2094 Awake Craniotomy With English and British Sign Language Mapping in a Patient With a Left Temporal Glioblastoma Reveals Discordant Speech-Sign Language Maps

INTRODUCTION: Awake craniotomy with direct electrical stimulation (DES) remains the gold standard for tumor resection in language eloquent brain regions. Currently, four cases of awake craniotomy with sign language mapping exist. METHODS: An awake craniotomy was undertaken with monitored anesthesia care for left temporal tumor with vasogenic edema extending into the frontal lobe and insular cortex. DTI reconstruction confirmed the proximity to the inferior longitudinal fasciculus. Cortical and subcortical mapping was performed with a bipolar stimulator with 5 mm spacing between probe tips, delivering biphasic current (square wave pulses, 60 Hz, 1 ms pulse width, 1-3 mA). The cortical surface was first mapped using English tests and subsequently with BSL testing using an interpreter. RESULTS: Stimulation of the pars opercularis did not result in any object naming or semantic errors in English testing whilst stimulation during BSL testing resulted in an inability to perform the semantic fluency task of attempting to sign three items within a category. Mild reductions in semantic and phonological fluency were identified on English testing with no reduction in performance seen in any test of BSL. CONCLUSIONS: The findings in this report may indicate that, in hearing people who acquire a signed language as a first language, topographical organization may differ to that of a second spoken language - this phenomenon is well described in multi-lingual patients fluent in two spoken languages where heterogeneity in location of first and second languages has been identified during awake craniotomy and is thus perhaps generalizable cross-modally.