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Site-Specific Transmission of a Floor-Based, High-Frequency, Low-Magnitude Vibration Stimulus in Children With
Harshvardhan Singh1, Daniel G Whitney1, Christopher A Knight1
1Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE.
Insights
High-frequency vibration amplified in the tibia but reduced in the femur of children with spastic cerebral palsy (CP). Vibration transmission was inversely related to spasticity, suggesting potential bone adaptation insights.
Area of Science:
- Biomechanics
- Pediatric Rehabilitation
- Neurology
Background:
- Children with spastic cerebral palsy (CP) often exhibit altered motor function and bone health.
- Whole-body vibration (WBV) is explored as a therapeutic intervention, but its transmission in this population is not well understood.
Purpose of the Study:
- To quantify the transmission of high-frequency, low-magnitude vibration from a floor-based platform to the distal tibia and femur in children with spastic CP.
- To investigate the relationship between vibration transmission and the degree of plantar flexor spasticity.
Main Methods:
- A cross-sectional study involving 18 children with spastic CP and 10 typically developing children (ages 4-12).
- Vibration signals were measured using accelerometers at the platform, distal tibia, and distal femur.
- Plantar flexor spasticity was assessed using the Modified Ashworth Scale.
Main Results:
- Vibration signals were amplified at the distal tibia in both CP and control groups compared to the platform.
- Vibration signals were amplified at the distal femur in controls but attenuated in children with CP.
- Higher spasticity was negatively correlated with vibration transmission to both the distal tibia and femur in children with CP.
Conclusions:
- Floor-based vibration transmission differs between children with and without CP, with amplification in the tibia and attenuation in the femur of those with CP.
- The degree of spasticity influences vibration transmission, potentially impacting bone adaptation.
- Further research is needed to determine if these transmission patterns affect bone adaptation in children with CP.
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.
