Snoring infants and children are more likely to experience learning and behavioural problems, Australian research shows.
But while an improvement in their condition often corresponded with improvements in learning, behavioural problems continued to dog children long after treatment.
About one million Australian children suffer from moderate to severe snoring, which is often caused by enlarged tonsils or adenoids, said Dr Sarah Biggs from Melbourne's Monash Institute of Medical Research.
Dr Biggs studied snoring in more than 160 children aged seven to 12 and found they suffered impaired learning, memory and behaviour.
Children whose condition improved four years later, including after surgery to remove their tonsils, had improvements in some areas including aspects of IQ but behaviour problems remained, Dr Biggs said.
'They still had behavioral problems when compared with our healthy children,' she told AAP.
'When there is improvement in the sleep disruption or disorder the brain recovers in terms of learning but the behaviour doesn't seem to change.'
Dr Biggs said it was possible that the sleep disruption caused by snoring was leading to poor behaviour during the day, but it could also be other factors that needed further investigation.
Researchers are now studying preschool children and following them up four years later to try and find a window of opportunity for earlier treatment, Dr Biggs said.
Dr Mark Kohler from the University of South Australia's Centre for Sleep Research has studied snoring infants and found the condition is associated with learning problems as early as six to 12 months.
About nine per cent of babies snore, Dr Kohler said.
The Adelaide researchers studied 450 snoring babies in 2010/2011 and found about a five per cent reduction in learning.
Those still snoring at six and 12 months were most likely to have learning problems, Dr Kohler said.
'What's unknown is whether these are going to be long term deficits, given that infancy is such a critical time of brain development,' Dr Kohler told AAP.
Dr Kohler said the initial study was to determine whether learning problems were present in babies. Researchers are now studying children aged one to four.
Dr Biggs and Dr Kohler presented their research findings this week at the Australasian Sleep Conference in Darwin.