Among a group of children with enlarged tonsils and adenoids who were suspected of having disordered breathing during sleep, those who snored a lot and spent less time in bed did less well on certain mental tests, according to a new study.

Snoring can be a sign of sleep apnea, in which airways become obstructed during sleep and cause brief but frequent breathing blockages.

A number of studies have suggested that children who snore every night have impaired mental performance, Dr Paul M. Suratt said.