Snoring due sleep apnea may impair brain function in a much worse way than previously thought, according to a new study.

Sufferers of Obstructive Sleep Apnea - experience similar changes in brain biochemistry as people who have had a severe stroke or who are dying, the research shows. OSA is caused by obstruction of the airway, a disorder characterised by pauses in breathing during sleep.

A study by University of New South Wales - Brain Sciences is the first to analyse, in a second-by-second timeframe, what is happening in the brains of sufferers as they sleep. Previous studies have focussed on recreating oxygen impairment in patients who are awake.

'It used to be thought that apnoeic snoring had absolutely no acute effects on brain function but this is plainly not true,' said study co-author Caroline Rae, professor at Prince of Wales Medical Research Institute.

Sleep apnea affects as many as one in four middle-aged men, with around three percent going on to experience a severe form of the condition characterised by extended pauses in breathing, repetitive asphyxia and sleep fragmentation.

Children with enlarged tonsils and adenoids are also affected, raising concerns of long-term cognitive damage.

Rae and collaborators from Sydney University's Woolcock Institute used magnetic resonance spectroscopy to study the brains of 13 men with severe, untreated, obstructive sleep apnea, said a UNSW release.

They found that even a moderate degree of oxygen desaturation during the patients' sleep had significant effects on the brain's bioenergetic status.

'The findings show that lack of oxygen while asleep may be far more detrimental than when awake, possibly because the normal compensatory mechanisms don't work as well when you are asleep,' said Rae.

These findings were published in the May edition of Journal of Cerebral Blood Flow and Metabolism.