Kinematics and postural muscular activity during continuous oscillating platform movement in children and adolescents with cerebral palsy

Abstract

Higher frequency platform movements proved more difficult for youth with CP, however, like TD youth, they shifted from reactive to anticipatory mechanisms when the platform frequency remained constant by taking advantage of knowledge of platform movement. When given control over perturbation onset, further evidence of anticipatory mechanisms was observed following the transition to a new oscillation frequency.

Does dual‐tasking affect the ability to generate anticipatory postural adjustments in young adults?

“…As the frequencies increased, the number of steps taken also increased in all conditions, reflecting the increasing difficulty, and thus the increased attentional demands of the postural task. Similar results were observed in a single‐tasking study, where adolescents were exposed to repeated anterior–posterior platform perturbations (Mills et al, 2018).…”

“…In each trial, the first 3–5 consecutive cycles without stepping at each frequency were considered “transition state” periods, where reactive postural responses were expected. In the last half of the trial, a series of 3–5 consecutive cycles without stepping at 0.10 Hz and 8–10 consecutive cycles without stepping for the remaining frequencies were considered the “steady state” period where anticipatory postural adjustments were likely to occur (Figure 2) (Bugnariu et al., 2006; Mills et al, 2018).…”

“…Postural muscle onset latencies were determined from raw EMG signals. The first burst of activity associated with a perturbation lasting more than 50 ms and greater than two standard deviations above the within‐trial baseline (i.e., quiet period with no activity) indicated muscle onset latency activity (Mills et al, 2018). Baseline was determined for each trial during the quiet stance period before platform movement initiation.…”

Children with developmental coordination disorder are less able to fine-tune muscle activity in anticipation of postural perturbations than typically developing counterparts

“…Despite the reduced stability of children with DCD, there was no detected difference in their global stabilization strategy compared to TD children. Children with DCD showed no preference for either a head-stabilized-to-trunk strategy, or a head-stabilized-in-space strategy ( Figure 5 ), whereas other populations with known balance deficits, such as children with cerebral palsy ( Mills et al, 2018 ) and adults with Parkinson’s disease ( Mesure et al, 1999 ), adopt a head-stabilized-to-trunk strategy. This may be explained by a poor organization of body movements in relation to the global environment, often associated with DCD ( Green and Payne, 2018 ).…”

“…While these reactive and anticipatory postural control strategies have been studied in children with other motor impairments (e.g., cerebral palsy; Mills et al, 2018 ), to our knowledge, they have not been studied in children with DCD during continuous dynamic movement. Additionally, no previous work has studied the structure of postural sway characteristics in children with DCD, nor evaluated the association with muscle activation and coordination.…”