Design Guidelines for the Implementation of an Interactive Virtual Reality Application that Supports the Rehabilitation of Amputees of Lower Limbs Patients with Post-Traumatic Stress Disorder (PTSD)

Abstract

This article describes the way in which emotions become a crucial component that complements the work of HCI in design and validation of applications created in virtual reality (VR) environments, applicable to the recovery processes of psychological disorders of being’s humans, such as PTSD.

1 Introduction

In this article, we review a series of strategies for the design and development of immersive virtual reality computer applications, which are aimed at the rehabilitation of post-traumatic stress disorder - PTSD. Today applications are implemented that contribute to the improvement of the quality of life of people and that in most cases suffer from different types of diseases: physical, movement limitations and disorders that require treatments.

Virtual reality design specifies the need to establish a hierarchy of needs that lead to an appropriate development of interaction. In the present article that aspect is oriented to recovery processes of psychological disorders. A description is made of the most representative aspects to design in RV and then the necessary criteria are established to consider the emotions in that design, in such a way that the relevance of the affective computation is denoted as a method to guarantee the satisfaction of the users. of interactive applications and feedback to the designer of this type of environment. The Human Computer Interaction (HCI) in conjunction with affective computing are a fundamental tool for the construction of virtual reality environments.

2 Guidelines to Address Psychological Treatments Related to Human Behavior

Cognitive-behavioral treatments have proven effective in the treatment of emotional disorders since they use the metaphor of man as an information system, that is, similar to a computer system [1]. Humans process information from the environment before issuing a response; classifies, evaluates and assigns meaning to the stimulus it receives based on the set of experiences it has stored in its memory, which are derived from its previous experiences, from the interaction with the environment, from its beliefs, assumptions, attitudes, visions of the world and self-assessments [2]. In this way to give an answer to the environment, previously with all that experience and knowledge acquired a hierarchy is created. Normally patients suffering from PTSD do not want to face situations that remind them of the trauma. Currently, the use of virtual reality in cognitive behavioral therapies is increasingly applied, is based on a principle: Teach the patient to unlearn their reaction to fear, undo that traumatic process suffered during the incident in an environment sure, so that you can gain control over your physiological reaction. Based on this premise, it highlights the importance of virtual reality software development, because they are controlled environments that give users greater confidence [3].

The DSM-V [4] is the diagnostic compendium of the American Psychiatric Association, which provides news regarding the coding, classification and diagnosis of mental disorders that have broad effects on many specialties. In the DSM-V posttraumatic stress disorder is coded with 309.8. On the other hand, in the international statistical classification of diseases and health-related problems ICD10 [5], a statistical classification of diseases must cover the entire range of states within a number of categories; according to the endorsement given by the World Health Organization (WHO) to this classification. In the ICD-10 the PTSD is coded with F43.1 and as in the case of the DSM-V, in this classification all the characteristic features of a person suffering from PTSD can be identified. At an international level there are disagreements regarding the codification made in the DSM-V, which is of North American origin and with a strong psychiatric focus, for this reason WHO is preparing the ICD-11 that will unify the classifications of diseases of origin mental [6].

3 Behavior Cognitive Treatment

Cognitive therapy states that emotional disorders arise from irrational thoughts. If the thoughts that are behind a behavior are analyzed and made logical and rational, the psychological problem will be solved. There is a systematic distortion in the processing of information, in this way the emotional disturbance depends on the potential of the individuals to perceive negatively the environment and the events that surround them.

Cognitive behavioral therapy (CBT) has several objectives:

• (1) Learn to evaluate relevant situations logically and realistically.

• (2) Cognitive behavioral therapy proposes a change in attention to take into account all the relevant data in these negative situations.

• (3) Learn to formulate alternative, logical and rational explanations in order to obtain an adaptive result in social interactions.

• (4) Change the thoughts, so that when an irrational automatic thought is detected, it is changed by the rational and logical thought that has been elaborated.

• (5) The CBT proposes to test rational thoughts, conducting behavioral experiments that provide opportunities to verify that they lead to a more adaptive behavior in the interaction with other people and in the resolution of problems.

