Serious game with electromyography feedback in children with unilateral spastic cerebral palsy and equinus gait: a prospective open-label study

The early brain injury (EBI) causes cerebral palsy (CP) especially unilateral spastic cerebral palsy (USCP) [1,2]. Children with USCP develop foot deformities due to a combination of factors including muscle disorders (plantarflexors extensibility stiffness) and neurological disorders (plantarflexors overactivity i.e. spasticity-cocontraction-dystonia and dorsiflexors weakness acting at the ankle joint resulting in an equinus gait pattern) [3]. These neurological (caused by reduced downstream command) and muscular disorders are concomitant and difficult to disentangle. The muscular disorder could have a predominant role on the intensity of neurological disorder [4,5]. Our first aim was to investigate the effects of serious game by electromyography feedback (EMGs_SG) and physical therapy (PT) in young children with unilateral spastic cerebral palsy (USCP) on clinical and gait velocity performances. The second aim was to better understand the mutual influence of muscule shortening on functions[6,7]. Prospective, open-label study. Children with USCP received four weeks of EMGs_SG sessions 2x/week including repetitive, active alternating training of dorsiflexors and plantar flexors in seated position[8–13]. In addition, each child received usual PT treatment ≤ 2x/week, involving plantar flexor stretching and command strengthening on dorsi- and plantar (soleus and gastrosoleus complex (GSC)) flexors. Five Step Assessment parameters, including preferred gait velocity (normalized by height), plantar flexor extensibility (XV1), angle of catch (XV3), maximal active ankle dorsiflexion (XA) and derived coefficients [14–16] of shortening (defined according to normative values of typically developed children of similar age range), spasticity and dorsiflexor weakness (in knee flexed and extended) were compared pre and post treatment (t-tests). Correlations were explored between the various coefficients and gait velocity at baseline. Significance was set at p<0.05. Thirty USCP children (age 7.6±2.1 yrs) were included. After four weeks of EMGs_SG+PT there was an increase in normalized gait velocity from 0.72±0.13 to 0.77±0.13 m/sec (p=0.025, d=0.43), a decrease in coefficients of shortening (soleus, 0.10±0.07 pre vs 0.07± 0.08 post, p=0.004, d=0.57; gastrosoleus complex (GSC) 0.16±0.08 pre vs 0.13±0.08 post, p=0.003, d=0.58), spasticity (soleus 0.14±0.06 pre vs 0.12±0.07 post, p=0.02, d=0.46) and dorsiflexor weakness (in knee flexed 0.14±0.07 pre vs 0.11±0.07 post, p=0.005, d=0.55). At baseline, normalized gait velocity correlated with the coefficient of gastrosoleus complex (GSC) shortening (R=-0.43, p=0.02). Four weeks of EMGs_SG and PT were associated with improved gait velocity and decreased plantar flexor shortening. The present findings further suggest the role of changes in the muscle disorder in improving command, that is the neurological disorder. In very young children, this study may thus emphasize the need to focus on muscle shortening treatment by applying dynamic and active stretching programs on antagonists and by activating descending command with active and alternating training[17]. A randomized controlled trial comparing EMGs_SG and conventional PT is needed.