[Cerebral activation during Stroop's test in a case of early focal brain injury]

Functional magnetic resonance imaging (fMRI) offers an important advantage over other functional neuroimaging techniques used with children because of its harmlessness. Previous studies conducted with adults with alexia suggested two ways the brain can reorganise reading after a brain injury affecting the left hemisphere, one contralateral and the other ipsilateral.

We describe a study carried out using fMRI of a 10 year old girl with an injury to the left hemisphere caused by a fishing harpoon when she was 6 years old. As a result of the accident the girl presented a right hemiparesia. The girl s parents and teachers also reported difficulties in the acquisition of reading writing and arithmetic, as well as a certain degree of attentional deficit. An fMRI exploration was performed while the girl was doing the Stroop test. The structural MR images showed left hemisphere cortical lesions in the orbital and angular gyrus regions, in addition to the caudate and putamen nuclei, and in the inferior longitudinal bundle. The fRMI revealed a strong overactivation of the right dorsolateral frontal cortex, in the evaluation of interference, and activations of the right angular and bilateral supramarginal gyri, in the evaluation of word reading.

The functional study suggests the existence of a reorganisation of reading that is both intra and inter hemispheric.