These steps include cognitive thinking and behavior content change techniques, which change patient behaviors [7]. To achieve success in the care process, it is necessary to create a team and build trust between the therapist and the patient. One of the most used practices in CBT management is Exposure Therapy (Exposure of the Imagine: Building a Hierarchy and choosing the first memory [1]), where the patient faces a real scene of the experiences in the moment of suffering the trauma.

Figure 1 shows a typical hierarchy of treatment processes considered in exposure TCC, the evaluation of the consequences of actions in the environment is noted. This is a first criterion to consider in the design recommendations for the RV App.

Fig. 1.

Hierarchy of the imagination in CBT behavioral therapy (Own).

4 Diagnostic Interview

In light of the DSM-V and the ICD-10, different types of psychological disorders can be found, which must be appropriately diagnosed for decision making in the treatment with CBT. In the case of a diagnosis of PTSD, the result of the diagnostic interview for PTSD should be taken into account. Currently this interview is structured in the CLINICIAN-ADMINISTERED PTSD SCALE FOR DSM-5 (CAPS-5) [8], which is a standard procedure to obtain essential qualifications and produce reliable and valid scores in the diagnostic determination. This process is performed by an expert in a PTSD diagnostic interview.

5 Inventory or Anxiety

This procedure is useful in the description that people make of themselves and allows to determine the degree of anxiety RASGO - ESTADO [9] in which the patient is. In this process, a rating scale is used, such as the following:

• (1) Not at all

• (2) A little

• (3) Pretty

• (4) A lot.

Where (1) corresponds to the lowest score associated with the feeling and (4) more present. These four rating scales apply to 40 affirmations. Figure 2 shows an example of the inventory:

Fig. 2.

Scales of qualification of feelings in anxiety inventory (own).

6 Virtual Reality and Psychological Treatments

Virtual reality (VR) allows simulating the “reality” in three-dimensional environments supported by a computer, which, equipped with the necessary interfaces, gives the user the possibility to “be” in the generated environments so that it can interact with virtual objects. The experience of “immersion”, of feeling there, of experiencing this experience as something real is what has been called “presence” [10] in RV environments. This is nothing more than a user experience that shows from the psychological point of view that this feeling of being and experiencing something significant and relevant is important, since it gives the possibility of using such virtual environments as powerful therapeutic tools that help the person to change, while protecting them while the change occurs [11]. In short, it is about being able to modify behaviors, thoughts, experiences, emotions… through “special” virtual experiences. Virtual experiences designed and adapted to the needs of the person, with the aim of promoting, facilitating and enhancing the process of change. Therefore, it is not surprising that in recent years its use has been extended in the field of psychological treatments. Among the most relevant applications that have been developed, are those that have to do with exposure techniques commonly used in the treatment of phobias. There has also been considerable progress in the fields of eating disorders.

6.1 Virtual Reality and Anxiety Disorders

This type of disorder in human behavior (disorder) is one of the most prevalent [12]. Exposure is one of the most effective therapeutic techniques to treat this type of disorder, because an important aspect of anxiety is the fact that the affected person avoids making contact with what causes the disorder. For example, in social phobia the person avoids situations in which he may receive a negative evaluation of others; people with panic disorder or agoraphobia, avoid situations in which you feel it is difficult to escape or seek help, in case of a threatening event, such as having a panic attack. The primary characteristic of exposure therapy is the confrontation with the dreaded situation; but this confrontation is carried out in a repeated, systematic and gradual manner. Emotional processing is implicit in the efficiency of exposure [13].

