Abstracts

Rationale: fMRI is used for presurgical work-ups in adults¹, is surpassing the Wada in outcome prediction², and is now used in children^3,4, even very young children^5,6. But fMRI memory paradigms are not yet widely used in children. We sought to develop a viable pediatric fMRI memory paradigm. We evaluated the efficacy of a modified adult task⁷ in a pediatric presurgical population. Methods: We retrospectively identified patients who had temporal lobe onset seizures and memory fMRI as part of presurgical work-ups at Seattle Children's Hospital. Our fMRI memory paradigm, a 4 minute block design task, requires visualization of autobiographical memories (activities in the home for HomeWalk and in the school for SchoolWalk) alternating every 30 seconds with covert counting. Prior to procedures neuropsychologists prepared patients who narrated out loud until mastery was clear. Memory scans were summed and analyzed using the FSL software package. We identified 31 patients assessed between 2009 and 2014. Patients were 6 - 20 years old, with 19 left and 12 right seizure onsets. We reviewed functional clinical radiology reports. A second radiologist, blinded to the cases, evaluated for parahippocampal activation only. Results: Of 31 cases, only 5 cases were determined by both radiologists to show no mesial temporal activation. 4 of 5 scans had motion artifact, suggesting difficulty with holding still during the memory tasks that follow sensory-motor and language testing. 1 subject showed activation of language areas only, suggesting the task was not being performed correctly. 26 cases (84%) showed mesial activation. 19 (12 right, 7 left seizure onset) showed contralateral greater than ipsilateral activation, 12 parahippocampal and 7 other structures (3 cingulate or retrosplenial, 3 posterior hippocampal, and one characterized as mesial temporal). 6 cases (all left) showed greater ipsilateral versus contralateral activation, including 4 parahippocampal and 2 posteriorly displaced by lesions. One subject showed symmetrical mesial activation. Conclusions: Results demonstrate that our autobiographical memory paradigm can be used effectively in children with epilepsy and activates mesial temporal lobe structures in individual cases. Limitations include the small number of patients studied and the lack of reported memory outcome data. Further research will examine whether this fMRI memory paradigm is viable for estimating post surgical functioning. 1.Binder JR et al 2010. Epilepsia, 51(4): 618-626. 2.Dupont S et al 2010. Radiology, 255(1): 128 - 134. 3. Byars AW et al 2002. J Child Neurol, 17(12): 885-890. 4. Everts R et al 2010. Epilepsia, 51(4): 627-638. 5. Gaillard WD et al 2007. Neurology, 69: 1762-1771. 7. Janzsky J et al 2005. Epilepsia, 46(2) 244-250.S 6. Shurtleff H et al, 2010. Journal of Neurosurgery Pediatrics, 5, 500-506.