Language Mapping With rTMS in Healthy Pediatric Patients

Repetitive transcranial magnetic stimulation (rTMS) is a potentially effective, noninvasive tool for language mapping. However, there is a paucity of data in pediatric patients. In this study, we aimed to map language sites in healthy pediatric participants with navigated rTMS.

Children aged 5 to 18 years underwent bilateral language mapping. Stimulation was delivered at 5 Hz during visual-naming and auditory verb-generation tasks in 1 to 2 second bursts. We targeted 33 standardized sites per hemisphere. In total, 34 participants completed the visual-naming task, and 27 participants completed the verb-generation task. Lateralization index (LI) and Wilcoxon signed-rank test were used to assess language lateralization. A difference of least squares means model was developed to determine the prevalence of visual-naming and verb-generation errors within lobar and hemispheric regions.

Weak left lateralization was observed for visual naming (LI 0.14; p = 0.038), and no lateralization was observed for verb generation (LI 0.08; p = 0.269). Using multiple least squares regression, left hemisphere errors were more likely to occur than right hemisphere errors for visual naming (OR 1.23; 95% CI 1.06-1.44), but no lateralization effect was observed for verb-generation errors (OR 1.11; 95% CI 0.93-1.27).

rTMS is likely to identify bilateral or weakly left-lateralized language sites in pediatric patients during language tasks. Although rTMS can be a useful noninvasive method for identifying potential language-positive sites, our results in healthy controls suggest that it cannot be used as a singular method for language mapping in the preoperative setting.