Immersive virtual reality, according to scientists, disrupts the child’s default coordination strategy, which should be considered when developing virtual reality rehabilitation protocols for children. While little is known about the effects of immersive VR on adults, little is known about the impact of such systems on young children’s sensorimotor abilities.
Jenifer Miehlbradt, an EPFL graduate, demonstrated her virtual reality setup in 2016 at EPFL’s Open House, allowing users to pilot drones using their torso. Users from the general public were invited to put on a VR headset and move their torsos to navigate a series of obstacles in a virtual landscape.
“Adults had no problem flying through the virtual obstacles using simple torso movements, but I noticed that children just couldn’t do it,” Miehlbradt recalls. “That’s when Silvestro invited me to his office.” Miehlbradt’s supervisor at the time was Silvestro Micera, the Bertarelli Foundation Chair in Translational Neuroengineering. They realized that their virtual reality torso experiment might be revealing something about how a child’s nervous system develops and that no study had assessed the effect of virtual reality headsets on children in the literature.
In collaboration with the Italian Institute of Technology, they began a multi-year study involving 80 children aged 6 to 10. The findings were published today in the journal Scientific Reports. “This study confirms technology’s potential to understand motor control,” says Micera.
Immersive virtual reality disrupts the child’s default coordination strategy, scientists show something that should be taken into account when developing virtual reality rehabilitation protocols for children.
The development of upper body coordination
Healthy adults have no trouble detaching their head movements from their torsos for piloting purposes, such as looking around while riding a bike. This necessitates the complex integration of multiple sensory inputs, including vision from the inner ear and proprioception, the body’s ability to sense movement, action, and location.
Because coordination of torso and head movement is still developing in children, differences with adults are to be expected. However, the EPFL study contradicts the dominant ontogenetic model of upper body coordination development over the last 25 years, which predicts a one-directional transition from rigid control to a decoupling of the head-torso system, and that postural control is essentially mature at 8 years.
“According to the model, children will control their upper body as a whole with rigid links between the trunk, head, and arms from the time they learn to walk around a year until they are 6-7 years old. After this age, children gradually learn to control all of their joints independently, but in difficult situations, they revert to the rigid strategy “Miehlbradt, who is currently completing a postdoc at the University of Lausanne, continues (UNIL). “Instead, we discovered that when using a virtual system controlled by body movements, younger children attempt to move their head and body separately, whereas adults use the rigid strategy.”
The experiment: collecting coins on the back of an eagle
Children are asked to play two games while wearing a VR headset and a movement sensor on their back. In both experiments, children demonstrate control abilities comparable to adults when using their heads, but struggle to control the games when using their torsos, unlike adults.
The child is asked to align their head or torso with a line displayed at different orientations within a virtual landscape in the first game, during which the alignment error and head-torso coordination are measured. The experiment demonstrates that children can learn to control their heads fairly easily. When asked to align their torsos with the virtual line, the youngest children consistently overestimate their movements and try to compensate by moving their heads.
The second game is a flight simulation. The child appears to be riding on the back of a flying eagle in the virtual world. The goal of the game is to collect golden coins that have been placed along a path. Controlling the eagle’s trajectory, as in the first game, is done with either the head or the torso. Again, using their heads to steer the bird’s flight is much easier for children, who are 80 percent closer to the target coins than in the torso-control condition.
Because the desired orientation is aligned with the visual input, the scientists believe that head control is easier in VR environments. Torso control, on the other hand, necessitates the user detaching vision from the actual control, which necessitates complex head-torso coordination. Young children rely more on visual input than internal sensations of body posture. The novelty of the virtual reality environment appears to overwhelm the child’s brain, causing it to pay less attention to internal signals.
“The findings show that immersive VR can disrupt the children’s default coordination strategy, reweighting the various sensory inputs — vision, proprioception, and vestibular inputs — in favor of vision,” Miehlbradt explains. The researchers also discovered that head-trunk coordination is not fully mature at 10 years old, as opposed to the previously assumed maturity age of 8.
Leisure and Rehabilitation using VR
“VR is becoming increasingly popular for therapeutic applications such as rehabilitation and neurorehabilitation, as well as the treatment of phobias or fearful situations. The variety of scenarios that can be created, as well as the playful aspect that can be introduced into otherwise tedious activities, make this technology especially appealing for children. However, we should be aware that immersive VR can disrupt the child’s default coordination strategy “Miehlbradt advises caution.