Article
Non-invasive mapping of prosopagnosia by navigated transcranial magnetic stimulation
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Published: | June 8, 2016 |
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Objective: Besides motor and language function, tumor resections within the frontal and parietal lobe were also reported to cause neuropsychological impairment, like prosopagnosia. Since non-navigated TMS was already used to detect and impair neuropsychological cortical function, this study now aims on the evaluation of the feasibility and spatial discrimination of navigated rTMS mapping for detection of prosopagnosia in healthy volunteers. Moreover the study was designed to establish this technique for preoperative mapping in brain tumor patients.
Method: 20 healthy and purely right-handed volunteers (11 female, 9 male) underwent rTMS mapping for cortical face recognition function using 5 Hz/10 pulses. Both hemispheres were investigated randomly with 13 to 16 days between both mappings. 52 predetermined cortical spots of the whole hemispheres were mapped. The task consisted of 80 portraits of popular persons which the subjects were instructed to name while rTMS pulses were applied.
Results: The highest error rate of 80% for all errors of all subjects was generated in the right middle middle frontal gyrus (mMFG). Concerning no response errors the highest error rate of 35% was achieved in bilateral triangular inferior frontal gyrus (trIFG). With regard to similar or wrongly named persons we observed 10% error rates mainly in bilateral frontal lobe.
Conclusions: rTMS seems feasible to locate cortical face recognition function and to generate prosopagnosia. Besides language function, the confirmed cortical localizations are well in accordance with the contemporary literature. Clinical usefulness of preoperative mapping in brain tumor patients has to be evaluated as the upcoming step.