Virtual reality game training on trunk to pelvis coupling in a child with cerebral palsy

Good control of trunk and pelvic movements is necessary for well controlled leg movements required to perform activities of daily living. The nature of movement coupling between the trunk and pelvis varies and depends on the type of activity. Children with cerebral palsy often have reduced ability to modulate coupling between the trunk and pelvis but movement patterns of the pelvis can be improved by training. The authors studied how pelvis to trunk coupling changed while playing a computer game driven by pelvic rotations.

Cerebral palsy diplegic child played the Goblin Post Office game on the CAREN virtual rehabilitation system for six weeks. He navigated a flying dragon in a virtual cave towards randomly appearing targets by rotating the pelvis around a vertical axis. Motion of the pelvis and trunk was captured in real-time by a Vicon 612 optoelectronic system tracking two clusters of three markers attached to the sacrum and thoracic spine.

Goblin Game

It resulted in increased coupling over game training. Increasing coupling appears to be an initial compensation mechanism using the better controlled trunk to drive rotation of the pelvis. Co-contractions causing increased coupling are expected to reduce over longer exposure to training. The control scheme of the training game can be set to facilitate de-coupling of pelvic movements from the trunk. Using large ranges of pelvic rotation required more coupling suggesting that training of selective pelvic movements is likely to be more effective close to a neutral pelvic posture.

The authors suggest that Goblin Post Office game has means to facilitate selective control of the pelvis and this might reduce the time needed to achieve improved selective movements. Pelvic rotation is helped more by trunk rotation at the ends of the pelvic rotation range due to mechanical constraints and so training of selective pelvic control is likely to be more productive near to the neutral orientation.

To access the full article click here