Not all New Year's Eve parties are loud and crowded. 'Sensory-friendly' events explained.

As millions prepare to celebrate New Year's Eve with crowds of people, loud music and fireworks, some Americans are ringing in the New Year a different way.

They're often called sensory-friendly events, and they're usually planned with young people, autistic people or people with post-traumatic stress disorder in mind. They aim to be an alternative to traditional NYE festivities that can overstimulate and overwhelm the senses for some people, experts say.

"There are plenty of kids with autism, or kids with sensory sensitivities and adults too, who deserve to be able to experience the same stuff as someone who might not have the same sensitivities," said Sophie Shippe, a communications director at the Port Discovery Children's Museum in Baltimore, which is having its first sensory-friendly New Year's Eve event this year.

Here's what you need to know about sensory-friendly NYE options.

What does 'sensory-friendly' mean?

Loud noises, like dramatic pops from fireworks, easily create sensory overload and discomfort for autistic people and people with sensory processing disorder, sometimes called SPD.

A sensory processing disorder is where a person has difficulty processing information from the senses, according to Columbia University's Irving Medical Center.

A sensory-friendly business or event means the environment is relaxed and calm for people with sensory processing disorders, according to the Minnesotan nonprofit Fraser.

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The cause of the disorder is unclear and can be present in a variety of other disorders and disabilities. Effects can include sensitivity to certain foods based on texture, being sensitive to specific fabrics or being uncomfortable with certain movements.

The STAR Institute, a sensory-processing nonprofit, says at least one in 20 people could have a sensory processing disorder.

Sensory-friendly New Year's Eve events pop up across US

This year, some communities are offering 'Noon' Year's Eve celebrations that are sensory-friendly.

About 50 people are expected to attend Port Discovery's sensory-friendly countdown to noon on Dec. 31, where there will be no-noise confetti and make-your-own 2024 number templates, Shippe said.

"It's really important to make sure people with those sensitivities can still celebrate New Year's, they can still come out, they can still participate, but making sure that they do it in a way that is comfortable for them, and is exciting and fun," she told USA TODAY.

In Reading, Pennsylvania, the Reading Public Museum is also have a sensory-friendly Noon Year's Eve inside the planetarium.

The Denver Zoo is also having a "low sensory" Zoo Light New Year's Eve event for people with SPD, the zoo's website says. Attendance will be capped at lower than normal and there will be quiet rooms available for breaks throughout the zoo "to meet the needs of those who may feel overwhelmed by typical Zoo Lights offerings," the zoo says.

Who might want to attend a sensory-friendly event?

Veterans, people with young kids and groups that include autistic people may all want to attend New Year's Eve celebrations that are labeled as sensory-friendly.

Military veterans can experience PTSD symptoms when they associate civilian sensory events, like fireworks, with similar past sensory events, according to the U.S. Department of Veterans Affairs.

"When fireworks or other loud noises occur, a veteran’s brain can feel in danger," the VA's website says.

Shippe said that the museum decided to expand its sensory-friendly programming to include New Year's Eve this year because it's part of the organization's mission to "be an accessible space for anyone," she said.

Throughout the rest of the year, the museum has sensory-friendly Sundays once per month and sensory-friendly headphones, fidget toys and weighted blankets for patrons who need them, Shippe said.