At the end of Collingswood High School's rollicking performance Friday morning of

Shrek the Musical

, the cast broke into the old Monkees' hit "I'm a Believer," and the audience rocked right along - nodding, dancing, clapping to the beat.

But even before that, audience members were far from sedate, aloof spectators - as they swayed to the music, perking up for the songs, clapping hands, some squealing, a few rising to their feet.

And that was OK. In fact, it was encouraged.

Collingswood's guests that morning were people with developmental disorders and disabilities, and the performance was an example of a growing means of inclusion: sensory friendliness.

As the handicapped access movement gave people physical access to places and events, sensory friendliness offers accommodations that help give experiential access and enjoyment to cultural and recreational activities.

"People are realizing small accommodations go a long way," said C.J. Volpe, spokesman for Autism Speaks, a national advocacy organization.

Accommodations may be dimming the lights and lowering the sound, providing "sensory rooms" for breaks from an event's stimulation, and allowing or serving food and drinks.

Broadway and Major League Baseball have held sensory-friendly events, Volpe said. FedEx sponsors an annual NASCAR race with sensory-friendly accommodations at Dover International Raceway. The John F. Kennedy Center for the Performing Arts in Washington has offered sensory-friendly programming since 2013 and has found it very popular.

Autism Speaks of Southern New Jersey's senior coordinator Emily Kreifels said that when her son Jackson, now 9, was diagnosed about five years ago, there were few sensory-friendly offerings locally.

Now some major movie theaters have sensory-friendly showings. The Sahara Sam and Diggerland action parks have sensory-friendly events, as does the New Jersey Discovery Music, to name a few.

"It's been in the past two years," Kreifels said, "that we've had the doors opened to us."

That's not to say there are enough.

Shrek's assistant director Regina Smith, who is also an autistic support teacher in Collingswood, was herself a theater kid. After her first year teaching, she took time off to play Sophie in an international production of Mamma Mia!

"Rarely do I find field trips for my children that are feasible during the day," she said.

So when special-education teacher and Shrek director Mary Baldwin asked her about doing a sensory-friendly performance, Smith was game.

To test the waters, Smith sent 16 e-mails to people in the special-education community.

"Within three days, we had over 400 people signed up. All the responses were: 'This is incredible.' "

Within a few weeks, students from Burlington, Camden, Gloucester, and Salem Counties were lined up to come.

Kevin T. Casey, executive director of the New Jersey Council on Developmental Disabilities, had kudos for Collingswood.

"This is exactly the type of thing that we'd like to see schools doing to assist their students and staff with disabilities," Casey said. "What this school is doing is very innovative, and we hope that other schools follow their example."

The Bancroft School for special-needs children in Camden County sent several classes of their students to Shrek.

"We absolutely love the opportunity to have our students be able to experience and appreciate the arts, especially in a sensory-friendly atmosphere," principal Matthew D. Sharp said.

Organizers in Collingswood thoughtfully planned their guests' theater experience.

In addition to lower light and softer sounds, Collingswood guests would get to meet cast members before the show to allay anxiety. Audience members would be allowed - encouraged - to sing, dance, clap, stand, and make noise during the performance. There would be two sensory break rooms. Collingswood special-needs student "ambassadors" would welcome guests as they arrived.

In addition to children on the autism spectrum, the show would welcome students with disabilities like Down syndrome, sensory processing disorder, and traumatic brain injury.

The Shrek cast includes a student with Down syndrome and two with autism. Smith's middle schoolers have been helping in staff supporting roles.

Over time, the students have learned from one another.

"They really don't let anyone fail," Smith said.

Carissa Schlichting, a senior with Down syndrome, has been in youth productions since the third grade. This year she has a speaking role as a Duloc resident.

"My favorite is the acting," Schlichting said. "I love to act."

Michelle Nigro, a junior playing Mama Bear and Queen Lillian, has been acting with Schlichting for years. The special-needs students teach by example, she said.

"They're more optimistic about everything," Nigro said. "I know when something goes wrong, I'll get upset. They'll move on to the next thing."

The cast, crew, and teachers didn't know what to expect Friday morning, but as the buses began to arrive, the student ambassadors where there to greet guests and help them to their seats.

Audrie Malony, an 11-year-old from the Bankbridge Elementary School for disabled children in Sewell, sat with her nurse, Bonnie MacMillan.

"She's so excited; she didn't even sleep all night," MacMillan said.

Smith welcomed them from the stage, explaining it was fine to dance, sing, stand, and clap. She told them if the band sounded too loud, let her know. She told them where the sensor rooms were.

The first act zipped along. Instead of intermission with confusing milling about and reseating, some of the lead actors took questions from the audience, such as "How do you get green?" to Sam Sobel, the student actor playing Shrek.

At the end of the play, "I'm a Believer" sung, Collingswood students went into the audience to mingle and chat with their departing guests. Photos were snapped. Hugs were exchanged. Shyness was gone.

Shawn White, 12, a Bancroft student, said it was his first play.

"It was good," he said.

He especially liked the end.

rgiordano@phillynews.com

856-779-3893 @ritagiordano