(AP) -- The afternoon performance of "Mary Poppins" was marked by loud yips, shouts and moans - and that was just fine.
It was the second autism-friendly performance of a Broadway show, and for many families with a child who suffers from the disorder, it turned out to be a practically perfect day.
"It is an amazing opportunity to bring our families here and enjoy the show, not be stressed, and relax and know that everyone in the theater is in our situation," said Paige Bravin, sitting with her 11-year-old daughter, Alexa, in the second row of the New Amsterdam Theatre.
The Theatre Development Fund, a nonprofit organization focused on providing access to live theater, bought all 1,797 seats for Sunday's matinee and offered reduced price tickets to families with an autistic member. They sold out in two days.
It was the second experiment following the autism-friendly showing of "The Lion King" in October. The Theatre Development Fund plans a third such show at "The Lion King" on Sept. 30. Tickets for that go on sale this summer on the fund's site.
At Sunday's matinees, about 40 autism specialists - many of them master's students at Hunter College, special education experts or social workers - roamed the theater, providing comfort and help to families. They wore black Supercalifragilisticexpialidocious T-shirts and held flashlights.
"They love participating and being part of this day and to see the magic," said Dr. Jamie Bleiweiss, a professor of early childhood special education at Hunter College and co-founder of the consultant and support group Autism Friendly Spaces. "It's such a rewarding way to give back and to share. This experience is pretty powerful."
To prepare the children, character guides and song lists had been made available ahead of the show so there were few surprises. Calming corners and activity areas were created in the cavernous New Amsterdam Theatre, where overwhelmed children could sit in beanbag chairs and watch a live stream of the show.
There were coloring books, puzzles, games and handy toys for fidgety patrons. Signalers on either side of the stage raised green glow sticks to warn theatergoers of upcoming loud noises or to signal that clapping was ahead.
"We're learning each time," said Victoria Bailey, TDF's executive director, who also credited Disney Theatrical Productions for allowing two of their shows to participate. "It's really clear that the demand is there."
To accommodate the special audience, a few changes were made to "Mary Poppins," including removing all strobe lights, lowering the tap sounds of "Step in Time," softening some transitions and lowering some pitches. The cast and musicians had rehearsed for several hours the day before to ensure that events at No. 17 Cherry Tree Lane were smooth.
"The power of the story remains," said David Caddick, the music supervisor. "We changed some elements to avoid a sensory overload but it doesn't in any way diminish it for the other family members."
Anthony Lyn, the show's associate director, said his team was happy to welcome a whole new audience. "I know everyone in the cast and in the building was incredibly delighted about doing today's performance," he said.
Autism disorders affect 1 in 88 U.S. children, according to U.S. government estimates. Children with the diagnosis are often sensitive to loud noises and harsh lights, and find it hard to sit still or remain quiet. Autism spectrum disorders include both severe and relatively mild symptoms.
The audience at the matinee illustrated the vast range of disabilities, from those with difficulty walking to those who just seemed shy. Many wore headphones to drown out loud sounds. Some grew tired sitting and preferred to wander the aisles or go to the unisex bathrooms. As the show progressed, some children who had been moaning or screeching became calmer. Some happily bopped along to the music.
"You don't have to worry. You're in the same position as everybody else is. You don't have to be embarrassed. It's OK that your kid is screaming, crying or carrying on," said Lisa Brodwin, whose 10-year-old daughter, Morgan, charmed the volunteers with her easy, outgoing nature.
"She loves music, she loves dancing and I wanted to take her and my other son, who's not autistic, as a family. So the four of us can do something together," said Brodwin, who is from Long Island. "I think this is so monumental. I think this is so beneficial."
The Theatre Development Fund, which also operates the TKTS booths, hopes to make such autism-friendly performances a regular event on Broadway and is happy to share what it's learned with other theater communities. It's already had several inquiries from across the nation.
"I think we're developing more awareness in the Broadway community and it's clear from surveys that we did after the first one that there's an appetite for `Spider-Man,' there's an appetite for `Wicked,' there's an appetite for Radio City," Bailey said. "Over time, I hope we would be able to do that."