Engineering a Showcase of Virtual Reality Exposure Therapy
uller1, Samuel Truman1, Sebastian von Mammen1and Kirsten Brukamp2
1University of W¨
urzburg, 2Protestant University Ludwigsburg
Abstract— Numerous research studies and controlled trials
have unveiled the potential of serious games in various health-
related areas . Their range of application can be even
further extended by the use of virtual reality (VR) technology,
which allows the realistic representation of interactive contents.
Virtual Reality Exposure Therapy (VRET) is a very promising
novel use case for the development of serious games. Held
in a virtual environment (VE) adaptive to the needs of the
patient, this form of therapy can outperform traditional real-
world measures , . One of its major success factors is
the engagement of the patient, which can be increased by
an immersive gaming experience. We show a demonstrator
of VRET application for a ﬁre-related post-traumatic stress
disorder (PTSD). In this demonstrator, features to support
actively guided VR experiences are improved on, focusing on
the interactive adaptivity of the VE.
In exposure therapy, an experienced therapist exposes
the patient gradually to stimuli that induce his pathological
fears. By this means he can reﬂect his undesired behavioral
patterns and develop effective countermeasures . Lack of
accessibility and adaptability of fear-inducing stimuli is this
therapy’s major disadvantage—consider the fear of ﬂying and
the therapist’s lack of control over an actual airplane .
VRET transfers the concepts of the real-world approach to
a VE that can be adapted to the speciﬁc needs of a patient.
Over 20 controlled trials have proven that VRET performs
at least as well as its real-world counterpart . Yet due
to the lack of knowledge to build a VR application that
ﬁts their speciﬁc needs, therapists largely refrain from using
VRET , . The company Virtually Better, Inc. (VBI) is
the market leader in VRET applications. One of their key
features is the interface the therapist uses for controlling the
VE and monitoring the patient. It shows the player’s view,
layout panels with input forms to trigger game events as well
as a separate form to log and make notes about the player’s
health condition. In VBI’s products, some phobia scenarios
are video recorded instead of rendered in real-time, which
reduces adaptability. Although the global game environment
can be modiﬁed at run-time with a slider menu, direct control
the parameters of certain stimuli is missing. The therapeutic
interface also lacks a preview mode of intended changes.
User interaction is also limited, e.g. lacking the means to
control one’s movements, to interact with 3D objects, or see
one’s own body. This lack of interaction lowers immersion
which, in turn, lowers the effectiveness of a serious game
II. CO NC EP T & REALI ZATI ON
A generic therapy cycle underlies all VRET use cases
, which we have condensed into the diagram shown in
Figure 1. The therapist continuously identiﬁes, classiﬁes the
stimuli that cause pathological fear according to the sever-
ity of symptoms and perceived threat levels, and controls
them . For VRET, the application requirements reﬂect
Fig. 1: In VRET, the therapist (a) selects an adequate
stimulus to (b-c) confront the patient. Based on (d) its impact,
the (f) the stage of the fear hierarchy is adapted and/or (g)
the session is stopped.
the needs of the therapist to control the outlined therapy
cycle and of the patient to ultimately be in charge of the
progression of the therapy at his own pace and that game
decisions are made based on his own free will. In addition, he
has to be praised and encouraged to step further . Figure
2 shows the supervision monitor, the interface of the therapist
of our demonstrator of a VRET for ﬁre-related PTSD. It
allows him to interact with the VE and observe the patient’s
situation. Fear-inducing stimuli in the overview at the bottom
are represented as red pins with a preview icon. Clicking on a
pin, a contextual window is opened that allows the therapist
to modify the respective stimulus’ intensity, see Figure 3.
With the help of a preview mode, the therapist can estimate
the possible impact of planned changes before conﬁrming
and actually presenting them to the patient. As shown in
Figure 4(a), the trajectory of the patient’s teleportation is
visualized by a trail of footsteps. He can pick up notes that let
the narrative progress or give him a hint on other interactive
elements. These notes are represented as blue pins on the
ﬂoor map and can be highlighted by the therapist. The patient
can observe his heart rate in real-time by a pulse sensor that
is attached to his wrist and represented by a ﬁtness watch
in virtual reality (as shown in Figure 4(b)). The integration
of sensor information serves two purposes: (1) It increases
the degree of immersion experienced by the patient. (2) It
can be used as a therapeutic medium to focus the patient’s
attention on his body signals. This allows him to become
aware of his own sensitive physiological reactions and thus
can help to calm himself . Overall, the design of the
supervision monitor is plain and functional. GUI elements
are sized, placed and colored to be quickly operated also in
Fig. 2: Top-left: Stream of the patient’s view. Top-center:
The patient’s heart rate and perceived fear level. Top-right:
Adjustment of global parameters. Bottom: VE map with the
patient depicted in pink. Pins represent conﬁgurable stimuli.
Fig. 3: The control window of a ﬁre stimulus and its preview
in the context of the ﬂoor map.
Based on a comprehensive review on VRET literature and
seminal existing applications, we have systematically ex-
tended the state-of-the-art in terms of interactive supervision,
visual feedback and patient immersion. To this end, we pre-
sented an intuitive and goal-oriented supervision monitor that
serves as the therapist’s interface to observe and control the
course of a therapy-supporting VRET session. The monitor
integrates various supportive technologies such as the real-
time stream of the patient’s view, his contextual tracking
in the VE, integration of additional sensory information for
(a) Footsteps. (b) Virtual ﬁtness watch.
Fig. 4: Visualization techniques in VR for (a) the navigation
system (b) and the heart rate.
both the player and the supervisor (e.g. the pulse tracker),
the ability to directly adjust global system parameters and
concrete stimuli, and to log therapy-critical events. Based
on our results, empirical studies have to be conducted as
next step to reinforce the effectiveness of aforementioned
concepts in practice.
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