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DOI: 10.1055/s-0029-1215727
Language lateralisation in childhood-onset focal epilepsy: Evidence from fMRI
Purpose: We investigated language lateralization using functional MRI (fMRI) in children suffering from left-sided, medically refractory, childhood-onset focal epilepsy and determined factors associated with atypical lateralization.
Methods: Twenty-four children suffering from drug-resistant, left-sided, early-onset epilepsy underwent fMRI-scanning using a covert verb-generation task. Twenty-nine healthy volunteers, matched for age and gender, served as controls. Images were analyzed using SPM5 and lateralization indices (LI) were calculated within regions of interest (Broca's area, temporal lobe, cerebellum) using the LI-toolbox (Wilke et al., J Neurosci Methods, 2007;163:128–36). Factors contributing to atypical language distribution were investigated including: age at seizure-onset, seizure frequency, handedness, lesion location, lesion size, size and asymmetry of the planum temporale (PT).
Results: A stepwise linear regression analysis including all variables mentioned above revealed that asymmetry of the planum temporale was the only significant predictor for language lateralisation, accounting for 50% of the variance (Beta=0.723, p<0.001).
Conclusions: In the presence of left-sided pathology the asymmetry of the planum temporale appears to indicate the efficacy of language reorganisation to the right hemisphere.