Experts believe that epileptic fits may originate in the temporal lobe, which is linked to memory.

They say studying the brainwaves of severely epileptic teenagers as they play with video games may help identify which parts of the brain are most associated with memory and could eventually provide a key to treatment.

Epilepsy, which affects around 400,000 people in the UK, results in recurrent fits or seizures which can lead to loss of consciousness and death.

It is thought to be characterised by sudden out of control brainwave patterns.

Virtual mazes

Writing in Nature magazine, US neuroscientists at Brandeis University and Children's Hospital in Boston describe how they used a video game which had been specifically designed by a 15 year old for the research.

It leads players through a series of virtual mazes and leaves them to find their own way out.

They therefore have to rely on their memory of how they got there.

The scientists attached wires to various parts of the teenagers' brains to monitor their electrical activity.

They found that different parts of the brain reacted to different parts of the video games.

Certain slower types of electrical activity were associated with spatial learning and were particularly marked when the teenagers were trying to find their way out of the mazes.

Previous research on rats and other animals has already shown a link between slower brainwaves or theta oscillations and spatial memory.

Dr Michael Kahana, one of the researchers, said: "Hundreds of papers have linked theta oscillations to spatial learning in rats and other animals; our study is the first to seal the link between theta and spatial learning in humans."

People with mild epilepsy can be treated with medication, but, in those with a severe form of the condition, doctors try to locate and remove the part of the brain which is thought to be the root of the problem.

But they worry that, unless they understand precisely where epilepsy originates, they might mistakenly cut out parts of the brain which may be vital for memory and other brain functions.

'Heroic teenagers'

Dr Joseph Madsen, another of the researchers, said the new research "may help to identify where memory functions are located in the brain and eventually help in the treatment of epilepsy using surgery or other methods".

Co-researcher Dr Robert Sekula commented: "By playing video games today, these heroic teenagers are helping the kids of the future have happier, healthier, seizure-free lives.

"With more work, we may be able to understand why the brain's rhythmic activity sometimes spins out of control.