The exhibition can be staged through the imagination of the stimulus that provokes the anxiety (exposure of the imagination); or by putting the person in a context in which he or she is exposed to a real-life situation that causes anxiety (live exposure). Here the therapeutic strategy that is involved is the identification of the keys that activate the anxiety and that are associated with the situation to which one is afraid. The person is then exposed to these keys and, with the therapist’s help, the person learns how to cope with the anxiety in the situation, until the anxiety gradually diminishes and disappears. VR allows you to simulate reality and help the patient face the situation he fears in an effective, safe and controlled way [11]. VR has been used for the treatment of panic and agoraphobia (TPA), by designing a series of virtual environments [14] and studies have also been carried out on its efficiency [40, 15, 16], They compared the results obtained through cognitive-behavioral treatment, including exposure through VR in one of them. The results showed that both conditions were equally effective. The work carried out by Botella carried out a study that included three experimental conditions, these are exposure through RV (which also allowed exposure to both external stimuli and interoceptive stimuli), live exposure and a waiting list control group. The results showed that exposure by RV and in vivo exposure were equally effective, with both conditions also obtaining results superior to the waiting list condition. In spite of the scarcity of studies carried out to date and the need to replicate them with broader clinical samples, the results obtained show that VR techniques have an important utility in the treatment of TPA.

The techniques of RV in the treatment of phobias, has been the most widespread field in relation to clinical psychology. An important reference is the work carried out by the Rothbaum group [17], in a case of acrophobia, which gave rise to the performance of many other works showing mostly the positive results and the effectiveness of these tools for the treatment of Phobias [18].

Along with the previous results, the phobia to fly is the specific phobia in which more studies on the effectiveness of VR techniques have been carried out. There are several studies about the effectiveness of VR in this problem.

In summary, several controlled studies have shown that exposure therapy by means of RV is more effective than non-treatment conditions and obtains the same efficacy as exposure in vivo. In addition, it has been observed that the benefits and gains obtained with the treatment through VR are maintained in the follow-ups carried out in the different studies. Finally, there is evidence of a preference on the part of patients for exposure by VR to exposure in vivo before beginning the treatment of phobias, both in subclinical and clinical samples [19].

6.2 Treatment of Phobias Through Virtual Reality

Probably the greatest development of current applications of virtual reality on mental disorders is that of phobias, it is stated that the pioneers in conceiving the idea of using VR for psychological disorders was North’s group, North, and Coble in the year of 1992 [20]. They started their work on phobias to fly, which is one of the most frequent and that affects and limits people to move generating social and labor consequences. In a first experiment, they simulated a city seen from above and treated a 32-year-old woman for eight 30-min sessions, at the beginning of each session, the elevated anxiety measures, but progressively diminished after the first minutes of exposure and reached the highest level, value of zero [21].

6.3 Virtual Reality and Eating Disorders

A field of great relevance in the application of VR is the treatment of eating disorders (TCA). This is caused by the presence of distorted body image; hence a premise in the treatment of eating disorders is to pay attention to body image [22].

The treatment consists of taking the patient to a confrontation with his body image, leading him to correct the wrong ideas he has about the figure and the weight. It is important to note that everything that is involved in what is the body image is something abstract and this hinders the methods with which it can be addressed in therapy. At this point, it is where the RV can be useful. VR can “physicalize” the mental image that the patient has about himself, creating a representation of it and also facilitating immediate communication between the therapist and the patient [14].

6.4 Applicability and Clinical Utility of Virtual Reality in PTSD in Criminal Violence

There is a reference of more recent works, where the therapies with RV have been applied with encouraging results. The work carried out by de la Rosa Gómez and Cárdenas López of the National Autonomous University of Mexico demonstrates this premise [3]. The study shows efficacy results of the treatment of Posttraumatic Stress Disorder (PTSD) for criminal violence using virtual reality. The clinical sample consisted of 20 participants from Cd. Juárez, Mexico, who voluntarily agreed to join the research, with ages between 18 and 65 years. All participants met the criteria of the Dignostic and Statistical Manual of Mental Disorders (DSM-IV-TR) for PTSD and were randomized to two treatment conditions:

• (a) prolonged exposure treatment using virtual reality (TERV; n = 10)

• (b) prolonged exposure treatment by imagination (TEI, n = 10).

The intervention was carried out in 12 sessions [23], two weekly sessions, in face-to-face and individual modality, of 90 min. Two virtual scenarios were used for exposure in the treatment of PTSD. There was an improvement in the measures of PTSD, anxiety and depression for the two groups that received the treatment. However, only statistically significant differences were reached between the treatment groups in the diagnostic measures and the avoidance subscale, obtaining superior therapeutic gains in Virtual Reality Exposure Therapy (TERV). The results support the spread of empirically validated and effective treatments in the area of mental health for the Mexican population. This work is based on the entire study carried out by Cristina Botella and the Rothbaum group, where once again the effectiveness of VR treatments is evident.

