Biomedical Engineering Reference
In-Depth Information
interactive user-controlled virtual environments. The impact of this shift has been
intensified by emergent technologies such as the
Nintendo Wii
(Nintendo Co. Ltd.,
Kyoto, Japan) and
Microsoft Kinect
(Microsoft Corp., Redmond, Washington) sys-
tems as well. These systems, and others like them, have led to the widespread cost-
effective availability of interactive VR and may provide new opportunities for the
application of VR interventions both inside the home and in local clinical settings.
All of these technological enhancements have potentially far-reaching implications
for clinical assessment and rehabilitation and, accordingly, serve as the impetus for
this chapter.
One of the primary advantages of VR is that it provides a platform for the devel-
opment of unique and customizable interventions that are not available or easily
implemented in the real world. Specifically, VR enables the manipulation of train-
ing duration, intensity and feedback to satisfy clinical demands for intensive and
repetitive patient training [
9
].
1
When developing VR interventions, it is important
to consider both the construction of the virtual environment and the interfaces for
measurement and feedback that accompany them. A useful framework to guide the
development of VR-based rehabilitation was introduced by [
74
] in the form of a
nested three-circle schema in Fig.
15.1
. The schema represents the VR-based reha-
bilitation process as it relates to the patient, with the three circles illustrating each
component of this process (listed in order from inner to outermost): (1) the interaction
space, (2) the transfer phase, and (3) the real world.
The inner circle, or
interaction space
, signifies the interface between the user and
the virtual environment. The user's characteristics (e.g., age and anthropometrics),
function (e.g., sensory and mobility deficits) and the targeted anatomical structures
engaged during the task all contribute to the user's interaction with the virtual world
[
75
]. This allows for a VR intervention that is aligned with the user's real world
experiences and results in a natural task environment with adequate visual and idio-
thetic information.
2
Further, the realism and ecological validity of VR environments
is important to the enhancement of training efficiency in VR-based rehabilitation
[
17
]. The middle circle, or band, represents the
transfer phase
and refers to the
transferability of learned skills from the virtual environment (i.e., interaction space)
to the real world. This phase requires varied levels of clinician support and train-
ing time depending on the severity and type of disability facing the patient [
26
]. It
may even require combining virtual imagery with the real world (e.g., augmented
reality)
3
to facilitate or catalyze skill transfer, in order to promote improved daily
1
It is important to note that there are two different applications of VR in rehabilitation. When
VR is used as an adjunct to rehabilitation, it is typically referred to as VR-augmented rehabili-
tation. Conversely, VR provided alone as a rehabilitation intervention is referred to as VR-based
rehabilitation [
8
]. The latter is the predominant focus of this chapter.
2
If the visual and idiothetic information are not aligned with the user's actions a disruption of the
user's sense of realness, or
presence
, in the virtual environment can result, leading to feelings of
physical disorientation and even nausea [
55
].
3
Augmented reality is a tool in which the virtual world is superimposed over the real world, with
the virtual information serving as a supplement to what is available in the real world alone [
17
].
