Well-publicized events involving professional athletes, along with a federal lawsuit and a Hollywood movie now in theaters, have spurred unprecedented interest in concussions - and set off a business boom.

Companies around the country are developing headbands, mouth guards, helmet padding, and skullcaps to try to protect athletes' heads during impacts.

Medical experts warn that no product can prevent concussions or the repeated subconcussive hits that may also cause lasting brain damage. But device makers hold that their products can provide a measure of protection.

One recent entry comes from a Chester County company, Defend Your Head, based in Chester Springs and led by former New York Jet John Roman.

It has developed a soft, polyurethane outer shell for football helmets meant to reduce head trauma by dispersing and reducing the force of impacts.

CEO Roman, a Jets offensive lineman from 1976 to 1983, officially announced the release of ProTech, the company's first product, on Jan. 13.

"I think it's particularly important for young players coming up to play a game that is as safe as it can be," said Roman, who suffered concussions at the high school, college, and professional levels and for whom headaches were normal while playing. The game has gotten safer over the years, he said, "but we still have so much work to do."

Defend Your Head, founded in spring 2013, is careful to say its product cannot prevent head or neck injuries.

More than 100 high schools and universities have agreed to try ProTech, including 10 area high schools, Roman said. He declined to identify the local schools until an official announcement by the company in the coming weeks.

Another local firm, Unequal Technologies, based in Glen Mills, Delaware County, offers helmet padding and introduced a headband a year ago that the company claims protects athletes' heads. Ali Krieger, a defender on the U.S. women's national soccer team, wore one of those headbands during last summer's Women's World Cup.

Brain-Pad Inc., based in Conshohocken, Montgomery County, sells mouth guards it says can help lessen head trauma. The company can no longer claim the mouth guards reduce the risk of concussions after a settlement it reached with the Federal Trade Commission in 2012. The agency found that the company's concussion claims were not backed by scientific evidence.

The technology from Defend Your Head is an improved version of a product called ProCap. Bert Straus, the engineer who created ProCap, is now a shareholder in Defend Your Head, the firm said.

Ben Franklin Technology Partners, a state loan-and-grant program for nascent tech companies, asked Richard Nelson, founder of Pennsylvania State University's Biomechanics Lab, to evaluate the technology. Nelson said ProTech's technology improves head protection for football players.

The company says it reduces acceleration after a hit by 18 percent, on average.

Elliot Kaye, chairman of the U.S. Consumer Product Safety Commission, said the agency is "concerned" about the false claims out there.

Kaye has talked to many parents who want reassurance that their children will be safe while playing sports. Some companies mislead them, Kaye said.

His message to parents: "A product will not solve your problem."

More-informed coaches trained to be aware of concussions can make a difference, he said.

That is the approach the West Chester Area School District takes, said athletic director Ken McCormick.

About five years ago, West Chester schools started using a concussion testing system developed by imPACT Applications of Pittsburgh to determine whether players can return to play, he said.

Coaches also have adapted their practices to try to prevent concussions, including avoiding hitting and tackling, when possible, he said.

About four years ago, the district considered using products to alter helmets, but its solicitor advised against it because of liability issues, McCormick said. Its helmet manufacturer, Riddell, the industry leader that dominates sales along with Schutt Sports, said anything that altered the helmet would invalidate the warranty.

The National Football League Players Association said that it had no comment on specific products but that it depends on experts to evaluate advances.

Most helmet testing does not address reducing the brain's rapid rotation in the skull during impacts, which is key to reducing concussions, said Douglas Smith, director of the University of Pennsylvania's Center for Brain Injury and Repair.

Current government standards for testing helmets focus on stopping skull fractures, which are comparatively rare, he said.

"We need to develop much better safety standard approaches to evaluate this," Smith said. "What needs to be done is actually quite difficult."