Research
Synopsis
Research Summary
Our aim is to develop neural rehabilitation systems for
hemi-spatial neglect. We propose to use multimodal virtual reality based
simulations that will pose tasks involving various modalities and hence
may lead to faster and more effective rehabilitation. It is hypothesized
that rehabilitation of hemispatial neglect can be achieved by the use of
the multimodal, adaptive, and context-aware virtual reality system.
My contribution to this research is at theoretical as well as implementational
level in terms of haptics. Priyamvada Tripathi designed the system and formulated
the basis for the system. The following paragraphs explain the conceptual
framework that guides this research.
Hemispatial neglect is a disorder marked by patient’s
inattention of hemi-space contralateral to the lesion in the brain. For
example, patients with lesions in the right hemisphere of the brain fail
to attend to the information in the left visual or tactile hemi-space and
vice-versa. Research has shown that neglect is a post-sensory disorder.
It has been found that neglect patients typically sense the environmental
stimuli but fail to process the information. This is a debilitating condition
resulting in impairment of self-care (dressing, eating) and restricts patients
from driving and other daily activities. Currently, rehabilitation of neglect
involves paper-pencil based tasks such as drawing and cancellation. Few
attempts have been made to translate these tasks to virtual reality (VR)
environments. However, both paper pencil tasks, and current VR tasks have
failed to show encouraging results in the performance of patients. While
the patients did show minor improve on the rehabilitation tasks, their performance
remained unchanged in the activities of daily living (ADL). Hence, it is
imperative that new rehabilitation tasks are designed which actively engage
patients and target a better carry-over effect to ADL.
Designing rehabilitation tasks in VR should involve an understanding of
the anatomical basis of neglect and its behavioral manifestation. Virtual
reality environments present an exciting opportunity to immerse the patients
in tasks that involve multiple modalities and engage the attentional network
in the brain more effectively than the conventional paper-pencil tasks.
This research proposes a VR based system with cognitive retraining tasks
for patients with hemispatial neglect that involve multi-modal coordination.
Research Approach
I designed the virutal reality setup and one of the tasks
for this experiments. he system has three components: a) visual and haptic
feedback component comprising of a computer screen and two CyberTouch®
haptic gloves b) electromagnetic Ascension® Trackers for measuring hand
movements and c) an interactive management software that acts as the central
control engine for the execution and management of the sessions. Additionally,
the system stores environmental variable, session variables, and profiles
of the patient. Together the gloves, trackers, and display form a visio-haptic
feedback loop.
Each rehabilitation session consists of two set of tasks involving varying
level of cognitive load. The first task is a program for cancellation of
3D objects. In this task, different shapes such as circles and squares are
presented on the screen. The patient is instructed to ‘cancel’
or remove the item of the requested shape by touching it with the virtual
hand and feeling a vibrotactile feedback. Scores are recorded for each task.
After each task, performance is evaluated on the basis of these scores and
reaction times. In the modified version, haptic cueing is incorporated into
the system to encourage performance. If the subject has omitted the shapes
in certain hemisphere, valid visual and haptic cue is provided indicating
the spatial location he/she should pursue. A screenshot of this simulation
is shown in Figure 1.
Figure 1. Cancellation Task in virtual Reality
The Video for a sample interaction is available here.
The second task was the tracking task which I proposed and designed. In this task a patient is requested to track a ball moving in the space. As soon as the patient catches the ball it moves to a new location. The motivation is provided by visual feedback and tactile feedback when the user touches the ball. The trajectory of the ball is configurable and we can vary it depending on the condition of the patient. Cueing is incorporated into the system to guide the user when needed to explore the neglected side of the visual field. While cancellation is essentially adapted from paper-pencil task, the tracking task is a novel task proposed by our team. Figure 2 shows a snapshot of the system.
Figure 2. Tracking Simulation
A Video of the tracking interaction is available here .
We are currently developing a third simulation that involves a story-telling task with gesture recognition. I have implemented the gesture recognition tasks, the virtual reality simulation.
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