With a few screen projectors, a pair of three-dimensional (3D) glasses and an 8-foot cubicle, researchers have transported adolescents with autism into shaky virtual worlds and discovered that they have surprisingly stable posture. The findings appeared online 13 July in the Journal of Autism and Developmental Disorders1.
Many studies have linked motor problems to autism. One of the disorder’s core features is repetitive motion, such as arm flapping, but delays in motor skills are also common. One study estimated that 79 percent of children with autism have trouble with some kind of motor task, such as throwing a ball2.
A few reports have also noted poor balance in autism. For instance, one found that when blindfolded and standing on foam, children with autism are less stable than are healthy controls3. Little is known about the source of these problems, however.
In the new study, researchers measured how well participants kept their balance while in virtual reality. In this virtual world — created by projecting graphics onto the walls and floor — participants tried to keep still as they stood inside a checkered tunnel that rhythmically slid in front of and behind them.
The researchers grouped 16 individuals with autism and 34 healthy controls into two age groups: 12 to 15 years old, and 16 to 33 years old. Participants wore 3D goggles equipped with a magnetic sensor that recorded their head movements, giving the researchers a measure of their balance.
There was no difference in body motion between the autism and control groups when the tunnel was static or when the volunteers closed their eyes, the study found.
When the tunnel oscillated at relatively slow speeds — once every eight seconds or every four seconds — all the participants tended to sway slightly with the motion. There was no difference in body balance between the volunteers with autism and controls.
But when the tunnel oscillated quickly, once every two seconds, the younger group of adolescents with autism did not sway with the tunnel as much as controls did.
The results suggest that balance issues in people with autism stem from visual perception, which is known to be different in autism, rather than from deficits in motor or vestibular systems. More specifically, the authors suggest that their balance problems result from a delay in learning to integrate visual and sensory information that are both rapidly changing over time.