Scientific Posters

Abstract

Objective: Anatomical imaging studies in cerebral palsy have largely focussed on classification of white matter injury and on properties of deep grey matter. This study aims to identify any regions in the cortex where cortical grey matter thickness correlates with upper limb function as measured by the Melbourne Assessment of Unilateral Upper Limb Function (MUUL). Design: Cross sectional study. Method: Nineteen subjects (aged 7y 8mos to 19y 7mos; 9 left hemiplegia; 10 right hemiplegia; GMFCS I=11, II=8) and 15 age and gender matched controls (aged 7y 6mos to 16y 2mos) were scanned with 3T Siemens MRI scanner at either the Centre for Advanced Imaging in Brisbane or the Royal Children’s Hospital in Melbourne. Surface based morphometry of pial and grey-white cortical surfaces were used to generate cortical thickness maps across the entire cerebrum. Differences in thickness between groups (left and right hemiplegia and controls) were assessed as well as identification of regions where cortical thickness correlated with MUUL scores. Identified regions were localised using automated parcellation. Statistical significance was determined by correcting for multiple comparisons using False Discovery Rate (FDR) of 0.1. Results: There were no regions of significant difference in thickness between groups (left and right hemiplegia and controls) in either hemisphere. In subjects with right hemiplegia upper limb motor function positively correlated with cortical thickness of a region in the left middle temporal gyrus (FDR 0.1). In subjects with left hemiplegia upper limb motor function negatively correlated with a focus on the right pre-central gyrus (FDR 0.05). Conclusion: The cortical thickness of the medial temporal gyrus has been previously shown to be important for complex visuo-motor learning. This may explain the correlation between increased cortical thickness in this region and upper limb function. The region identified at the pre-central gyrus was situated at the upper limb of the motor homunculus. The inverse relationship between thickness at this region and upper limb function may suggest compensatory plastic changes in the motor cortex of impaired children.