HARRISON, Wis. -- A 13-year-old Wisconsin boy who died this week suffered a brain injury while attempting to get high playing ``the choking game.''

Calumet County Sheriff's Department investigators said Thursday the practice is common among several students in Appleton middle and high schools.

Kyle Kelly McCarthy, who attended Madison Middle School, died early Monday at Children's Hospital of Wisconsin after being found unconscious in his home Sunday, Calumet County Medical Examiner Mike Klaeser said.

After confirming the cause of death, Madison Principal Chris VanderHeyden said Thursday night he would encourage staff members Friday to ``share the facts with students to quell the rumors.'' He added in-depth prevention measures would come next week after he met with the school's crisis response team and staff.

"I certainly intend that Madison will take this information and get it to parents and do our part so kids understand this is dangerous," he said.

According to several Web sites, teens or pre-teens who play the "game" experience a floating sensation or "high" using bags, belts, ties or their own hands to cut off oxygen to their brain.

The practice is also known as the pass out game, the fainting game, the tingling game, the something dreaming game, as well as funky chicken, blackout, flatliner, airplaning, suffocation roulette and space monkey.

In July, USA Today reported that children as young as 10 have tried it; older teens tend to do it looking to increase sexual pleasure; while others are seeking a non-drug high.

Calumet sheriff's department Sgt. Wendy Baldwin said McCarthy used a cloth rope in the basement to make himself unconscious, but the teen never regained consciousness after the incident about 4:00 p.m. Sunday.

He was found in the basement about 15 minutes later by his father, who resuscitated him after using directions from staff at the county 911 center.

Sgt. Mark Wiegert said investigators were surprised at how common the practice, which has been highlighted on TV shows such as ``20/20,'' ``Oprah'' and ``Dr. Phil,'' seemed to be in Appleton schools.

"I have a feeling we've only uncovered the tip of the iceberg," he said. "It just goes on. One kid passes it on to another, and they pass it on to another."

"It can be by themselves or in groups."

In groups, after the teen passes out friends will ease him to the floor and wait for him to regain consciousness.

"There is a perception that if we do this gently and do this right, it will be OK. It's not that way," Wiegert said.

He said there are Web sites with information on the practice, as well as several sites run by parents whose children died trying it.

But Wiegert said it is difficult to know how common it is.

"I think it is so new at this point, in the last year or so, there are not a lot of statistics," he said.

Klaeser said the practice is dangerous since each time a youth passes out, it means the brain has been deprived of oxygen.

"Every time you do this you injure your brain," he said.

Klaeser said it would have been easy for investigators to miss the signs indicating ``the choking game'' was a factor and rule the boy's death a suicide.

He said officials were hesitant to talk publicly about the death.

``We are trying not to open the floodgates, but obviously we are too late for that,'' he said about educating youths about the practice and its dangers.

Baldwin, who responded to the 911 call at the home, said the family is ``very loving, supportive, very close,'' and eventually wants to educate children and their parents about the game.

But she said that won't happen right away.

"They are going to need some time to heal from this," she said.

"The family really wants to feel like they are making a difference through Kyle."