Epilepsy Research (2011) 93, 155—163 journal homepage: www.elsevier.com/locate/epilepsyres Cortical reorganization and reduced efficiency of visual word recognition in right temporal lobe epilepsy: A functional MRI study Elizabeth J. Jensen a,f , Ian Hargreaves b,e , Adam Bass e,f , Penny Pexman b,e , Bradley G. Goodyear c,d,e,f , Paolo Federico c,d,e,* a Department of Neuroscience, University of Calgary, Canada b Department of Psychology, University of Calgary, Canada c Department of Radiology, University of Calgary, Canada d Department of Clinical Neurosciences, University of Calgary, Canada e The Hotchkiss Brain Institute, Canada f The Seaman Family MR Research Centre, Canada Received 24 June 2010; received in revised form 4 November 2010; accepted 7 December 2010 Available online 6 January 2011 KEYWORDS Lexical decision; Lexical processing; Seizures; Behavioural; Neuroimaging Summary Purpose: We investigated the efficiency of lexical and semantic processing in participants with right temporal lobe epilepsy (TLE). We also mapped brain activation patterns during this processing using functional magnetic resonance imaging (fMRI). Methods: Ten participants with right TLE and 12 healthy controls were studied. All participants underwent a 3 T fMRI investigation during a lexical decision task (LDT). Stimuli included words (concrete and abstract) and nonwords. Lexical and semantic processing were examined by comparing behavioural (response times and accuracy) and fMRI data associated with words and nonwords (lexicality) and with concrete and abstract words (concreteness), respectively. Results: Both groups exhibited significant behavioural effects of lexicality and concreteness. However, right TLE participants showed a larger lexicality effect and had longer response times compared to controls. The right TLE group exhibited different patterns of fMRI activation com- pared to controls. Specifically, increased left hemispheric activation was seen, particularly in the left inferior frontal gyrus (IFG) during nonword processing. Discussion: Right TLE negatively affects the efficiency of lexical processing and lexical decision making. Increased involvement of the left IFG suggests that compensation occurs in the cortical networks involved in lexical processing occurred as a result of pathology in the right hemisphere. © 2010 Elsevier B.V. All rights reserved. ∗ Corresponding author at: Departments of Clinical Neurosciences and Radiology, University of Calgary, Room C1241a, Foothills Medical Centre, 1403 29th Street N.W., Calgary, AB, Canada T2N 2T9. Tel.: +1 403 944 4091; fax: +1 403 283 2270. E-mail address: pfederic@ucalgary.ca (P. Federico). 0920-1211/$ — see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.eplepsyres.2010.12.003