Language mapping during awake brain surgery in a deaf patient with a brain tumor: illustrative case.

Background: Signed language integrates complex sensorimotor processes involving visual and motor networks. The contribution of language regions such as Broca's and Wernicke's areas during signing is not well established. Here, the authors report the case of a 45-year-old right-handed male with congenital deafness, who communicates using American Sign Language (ASL) and Signed English, presenting with focal seizures. Imaging showed a diffuse infiltrative glioma in the right cerebral hemisphere.

Observations: Remarkably, preoperative functional MRI language activations were bihemispheric and overlapped for both traditional language paradigms and sign paradigms, suggesting that the same cortical regions of the brain are used for language processing in this patient. This case is unique because it is the first reported awake craniotomy performed in a deaf patient with a right hemispheric glioma. The authors also found that direct cortical stimulation of the right premotor cortex (Exner's area) resulted in interruption of signing, which has not been previously reported in the literature in a deaf patient.

Lessons: Prior to surgery for brain lesions in deaf patients, careful preoperative assessment and intraoperative testing (including the presence of an experienced ASL sign interpreter) is required to understand the distribution of language processing within the brain and to minimize postoperative morbidity. https://thejns.org/doi/10.3171/CASE2597.