Mapping action naming in patients with gliomas: The influence of transitivity

Patients with left perisylvian gliomas might undergo language mapping with nTMS in preparation for awake brain surgery. Action naming is an important addition to the presurgical language mapping protocol. However, it has not yet been determined whether specific action stimuli can influence mapping outcomes in terms of number and/or localisation of induced errors.

We investigated this question by employing tractography-based nTMS language mapping of the left arcuate fasciculus (AF) with two types of verbs: transitive and intransitive. Data were collected from 22 patients with a left perisylvian glioma.

Our results demonstrated that nTMS induced a higher error rate with transitive rather than intransitive verbs, specifically during stimulation of the posterior temporal terminations of the left AF (transitive error rate: 8.3%; intransitive error rate: 4.8%). The effect was absent when gliomas displaced the temporal terminations of the AF. Also, nTMS triggered a higher number of semantic errors with transitive (vs intransitive) actions during stimulation of the posterior temporal terminations of the AF (semantic error rate - transitives: 3.3%; semantic error rate - intransitives: 0%).

Our work highlights that clinical outcomes of language mapping with nTMS are affected by the choice of linguistic stimuli. Transitive verbs may be suited to achieve optimal nTMS mapping outcomes in posterior temporal areas of the left AF in this population. Displacement of white matter terminations due to the tumor can affect these results, and semantic errors may indicate core language processes that can be mapped when administering transitive verbs.