Sleep apnoea in kids 'harms the developing brain'
17th March 2017 – Children who have obstructive sleep apnoea are at higher risk of experiencing problems with brain development, results of a small study suggests.
US researchers say they found significant reductions in grey matter in several regions of the brain among children aged between 7 and 11 who had moderate or severe apnoea.
These areas contain brain cells responsible for movement, memory, emotions, speech, perception, decision making and self-control.
Fatigue and poor concentration
"Obstructive sleep apnoea (OSA) is characterised by intermittent obstruction of the upper airway during sleep," explains Dr Francis Gilchrist, a consultant in paediatric respiratory medicine at Royal Stoke University Hospital, who was not involved in this research. "In children it is usually caused by enlargement of the tonsils and adenoids.
"OSA is associated with snoring, pauses in the child's breathing and lower oxygen levels. It is known that if left untreated, OSA can affect the child's behaviour and performance at school."
Behaviour and school performance usually improve following treatment, which usually means removal of the tonsils and adenoids.
The latest study suggests there may be a strong link between this common type of sleep disturbance and the loss or delayed growth of neurons. These are cells in the brain that transmit messages.
Cognitive tests and MRI scans
Researchers from the University of Chicago based their findings on 16 children with OSA who underwent night time monitoring in a children's sleep laboratory. Each child was tested for thinking skills and underwent magnetic resonance imaging (MRI) scans.
The results of the tests were compared with those of 9 other children who did not have OSA and a further group of 191 children who had undergone brain scans as part of a separate study.
Cortical regions of significantly reduced regional grey matter volume in obstructive sleep apnoea over control subjects displayed in yellow on the cortical surface on a single subject. Photo credit: Mona Philby, Paul Macey, Richard Ma, Rajesh Kumar, David Gozal and Leila Kheirandish-Gozal
Missing grey matter
The study, in the journal Scientific Reports, revealed reductions in the volume of grey matter in several regions of the brains of children with OSA. These included:
- The frontal cortices, which handle movement, problem solving, memory, language, judgement and impulse control
- The prefrontal cortices, responsible for complex behaviours, planning and personality
- The parietal cortices, which integrate sensory input
- The temporal lobe, which handles hearing and selective listening
- The brainstem, which is responsible for controlling cardiovascular and respiratory functions
The researchers say that although the reductions in grey matter were extensive, it is hard to measure the consequences this might have on children's brain development. They suggest this should be a matter for follow-up research.
"These brain changes may be responsible for the problems with behaviour and school performance," comments Dr Gilchrist, who is also a trustee for the British Lung Foundation. "We do not know if these MRI changes return to normal (as behaviour and school performance do) once the OSA is successfully treated.
"Parents who are concerned that their child [is] affected by OSA should ask to be referred to a respiratory paediatrician."