Artikel
Novel tractography-informed TMS language mapping protocol
Neues Traktographie-basiertes TMS Sprachkartografie-Protokoll
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Veröffentlicht: | 4. Juni 2021 |
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Gliederung
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Objective: Navigated repetitive transcranial magnetic stimulation (nTMS) is used for language mapping in patients with tumors of the language system for general preoperative analyses and preoperative planning. The aim of this study was to improve the reliability and reproducibility of language nTMS mapping by using patient-specific cortical ends of language-related fiber bundles as targeted stimulation areas.
Methods: nTMS based language mapping was performed in 44 right-handed female (23) and male (21) patients, age-range 24-78 (M=53.3, SD=13.9) with left-hemispheric language-eloquent gliomas (WHO grade II (4), III (12), IV (25)) and metastases (3). The patients were further divided into two groups. Group 1 (n=22) received an earlier protocol, in which the entire perisylvian cortex was stimulated, while group 2 (n=22) received the novel tractography-based protocol, which stimulated individual cortical endings of the before delineated arcuate fascicle (AF) and peritumoral areas.
Results: nTMS and delineation of the AF was successful in all 44 patients. We observed a significant increase in error rates between group 2 (M = 5.0%, SD = 2.8%) and group 1 (M = 3.2%, SD = 2.1%), t(42) = 2.4, p = 0.02. Additionally, there was a significantly higher percentage of no response errors in group 2 (Mdn = 10%) than in group 1 (Mdn = 0%), U(NGroup 1 = 22, NGroup2 = 22) = 147, z = -2.4, p = 0.015. Our results also showed a significant difference in the distribution between nTMS-induced errors compared to non-errors using Brodmann areas (BA) X2 (25, N = 959) = 54.9, p = .001. There was a higher percentage of errors than non-errors intersecting BA 45 (errors: 9.1% vs. non-errors: 3.6%), BA 41 (errors: 4.5% vs. non-errors: 0.7%), BA 37 (errors: 4.5% vs. non-errors: 0.3%), and BA 13 (errors: 2.3% vs. non-errors: 0.0%).
Conclusion: We have demonstrated that by considering the individual anatomy and stimulation of the AF, we were able to improve the efficacy to disrupt object naming via nTMS. Thus, the newly introduced method shows promising results to obtain more reliable non-invasive personalized language maps.