Cognitive outcomes in children with mild obstructive sleep disordered breathing

Abstract

Introduction: Sleep disordered breathing (SDB) is common in children and ranges from primary snoring (PS) to obstructive sleep apnoea (OSA) and is thought to represent a spectrum of SDB from mild to severe. Distinction between PS and OSA is made by polysomnography (PSG) evaluation; an obstructive apnoea-hypopnoea index (OAHI) -1/hr is taken to be diagnostic of OSA and those who snore but have few or no events (OAHI < 1/hr) are referred to as PS. Previously PS was considered to be a benign condition but in recent years a growing body of evidence suggests that school-aged children are also at risk of cognitive and behavioural deficits. Whether similar deficits are also evident in pre-school children with PS and OSA remains to be fully tested. This study reports on the baseline cognitive outcomes in children 3-5 y with PS (OAHI < 1/hr) and those with mild-moderate OSA (OAHI 1-10/hr) prior to treatment with adenotonsillectomy. Materials and methods: The Pre-School OSA Tonsillectomy Adenoidectomy Study (POSTA) is a multi-centre randomised controlled trial undertaken to evaluate whether IQ deficits in pre-school children with mildmoderate OSA are corrected by adenotonsillectomy. Alongside this group, children who are primary snorers, with an OAHI < 1/hr and clinical symptoms of OSA, have also been studied in a similar manner. Children aged 3-5 y referred to ENT for assessment of OSA symptoms were screened by clinical evaluation and with the paediatric sleep questionnaire (PSQ). Those with positive PSQ results underwent baseline PSG testing and neurocognitive assessment using the Woodcock- Johnson IIIda cognitive assessment instrument validated in this age group. In this study, baseline data is compared for those children recruited to POSTA, with OAHI 1-10/hr and those children not meeting criteria with PS [OAHI < 1/hr]. Results: 88 children have been enrolled in the study and complete data is available on 71 children. The mean (SD) age = 48.5 (8.0) mths and range = 31-69 mths. BMI ranged from 13.5-24.2 kg/m2 with a mean of 16.3 kg/m2. There was a normal distribution of WJIII-GIA scores (70-143 with a mean (SD) = 104.6 (13.9)). There was no significant difference between the two subgroups of OAHI of < 1 (n=33) and those with OAHI of 1-10 (n=38). Even when subdivided into those with an OAHI of < 1(n=33), OAHI of 1-5 (n=31) and an OAHI of >=5 (n=7) there was no significant difference in BMI, age, PSQ or general cognitive functioning. There was a significant difference between OAHI groups in clinical assessment of tonsil size (p=0.007). There was some skewing of the data towards a higher BMI in the higher OAHI group but numbers were small. ANOVA using BMI and clinically evaluated tonsil size was able to predict the higher OAHI group (p=0.002). Conclusions: This study shows no significant cognitive differences between PS and mild or moderate OSA as classified by OAHI in this preschool age group.L6207881222018-02-27 <br />