The cap pumps a liquid coolant round the front of the scalp and the forehead.
This chills the prefrontal cortex, a part of the brain thought to play a role in prompting deep sleep.
Tests show insomniacs have higher levels of activity in this part of the brain at night than those who have no trouble nodding off.
But cooling the brain seems to dampen this activity and allows it to switch off properly for a good night’s sleep.
Eight volunteers wore the cap for an hour before bedtime and the first hour of sleep, after which researchers removed it.
Scans taken during the night showed wearing the cap caused a marked decline in brain metabolism, the rate at which cells in the frontal cortex process sugars and chemicals in the blood.
Six of the volunteers reported more refreshing sleep, fewer distracting thoughts at bedtime and waking up less in the night.
One in four people is affected by insomnia – most have ‘primary’ insomnia, an inability to fall asleep because of worries or stress.
Secondary insomnia, which is due to existing illness or a side-effect of prescription drugs, is less common.
Lots of money are being spent every year towards sleeping pills. Many sufferers rely on drugs such as benzodiazepines, which act as tranquillisers, to help them.
In England alone, there are ten million prescriptions for sleeping pills every year.
Yet the drugs can have side effects, such as memory and concentration problems, and make you more likely to have an accident.
In the search for drug-free alternatives, scientists at the University of Pittsburgh have spent the past few years studying the brain’s metabolism at night.
They found insomnia patients have increased activity, especially in the frontal cortex. Essentially, their brain cells continue to work at full capacity at night when they should be resting.
Professor Eric Nofzinger, who led the research, said they then searched for ways to slow the brain’s metabolic rate. ‘That’s when we came across cerebral hypothermia or brain cooling,’ he says.
This technique is already used in medicine. Researchers first discovered its benefits ten years ago, when they found babies starved of oxygen at birth had a better chance of survival if their brains were quickly cooled from the normal temperature of 37c to 32c.
This stops brain cells from committing suicide when deprived of oxygen.
Scalp cooling is also used as a way to minimise hair loss in cancer patients undergoing chemotherapy.
Professor Nofzinger and his team recruited eight patients with primary insomnia and scanned their brains to measure activity levels in the frontal cortex at night.
They then used the cooling cap to see if it made a difference.
The results, presented at a recent conference in Seattle, showed a significant drop in activity levels once the brain was chilled.
‘There was an increase in deeper, restorative sleep, feelings of relaxation and a reduction in distracting thoughts before sleep,’ says Professor Nofzinger.
But British sleep specialists say there are simpler ways to cool the body to aid sleep.
Professor Jim Horne, from Loughborough University, says that a bedside fan that blows cool air over the face can help.
As cooled blood from the cheeks flows back to the heart, it runs alongside an artery transporting warmer blood in the other direction to the brain.
‘It’s like having a hot water pipe next to the cold pipe,’ Professor Horne says.
‘Cooler blood enters the brain and leads to better sleep. A gentle breeze over the face is all that’s needed.’
Source: Mail Online. 14th. July.2009