Diagnosing fetal alcohol spectrum disorder in children has always been notoriously difficult. Now, Canadian researchers have developed what they say is a new and simple test.

FASD includes a range of disorders caused by prenatal exposure to alcohol. Milder forms do not always carry the hallmarks of severe fetal alcohol syndrome, such as distinctive facial malformations and growth restrictions. Yet FASD still causes lifelong cognitive and developmental disabilities and behavioural problems.

It's considered the leading cause of these disabilities in Canada, yet often goes undiagnosed because there is no one clinical feature that identifies the disorder. Until now, there has been no accurate laboratory test to aid diagnosis, but that may soon change.

James Reynolds, a professor at the Department of Pharmacology & Toxicology at Queen's University in Kingston, Ont. has developed a test that he believes can pinpoint those children with the disorder.

Reynolds has found that children exposed to alcohol in utero have slower eye movements than healthy children.

His eye that requires patients to track dots flashed on a computer screen. The children are instructed to either look toward or away from a light that appeared in their peripheral visual field. He's found that FASD children have much longer reaction times to initiate eye movement both towards and away from the flashes.

"This simple test tells us a lot about what may be going on in the brain," he tells CTV News. "It tells us there is a brain injury."

"It's simple, it's non-invasive, it's objective, and it doesn't require decades of specialized training to carry it out. And it's affordable."

After initial testing of the eye test on a small group of children, Reynolds is now crisscrossing the country testing more than 200 children in nine different Ontario and Alberta locations.

"Establishing a mobile laboratory allowed us to go where the kids are, and carry out these experiments in community settings," he says.

As they test more children, Reynolds' team is building a database of the results. Once the team can establish what 'typical' eye movement is, they can better identify the signature characteristics among the spectrum of disorders.

"Now we know that the results of eye movement testing are consistent across different geographical locations - something that is absolutely critical if this type of testing is to be widely applicable."

The test results are highlighted today in an online article in the European Journal of Neuroscience.

Dr. Brenda Stade of St. Michael's Hospital in Toronto says that as many as a quarter of the children she sees at her FASD clinic don't have typical outward signs of the disorder. She's excited that this simple test could change that.

"I think in two to three years, this will become an accepted test for fetal alcohol disorders," says Stade.

While the test won't be available for general use until researchers complete the studies to further define its accuracy, they are fairly certain they have found a way to identify a young brain has been scarred by alcohol.

Researchers add that because the eye problems that the test looks for last throughout one's lifetime, the test can also be used to find adults with Fetal Alcohol Spectrum Disorders who have never received a proper diagnosis.

Ten-year-old Crystal was part of the study. For years, her grandparents didn't know what was wrong with her.

"She was definitely delayed, she couldn't listen, she couldn't reason," recalls her grandfather Doug Nugent. "She used to lie there kicking and punching the bed, banging her head."

Now diagnosed, Crystal is getting treatment for her disorder and is doing well. But her grandparents know many others who were missed, wrongly treated for attention disorders or even autism.

"A lot of kids are misdiagnosed," says Nugent. "These children, they need a proper diagnosis they need proper intervention, they need help."

With a report by CTV's Avis Favaro and producer Elizabeth St. Philip