Language localization in pediatric epilepsy patients using novel, task-free neuroimaging techniques
Audrey Nath, MD, PhD
BACKGROUND: Epilepsy currently affects 470,000 children in the United States, and around one third of these children have medically intractable seizures which may require a surgical resection for cure of epilepsy.
GAP: The inability to localize language in pediatric epilepsy patients with cognitive deficits poses a significant barrier to the cure of epilepsy by surgical resection.
HYPOTHESIS: In pediatric patients, language laterality may be identified accurately using resting state fMRI (RS) due to within-subject differences in connectivity in a language network including Broca’s and Wernicke’s areas. During the naturalistic, spontaneous production of speech, there will be a significant increase in broadband gamma activity (BGRA) in cortical regions involved in expressive language, and this BGRA will be spatially concordant with the regions of expressive language cortex as identified with cortical stimulation mapping (CSM).
METHODS: The study population consists of pediatric epilepsy patients undergoing pre-surgical workup, all of who will undergo a 7-minute RS scan; the correlations between the timeseries of activity between each subject’s left and right Broca’s and Wernicke’s areas will be determined, and these values will be used to create a logistical regression leave-one-out classifier to predict language laterality for each subject. In patients who are undergoing CSM language mapping, electrodes that show a significant increase in the 75-150 Hz frequency band (BGRA) following speech onset will be considered as an electrode necessary for expressive language.
IMPACT: We would plan to use these techniques in subsequent patients to localize language and guide surgical planning with the goal of curing epilepsy in pediatric patients with focal lesions.