Abstracts

Rationale: Patients with medically refractory partial seizures who are candidates for Resective Epilepsy Surgery frequently undergo language mapping as to minimize resection of eloquent cortex. Unique representation of language in Epilepsy patients especially these with childhood onset of seizures may alter the surgical approac Methods: We used a large array 148 channel Magnetometer (MEG, 4D Neuroimaging) and multiple tasks (Auditory Word Recognition, Visual Verb Generation and Picture Naming) in 16 candidates for resective epilepsy surgery to investigate cortical organization for receptive and productive language function.Laterality indices were calculated (R-L)/(R+L) after Galaburda et al., 1978 for left and right hemisphere late fields ~150-400ms. Values fell between +/-1.0, with negative values reflecting left-biased processing.Laterality indices were calculated (R-L)/(R+L) after Galaburda et al., 1978 for left and right hemisphere late fields ~150-400ms. Values fell between +/-1.0, with negative values reflecting left-biased processing. Results: 5/16 patients showed leftward laterality for all three tasks 4/16 patients showed rightward laterality all three tasks. 6/16 of those patients had laterally discordant receptive and productive language function. 1/16 showed bilateral receptive language and leftward expressive language Conclusions: Receptive and Expressive language may have divergent hemispheric dominance in patients with Medically Refractory Epilepsy with childhood and adolescent onset of seizures. The right sided receptive language hemispheric dominance in epilepsy patients may have implications for surgical planning as well as emphasize the need to separately assess both receptive and expressive language in these patients. MEG with multiple language tasks can be used non-invasively to assess language in both hemispheres. This group larger than our previously reported cohort and shows that atypical representation is frequent