Language Mapping with navigated repetitive Transcranial Magnetic Stimulation: an experimental study in 2 healthy speech therapist (presentation + poster)

Elke De Witte, Eline Verwilligen, Erik Robert, Henry Colle

Research output: Chapter in Book/Report/Conference proceedingMeeting abstract (Book)


OBJECTIVE: The use of Navigated Transcranial Magnetic Stimulation (nTMS) in presurgical mapping is increasing. Good correlations have been found for TMS and Direct Electrical Stimulation (DES) when motor mapping is studied. Language mapping with TMS is far more complex. However, a recent study of Picht et al. (2013) showed promising results regarding the use of nTMS and DES for language mapping in eloquent brain regions. Repetitive TMS (rTMS) is required to disrupt language processing and to assess language lateralisation. The deficits typically reflect a delay in response times rather than a decline in accuracy, but rTMS may also cause 'speech arrests'. The interpretation of speech arrests is often neglected, although it provides useful information regarding the specific function-location relationship. Does the speech arrest represent a pure motor speech problem or a specific linguistic disorder (e.g. anomia)?
METHODS: In this study we used for the first time two speech therapists as healthy subjects to study language mapping with TMS during a confrontation naming task. Firstly, we wanted to investigate if TMS elicits pure language problems or mainly motor speech problems. Secondly, anatomoclinical correlations were studied. At the first test moment (T1), the speech therapists had to name 210 low-, middle-, and highfrequent unknown coloured pictures.
3 weeks later (T2) and 3 months later (T3) naming was assessed using navigated repetitive TMS (nrTMS) (Nexstim - 4.0; F: 7Hz, I: 110-120% MT) of the left frontal, temporal and parietal regions. Only the pictures that they were able to correctly produce at T1 were presented during T2 and T3, but in a randomized order. Reaction times (RT) were measured and audiovisual recordings were made at all test moments. Afterwards, the speech therapists were asked to classify the errors into language/motor/apractogenic/other deficits. Statistical analyses were performed using repeated measures ANOVA (reaction times) and the binomial exact test (errors per stimulation site).
RESULTS: There was a large interindividual difference since many more deficits were observed for speech therapist 2 at T2 and T3. Performance errors (dysartric/apractogenic distortions, restarts, prolonged reaction times) were the most frequently made errors followed by semantic paraphasias. Performance errors were triggered by stimulations in the superior temporal gyrus (STG), inferior frontal gyrus (IFG), supramarginal gyrus (SMG), precentral gyrus (PrCG) and angular gyrus (AG). Semantic paraphasias were elicited when the AG, PrCG and SMG were stimulated. There was a trend for prolonged reaction times at T2 when compared with T1. However, there was a significant difference between T1 versus T3 and T2 versus T3 with shorter RT at T3 for speech therapist 2.
CONCLUSION: nrTMS might prolong reaction times and elicits motor speech deficits as well as language deficits. Stimulation of the left IFG, PreCG, SMG, AG, STG, AG triggered a significant higher number of errors. Since a clear learning effect was found at T3, the time between the three trials should be extended in future studies. The use of different language tasks in a larger study group would be interesting to compare the type of linguistic errors and the anatomoclinical correlations.
Original languageEnglish
Title of host publicationAbstracts from the 5th International Symposium on NBS in Neurosurgery
Publication statusPublished - 2014
Event5th International Symposium on Navigated Brain Stimulation in Neurosurgery - Berlin, Germany
Duration: 13 Dec 201414 Dec 2014


Conference5th International Symposium on Navigated Brain Stimulation in Neurosurgery


  • Transcranial Magnetic Stimulation
  • Language Mapping
  • Speech Therapists


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