Methods

Requisites for a valuable new multimodal task include:

  1. Speed: fitting within a time constraint of 4 seconds (5 seconds including evaluation). For operations in awake conditions, managing the duration of the awake phase is essential due to the unpredictable fatigability of the patient. Prolonged cortical mapping reduces the time available for subcortical mapping, with maximal tumor resection under functional control being paramount.

  2. Reliability: unequivocal evaluation of correct/not correct responses, avoiding false positives and negatives, and not amenable to subjectivity. The primary question for the stimulated area is whether it should be resected. The secondary question, regarding the specific function, can be addressed if time permits. If a function is detected within a particular area, this tissue should not be resected, regardless of its specificity. Once an error is detected, the specificity of the presumed function can be defined.

  3. Sensitivity: fast detection of errors. Sensitivity predominates over specificity. Higher sensitivity leads to a higher detection rate and fewer false negatives.

  4. Broad scanning: over different networks. This is achieved by the simultaneous activation of different cognitive pathways via various inputs and outputs. Most current tests (e.g., Dutch Linguistic Intraoperative Protocol/ DuLIP) are based on one language pathway.

Implementation of the Global Evoked Naming Task

The most common grammatical structure in almost all languages is the Subject-Verb-Object sentence. In combination with visual object presentation, it allows the verification of visual, auditory, semantic, phonological, and syntactic pathways.

This "Global Evoked Naming Task" provides a sensitive simultaneous analysis of visual, auditory, lexical, phonological, and semantic pathways, as well as syntax and sentence production.

The optimization of awake lesion-resection testing coincides with the speed and simplicity of the tests, as well as with sensitivity and specificity.

The four objects are best rendered as drawn (black and white, standardized) images since written words are slower to identify within the 4-second timeframe. Complex line or shadow drawings, backgrounds, and colored pictures are avoided to prevent patient distraction. The single subject or verb written at the center of the slide can be quickly read, allowing the evaluation of the patient's reading capabilities.

Verbs are better presented as spoken or written words rather than drawings, due to their more abstract nature. The infinitive form is used, requiring grammatical processing. Both transitive verbs (SOV) and intransitive verbs (with the need for a preposition) are used, in active or passive forms. In English, verbs are presented preceded by "To," as many nouns and verbs are similar (with nouns written with a capital letter).

The auditory input should be as short as possible to maximize the time in which the patient can utilize semantic and syntactic pathways, constrained to the 5-second task presentation.

The multiple possible combinations of these items allow extensive testing. Since the proposed basic scheme is always the same, reproduction is fast and ready for use in O.R. and/or nTMS procedures.