Adaptive Motor Decisions in Children with Hemiplegic Cerebral Palsy

PURPOSE AND BACKGROUND: The present study examined motor decisions for reaching in hemiplegic children. Specifically, we compared children’s motor decisions for reaching at targets of variable distances using their hemiplegic and nonhemiplegic hand.

Children with hemiplegic cerebral palsy (HCP) frequently display problems in sensation, strength, range of motion, and coordination of the extremities and trunk on the affected body side (Auld et al., 2012). They present with impairments in body mechanics and goal-directed skills such as reaching (Imms, 2008). Studies examining reaching abilities in children with congenital hemiplegia have focused on the biomechanical consequences of the impairment. Findings suggest that children reach using compensatory patterns characterized by increased trunk muscle activation and slow arm–hand movements that are inconsistent in trajectory and timing, resulting in limitations in skillful reaching.

However, occupational engagement and functional participation require adaptive motor decisions and flexibility of behavior. Recent evidence suggests that children with hemiplegia also have problems with prospective planning and adaptive decisions in goal-directed motor actions. They present with major difficulties modulating postural and upper extremity adjustments to the constraints of the task (Craje et al., 2010; Mutsaarts et al., 2007). Taken together, these findings suggest that there is a need to better understand the impact of neural lesions on the development of skillful motor actions for children with congenital hemiplegia.

METHOD: A one-group, within-subjects design was used to compare adaptive motor decisions of children as they reached with their affected and unaffected side. Participants were 12 children aged 6–12 diagnosed with HCP who were able to function at Levels I and II of the Gross Motor Function Classification System. Children with health or medical problems unassociated with CP or severe visual problems were excluded, as were children who had had any of the following procedures or treatments for the involved lower extremities: orthopedic surgery, dorsal rhizotomy, botulinum toxin therapy in the past 6 mo, or intrathecal baclofen.

Children reached while sitting toward targets presented at various distances (0–150 cm, adjusted in 2-cm increments). An experimenter used a psychophysical procedure to determine the distance from trial to trial. We were able to make individual estimates of distances that children could reach and a threshold estimate of the maximum possible distance for each child. We used wearable motion analysis sensors (inertial measurement units) to record biomechanical strategies children used. We used a mixed methods repeated measures analysis of variance to analyze participants’ motor strategies.

RESULTS: Participants overestimated actual possibilities for action and attempted to reach for larger distances. They were more reluctant to reach with their affected hand, but their decisions on trials when they reached were similar to those with their unaffected hand.

CONCLUSIONS: Results are discussed in terms of the children’s decision criterion (the penalty for errors was low), developmental changes, and effects of impairment.

IMPACT STATEMENT: Biomechanical and motor decision constraints affect children’s functional performance. Understanding the mechanisms underlying these constraints can inform treatment protocols. This project informs the development of intervention strategies (i.e., combination of motor and cognitive) that can facilitate better improvement of functional performance.

References

Auld, M. L., Boyd, R. N., Moseley, G. L., Ware, R. S., & Johnston, L. M. (2012). Impact of tactile dysfunction on upper-limb motor performance in children with unilateral cerebral palsy. Archives of Physical Medicine and Rehabilitation, 93, 696–702. https://doi.org/10.1016/j.apmr.2011.10.025

Craje, C., Aarts, P., Nijhuis-van der Sanden, M., & Steenbergen, B. (2010). Action planning in typically and atypically developing children (unilateral cerebral palsy). Research in Developmental Disabilities, 31, 1039–1046. https://doi.org/10.1016/j.ridd.2010.04.007

Imms, C. (2008). Children with cerebral palsy participate: A review of the literature. Disability and Rehabilitation, 30, 1867–1884. https://doi.org/10.1080/09638280701673542

Mutsaarts, M., Steenbergen, B., & Bekkering, H. (2007). Impaired motor imagery in right hemiparetic cerebral palsy. Neuropsychologia, 45, 853–859. https://doi.org/10.1016/j.neuropsychologia.2006.08.020