title: Growth hormone therapy, muscle thickness, and motor development in Prader-Willi syndrome: an RCT.
abstract: OBJECTIVE
  To investigate the effect of physical training combined with growth hormone (GH) on muscle thickness and its relationship with muscle strength and motor development in infants with Prader-Willi syndrome (PWS).
  
  
  METHODS
  In a randomized controlled trial, 22 infants with PWS (12.9 ± 7.1 months) were followed over 2 years to compare a treatment group (n = 10) with a waiting-list control group (n = 12). Muscle thickness of 4 muscle groups was measured by using ultrasound. Muscle strength was evaluated by using the Infant Muscle Strength meter. Motor performance was measured with the Gross Motor Function Measurement. Analyses of variance were used to evaluate between-group effects of GH on muscle thickness at 6 months and to compare pre- and posttreatment (after 12 months of GH) values. Multilevel analyses were used to evaluate effects of GH on muscle thickness over time, and multilevel bivariate analyses were used to test relationships between muscle thickness, muscle strength, and motor performance.
  
  
  RESULTS
  A significant positive effect of GH on muscle thickness (P < .05) was found. Positive relationships were found between muscle thickness and muscle strength (r = 0.61, P < .001), muscle thickness and motor performance (r = 0.81, P < .001), and muscle strength and motor performance (r = 0.76, P < .001).
  
  
  CONCLUSIONS
  GH increased muscle thickness, which was related to muscle strength and motor development in infants with PWS. Catch-up growth was faster in muscles that are most frequently used in early development. Because this effect was independent of GH, it suggests a training effect.
authors.affiliation: Department of Rehabilitation, Pediatric Physical Therapy, Scientific Institute for Quality of Healthcare, lin.reus@gmail.com.
authors.forename: Linda
authors.initials: L
authors.lastname: Reus
authors.affiliation: Child Development and Exercise Center, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, Netherlands;
authors.forename: Sigrid
authors.initials: S
authors.lastname: Pillen
authors.affiliation: Faculty of Social Sciences, and.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Pelzer
authors.affiliation: Department of Pediatric Endocrinology, Radboud University Medical Center, Nijmegen, Netherlands;
authors.forename: Janielle A A E M
authors.initials: JA
authors.lastname: van Alfen-van der Velden
authors.affiliation: Dutch Growth Research Foundation, Rotterdam, Netherlands; Department of Pediatric Endocrinology, Erasmus Medical Centre Rotterdam, Rotterdam, Netherlands; and.
authors.forename: Anita C S
authors.initials: AC
authors.lastname: Hokken-Koelega
authors.affiliation: Kempenhaeghe, Epilepsy Centre, Heeze, Netherlands.
authors.forename: Machiel
authors.initials: M
authors.lastname: Zwarts
authors.affiliation: Department of Pediatric Endocrinology, Radboud University Medical Center, Nijmegen, Netherlands;
authors.forename: Barto J
authors.initials: BJ
authors.lastname: Otten
authors.affiliation: Department of Rehabilitation, Pediatric Physical Therapy, Scientific Institute for Quality of Healthcare.
authors.forename: Maria W G
authors.initials: MW
authors.lastname: Nijhuis-van der Sanden
mesh_terms: D002675:Child, Preschool; D003131:Combined Modality Therapy; D005081:Exercise Therapy; D005260:Female; D019382:Human Growth Hormone / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009048:Motor Skills / Q000187:drug effects*; D053580:Muscle Strength / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000187:drug effects*; D009426:Netherlands; D011218:Prader-Willi Syndrome / Q000175:diagnosis / Q000188:drug therapy*; D016037:Single-Blind Method; D014463:Ultrasonography
chemical_list: D019382:Human Growth Hormone
keywords: Prader-Willi syndrome; body composition; growth hormone; infants; motor development; muscle development