Methods Retrospective case note analysis of all outpatient attendees over a 25 month period, to identify those with symptoms documented in the case notes (including snoring, mouth breathing, nocturnal pauses, restless sleep, frequent waking). A questionnaire (Hong Kong Children Sleep Survey Questionnaire) was subsequently conducted via telephone to the parents of all attendees with no documented symptoms of OSAS. Overnight pulse oximetry studies (POS) were subsequently performed for the group of children identified to have 3 or more symptoms (a ‘cluster’) from the questionnaire.
Results 44 patients (age 6 months–18years; mean 6 years; 23 male) were followed up in the district outpatient neurodevelopmental paediatric clinic. The prevalence of one or more documented symptoms in our population was 34% (15/44). The prevalence of diagnosed OSAS was 16% (7/44; age 6 months to 18 years; mean 7 years), with all diagnosed patients reporting cluster of symptoms prior to diagnosis. From the group with no documented symptoms, 46% (11/24) of parents reported a cluster of symptoms during telephone questionnaire. POS were done in 7/11 of these children and found to be normal.
Conclusion The prevalence of OSAS in our population is lower than previously reported in similar populations but a further 25% were found to have a cluster of symptoms on direct parental questioning. Parents of children with DS significantly underestimate the severity of their child’s sleep disturbance, with poor correlation reported between symptoms and POS results. Our results may point to the need for objective screening for OSAS in children with DS.