title: Autonomic nervous system reactivity: children with and without sickle cell disease.
abstract: BACKGROUND
  Previous studies of healthy children have indicated a link between autonomic nervous system (ANS) reactivity and health outcomes, but there is limited research on whether ANS reactivity is similar for children with chronic conditions.
  
  
  OBJECTIVE
  The aim of this study was to determine if ANS reactivity differs for children with sickle cell disease (SCD) compared with a community sample of children without SCD.
  
  
  METHODS
  In two cross-sectional, descriptive studies, 32 public school children without chronic health problems were compared with 33 children with SCD. The children were 5-8 years old and they completed standardized protocols measuring ANS responses (respiratory sinus arrhythmia and preejection period) during rest and challenge conditions in social, cognitive, sensory, and emotion domains. Reactivity was calculated as the difference between challenge response minus rest for each domain and overall.
  
  
  RESULTS
  There were differences in the distributions of the samples in parent education and child age, so these variables were adjusted for in subsequent analyses. The community sample showed parasympathetic withdrawal (low respiratory sinus arrhythmia scores) and greater parasympathetic reactivity (low respiratory sinus arrhythmia difference scores and percentage of negative scores) compared with the children with SCD in the social (p < .05) and sensory (p < .05) domains. The children with SCD showed greater sympathetic reactivity (low preejection period difference scores) compared with the community children in the cognitive domain (p < .05), and a greater percentage of children with SCD versus the community children showed negative preejection period difference scores (sympathetic reactivity) in the social domain (p < .05). The community sample, but not the children with SCD, showed changes in respiratory sinus arrhythmia across domains (p < .05).
  
  
  CONCLUSIONS
  Children with SCD may display a different pattern of ANS responses to laboratory challenges compared with children without SCD from the same community.
authors.affiliation: Department of Hematology/Oncology, Children's Hospital & Research Center Oakland, California 94609, USA. mtreadwell@mail.cho.org
authors.forename: Marsha J
authors.initials: MJ
authors.lastname: Treadwell
authors.forename: Abbey
authors.initials: A
authors.lastname: Alkon
authors.forename: Lori
authors.initials: L
authors.lastname: Styles
authors.forename: W Thomas
authors.initials: WT
authors.lastname: Boyce
mesh_terms: D000755:Anemia, Sickle Cell / Q000503:physiopathology*; D001146:Arrhythmia, Sinus / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010275:Parasympathetic Nervous System / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*