The New Jersey Institute of Technology Robot-Assisted Virtual Rehabilitation (NJIT-RAVR) system for children with cerebral palsy: a feasibility study

Abstract

Background: We hypothesize that the integration of virtual reality (VR) with robot assisted rehabilitation could be successful if applied to children with hemiparetic CP. The combined benefits of increased attention provided by VR and the larger training stimulus afforded by adaptive robotics may increase the beneficial effects of these two approaches synergistically. This paper will describe the NJIT-RAVR system, which combines adaptive robotics with complex VR simulations for the rehabilitation of upper extremity impairments and function in children with CP and examine the feasibility of this system in the context of a two subject training study.

Methods: The NJIT-RAVR system consists of the Haptic Master, a 6 degrees of freedom, admittance controlled robot and a suite of rehabilitation simulations that provide adaptive algorithms for the Haptic Master, allowing the user to interact with rich virtual environments. Two children, a ten year old boy and a seven year old girl, both with spastic hemiplegia secondary to Cerebral Palsy were recruited from the outpatient center of a comprehensive pediatric rehabilitation facility. Subjects performed a battery of clinical testing and kinematic measurements of reaching collected by the NJIT-RAVR system. Subjects trained with the NJIT-RAVR System for one hour, 3 days a week for three weeks. The subjects played a combination of four or five simulations depending on their therapeutic goals, tolerances and preferences. Games were modified to increase difficulty in order to challenge the subjects as their performance improved. The testing battery was repeated following the training period.

Results: Both participants completed 9 hours of training in 3 weeks. No untoward events occurred and no adverse responses to treatment or complaints of cyber sickness were reported. One participant showed improvements in overall performance on the functional aspects of the testing battery. The second subject made improvements in upper extremity active range of motion and in kinematic measures of reaching movements.

Conclusion: We feel that this study establishes the feasibility of integrating robotics and rich virtual environments to address functional limitations and decreased motor performance in children with mild to moderate cerebral palsy.

Figure 1

Subject positioned in Leckey Chair interfaced with the Haptic Master using a ring gimbal.

Figure 2

Screen presentations of a) Bubble Explosion, b) Cup Reach, c) Falling Objects, d) Hammer, and e) Car Race.

Figure 3

Right panel) Hand trajectories performed to accomplish the Bubble Explosion simulation task on day one by subject S2. Left Panel) Hand trajectories of the same subject performing the Bubble Explosion task on the final day of training.

Figure 4

Depicts subject S2 making a single right turn during the Car Race simulation, on three separate occasions over the training period. Green bold line depicts roll angle. Blue thin line is horizontal (pushing) force. S2's ability to coordinate the sagittal plane pushing needed to accelerate the car with the supination required to turn the car progresses from multiple unsuccessful attempts on day one (top panel), to a slow and disjointed sweeping turn on day five(middle panel), to a single sharp turn without a loss in speed on day 9 (bottom panel).