Electromyographic biofeedback-driven gaming to alter calf muscle activation during gait in children with spastic cerebral palsy

Background: Children with cerebral palsy often show deviating calf muscle activation patterns during gait, with excess activation during early stance and insufficient activation during push-off.Research question: Can children with cerebral palsy improve their calf muscle activation patterns during gait using one session of biofeedback-driven gaming?Methods: Eighteen children (6-17 y) with spastic cerebral palsy received implicit game-based biofeedback on electromyographic activity of the calf muscle (soleus or gastrocnemius medialis) while walking on a treadmill during one session. Biofeedback alternately aimed to reduce early stance activity, increase push-off activity, and both combined. Early stance and push-off activity and the double-bump-index (early stance divided by push-off activity) were determined during baseline and walking with feedback. Changes were assessed at group level using repeated measures ANOVA with simple contrast or Friedman test with post-hoc Wilcoxon signed rank test, as well as individually using independent t-tests or Wilcoxon rank sum tests. Perceived competence and interest enjoyment were assessed through a questionnaire.Results: Children successfully decreased their electromyographic activity during early stance feedback trials (relative decrease of 6.8 & PLUSMN; 12.2 %, P = 0.025), with a trend during the combined feedback trials (6.5 & PLUSMN; 13.9 %, P = 0.055), and increased their electromyographic activity during push-off feedback trials (8.1 & PLUSMN; 15.8 %, P = 0.038). Individual improvements were seen in twelve of eighteen participants. All children experienced high levels of interest-enjoyment (8.4/10) and perceived competence (8.1/10).Significance: This exploratory study suggests that children with cerebral palsy can achieve small within-session improvements of their calf muscle activation pattern when provided with implicit biofeedback-driven gaming in an enjoyable manner. Follow-up gait training studies can incorporate this method to assess retention and longterm functional benefits of electromyographic biofeedback-driven gaming.