CAREN for Children: Virtual Reality in Children Rehabilitation

H. van Keeken, Department of Rehabilitation Academical Medical Centre Amsterdam
I.J.M. de Groot, Department of Rehabilitation Academical Medical Centre Amsterdam
A. Beelen, Department of Rehabilitation Academical Medical Centre Amsterdam
E. Otten, Medical Physiology, Rijksuniversity Groningen
O. Even-Zohar, Motek, Amsterdam

With CAREN (Computer Assisted Rehabilitation Environment), also known as ‘virtual reality’, a user can move and manipulate objects. Can the CAREN-user maintain a joint position without losing balance? Is there any difference between healthy children and children with balance disorders having hereditary motorical and sensitive neuropathy (HMSN)? Researchers from Amsterdam and Groningen try to answer these questions in cooperation with each other.

At the first of august 2000, the Rijksuniversity of Groningen, Motek (an animation- and motion-capture studio) from Amsterdam and the department of Rehabilitation from the Academical Medical Centre of Amsterdam, started a research of the use of CAREN as a measuring instrument for dynamic stability. A subsidy of the Johanna Children funds made this study possible.

CAREN stands for Computer Assisted Rehabilitation Environment. A powerful computer system directs a movable platform (the kinetic environment), a video wall with stereo projection (the visual environment) and an audio system (the acoustic environment). Like this, an artificial world is being created around the subject. It is possible for the user of this world, to move and manipulate objects. With an infrared-camera system and markers, fixed on the body, movements of the subjects are being registered, analysed and processed. By making use of the realtimefeedbackloop with a delay of time less then 0,04 seconds, the system can respond to the movements of the subject. This principle is being called Virtual Reality.

With this study the researchers try to answer three research questions.

• Which changes are there in the dynamic stability of the lower extremities of healthy children without balance disorders in giving different virtual environments (visual and/or physical stimuli)?
• Which changes are there in the dynamic stability of the lower extremities of children with proved balance disorders (children with HMSN) in giving different virtual environments (visual and/or physical stimuli)?
• Which differences are there in the dynamic stability in different virtual environments between healthy children without balance disorders and children with HMSN?

Dynamic stability is the possibility to preserve a indiscriminate joint position with normal variation without losing balance.

Four environments are being offered:

• standing without virtual environment
• standing with visual input (a projected computer generated roller coaster)
• standing with kinetic input (moving platform)
• standing with visual as well as kinetic input

Valid for healthy children is, that they, depending on their age, score normal on the Movement-ABC-test or score 56 points on the Berg Balance Scale. The HMSN-children are selected by a call through the VSN and by making use of the patient’s register of the Trappenberg and the AMC. The HMSN-children should have a tolerably balance.

The measures of outcome are being expressed in angle, angle rate and angle acceleration. Average standard deviation; frequency-capacity, trend and variation in maximal amplitudes are being calculated.

By now there are more then forty healthy children and seventeen children with HMSN tested. At this moment data is being analysed. Soon, we hope to present the first results, after that we can do recommendations for intervention research.