7 Hierarchy of Needs of Virtual Reality

In keeping with Maslow’s theory of basic needs and human essence, an equivalent hierarchy of needs in virtual reality is established: Comfort, ease of interpretation, utility and delight. To achieve user experience in presence these levels must be incorporated into the design and development of interactive applications.

Figure 3 shows the equivalent hierarchy, assumed by Beau Cronin [24] when making an analogy with Maslow’s hierarchy, which proposes the needs and factors that motivate people; this hierarchy is modeled by identifying four categories of needs and is constructed considering an ascending hierarchical order according to its importance for survival and the ability to motivate.

Fig. 3.

Equivalent hierarchy [24]

7.1 Comfort

It integrates some very basic requirements, many of which refer to the accurate representation of the simulated environment in immediate response to the head and body movements. This level consists of satisfying our deeply unconscious expectations about the nature of our sensory inputs and how they interact with our actions. It is largely the responsibility of the RV hardware, such as the Head Mounted Display - HDM and the video accelerator card. At this level of the hierarchy, the quality of the render is defined, as well as the frameworks used to create and represent the content or application.

7.2 Interpretability

It is essential to satisfy the need for the simulated environment to be coherent: so that the senses can assimilate it, that it contains enough signals to guide us without being overwhelming, and to follow the logic normally found in everyday experience. The RV has the ability to break some guidelines of the rules of physics: we can fly, exhibit superhuman strength and even deform time and space. But these improved experiences must be quantitative and metaphorical extensions of normal life, which give the user that feeling of presence in the simulated environment.

Another way of thinking about Interpretability is that, of all the stimuli we can create with virtual reality systems, in only a small fraction of them will they have any meaning for our perceptual systems. The better the rules that govern these limitations are understood, the more efficient we will be in creating immersive environments. For this reason, interpretability depends to a large extent on rules and conventions, although it is largely supported by software frameworks that channel creativity in the appropriate directions [24].

7.3 Utility

This is a very specific concept of the application, but it really comes down to assessing the following premises:

Did the virtual reality experience fulfill its basic value proposition? In the case of psychological treatments to recover trauma such as post-traumatic stress, by applying cognitive behavioral therapies of exposure, you must work the design in a way that satisfies giving value to the user, for example losing the fear of facing scenarios that caused the trauma [3].

Does the film tell a story that makes sense? UX-VR virtual reality user experience must be added.

Did the presence session allow a rich and high fidelity communication? In these cases, it is extremely important to have a sufficiently robust team to guarantee the fidelity and availability of communication.

Did the virtual tour give you a precise idea of the context of therapy exposure? In utility, the most robust artifacts of the hierarchy of needs are conceived given that it is closely linked to the basic structure of what will be the satisfaction of the user according to ISO/IEC 25010 within the subcategories of quality in use, the utility contributes to satisfaction and puts a series of indicators that relate to this hierarchy.

7.4 Delight

Define is the realm of design art:

Did the user experience leave you thinking for days afterwards?

Was the presence session almost as good as visiting the site that caused the traumatic event?

Do you experience so much impact that the user wants to return to the next therapy? If the development fully meets the answers to these questions, it is imperative the effort that must be made to ensure the delight, first conquer the needs of lower level through engineering, design and attention to detail.

Although these levels are different, the boundaries between them are still quite permeable. The tools and frameworks must mature considerably, for example before a designer of interactive virtual reality applications can feel free of the basic problems of Comfort and Interpretability.

