Clinical implications of naming performance and seizure lateralization in bilingual children with epilepsy

Naming difficulty is a common symptom of left (i.e., language dominant) hemisphere epilepsy. As such, in the presurgical evaluation for drug-resistant epilepsy, which aims to localize the epileptogenic region, identification of a naming deficit typically implicates the left temporal region. However, the well-established finding of poor naming in those with left but not right (i.e., nondominant) hemisphere seizures in monolingual patients is unreliable in bilingual adults with epilepsy, despite proficiency in the language tested. We aimed to examine naming performance and its relation with seizure lateralization in bilingual children with epilepsy.

This multisite study included 57 bilingual and 202 monolingual pediatric epilepsy patients, aged 6-17 years. All patients underwent neuropsychological evaluation including assessment of auditory and visual object naming in English.

In the context of age-appropriate English expressive vocabulary skills, bilingual children with epilepsy demonstrated significantly weaker auditory and visual naming than monolingual patients. Additionally, unlike monolingual patients, who showed poorer naming among those with left compared to those with right hemisphere seizures, bilingual children with unilateral left and right hemisphere seizures demonstrated similarly weak naming performances. Furthermore, naming score cutoffs failed to differentiate individual bilingual patients with left versus right hemisphere seizure onset as they did among monolingual patients.

Despite conversational proficiency and normal English expressive vocabulary, the relation between seizure laterality and naming performance demonstrated in monolingual children with unilateral seizures was not observed in a comparable group of bilingual children. Consequently, poor naming performance in bilingual children with epilepsy may be misinterpreted, most seriously in those with nondominant hemisphere seizures, as scores may be erroneously interpreted to reflect dominant hemisphere seizure involvement, potentially leading to unnecessary invasive and costly procedures. Results suggest cautious interpretation of naming performance in bilingual children with epilepsy.