Dr. Hannah Burns: Cognitive outcomes in Children with mild OSA.

Chawla J, Harris MA, Black R, Leclerc MJ, Burns H, Waters KA, Bernard A, Lushington K, Heussler H. Cognitive parameters in children with mild obstructive sleep disordered breathing. Sleep Breath. 2021 Sep;25(3):1625-1634. doi: 10.1007/s11325-020-02264-1. Epub 2021 Jan 7. PMID: 33411186.

Few high level studies exist examining the efficacy of adenotonsillectomy for paediatric OSA. The highly regarded CHAT study, a randomised control study comparing adenotonsillectomy to watchful waiting is most often cited. As expected it confirmed tonsillectomy improved polysomography perimeters and QOL scores. It did not confidently show improved cognitive function in the surgical arm, although in further analysis nonverbal reasoning, attention and fine motor skills did correlate with improved respiratory scores.

The recently published POSTA study again looked at mild and moderate OSA and randomised children to early intervention vs twelve month observation This study examined a younger cohort, the preschool group. The hypothesis being that earlier age of intervention may result in cognitive improvements.

190 children between 3 to 5 were recruited from ENT clinics across Australia with symptoms of sleep disordered breathing ( using the Paediatric Sleep Questionnaire) and an AHI less than 10. They were randomised to early surgery versus the routine 12month waitlist for surgery. All children underwent cognitive tests, medical review, audiology, behavioural assessments and PSG at baseline and 12month followup.

76% attended followup. Intellectual ability and executive function showed no improved outcomes for the surgical arm at 12 months. Improvements were however seen in the scores reflective of behaviour, somatatisation, parent reports of sleep quality, snoring and eating. The surgical children greatly reduced their daytime naps compared to their matched cohort. Not suprisingly PSG scores were also better in the intervention group.

Previous observational studies had suggested IQ improvement with adenotonsillectomy, this randomised controlled study however would conclude that IQ improvement may reflect expected changes with age and development. It can serve to reassure physicians and surgeons that waiting times of 12 months are unlikely to negatively impact intellectual development in this age group.

Of note this study group included children with AHI < 1, ie primary snorers and excluded children with severe OSA ( AHI>10). Statistical analysis however did not suggest that including these mild OSA or primary snorers diluted the cognitive results. A followup study published this year, "Cognitive parameters in children with mild obstructive sleep disordered breathing." Chawla, Jasneek, et al. Sleep and Breathing (2021): 1-10, compared the cognitive and behavioural scores between the simple snores and those with mild OSA based on AHI scores. This found no symptomatic difference between the groups concluding that PSG alone should not be used to guide management of this patient group. Further studies looking at children with moderate or severe scores PSG would be helpful to further illicit the effect of OSA on cognition.