Effects of high-frequency, low-magnitude vibration on muscle activity in children with spastic cerebral palsy
Date
2015
Authors
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Publisher
University of Delaware
Abstract
Cerebral palsy (CP) is one of the most common causes of disability in children and is a neuromuscular disorder that limits mobility, impairs motor control, and is damaging to the musculoskeletal system. One treatment that has shown promise in offsetting the limited musculoskeletal development in children with CP is high-frequency, low-magnitude vibration (HLV). The purpose of this study was to determine if an HLV stimulus emitted by a floor-based platform increases muscle activity in the lower extremities of children with spastic CP. We hypothesized that an HLV stimulus would increase muscle activity in children with spastic CP. Children with spastic CP between the ages of 4-11 with a gross motor function classification of I-III (n = 11) and TD children of similar age (n=10) took part in this study. Muscle activity was measured for the tibialis anterior (TA), lateral gastrocnemius (LG), medial gastrocnemius (MG), soleus (SOL), biceps femoris (BF), and vastus lateralis (VL) using surface electromyography (EMG). Children stood on a platform that emits an HLV (30 Hz at 0.3 g) for three conditions that lasted thirty seconds each. First, the platform was off (pre-HLV), then on (HLV), then off again (post-HLV). Root mean square (RMS) values were obtained from the EMG data collected from all muscles, and differences between conditions and groups were tested. There were no significant differences between pre-HLV and post-HLV conditions in children with CP or TD children (p > 0.05). A significant condition effect suggests that there was greater muscle activity during the HLVon condition versus the HLVoff condition in the MG, SOL and BF muscles (p < 0.05). Furthermore, there was a significant group-by-condition effect with greater muscle activity during the HLV condition in the TA, LG, and VL muscles (p < 0.05) for the CP group but not the TD group. The results from this study indicate that a floor-based HLV stimulus increases the activity of the lower extremity muscles in children with spastic CP. The enhanced sensitivity of muscle to HLV in children with spastic CP may explain, at least in part, the previously shown positive effect of HLV on the musculoskeletal system in children with CP.