In this week’s excursion we visited Nexstim, which is a company that sells transcranial magnetic stimulation devices. Transcranial magnetic stimulation is used to treat depression but also for pre surgical mapping. Pre surgical mapping helps planning surgeries as well as makes them safer, because it I possible to determine the functions to the respective brain area. Previously we knew what the brain looked like and what functions it has. However it has been unknown for a long time which brain area corresponds to which function. The representative of Nexstim compared it to a city map, where we know what buildings exist, for example a post office, but not where they are. Invasive electro-stimulation first enabled the linking. TMS is another way with the huge benefit of being non-invasive. What characterises Nextstim in comparison with other TMS manufacturers is there accuracy and precision. They are so far the only device on the market which is licensed for surgery not only in Europe but also in the United States of America.
The presentation also included a demonstration on a subject. Therefore MR images that were previously acquired were opened in the software. The dominant landmarks, such as nose and ears along with other points of the head were registered with a pointer and a reference on the subjects head. This enabled matching the head with the MRI with an accuracy of 1.5 mm. EMG-electrodes have been fitted on the thumb (APB) and the lower arm (EDC). When stimulating the contralateral motor cortex, it not only allowed us to see signals in both muscles, but also see a difference in latency.
The excursion was very educative and it was nice to get to know the company Nexstim with their TMS devices.