Clinical Pearls and Methods for Intraoperative Awake Language Mapping

Abstract

Intraoperative language mapping of tumor and peritumor tissue is a well-established technique for avoiding permanent neurological deficits and maximizing extent of resection. Although there are several components of language that may be tested intraoperatively (eg, naming, writing, reading, and repetition), there is a lack of consistency in how patients are tested intraoperatively as well as the techniques involved to ensure safety during an awake procedure. Here, we review appropriate patient selection, neuroanesthetic techniques, cortical and subcortical language mapping stimulation paradigms, and selection of intraoperative language tasks used during awake craniotomies. We also expand on existing language mapping reviews by considering how intensity and timing of electrical stimulation may impact interpretation of mapping results.

Keywords: Awake craniotomy; Direct cortical stimulation; Language mapping.

FIGURE 1.

Intraoperative language tasks. Intraoperative testing can include PN, counting, word repetition, reading, writing, and assessing language syntax.

FIGURE 2.

Concerns and relative contraindications to awake language mapping and identified solutions.

FIGURE 3.

Intraoperative language tasks based on tumor location.

FIGURE 4.

Electrical stimulation-task response paradigms. Standard stimulation paradigms involve delivery of an electrical stimulus 1.4 s prior to a visual or auditory stimulus with the goal of focal network disruption during the motor planning phase of speech production (ie, response). Alternative stimulation paradigms may modify stimulation-response timing. Delivery of the electrical stimulus at the point of visual stimulus delivery (rather than prior) may capture speech output ie, verbal response. Additionally, lengthening the stimulus duration through both presentation of the visual stimulus and verbal response may influence different temporal-dependent cognitive networks.