B - 9 Implications of Cognitive Reserve (CR) in Pre-Surgical Epilepsy Patients: a Case Series

Abstract Objective Localization-related epilepsy is a chronic neurological condition for which neurosurgical interventions are effective. The pre-surgical evaluation process requires careful analysis of neuropsychological data to localize and lateralize areas of underlying neuropathology to guide surgical planning and post-operative prognostication. While it is well-described throughout the literature that global impairments may obscure patterns of discernable neurocognitive strengths and weaknesses, specifically in pre-surgical epilepsy evaluations, less is known about the impact of cognitive reserve (CR). CR, often described in the aging literature, refers to high levels of mental reserve acquired from educational, vocational and intellectual capacities, with the potential to guard against neurocognitive decline. Method Four right-handed patients (ages 24–44) with localization-related, medically-refractory epilepsy with left hemisphere onset (2 temporal and 2 extra temporal onset) underwent a comprehensive neuropsychological evaluation as part of a comprehensive pre-surgical workup. Results The CR conglomerate for these four patients (i.e., educational, vocational attainment and scores on premorbid cognitive metrics) fell in the Very High range. Three out of four patients did not evince the clinically-significant pattern of deficit (>1.5 SD lower than premorbid estimate) on verbally-mediated tasks often seen in right-handed individuals with left-sided seizure onset (i.e., diminished naming and verbal learning). Conclusion The reasons underlying the manifestation of definitively localizing or lateralizing neuropsychological profile differs from patient-to-patient (i.e., handedness, duration of epilepsy, structural lesion, language(s) spoken); however, CR should also be considered an important confound when interfacing with data of questionable clinical utility and prognostic value.