Analysis of naming errors during cortical stimulation mapping: Implications for models of language representation

Abstract

This study reports on the characteristics and distribution of naming errors of patients undergoing cortical stimulation mapping (CSM). During the procedure, electrical stimulation is used to induce temporary functional lesions and locate ‘essential’ language areas for preservation. Under stimulation, patients are shown slides of common objects and asked to name them. Cortical stimulation can lead to a variety of naming errors. In the present study, we aggregate errors across patients to examine the neuroanatomical correlates and linguistic characteristics of six common errors: semantic paraphasias, circumlocutions, phonological paraphasias, neologisms, performance errors, and no-response errors. Aiding analysis, we relied on a suite of web-based querying and imaging tools that enabled the summative mapping of normalized stimulation sites. Errors were visualized and analyzed by type and location. We provide descriptive statistics to characterize the commonality of errors across patients and location. The errors observed suggest a widely distributed and heterogeneous cortical network that gives rise to differential patterning of paraphasic errors. Data are discussed in relation to emerging models of language representation that honor distinctions between frontal, parietal, and posterior temporal dorsal implementation systems and ventral-temporal lexical semantic and phonological storage and assembly regions; the latter of which may participate both in language comprehension and production.

Combined noninvasive language mapping by navigated transcranial magnetic stimulation and functional MRI and its comparison with direct cortical stimulation

“…Yes, they are, regarding the wealth of experience of DCS and its status as the gold standard for the detection of language-eloquent brain regions. 7,9,26,44,45,62,65 Noninvasive mapping techniques for identifying human language function have to compete with results mapped during awake surgery. Having no other modalities, however, we still do not know exactly the role played by these DCS-identified language-positive points.…”

“…13,17,30,66 This has been shown in several studies and for each of the 3 modalities. 9,30,40 However, it has also been shown that fMRI language mapping is more sensitive to anterior than to posterior language-related cortical regions. 3 The more frequently detected occurrence of positive BOLD signals within the anterior language-related regions could be approved by our study and these circumstances have to be considered in case of assessing the accuracy of fMRI language mapping (Fig.…”

“…The detected language errors were documented and categorized into 7 groups: no responses, performance errors, hesitations, neologisms, semantic paraphasias, phonologic paraphasias, and circumlocutions. 9,67 Language errors related to muscle stimulations or pain were discarded.…”

“…6,71 Today, the most precise way to localize individual language-eloquent regions is direct cortical stimulation (DCS) during awake craniotomy. 9,12,26,44,45,54,62,65,74 Using only DCS, however, we cannot provide the longitudinal abbreviatioNs BOLD = blood oxygen level-dependent; CPS = cortical parcellation system; DCS direct cortical stimulation; ER = error rate; ERT error rate threshold; fMRI = functional MRI; IPI = interpicture interval; NPV = negative predictive value; nTMS navigated TMS; PPV = positive predictive value; PTI = picture-to-trigger interval; RMT = resting motor threshold; ROC = receiver operating characteristic; rTMS repetitive navigated TMS; TMS = transcranial magnetic stimulation. obJect Repetitive navigated transcranial magnetic stimulation (rTMS) is now increasingly used for preoperative language mapping in patients with lesions in language-related areas of the brain.…”

Contemporary model of language organization: an overview for neurosurgeons

“…Early models described a serial organization of these naming subprocesses; however, a new framework proposed by Hughes Duffau and colleagues argues that the phonological and semantic subprocesses occur in parallel, with dorsal and ventral streams, in a manner similar to that described by the Hickok-Poeppel model (see Duffau et al, 2014 for an excellent review). 34,61 Although the most common effect of cortical stimulation during naming is no response, 18 when less frequent but specific errors are elicited, they can help further differentiate some selective linguistic subprocesses. For example, visual paraphasias have been reproducibly elicited during stimulation of the basal occipitotemporal cortex.…”