Impact of Priming on Effectiveness of TMS in Detecting Language-eloquent Brain Areas in Tumor Patients

Abstract

Background and Study Aims Language is characteristically human, and preserving it is critical when resecting tumors in language-eloquent brain areas. Navigated repetitive transcranial magnetic stimulation (nrTMS) has been used in recent years as a noninvasive technique to identify preoperatively the language-eloquent cortical areas in tumor patients. An important objective is to increase the sensitivity and specificity of nrTMS in detecting language-related areas and increase the positive correlation of its results to that of intraoperative direct cortical stimulation (DCS). Although the technical aspects of the procedure have received enormous interest, factors related to the targeted cortical area such as previous cortical history or activity have been neglected. Therefore, the present study explores the impact of previous cortical history or activity on the effectiveness of a subsequent nrTMS mapping paradigm. Materials and Methods Twelve right-handed patients with a left hemispheric glioma underwent presurgical nrTMS language mapping and intraoperative language mapping with DCS. nrTMS was performed using a continuous theta burst stimulation paradigm to inhibit possible language relevant areas in the vicinity of the tumor, determined anatomically or based on functional magnetic resonance imaging hotspots. The nrTMS was applied in two separate sessions. One of the sessions randomly included a priming paradigm to precondition the targeted cortical areas. Results Priming stimulation decreased the error detection of the subsequent nrTMS mapping paradigm. This effect was more robust on major types of errors such as speech arrest and hesitation. Conclusion Prior cortical activity as induced by the priming stimulation has a profound impact on the responsiveness to the nrTMS mapping paradigm. Our findings further showed that metaplasticity, a type of homeostatic plastic process, could be elicited even in cortical areas affected by a growing tumor.

Assessing the Capabilities of Transcranial Magnetic Stimulation (TMS) to Aid in the Removal of Brain Tumors Affecting the Motor Cortex: A Systematic Review

“…Of the included articles, thirteen mentioned adverse event analysis, with 11 mentioning that any adverse event occurred, one reporting the occurrence of minor headaches or small scalp pinch, 43 and one reporting that 7 of 12 patients had complained about strong facial contractions 51 ( Table 1 ).…”

The Role of Extra-Operative Cortical Stimulation and Mapping in the Surgical Management of Intracranial Gliomas

“…Although the reported sensitivity is 100%, the positive predictive value is as low as 34%, while the accuracy is only eight percent. It should be kept in mind that this is a rapidly evolving method, with a constantly increasing accuracy and clinical utilization [ 21 , 27 , 28 , 29 , 30 , 31 , 32 ].…”

Disruption to left inferior frontal cortex modulates semantic prediction effects in reading and subsequent memory: Evidence from simultaneous TMS-EEG

“…Short, controlled bursts of TMS can create temporary "virtual lesions" that induce transient changes in language (Nuñez et al, 2020;Klaus & Hartwigsen, 2019;Hartwigsen et al, 2015) and memory (Ferrari et al, 2018;Wang et al, 2018;Gatti et al, 2021). Importantly, TMS has been used successfully to disrupt cortical activity and impair speech production (e.g., Pascual-Leone et al, 1991;Epstein et al, 1999;Hauck et al, 2015;Freigang et al, 2020;Krieg et al, 2014;Rösler et al, 2014). So-called "speech mapping protocols" combine a production task (e.g., object naming) with (typically) a 5-pulse train, 5-Hz repetitive TMS stimulation, with stimulation time-locked to the onset of the visual object.…”