Localization patterns of speech and language errors during awake brain surgery: a systematic review

Area of Science:

• Neurosurgery
• Neurolinguistics

Background:

• Awake craniotomy with direct electrical stimulation (DES) is standard for eloquent area gliomas.
• Accurate language mapping is crucial for preserving quality of life by avoiding functional deficits.
• Current language mapping tasks may not fully capture all speech and language error types and their precise brain locations.

Approach:

• A systematic review of 102 studies was conducted, analyzing speech and language errors during DES in adult glioma patients up to July 2020.
• Findings were mapped to corresponding brain locations, focusing on both cortical and subcortical areas.
• Observed error patterns were compared with existing dual-stream and DuLIP models of language processing.

Key Points:

• 40% of reported errors occurred at the subcortical level, despite less frequent intraoperative investigation.
• Nearly 60% of errors were identified at the cortical level.
• New locations were identified for articulation/motor speech, phonology, reading, and writing errors, refining language localization.

Conclusions:

• The study proposes an updated Dutch Linguistic Intraoperative Protocol (DuLIP) model based on observed error patterns.
• This updated model facilitates more accurate "location-to-function" task selection for intraoperative language assessment.
• Improved intraoperative language monitoring may lead to better postoperative language outcomes for glioma patients.