Human-Computer Interaction and Presence in Virtual Reality

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Chapter 3 When the therapist chooses to move the patient to another location, this is often preceded by an announcement by the therapist that he or she will do so. Further analysis showed the joystick to be preferred over the autopilot: only 19% of the movement acts were performed with the autopilot. After having moved the patient to a new position, the therapist almost always asks the patient to look in a certain direction, followed by a request for the patient to report his or her level of fear. Apart from looking at the absolute number of transitions, we can also look at the relative number of transitions. Table 3.5 shows the fractions of transitions from one event to the other, compared to the total number of transitions from that event. These fractions can be seen as probabilities, showing that very few transition types can clearly be predicted. However, the transitions from some of the most prevalent event types are far more deterministic, such as the transition from event type 4 to event type 11, which is the subconversational structure of the therapist trying to determine the fear level of the patient. Therapist 1. Regulative: Look 2. Regulative: Move 3. Regulative: Posture Therapist 1. Regulative: Look 5 6 2 48 10 0 0 6 2 9 12 2. Regulative: Move 30 0 6 36 8 0 0 8 0 1 2 3. Regulative: Posture 26 9 0 40 11 0 0 6 0 6 3 4. Regulative: Report 0 0 0 1 0 0 0 0 1 98 0 5. Imperative: Control VE 52 11 4 11 6 1 1 6 0 6 1 6. Constative: Rationale 14 0 0 36 0 0 0 43 0 7 0 7. Constative: VE 28 0 6 22 11 11 0 6 0 0 17 8. Constative: Move 5 0 1 1 93 0 0 1 0 0 0 Patient 9. Regulative: Question 6 0 0 0 0 18 76 0 0 0 0 11.Expressive: Fear 25 3 5 21 3 2 1 17 2 6 15 Silence 16 2 1 51 4 0 0 9 2 14 0 Table 3.5: Transition probabilities in percentages between events: probability of the top event occurring next, given the fact that the left event has just occurred. Grey indicates the probability is higher than 50% 3.5.6 Conclusions In the previous paragraph the typical course of a therapy session has been analyzed and described. In this sense the description is similar to a scenario as often used in HCI design. However, our analysis also includes detailed information of the relative occurrence of the various sequences of events, and therefore provides a more thorough basis for the design process. It will form an important part of our overall task model as described in paragraph 40 4. Regulative: Report 5. Regulative: Control VE 6. Constative: Rationale 7. Constative: VE 8. Constative: Move Patient 9. Regulative: Question 11.Expressive: Fear Silence
Analysis 3.7, and since it provides quantitative information concerning the various task elements, it can be used to identify opportunities for increasing the usability such as frequent repetitive tasks that could be automated or determining which improvement will have the highest impact on overall system usability. 3.6 Current In Vivo therapy Most phobias can be treated effectively with exposure therapy. (Bouman et al., 1992) Here, the patient is exposed to stimuli that produces the anxiety and by a process known as habituation the fear will gradually diminish. Usually, the patient is gradually exposed to more fearful stimuli. Until recently, the stimuli could be either imaginary or real (in vivo). A review of literature shows gradual exposure therapy in general to consist of the following steps: (Bouman et al., 1992) (Davidson & Neale, 1996) (Orlemans et al., 1995) 1. Function analysis. Determining the actual cause of the symptoms and its context. 2. Determining type of therapy and goals to be achieved. 3. Setting up a hierarchy of anxiety-producing situations. In this hierarchy, the scariest situations for the patient are placed at the top. 4. Exposure. Following the hierarchy, patients are gradually exposed to more fearful situations. The patient remains in a specific situation until the anxiety has decreased to a certain level. 5. Evaluation. The effectiveness of the therapy, usually measured against the predefined goal, is evaluated and can initiate other psychological help. 3.6.1 Current In Vivo practice In the daily practice of therapists, treatment may not be performed exactly according to literature. To create a usable design, we need to understand the real problems that the users are facing. Unfortunately, because of privacy reasons and patient confidentiality, it is not possible to observe and record real therapy sessions. As an alternative, we have interviewed therapists about their work. Six therapists from five different institutions in the west of the Netherlands have been found willing to participate in this study. A semidirected interview (Sebillote, 1995) was used, with questions regarding the therapist’s experience with different phobias, work method, possible problems with the current way of working and suggestions for the system to be designed. The protocol for the interviews is provided in appendix A. The interviews took place in the offices of the therapists and were recorded on tape for later analysis. The results of these interviews have been summarized in the next paragraphs. Patient population In the interviews, the therapists reported that most patients have more than one problem. A choice is made about which one of these problems will be solved during therapy. Of all phobias, therapists encountered agoraphobia the most. Agoraphobia is defined as the fear of being in places or situations from which escape might be difficult or embarrassing, such as being in a crowd, traveling in an automobile, bus, plane or being in an elevator (American Psychiatric Association, 1994). Other phobias, such as claustrophobia and acrophobia, are quite common but people do not often seek therapy for these phobias alone. 41
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Chapter 5 Measures Prior to the exp
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Chapter 5 Unstandardized Coefficien
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Chapter 5 phobia that often involve
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Chapter 5 subjects were all diagnos
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Chapter 5 VE does show a significan
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Chapter 5 possible explanation coul
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Chapter 5 Large drop Large drop A2
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Chapter 5 5.5.2 Results Subjects Mi
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Chapter 5 the SUD scores in the dif
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Chapter 5 The third experiment clea
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6 Therapist's user interface The UI
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6.2.1 SUDs recording During therapy
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Therapist’s user interface Figure
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Therapist’s user interface The st
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Therapist’s user interface The 2D
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Therapist’s user interface Heartr
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Therapist’s user interface • To
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Therapist’s user interface elemen
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7 Conclusions In this dissertation
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7.1.2 Determining the patient's fea
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Conclusions patient control allowed
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Conclusions Guideline 5: A tool for
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References Alcaniz , M. Banos , R.M
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References Dietz, J.L.G., Widdersho
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References Hodges, L., Rothbaum, B.
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References Lombard, M., Ditton, T.(
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References Reeves, B., Nass, C. (19
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Slater, M. (1999). Measuring Presen
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References van Welie, M. (2001) Tas
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UED User Environment Design VE Virt
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Appendix A Complaints and wishes 'F
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Appendix A A.4 Experiment 3 Compute
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Appendix A 3. Were you able to see
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Appendix A 28. 'If you had to choos
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Appendix B Element: Instruct patien
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Appendix B Element: Inform patient
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Appendix B Element: Listen for resp
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De TA methode is getoetst door deze
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Curriculum vitae Martijn Schuemie w
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2000-1 Frank Niessink (VU) Perspect
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2002-09 Willem-Jan van den Heuvel(K
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