Improving preoperative nTMS with a dual-task protocol: the contribution of Action Naming to language mapping

In order to perform safe brain tumor surgery that affects cognitive skills as little as possible, it is important to know exactly which brain areas around the tumor are hosting crucial skills, such as language. The non-invasive brain stimulation method of navigated Transcranial Magnetic Stimulation (nTMS) allows us to locate these areas even before surgery: We can probe small brain areas by applying the disrupting stimulation and having the patient perform a language task. Errors during the task suggest language involvement in this area. The neurosurgeon will then try to spare this area during resection. Until recently, only object naming in which the patient has to produce the name of a noun picture (e.g. This is a table) was used. This thesis explores the potential of employing an additional action naming task (e.g. The woman reads), that is linguistically more complex. First, we described the design of a standardized protocol, consisting of both Object Naming and Action Naming. Secondly, we applied it under nTMS in healthy participants to evaluate its usefulness in localizing language on the brain surface and the underlying network. Finally, we investigated its feasibility in brain tumor patients. Our results indicate that Action Naming is more successful than Object Naming in revealing language areas and networks. We provide evidence that clinicians should use both Object and Action Naming, because these tasks require partly different networks in the brain that both need to be preserved during surgery in order to avoid worsening of language after surgery.