Dutch Linguistic Intraoperative Protocol Extended: new standardized items and tasks for language monitoring in awake glioma surgery for mild to severe aphasia

Background Awake surgery is the standard treatment for low-grade glioma patients in eloquent areas, but also seems to result in better surgical outcomes in glioblastoma patients. The Dutch Linguistic Intraoperative Protocol (DuLIP) is a validated tool for intraoperative language monitoring. However, in clinical practice, there is a need for additional items and tasks. Therefore, we aimed to develop and standardize an extended version of DuLIP (DuLIP-Extended). Methods We developed 1) Extra items for word repetition and the original semantic tasks. 2) Additional tasks for phonology, semantics and syntax. 3) Tasks for severely aphasic patients for phonology, semantics, and object naming of high-frequent words. DuLIP-Extended was administered in 160 healthy native speakers of Dutch and in 3 patients for clinical illustration. The accuracy rate was calculated per item and per task. Differences on task performance between groups of sex, age, and education were investigated. Results All tasks had an accuracy rate of ≥ 90%. Some effects for sex, age, and education were found. Cut-offs were created per task, based on these significant predictors. Successful intraoperative application of DuLIP-Extended was demonstrated in three cases. Conclusions DuLIP-Extended appeared to be feasible in a large group of healthy participants and in three glioblastoma patients where positive language areas and/or functional boundaries were identified. Combined use of the original DuLIP and DuLIP-Extended will enable to select from a larger variety of items and tasks and has promising results for glioma patients with mild to severe aphasia.