Leon S Siriwardhana1, Gillian M Nixon2, Margot J Davey2, Dwayne L Mann3, Shane A Landry4, Bradley A Edwards4, Rosemary S C Horne5. 1. The Ritchie Centre, Department of Paediatrics, Monash University and Hudson Institute of Medical Research, Melbourne, Australia. 2. The Ritchie Centre, Department of Paediatrics, Monash University and Hudson Institute of Medical Research, Melbourne, Australia; Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, Australia. 3. Sleep and Circadian Medicine Laboratory, Department of Physiology, Monash University, Melbourne, Australia; Institute for Social Science Research, The University of Queensland, Brisbane, Australia. 4. Sleep and Circadian Medicine Laboratory, Department of Physiology, Monash University, Melbourne, Australia; School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Australia. 5. The Ritchie Centre, Department of Paediatrics, Monash University and Hudson Institute of Medical Research, Melbourne, Australia. Electronic address: rosemary.horne@monash.edu.
Abstract
OBJECTIVES: To investigate the role of ventilatory control instability (i.e. loop gain) in children with Down syndrome and sleep disordered breathing. METHODS: Children (3-19 years) with Down syndrome and sleep disordered breathing (n = 14) were compared with typically developing children (n = 14) matched for age, sex and sleep disordered breathing severity. All children underwent overnight polysomnography. Spontaneous sighs were identified and a 180s analysis window (60s pre-sigh to 120s post-sigh) containing flow measurements and oxygen saturation were created. Loop gain, a measure of the sensitivity of the negative feedback loop that controls ventilation, was estimated by fitting a mathematical model of ventilatory control to the post-sigh ventilatory pattern. Results; Loop gain was significantly higher in children with Down syndrome compared to matched typically developing children (median loop gain [interquartile range]: 0.36 [0.33, 0.55] vs 0.32 [0.24, 0.38]; P = 0.0395). While children with Down syndrome also had significantly lower average oxygen saturation associated within each analysis window compared to typically developing children (mean ± standard deviation: 96.9 ± 1.3% vs 98.0 ± 1.0%; P = 0.0155), loop gain was not related to polysomnographic measures of hypoxia. CONCLUSIONS: Higher loop gain in children with Down syndrome and sleep disordered breathing indicates that these children have more unstable ventilatory control, compared to age, sex and sleep disordered breathing severity matched typically developing children. This may be due to an inherent impairment in ventilatory control in children with Down syndrome contributing to their increased risk of sleep disordered breathing which may inform alternative treatment options for this population. Crown
OBJECTIVES: To investigate the role of ventilatory control instability (i.e. loop gain) in children with Down syndrome and sleep disordered breathing. METHODS:Children (3-19 years) with Down syndrome and sleep disordered breathing (n = 14) were compared with typically developing children (n = 14) matched for age, sex and sleep disordered breathing severity. All children underwent overnight polysomnography. Spontaneous sighs were identified and a 180s analysis window (60s pre-sigh to 120s post-sigh) containing flow measurements and oxygen saturation were created. Loop gain, a measure of the sensitivity of the negative feedback loop that controls ventilation, was estimated by fitting a mathematical model of ventilatory control to the post-sigh ventilatory pattern. Results; Loop gain was significantly higher in children with Down syndrome compared to matched typically developing children (median loop gain [interquartile range]: 0.36 [0.33, 0.55] vs 0.32 [0.24, 0.38]; P = 0.0395). While children with Down syndrome also had significantly lower average oxygen saturation associated within each analysis window compared to typically developing children (mean ± standard deviation: 96.9 ± 1.3% vs 98.0 ± 1.0%; P = 0.0155), loop gain was not related to polysomnographic measures of hypoxia. CONCLUSIONS: Higher loop gain in children with Down syndrome and sleep disordered breathing indicates that these children have more unstable ventilatory control, compared to age, sex and sleep disordered breathing severity matched typically developing children. This may be due to an inherent impairment in ventilatory control in children with Down syndrome contributing to their increased risk of sleep disordered breathing which may inform alternative treatment options for this population. Crown