in 3D. It allows a much more reassuring exposure under control for certain patients refractory to in vivo exposure. In fact, patients generally experience less reluctance to face the objects of their anxieties with this tool since it is not a question of reality. This is a big advantage for making an exhibition because the progress and learning acquired in these EVs are directly transposed into real life.
Save time and resources
The therapist's role in dealing with these psychological disorders is to accompany the patient in situations that put him in distress. Unfortunately this requires a lot of financial and time resources. For certain phobias such as aviophobia (fear of flying) for example, it would be difficult and very expensive to set up real exposure to the anxiety-provoking situation. One of the advantages of virtual reality is that we can simulate virtually and more economically the specific situations that distress the patient (baggage preparation, boarding, takeoff of the plane, landing ...). In addition, this simulation of reality can be done repeatedly during the same session (10 takeoffs in 30 minutes of session for example). These advantages also apply to situations triggering craving. So we can simulate a coffee break at work, traffic jams or an evening in a tropical bar.
Limits
These artificial sensory simulations can be the cause of more or less significant sensorimotor disturbances when individuals react badly to the virtual interface. The different types of illness caused by VR can be compared to seasickness or transportation sickness, especially when a person sitting in reality is moving in the virtual universe. The main symptoms are: dizziness, disorientation, nausea, vomiting, or eye-motor symptoms. They can last more than 24 hours after exposure to VR.
The exact cause of these simulated diseases remains unknown, but the theory of sensory conflict ( Reason & Brand, 1975 ) and the theory of postural instability ( Riccio & Stoffregen, 1991 ) provide some answers. The theory of sensory conflict postulates that all situations causing simulated diseases present a sensory rearrangement in which the eyes, the vestibular system (responsible for hearing and balance) and the non-vestibular proprioception systems receive different signals from each other, but also different from those expected, from past experiences. The theory of postural instability suggests rather that illnesses are due to the prolonged maintenance of an unstable posture. The latter theory would nevertheless be insufficient to explain the cause of these diseases, especially when the participant is perfectly still and the movement is only simulated visually. More recently, the theory of eye movements ( Ebenholtz, 2001 ) has emerged . She postulates that specific eye movements, optokinetic nystagmus (rapid eye movements to follow target objects to the limits of the visual scene) and oculo-vestibular responses (keep a target object in the fovea when the head turns) are believed to cause these illnesses as well as headaches, eye strain and difficulty concentrating.
Fortunately, repeated exposure to VR can lead to reduced symptoms and habituation. Similarly, the more the individual feels involved and present in virtual reality, the less likely he or she will be sick ( Gavgani, Nesbitt, Blackmore & Nalivaiko, 2017 ). Furthermore, it would seem that when individuals manage their movements only with a virtual reality headset, this is more disturbing than if they also benefit from manual control. It is therefore best to combine the movement process with a joystick or remote control. If however this is not enough there are other ways to alleviate these symptoms, either by nausea or headache medication, or by eye-motor coordination exercises aimed at recalibrating the vestibular system (Champney and al. 2007). In the design of interfaces, it is advisable to include a visual "anchor", that is to say a fixed object on which the participant can focus his attention to reduce the feeling of disorientation and all the symptoms mentioned above ( Whittinghill , Ziegler, Case & Moore, 2015 ).