A new study explains why autistic children have communication problems and trouble bonding with other people. Researchers at the Vanderbilt University in Nashville, Tennessee, have found that autistic children do not instantaneously connect sounds with the sources, or relate the words they hear, with the speakers.

"We are very excited about it, this is truly transformative," said Mark Wallace, director of the Vanderbilt Brain Institute, who led the research. "There is a huge amount of effort and energy going into the treatment of children with autism, virtually none of it is based on a strong empirical foundation tied to sensory function."

The researchers compared 32 typically developing children who are between ages 6 and 18 with 32 high-functioning children with autism, matching them in every possible way including IQ. The researchers used audiovisual stimuli and asked the participants to tell if the visual and auditory events happened at the same.

"On every test, the children are asked to basically make a judgment about the timing of a light and a sound," Wallace said. "It can be very simple - a flash of light and a burst of sound. One of the examples we have is a bumblebee. The children are asked to differentiate between male bumblebees and female bumblebees. With male bumblebees, the flash and sound are absolutely at the same time. With female bumblebees, the flash and the sound are at different times."

They found that children with autism have trouble with simultaneous information from their eyes and their ears. "It is like they are watching a foreign movie that was badly dubbed, the auditory and visual signals do not match in their brains," study co-author Stephen Camarata, a professor of Hearing and Speech Sciences, said. The problem is apparently caused by an enlargement in temporal binding window (TBW) that causes the brain to have trouble associating visual and auditory events that happen within a certain period of time.

Wallace said that computer games could help autistic children improve their sensory skills. A carefully planned exercise that would reward them when they get the right answer could also help them better connect noises with sources.

The study, which was published in The Journal of Neuroscience, Tuesday, is the first to discover the link between autism and sensory functions. "If we can fix this deficit in early sensory function then maybe we can see benefits in language and communication and social interactions," Wallace said.