Human-Computer Interaction and Presence in Virtual Reality

Chapter 7
7.3 User Interface design for VRET
The TA method and presence model were used
to achieve the first part of the goal of this
dissertation: to propose guidelines for the
Human-Computer Interaction of Virtual Reality
Exposure Therapy Systems for treatment of
phobias to improve the usability and effectiveness
of these systems. The second part of the
research goal, the validation of these guidelines,
took place in the shape of the experiments
described in chapters 5 and 6. Based on these
experiments, we can make the following
conclusions regarding what the user interfaces
should look like for VRET systems:
Guideline 1: Control over the position of the
patient is best performed by the therapist instead
of the patient.
With therapist control, the usability for both the
patient and the therapist is higher. For the
patient, it will lead to higher levels of fear and
presumably to a more effective therapy. For the
therapist, it reduces the complexity of the HCI
and provides the therapist with better overview
over the therapy.
Although less relevant given the above
conclusion, in case the patient should be given
control, results show that:
Guideline 2: The most natural patient locomotion
technique is best suited for VRET.
The most natural locomotion technique can
provide patients with the highest sense of
presence and the highest levels of fear, again
presumably leading to more effective therapy.
Figure 7.4: A patient and the therapist,
using the proposed UI.
Figure 7.5: Overview of the 2D / 3D
interface for the therapist.
Guideline 3: Compared to a minimal UI for the therapist that shows only the patient’s point
of view and accepts only keyboard and joystick commands, an interface based on a
combination of 2D and 3D elements should be preferred.
The UI elements that were incorporated in the latter interface were all considered to add to
the usability of the system according to the subjective ratings of therapists:
Guideline 4: An autopilot based on a path displayed on a 2D map should be provided for the
therapist.
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