title: Site-Specific Transmission of a Floor-Based, High-Frequency, Low-Magnitude Vibration Stimulus in Children With Spastic Cerebral Palsy.
abstract: OBJECTIVE
  To determine the degree to which a high-frequency, low-magnitude vibration signal emitted by a floor-based platform transmits to the distal tibia and distal femur of children with spastic cerebral palsy (CP) during standing.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Children with spastic CP who could stand independently (n=18) and typically developing children (n=10) (age range, 4-12y) participated in the study (N=28).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The vibration signal at the high-frequency, low-magnitude vibration platform (approximately 33Hz and 0.3g), distal tibia, and distal femur was measured using accelerometers. The degree of plantar flexor spasticity was assessed using the Modified Ashworth Scale.
  
  
  RESULTS
  The high-frequency, low-magnitude vibration signal was greater (P<.001) at the distal tibia than at the platform in children with CP (.36±.06g vs .29±.05g) and controls (.40±.09g vs .24±.07g). Although the vibration signal was also higher at the distal femur (.35±.09g, P<.001) than at the platform in controls, it was lower in children with CP (.20±.07g, P<.001). The degree of spasticity was negatively related to the vibration signal transmitted to the distal tibia (Spearman ρ=-.547) and distal femur (Spearman ρ=-.566) in children with CP (both P<.05).
  
  
  CONCLUSIONS
  A high-frequency, low-magnitude vibration signal from a floor-based platform was amplified at the distal tibia, attenuated at the distal femur, and inversely related to the degree of muscle spasticity in children with spastic CP. Whether this transmission pattern affects the adaptation of the bones of children with CP to high-frequency, low-magnitude vibration requires further investigation.
authors.affiliation: Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE.
authors.forename: Harshvardhan
authors.initials: H
authors.lastname: Singh
authors.affiliation: Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Whitney
authors.affiliation: Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Knight
authors.affiliation: Department of Orthopedics, Nemours AI duPont Hospital for Children, Wilmington, DE.
authors.forename: Freeman
authors.initials: F
authors.lastname: Miller
authors.affiliation: Department of Mechanical Engineering, University of Delaware, Newark, DE.
authors.forename: Kurt
authors.initials: K
authors.lastname: Manal
authors.affiliation: Christiana Care Outcomes Research, Christiana Care Health System, Newark, DE.
authors.forename: Paul
authors.initials: P
authors.lastname: Kolm
authors.affiliation: Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE. Electronic address: modlesky@udel.edu.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Modlesky
mesh_terms: D061725:Accelerometry; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000502:physiology*; D006801:Humans; D008297:Male; D009128:Muscle Spasticity / Q000503:physiopathology; D011187:Posture / Q000502:physiology; D012720:Severity of Illness Index; D013977:Tibia / Q000502:physiology*; D014732:Vibration
keywords: Bone and bones; Cerebral palsy; Muscle spasticity; Rehabilitation; Vibration