Research increasingly points to historically unappreciated cortical effects of multiple sclerosis (MS), with two-fold elevated risk of seizures. Nevertheless, epilepsy only occurs in 2-5% of cases. We present a 42-year-old, right-handed, woman with epilepsy and MS under consideration for epilepsy surgery.
Epilepsy and MS were diagnosed concurrently at age 31; seizures were the presenting symptom. Despite infrequent MS flares, seizures are weekly-to-monthly focal aware, focal unaware and focal-to-bilateral, starting with right head version, dysarthria, and spinning, followed by secondary generalization, at times occurring in clusters. Brain MRI revealed bilateral MS lesions including in left medial-frontal lobe and left hippocampus (Figure 1). Phase I EEG suggested left-lateralized seizures with broad frontotemporal evolution and rapid bifrontal synchrony. Interictal PET was unrevealing. fMRI determined left-hemisphere language dominance. Neuropsychological evaluation (NPE) was ordered to estimate cognitive risks of left-sided surgery.
NPE revealed relatively intact language and verbal learning/memory with exceptionally low visual learning/memory. Visuospatial skills were below average to exceptionally low. Although motor dexterity was exceptionally low bilaterally, her left-hand was markedly slower. Executive functioning, processing speed, and sustained attention were exceptionally low. Risk stratification drew upon traditional epilepsy surgery outcomes, as only 2 cases of epilepsy surgery in vastly different MS patients have been published.
NPE suggested high functional adequacy of the left hemisphere with low functional reserve of the right hemisphere. Due to paradoxical findings across structural/functional brain imaging, EEG, and NPE, with unclear effects/implications of MS, cautions were raised about surgery. Stereo-EEG and magnetoencephalography were recommended/ordered to determine the safest surgical option.

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