Brain activation changes following motor training in children with unilateral cerebral palsy: An fMRI study

Abstract

Background Intensive motor-learning-based interventions have demonstrated efficacy for improving motor function in children with unilateral spastic cerebral palsy (USCP). Although this improvement has been associated mainly with neuroplastic changes in the primary sensori-motor cortices, this plasticity may also involve a wider fronto-parietal network for motor learning. Objective To determine whether hand-arm bimanual intensive therapy including lower extremities (HABIT-ILE) induces brain activation changes in an extensive network for motor skill learning and whether these changes are related to functional changes observed after HABIT-ILE. Methods In total, 25 children with USCP were behaviourally assessed in manual dexterity and everyday activities before and after HABIT-ILE. Functional imagery monitored brain activity while participants manipulated objects using their less-affected, more-affected or both hands. Two random-effects-group analyses performed at the whole-brain level assessed the brain activity network before and after therapy. Three other random-effects-group analyses assessed brain activity changes after therapy. Spearman's correlations were used to evaluate the correlation between behavioural and brain activity changes. Results The same fronto-parietal network was identified before and after therapy. After the intervention, the more-affected hand manipulation elicited a decrease in activity on the motor cortex of the non-lesional hemisphere and an increase in activity on motor areas of the lesional hemisphere. The less-affected hand manipulation generated a decrease in activity of sensorimotor areas in the non-lesional hemisphere. Both-hands manipulation elicited an increase in activity of both hemispheres. Furthermore, we observed an association between brain activity changes and changes in everyday activity assessments. Conclusion Brain activation changes were observed in a fronto-parietal network underlying motor skill learning with HABIT-ILE in children with USCP. Two different patterns were observed, probably related to different phases of motor skill learning, representing an increased practice-dependent brain recruitment or a brain activation refinement by more efficient means.