Comprehensive Epilepsy Center

Transcranial Magnetic Stimulation (NexStim)

Transcranial Magnetic Stimulation (NexStim) is a high-tech, non-invasive test that maps the part of the brain that controls speech and motor functions. This part of the brain is known as the eloquent cortex, and it can be difficult to identify the origin of seizure activity in this area.

If you child is a candidate for possible epilepsy surgery it is important to determine if the area causing the seizures may be close to regions of functions including motor sensory or speech. Transcranial Magnetic Stimulation is a non-invasive test that maps the part of the brain that controls both speech and motor function. That part of the brain is known as the Eloquent Cortex. This in turn can be mapped on your child’s MRI and this along with other test can differentiate where the seizures are originating versus the areas of Eloquent Cortex.

Before TMS

The patient usually can eat and drink prior to the procedure unless otherwise specified.

As described above, TMS uses magnets in the magnetic field to stimulate parts of the brain because of this it is important that the person performing the procedure know of any potential implants such as a vagal nerve stimulator or pacemakers, or other devices. It is also important that they know of any other piercings. It has been suggested that a patient receiving TMS, that the hair is washed and products affecting the hair such as hairspray or oil should be avoided. Metal objects and glasses will be removed during the procedure. In order to comfort your child, one may want to bring a comfort toy such as a teddy bear.

Caffeinated products should be avoided on the morning of testing.

Maximum duration of the event is approximately two hours.

During TMS

A device called a coil is place near the head of the person receiving the treatment. The coil produces vary subtle stimuli directly over the region of the brain in question. This in turn causes pulses of the stimulus to affect this region and may cause movement on the opposite side of the body from where the stimulus is or may affect understanding or expressive language in the regions which control language. The tests are usually painless and non-invasive. It works by magnetic pulses penetrating the regions of the brain or cerebral cortex that elicit these functions.

After TMS

Your child will not experience any recovery time following the test and normal activities and diet can be resumed.