Anteroposterior balance reactions of children with and without cerebral palsy: a cross-sectional, observational study of children age 5-12 years

ABSTRACT Aim To compare anterior and posterior standing balance reactions, as measured by single-stepping thresholds, of children with and without cerebral palsy (CP). Method Seventeen ambulatory children with CP and 28 typically developing children, all 5-12 years of age, were recruited for this cross-sectional, observational study. Balance reaction skill was quantified as anterior and posterior single-stepping thresholds, or the treadmill-induced perturbations that consistently elicited a step in that direction. In order to understand underlying mechanisms of between-group differences in stepping thresholds, dynamic stability was quantified using the minimum margin of stability. Ankle muscle activation latency, magnitude, and co-contraction were assessed with surface electromyography. Results We observed large between-group differences in anterior, but not posterior, thresholds. Between-group differences were most evident in older children, with typically developing children having larger anterior thresholds than those with CP. In response to near-threshold anterior perturbations, older typically developing children recovered from more instability than their CP peers. Older children had no between-group differences in ankle muscle activity. Interpretation The effects of CP on balance reactions are age- and direction-specific. In response to an anterior perturbation, older typically developing children recovered from more instability than their peers with CP. What this paper adds Children with CP have age- and direction-specific balance-reaction impairments. Impairment was most evident in the anterior reactions of older children (≈11 years). Typically developing children recovered from more anterior instability than those with CP. Graphical Abstract