Development of bilateral motor control in children with developmental coordination disorders

Abstract

This research examined behavioral (i.e. movement time) and neuromuscular (EMG) characteristics of unilateral and bilateral aiming movements of children with normal motor development and children with developmental coordination disorders ( D O ) . Two age groups of children were studied 6 to 7, and 9 to 10 year olds. Bilateral aiming movements involved moving the two hands to targets of either (1) the same amplitude -symmetrical bilateral movements, or (2) different amplitudes -asymmetrical bilateral movements.Unilateral aiming movements involved moving one hand to either near or far targets associated with that hand. In general, unilateral and bilateral movement times were slower in younger than older children, and in children with DCD than children with normal motor development. Our neuromuscular data suggest that the faster movement times that typically accompany increasing age in children may be the result of a change in the capacity to initiate antagonist muscle contractions. The prolonged burst of agonist activity and delayed onset of antagonist activity observed in children with DCD mag contribute to their inability to produce fast. accurate unilateral movements. On both symmetrical and asymmetrical bilateral aiming movements, children with DCD had more performance errors and greater temporal inconsistencies between neuromuscular (EMG) parameters and behavioral (movement time) parameters than children with normal motor development. These new neuromuscular data suggest that there are important differences in the way the motor control systems of children with and without DCD organize bilateral aiming responses.

Ball catching in children with developmental coordination disorder: control of degrees of freedom

“…Thus, both groups of participants introduced tight couplings between DF to render the movement system controllable. 13,[16][17][18][19] Progress of skill acquisition involves the release of DF. 12,15 This was shown in the AMC group as their elbows became more involved in the task of two-handed catching (Table I; Fig.…”

“…Thus, when initially solving a complex movement problem with redundant DF, children with DCD do so by rigidly coupling their limbs. 7,12,13,16 However, under the assumption that skill acquisition is a process of trying to find ways of controlling the redundant DF and exploiting them during movement coordination, ensuring flexibility of the motor apparatus, 12,13 it appears that children with DCD need help with this process, which may have important implications for intervention. 7 …”

Altered postural control strategies and sensory organization in children with developmental coordination disorder

“…Previous studies have also suggested that neuromuscular deficits in children with DCD may contribute to their altered balance strategies (Huh et al, 1998;Johnston et al, 2002;Raynor, 2001;Smits-Engelsman, Westenberg, & Duysens, 2008). Their motor impairments typically include lower maximal knee muscle strength and power, increased knee flexor and extensor co-activation (Raynor, 2001); less steady force production (Smits-Engelsman et al, 2008); inconsistent and less efficient motor-control strategies to execute movements (Huh et al, 1998); inconsistent timing of postural muscle activation (Johnston et al, 2002;Williams, 2002); proximal to distal muscle activation patterns; and increased and prolonged activation or co-contraction of the ankle muscles in standing (Geuze, 2003;Williams & Castro, 1997).…”

“…Their motor impairments typically include lower maximal knee muscle strength and power, increased knee flexor and extensor co-activation (Raynor, 2001); less steady force production (Smits-Engelsman et al, 2008); inconsistent and less efficient motor-control strategies to execute movements (Huh et al, 1998); inconsistent timing of postural muscle activation (Johnston et al, 2002;Williams, 2002); proximal to distal muscle activation patterns; and increased and prolonged activation or co-contraction of the ankle muscles in standing (Geuze, 2003;Williams & Castro, 1997). These may partly explain the ineffective motor strategies demonstrated by our DCD group in more challenging environments.…”

“…In children with DCD it is well known that motor control strategies for regulating muscle activity are less uniform and consistent than in children following the normal developmental milestones (Huh, Williams, & Burke, 1998;Williams, 2002). For example, Johnston, Burns, Brauer, and Richardson (2002) reported that the timing and pattern of postural muscle activation used to maintain posture were altered during goal directed reaching in children with DCD.…”