Anteroposterior balance reactions in children with spastic cerebral palsy

Abstract

Aim To compare anterior and posterior standing balance reactions, as measured by single‐stepping thresholds, in children with and without spastic cerebral palsy (CP). Method Seventeen ambulatory children with spastic CP (eight males, nine females) and 28 typically developing children (13 males, 15 females; age range 5–12y, mean [SD] 9y 2mo [2y 3mo]), were included in 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 the 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 an age and group interaction for anterior thresholds (p=0.001, partial η2=0.24). At older (≈11y; p<0.001, partial η2=0.48), but not younger (≈7y; p=0.33, partial η2=0.02) ages, typically developing children had larger anterior thresholds than those with CP. In response to near‐threshold anterior perturbations, older typically developing children recovered from more instability than their peers with CP (p=0.004, partial η2=0.18). Older children had no between‐group differences in ankle muscle activity. No between‐group differences were observed in posterior thresholds. Interpretation The effects of CP on balance reactions are age‐ and direction‐specific. Older typically developing children are more able or willing to withhold a step when unstable. What this paper adds Children with spastic cerebral palsy have age‐ and direction‐specific balance‐reaction impairments. Lower anterior stepping thresholds were observed in older, but not younger children. Older typically developing children withheld a forward step at higher levels of instability. No between‐group differences were seen in posterior stepping thresholds.

Individuals with cerebral palsy show altered responses to visual perturbations during walking

“…Thus, both sensory and motor deficits can impair the functioning of this sensorimotor control loop and contribute to balance problems and fall risk. Rehabilitation approaches generally focus on the motor aspect of balance control, and most studies in CP examine the postural control strategies due to altered muscle recruitment strategies ( Roncesvalles et al, 2002 ) and kinetics ( Chen and Woollacott, 2007 ), often using mechanical perturbations ( Tracy et al, 2019 ; Crenshaw et al, 2020 ). However, the effect of sensory deficits on sensorimotor control of balance in walking is currently not well understood.…”