As in Maslow’s original hierarchy, it makes little sense to worry about the higher levels before the lower ones are in place. One interpretation of the recent rebirth in virtual reality is that Oculus finally deciphered the Comfort code, through a combination of low weight, wide field of vision and fast and accurate tracking of the head [4]. For a long time people have ideas on how to offer interpretable, useful and delightful virtual reality experiences, and now we can finally prove them. The first two levels, Comfort and Interpretability, determine to a large extent the sensation of presence. The user should feel comfortable in the simulation, and the environment should be “read” as something natural, not necessarily realistic, but obeys the basic expectations we have about how our body interacts with its environment. If these conditions are met, then you will feel as if you are inhabiting the simulation; Of course, if it is useful and emotionally attractive.

If you want to obtain a viable minimum product - MVP, it is necessary to try to cover a vertical part throughout this hierarchy, ideally extending from Comfort to delight. On the one hand, it would be a mistake to think that addressing Comfort and Interpretability is sufficient:

Why would users want to continue using the experience, or recommend it to others if it is not useful and enjoyable?

These levels are also acceptable in an interesting and not obvious way, for brain stimulation systems supported in immersive virtual reality experiences. It can be concluded from this first part that the hierarchical levels proposed are coherent with the need to be able to generate delight for users who have suffered traumatic events that cause them avoidance, isolation and fear.

8 Frameworks

There are three main frameworks to choose from when designing for RV: Mozilla A-frame, Daydream VR and Unity VR/Unreal SDK.

• (1) Mozilla A-frame is used for virtual reality applications and can be used on platforms such as Google Cardboard, Samsung Gear and Oculus Rift.

• (2) Daydream VR is for mid-range Virtual Reality and works only with mobile phones.

• (3) Unity VR/Unreal SDK are for high-end equipment that include Oculus Rift, HTC Vive and HoloLens (AR).

9 Emotions

The new wave of research also questioned the old Cartesian dualistic division between the mind and the body. The emotional experiences do not reside in our minds or brains only, they are experienced throughout our body: in hormonal changes in our bloodstream, nerve signals that go to the muscles tensing or relaxing, running through the blood to different parts of the body, postures bodily movements, facial expressions [25]. Our bodily reactions in turn feed back into our minds, creating experiences that regulate our thinking, in turn feeding our bodies. In fact, an emotional experience can begin through bodily movements; For example, dancing wildly could make you happy. Neurologists have studied how the brain works and how emotional processes are a key part of cognition. Figure 4 shows one of the emotional processes that are basically in the middle of most of the processing mechanisms, from the frontal lobe in the brain, through the brainstem to the body and back [26].

Fig. 4.

Model of fear of LeDoux when seeing a snake [26]

Emotion is a mechanism of social and dynamic communication. We learn how and when certain emotions are appropriate, and we learn the appropriate expressions of emotions for different cultures, contexts and situations. The way in which we make sense of emotions is a combination of the experiential processes in our bodies and how emotions arise and are expressed in specific situations in the world, in interaction with others, projected by the cultural practices we have learned. A valid claim is that we are physically affected by the emotional experiences of others. A clear example of this is that smiles are contagious.

In HCI, the importance of considering the emotions of users explicitly in the design and evaluation processes is highlighted. In general terms, HCI research is established in three different directions with three very different theoretical perspectives on emotion and design.

• 1. The first perspective, widely known and very influential, is that of Rosalind Picard and his group at MIT, later adopted by many other groups, in Europe, in particular by the HUMAINE network. The cognitivistically inspired design approach he named Affective Computing in his groundbreaking 1997 book.

• 2. The second design approach could be seen as a reaction contrary to Affective Computing. Instead of starting from a more traditional perspective of cognition and biology, the Affective Interaction approach starts from a constructively and culturally determined perspective on emotion. Its best known defenders are Phoebe Sengers, Paul Dourish, and Bill.

• 3. Finally, the approach that distinguishes emotions from general interaction leads astray. Instead, see emotion as part of a broader set of experiences for which we can design; it is called the Technology as Experience movement [27]. In a certain sense, this is what traditional designers and artists have always worked on [28], creating interesting experiences where a particular emotion is a cementing and congruent force that unites the different parts of the general system of art pieces and viewer/artist. The defenders of this direction are, for example, John McCarthy, Peter Wright, Don Norman and Bill Gaver [29].

