Effect of motor imagery in children with unilateral cerebral palsy: fMRI study

Abstract

Background: Motor imagery is considered as a promising therapeutic tool for rehabilitation of motor planning problems in patients with cerebral palsy. However motor planning problems may lead to poor motor imagery ability.

Aim: The aim of this functional magnetic resonance imaging study was to examine and compare brain activation following motor imagery tasks in patients with hemiplegic cerebral palsy with left or right early brain lesions. We tested also the influence of the side of imagined hand movement.

Method: Twenty patients with clinical hemiplegic cerebral palsy (sixteen males, mean age 12 years and 10 months, aged 6 years 10 months to 20 years 10 months) participated in this study. Using block design, brain activations following motor imagery of a simple opening-closing hand movement performed by either the paretic or nonparetic hand was examined.

Results: During motor imagery tasks, patients with early right brain damages activated bilateral fronto-parietal network that comprise most of the nodes of the network well described in healthy subjects. Inversely, in patients with left early brain lesion brain activation following motor imagery tasks was reduced, compared to patients with right brain lesions. We found also a weak influence of the side of imagined hand movement.

Conclusion: Decreased activations following motor imagery in patients with right unilateral cerebral palsy highlight the dominance of the left hemisphere during motor imagery tasks. This study gives neuronal substrate to propose motor imagery tasks in unilateral cerebral palsy rehabilitation at least for patients with right brain lesions.

Figure 1. Statistical maps illustrating the brain activations during motor imagery tasks across all conditions.

The results are superimposed in red on a standard rendered single subject brain (available on SPM8). Results are showed with a significance of p<0.05 corrected for multiple comparisons (alpha-simulation). The black and white stars indicate schematically the ipsilesional hemisphere. Notes: MI, motor imagery.

Figure 2. Statistical maps illustrating the influence of the side of imagined hand movement.

Motor imagery of nonparetic hand movement > motor imagery of paretic hand movement is represented in red color. The black and white stars indicate schematically the ipsilesional hemisphere. Results are showed with a significance of p<0.05 corrected for multiple comparisons (alpha-simulation). Notes: CL, contralesional hemisphere; IL, ipsilesional hemisphere; nph, nonparetic hand; ph, paretic hand; MI, motor imagery.

Figure 3. Statistical maps illustrating the influence of brain lesion’s side on brain activations following motor imagery tasks.

Brain activations in subjects with right early brain lesion > subjects with left early brain lesion is superimposed in red on a standard rendered single subject brain (available on SPM8). Results are showed with a significance of p<0.05 corrected for multiple comparisons (alpha-simulation). The black and white stars indicate schematically the ipsilesional hemisphere. Notes: CL, contralesional hemisphere; IL, ipsilesional hemisphere; nph, nonparetic hand; ph, paretic hand; MI, motor imagery.