When Mac Dawson-Moore was 3, his parents were told he'd probably never learn to talk. A family video shows him spinning in circles and struggling to make the sound "bah" -- while his twin sister, Eleanor, talks in full sentences. "We'd been told his IQ was below 50," said his mother, Amy Dawson. "I didn't have any hope for his future at all."

Today, at age 7 1/2, Mac is "talking up a storm" and getting ready to be mainstreamed in school next fall. His IQ has shot up by 58 points. He is, she says, doing better than she ever imagined.

Dawson, a lawyer and autism advocate, credits the transformation to an intense form of behavioral treatment known as Applied Behavior Analysis, or ABA. It's intrusive, expensive -- and the subject of debate in many state legislatures, including Minnesota's.

But it's widely sought after by parents who hope for success stories like Mac's.

From all appearances, Mac is a playful, happy kid, with a smile that's a carbon copy of his mother's.

Instead of going to school, he gets an average of 36 hours of ABA therapy at home every week, as he has for almost four years. Five or six days a week, a tag team of specially trained therapists from the Lovaas Institute Midwest descends on his house in south Minneapolis with one goal: to teach Mac to overcome his autistic impulses.

One afternoon in early February, he lit up with excitement when his therapist, Aga Kettlewell, asked if he'd like to play a sci-fi game called "Time Cruiser."

"Can I be the evil Time Twister?" he asked, sprawling on the floor.

Kettlewell, a senior therapist at Lovaas, let him enjoy the game for a few minutes before she announced: "I'm bored."

She said she really wanted to try another board game, about farming. "So what do you think we should do?" she asked.

Mac thought for a moment and replied, without much enthusiasm: "We should do your game."

For Mac, that was a milestone.

The very concept of taking turns -- of deferring to someone else's wishes -- can be a huge leap for kids with autism. The label comes from the Greek word for "self," and one of its defining features is that people seem trapped in their own worlds. That was Mac, his mother says, when he got the diagnosis in 2006.

Mac had been "medically fragile" since birth, she said. Nine weeks premature, he struggled with one medical crisis after another and spent his first six months in the hospital. By the time he was 2, his mother began to notice strange behaviors. "He was very withdrawn and seemed very spaced-out," she said. He mostly ignored his twin sister, who was talking and blossoming.

The diagnosis -- autism -- was a devastating blow. For Dawson, it was a struggle to take Mac anywhere because of his unpredictable behavior. "We stopped going to church," she said. "We were really very isolated."

He started treatment in the spring of 2007 and within a few months, says his mother, "his speech took off."

The ABA program uses an elaborate system of repetition and rewards to help children learn the skills they often lack: to speak, to make eye contact, to respond to other people, and to "extinguish" troublesome behaviors, like tantrums.

It's painstaking and time-consuming.

Some days, Mac is scheduled with therapists nonstop from 8 a.m. to 6:30 p.m. His mother, who is divorced, undergoes weekly training so she can carry on the system 24/7.

Like Mac's therapists, his mother makes a point of praising small victories.

"Hey, you're doing a good job of sitting quietly, Mac," she said as they played the board game Sorry.

Even now, some things are a challenge. Mac can sit still and listen to a story for about six minutes, Kettlewell said, but her goal is 30.

Dawson, who founded the Autism Advocacy and Law Center, readily admits that not all children respond to the treatment as well as Mac. "Nobody really knows why some kids do really well and some kids don't," she said.

But she has no doubt she made the right choice. After years of isolation, she can take her children to restaurants. They go to church again as a family. "Mac prays," she said. "He thanks God for things like thunder and the planets."

At dinner recently, Mac led grace.

"These experiences are, for me, miraculously normal," says Dawson. She has faith, she says, that "my son will live a life of independence with as much chance at happiness as any other child."

Maura Lerner • 612-673-7384