10 Emotional Computing

The field of artificial intelligence (AI) picked up the idea that human rational thinking depends on emotional processing. “Affective Computing” by Rosalind Picard had an important effect in the fields of AI and HCI [30]. His idea, in short, was that it should be possible to create machines that relate to, arise or deliberately influence emotion or other affective phenomena. The roots of affective computing really come from neurology, medicine and psychology. It implements a biological perspective of the emotional processes in the brain, the body and the interaction with others and with machines.

Emotions or affects in users are considered identifiable states or, at least, identifiable processes. Based on the identified emotional state of the user, the objective is to achieve an interaction as real or human as possible, adapting without problems to the emotional state of the user and influencing it through the use of several expressions [31]. Figure 5 shows Ortony’s model of emotions.

Fig. 5.

Emotion model of Ortony, Clore and Collins [31]

This model has its limitations, both in its requirement to simplify the human emotion to model it, and in its difficult approach on how to infer the emotional states of the end user through the interpretation of human behavior, through the signs and signals that we issue That said, it still provides a very interesting way to explore intelligence, both in machines and in people [27].

11 Affective Interaction

An interactive perspective on the design does not attempt to detect a singular explanation of the “correct” or “true” emotion of the user or to illustrate about it, as in a prototypical affective computer application, but rather makes available emotional experiences for reflection. This type of systems creates a representation that incorporates the daily experiences of the people on which they can reflect. The own and richer interpretation of the users guarantees that it will be a more “true” story than what they are experiencing.

According to Boehner [32], the interaction approach for design:

• 1. Recognizes affection as a social and cultural product.

• 2. Entrust and support interpretative flexibility.

• 3. Avoid trying to formalize what is not formalized.

• 4. Supports a wide range of communication acts.

• 5. It focuses on people who use systems to experience and understand emotions.

• 6. It focuses on designing systems that stimulate reflection and knowledge of affect.

Kristina Hook and her research group modify two of these considerations:

• 1. Modification of # 1: The interaction approach recognizes affect as a social, bodily and cultural product incorporated.

• 2. Modification of # 3: the interactional approach is non-reductionist.

The first change is related to the bodily aspects of emotional experiences. But explicitly pointing to them, some of the physical and bodily experiences that could involve an interaction with an interactive affective system are added. They also take a slightly different position with respect to design principle number three, “the interactional approach avoids trying to formalize the non-formalizable”. To avoid reductionist ways of accounting for subjective or aesthetic experiences, Boehner and his colleagues try to protect these concepts by claiming that the human experience is unique, interpretive and ineffable.

12 Considerations

It is important to highlight the eleven initial considerations commented for the establishment of the design requirements or what we can call the requisite requirements. These guidelines are a fundamental part in the success of the development of interactive virtual reality applications for the treatment of PTSD.

The guidelines for the breakdown of this type of applications are considered taking into account the phases of the traditional development process such as: definition of requirements, design, development and validation. This allows us to propose a taxonomy of our own that allows us to specify the management of the own processes of software development.

Figure 6 shows the own taxonomy, which shows the different stages that must be met for the development of this type of applications, highlighting the validation stage where prototyping is the basis to add value to the application. These prototypes are validated with the principle of design science, which allows evaluating lessons learned, benefits and aspects to be improved. These topics are consistent with the needs of virtual reality to reach the user’s delight.

Fig. 6.

Taxonomy of the own process model (own)

To address the development of interactive applications that are related to processes of psychological rehabilitation of PTSD, it is essential that there is a multidisciplinary team of expert psychotherapists, to achieve an adequate interpretation of the requirements by the designers of the software.

Attitudes, decision-making, human behaviors in the face of traumas obey a series of hierarchies that determine the process for the achievement of a pleasant experience or delight of the user.

For application design processes that require detecting or identifying reactions that are not necessarily physical or not psychic, it is essential to consider Russell’s OCC- model, so that behaviors can be coupled with learning in the virtual reality treatment process.

There is a clear convergence between the hierarchy of needs of virtual reality, cognitive behavioral therapy and affective interaction, since the latter handles a series of approaches associated with emotional experiences, which ultimately must be standardized to achieve improvement in the treatment of PTSD.