Review of Functional Magnetic Resonance Imaging Language Mapping in Patients with Epilepsy

In cases where patients with epilepsy require surgery to help reduce the frequency and severity of their seizures, information about the areas of the brain involved with language function, such as the anterior temporal pole, can be valuable in predicting and minimising language difficulties that may arise after brain surgery. The aim of the project was to first evaluate the current group of functional magnetic resonance imaging (fMR.I) language tasks used in the Epilepsy Centre of St Vincent's Hospital Melbourne (SVHM). This group of task included sentence completion, verbal fluency, and picture-naming tasks. Secondly, two new language tasks, reading and semantic decision-making were examined in an attempt to improve upon the existing battery's ability to detect anterior temporal pole activation for patients undergoing anterior temporal lobectomy. Healthy controls and patients with epilepsy performed tasks in the original battery on one of two standard 1.5 tesla MRI scanners (an older Siemen Magnetom or a newer Siemen Avanto). With the older scanner, the sentence completion task was the only original SVHM fMRI language task to show consistent activation. In contrast, with the newer scanner, all four original tasks, along with the new reading and semantic decision tasks, demonstrated consistent language activation when thinner slices covering a larger area were obtained. When used on the newer MRI imager, the new reading, the picture naming, and the sentence completion tasks produce the highest levels of anterior temporal lobe activation. The reading and picture naming tasks tended to show more temporal lobe activation, while the semantic decision and verbal fluency tasks tended to show more frontal lobe activation. Practical and theoretical implications of the research for presurgical fMRI evaluation are discussed