Development of Culturally Appropriate Spanish Language Tests for Neuropsychological Assessment and Brain Mapping

PROJECT SUMMARY Producing the right words while speaking is critical for social, academic, and occupational success. Word finding or “naming” ability is highly dependent on dominant temporal lobe function, and is commonly impaired after temporal lobe resection for seizure control. Thus, naming assessment plays multiple roles in the epilepsy surgery evaluation: Accurate diagnosis of naming impairment implicates the left (i.e., dominant) temporal lobe as the epileptogenic zone, and naming is the primary task used in electrical stimulation mapping (ESM) to identify and spare essential language areas from resection to preserve naming postoperatively. Previously, we enhanced the sensitivity and accuracy of both of these roles by expanding traditional visual object naming assessment to include clinically relevant auditory-verbal naming, and by incorporating hallmark symptoms of word finding difficulty in the performance metrics. However, these measures are available only in English, and available Spanish measures are highly flawed. As a result, we are unable to provide the same level of care for primary Spanish speakers or Spanish-English bilingual patients due to lack of appropriate tools and techniques. This highlights an unacceptable racial/ethnic disparity in care in the context of an increasing proportion of Spanish-English bilingual patients presenting for epilepsy surgery. We have already shown that using English-only testing for bilingual patients may result in inaccurate dysfunction localization, potentially confounding the surgery evaluation and leading to increased invasive procedures, or withholding of potentially curative treatment. Additionally, limiting ESM to one language risks missing critical sites for the other, potentially resulting in inadvertent removal of brain areas that are critical for the unmapped language. To address this disparity of care, and advance our understanding of brain-language relations of bilingualism, we will test Spanish-English bilinguals undergoing epilepsy surgery evaluation, capitalizing on unique diagnostic studies that permit assessment of brain areas that are critical for bilingual functioning. Specifically, this project will 1) develop and standardize linguistically appropriate Spanish auditory-verbal and visual naming measures applicable across Spanish dialects, 2) validate these by testing whether Spanish naming performance better lateralizes epilepsy-related dysfunction than English naming in bilingual patients with unilateral TLE, 3) utilize these tools to a) tailor stimuli for ESM to identify critical first and second language brain sites, and b) elucidate key factors that predict the presence and location of distinct unilingual vs co-localized, bilingual naming sites, and 4) characterize postoperative Spanish and English naming one-year postoperatively. Results promise a novel, linguistically appropriate Spanish language toolset for clinical and research use, more accurate Spanish naming assessment for lateralization of cerebral dysfunction, neuroscientifically based guidance for pre- resection clinical language mapping in bilinguals, and significant improvement in the level of care for Spanish speakers, not only for epilepsy, but also the multiple neurological conditions that affect expressive language.