Effect of balance training on muscle activity used in recovery of stability in children with cerebral palsy: a pilot study

Abstract

This study explored possible neural mechanisms that contribute to improvements in balance control produced by reactive balance training in children with cerebral palsy (CP). Six children with CP (four males, two females; mean age 9y 4mo), two with spastic hemiplegia (Gross Motor Function Classification System [GMFCS] level I) and four with spastic diplegia (GMFCS level II,) were given 5 days of intensive training in reactive balance control (100 perturbations per day on a moveable force platform). Surface electromyography was used to characterize changes in neuromuscular responses pretraining, immediately posttraining, and 1 month posttraining. Training in reactive balance control resulted in improvements in directional specificity of responses (a basic level of response organization) and other spatial/temporal characteristics including: (1) faster activation of muscle contraction after training, allowing children to recover stability faster; (2) emergence of a distal-proximal muscle sequence; and (3) improved ability to modulate the amplitude of muscle activity (increased amplitude of agonist and decreased amplitude of antagonist, reducing coactivation). Each child with spastic hemiplegia or diplegia showed a different combination of factors that contributed to improved performance; the level of change in neural factors depended on the severity of involvement of the child: hemiplegia vs diplegia, and level of involvement within each diagnostic category.

Effects of balance training with visual feedback during mechanically unperturbed standing on postural corrective responses

“…These time periods are consistent with previous works [19,22]. The response amplitude was reported as a ratio with respect to the background level of activity preceding the perturbation (100 ms) [3].…”

Electromyographic patterns in children with cerebral palsy: Do they change after surgery?

“…More recent studies showed that the activity of the tibialis anterior muscle reduced when patients with an excessive plantarflexion at initial contact used ankle-foot orthoses [11]. Even short-term intensive balance training improved muscle coordination, but the level of adaptation depended on the severity of the child's disability [12]. These studies also suggested that muscle recruitment in patients with CP may change after an intervention.…”

Random perturbation: A potential aid in treatment of children with cerebral palsy

“…RP fits into the theory that the neuromuscular control system must allow for the inherent mechanical properties of inactive muscle fibers to relax in order to control movements with precision and that the motor controller adjusts to changes in resting tension of the muscles [17,33]. Judgments of the importance of clinical changes in relationship to measured changes in GMFM-66 scores are not yet established.…”

“…Shumway-Cook et al [16] demonstrated that postural balance recovery and stability was improved following training by mechanical perturbations in children with CP. Woollacott et al [17] suggested that reactive balance training by mechanical perturbations could result in changes in specific neural factors of balance control.…”