Harshvardhan Singh1, Daniel G Whitney1, Christopher A Knight1, Freeman Miller2, Kurt Manal3, Paul Kolm4, Christopher M Modlesky5. 1. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE. 2. Department of Orthopedics, Nemours AI duPont Hospital for Children, Wilmington, DE. 3. Department of Mechanical Engineering, University of Delaware, Newark, DE. 4. Christiana Care Outcomes Research, Christiana Care Health System, Newark, DE. 5. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE. Electronic address: modlesky@udel.edu.
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. DESIGN: Cross-sectional study. SETTING: University research laboratory. PARTICIPANTS: 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). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: 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.
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. DESIGN: Cross-sectional study. SETTING: University research laboratory. PARTICIPANTS: 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). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: 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: Lubomira Slatkovska; Shabbir M H Alibhai; Joseph Beyene; Hanxian Hu; Alice Demaras; Angela M Cheung Journal: Ann Intern Med Date: 2011-11-15 Impact factor: 25.391
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