Almost a third of U. S. doctors have never heard of the choking game played by many teens, nor can they spot the tell-tale signs of the fatal past-time.

In the choking game, participants attempt to gain a euphoric feeling by depriving the brain of oxygen by applying pressure with another person’s hands or with belts, neckties, or other devices. Another way is one person taking a deep breath and holding it while a second person hugs them from behind until the first person feels dizzy and passes out.

The game can also cause seizures, headaches, bone breaks and brain injury, if not death.

"I have seen three to four kids affected by this and it seems if it causes death then it should be talked about," said Dr Nancy Bass, senior author of the paper and an associate professor of pediatrics and neurology at Rainbow Babies and Children's Hospital, University Hospitals Case Medical Center in Cleveland.

“A more uniform approach is needed to educate doctors," said study first author Dr Julie McClave, a pediatric resident at Rainbow Babies.

A recent CDC report estimated that about 85 deaths from 1995 to 2007 were possibly caused by participation in choking games, and several incidences of brain injuries were reported.

This survey of 163 pediatricians and family doctors revealed that more than 68 per cent had heard of the choking game, the majority of those (61.3 percent) through popular news sources, indicating they had only a superficial knowledge of the phenomenon.