Speech Mapping with Transcranial Magnetic Stimulation

The identification of eloquent cortical regions associated with language function is of great relevance to basic scientists as well as clinicians. Repetitive transcranial magnetic stimulation (rTMS) is a relatively novel technique that allows for noninvasive, lesion-based identification of critical language sites. The integration of frameless stereotactic navigation systems with rTMS allows for precise targeting and identification of the cortical region that is being stimulated. Integration of this navigational data also allows for accurate, real-time analysis of magnetic field strength in the stimulated region of interest. Thus, navigated rTMS allows the investigator to identify precisely the threshold of stimulation necessary to interrupt the language function of a given cortical locus. The most common rTMS language mapping protocols are safe, with a nominal risk of seizure being the predominant serious adverse effect. They are also well-tolerated by the patient. Validation studies have found that navigated rTMS language maps correlate well with language maps obtained using direct cortical stimulation (DCS), the current gold-standard. Future studies will focus on improving the protocols used for rTMS language mapping, as well as exploring and validating the language tasks which yield the most relevant and accurate language maps.
Source: Springer protocols feed by Neuroscience - Category: Neuroscience Source Type: news