title: Development and validation of a measurement system for assessment of energy expenditure and physical activity in Prader-Willi syndrome.
abstract: OBJECTIVE
  The morbid obesity associated with Prader-Willi syndrome (PWS) may result from either excessive energy intake or reduced energy expenditure (EE). In this report, we describe the development and validation of an Activity-Energy Measurement System (AEMS) to measure EE and physical activity components in an environment approximating free-living conditions.
  
  
  METHODS
  The AEMS consists of a live-in, whole-room indirect calorimeter equipped with a novel force platform floor system to enable simultaneous measurements of EE, physical activity, and work efficiency during spontaneous activities and standardized exercises. Free-living physical activity and estimated free-living EE are measured using portable triaxial accelerometers individually calibrated in each subject during their stay in the AEMS.
  
  
  RESULTS
  Representative data from two PWS patients and two matched control (CTR) subjects displayed EE during their inactive lifestyles.
  
  
  CONCLUSIONS
  This combination of methods will allow the quantification of daily EE and its components, the amount and energy cost of physical activity, and the relationships between body composition and EE, in order to determine their roles in the development and maintenance of the morbid obesity in PWS.
authors.affiliation: Department of Medicine, Vanderbilt University, Nashville, TN 37232-4453, USA. kong.chen@mcmail.vanderbilt.edu
authors.forename: K Y
authors.initials: KY
authors.lastname: Chen
authors.forename: M
authors.initials: M
authors.lastname: Sun
authors.forename: M G
authors.initials: MG
authors.lastname: Butler
authors.forename: T
authors.initials: T
authors.lastname: Thompson
authors.forename: M G
authors.initials: MG
authors.lastname: Carlson
mesh_terms: D000293:Adolescent; D000328:Adult; D002153:Calorimetry, Indirect / Q000379:methods; D002648:Child; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000503:physiopathology; D011218:Prader-Willi Syndrome / Q000378:metabolism / Q000503:physiopathology*; D018709:Statistics, Nonparametric