Postdoctoral Researcher University of Pennsylvania, Pennsylvania
Rationale: To investigate alterations of language networks and their relation to impaired naming performance in temporal lobe epilepsy (TLE) using functional MRI. Methods: Seventy-two adult TLE patients (41 left) and 36 controls were studied with overt auditory and picture naming fMRI tasks to assess temporal lobe language areas, and a covert verbal fluency task to probe frontal lobe language regions. Correlation of fMRI activation with clinical naming scores, and alteration of language network patterns in relation to epilepsy duration, age at onset and seizure frequency, were investigated with whole-brain multiple regression analyses. Results: Auditory and picture naming fMRI activated the left posterior temporal lobe, and stronger activation correlated with better clinical naming scores. Verbal fluency MRI mainly activated frontal lobe regions. In left and right TLE, a later age of epilepsy onset related to stronger temporal lobe activations, while earlier age of onset was associated with impaired deactivation of extratemporal regions. In left TLE patients, longer disease duration and higher seizure frequency were associated with reduced deactivation. Frontal lobe language networks were unaffected by disease characteristics. Conclusions: While frontal lobe language regions appear spared, temporal lobe language areas are susceptible to dysfunction and reorganization, particularly in left TLE. Early onset and long duration of epilepsy, and high seizure frequency, were associated with compromised activation and deactivation patterns of task-associated regions, which might account for impaired naming performance in individuals with TLE. Funding: Please list any funding that was received in support of this abstract.: This study was supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. We are grateful to the Epilepsy Society for supporting the Epilepsy Society MRI scanner. We are grateful to the European Academy of Neurology (EAN) and the Austrian Society of Neurology (OEGN) who each supported K.T. with a one-year fellowship. L.C. acknowledges support from a PhD scholarship by Brain Research UK.