Early signs of autism can be easily confused for a shy personality, speech difficulties, bad parenting or obsessive compulsive tendencies. Childhood development experts say the list of red herrings goes on.
Consider the number of problems that can mimic autism symptoms -- Rhett Syndrome, fragile X, hearing difficulties or more -- and experts say the diagnosis quickly becomes very complicated for the average family doctor.
When children do see a specialist, the diagnosis can take hours and the waiting lists can be months long.
Autism specialists need detailed family histories and timelines of developmental milestones such as the age of the first word, or first steps.
When a young child comes to her office, Lynda Geller, clinical director of the Asperger's Institute at the New York University Child Study Center in New York, pays careful attention to the way a child plays. At the crux of the autism diagnosis lies in interviews and playtime.
If a toddler spins the wheel of the truck hundreds of times, but never pretends the truck is driving, it can be a warning sign, said Geller.
A failure to understand certain universal gestures is another red flag -- for example, said Geller, a toddler who doesn't understand pointing. At 15 months of age, it's natural to follow the direction of the finger instead of staring at the hand.
Geller says first-time parents like Ahrens can miss these subtle differences.
"Often it depends if it's their only child, because they're not aware that it's different," says Geller. "It's not something we necessarily teach in high school."
Autism Speaks has developed a unique video library (http://www.autismspeaks.org/video/glossary.php) that helps demonstrate the subtle differences between autistic and non-autistic children's play. Geller uses some of the same techniques in the videos, such as blowing bubbles to check for what's called joint attention, or the tendency to draw others into your experience with looks and gestures.
"I might blow bubbles with the child," says Geller. "What I want to see if the child is looking over at their mom and dad as a sharing of their enjoyment."
Joint attention is crucial to learning language, and a language deficit is a signature of autism. Early signs that a child is autistic, such as a lack of joint attention, will differ from the common delayed speech red herring diagnoses many children receive.
In fact, when Ahrens first took Matthew to the pediatrician, all she heard was that he might have a speech delay.
"Autism was never on my mind -- never thought of it, people never said anything, nothing," says Ahrens.
Her pediatrician advised her to wait to see if Matthew learned more than 10 words. He told her to come back when he was two, then asked her back again when he was two and a half.
"The reason people should go to a specialist in autism is because people who are familiar with autism can diagnose it early," says Geller. "A pediatrician might say, 'He'll outgrow it maybe in six months.' Someone who's an expert in autism would not say that -- and those six months are critical."
Before his third birthday, Ahrens got Matthew in to the Early Childhood Intervention Services, a federally funded program to help teach children who have cognitive, motor or communication delays.