33 Pre-Surgical Evaluation of Bilingual Epilepsy Patients; A Case Study Demonstrating the Importance of Bilingual Assessment

Abstract

Objective:

In the US, >20% of individuals aged 5 years and older speak a language other than English at home, with rates of bi- and multilingualism increasing. Providing linguistically- and culturally- competent care to increasingly diverse populations is a necessary task for neuropsychologists. The need for close attention to bilingualism is even more glaring in the context of neurosurgical interventions, such as in intractable epilepsy. Pre-surgical epilepsy evaluations serve as a baseline for post-surgical change, inform lateralization and localization, and help determine cognitive risks associated with surgery. The importance of evaluating bilingual status and assessing cognitive abilities in both languages, if needed, in presurgical epilepsy evaluations is examined. We present the neuropsychological profile of a 10-year-old bilingual male with intractable epilepsy participating in a pre-surgical epilepsy evaluation.

Participants and Methods:

This right-handed male is a sequential language learner, exposed to Spanish at birth and English when he began kindergarten. His parent reported he was primarily English speaking. Developmental milestones were met within expected timeframes. Seizures began at age 5. He is prescribed Vimpat and Lamictal. vEEG during admission revealed right temporal-onset seizures. Neuropsychological assessment was conducted in English based on parent report; however, expressive language testing revealed significantly higher performance in Spanish (average) compared to English (exceptionally low). Subsequently, a bilingual provider was consulted, and supplemental Spanish verbal reasoning and verbal memory measures were administered.

Results:

The patient’s neuropsychological profile captured a significant difference between English and Spanish verbal abilities. WISC-V Similarities scaled scores (ss) were 5 and 11 in English and Spanish, respectively. Vocabulary scaled scores were 8 and 15 in English and Spanish, respectively. Regarding verbal memory, list learning was below average in English (ss = 5), but low average in Spanish (ss = 6). Contextual verbal memory was only administered in Spanish; scores were average (ss = 10). Verbal Fluency administered in English was low (phonemic fluency ss = 5, categorical fluency ss = 6). fMRI verbal tasks were performed in English and revealed left-sided language lateralization.

Conclusions:

In pre-surgical epilepsy evaluations of bilingual children, consideration of language is essential. Assessment of language dominance is a minimum requirement in bilingual families, followed by full bilingual evaluation if necessary. In this case, starkly different conclusions regarding lateralization and localization may have been made if the child had not been evaluated in both languages. In English, a significant split between verbal and non-verbal cognition was apparent, possibly suggesting involvement of the dominant left hemisphere. With Spanish testing, this split disappeared, with high average verbal skills. While a growing proportion of children in the US are bilingual, bilingual assessments are not commonly conducted in pre-surgical epilepsy evaluations. In fact, very little work has been done examining language functioning in bilingual epilepsy patients, particularly in children. With both epilepsy-and language-related factors at play in a developing brain, we encourage closer attention to these issues, particularly in the context of neurosurgical procedures.