Epilepsy Center | Brain Stimulation for Epilepsy

When medications do not adequately control seizures, noninvasive brain stimulation, sometimes called neuromodulation, may soon be another option. Devices, research, and interest in brain stimulation have exploded in the 21st century, fueled by technical advances and a growing recognition that a large fraction of neurologic and psychiatric disorders like epilepsy, chronic pain, and major depression are resistant to medication.

TMS vs. tDCS: Unlike earlier methods that require surgery to implant the brain stimulator, TMS and tDCS are completely noninvasive. TMS uses a focused magnetic field to induce an electrical field, causing brain cells to fire. Over time, this seems to change long-term brain cell activity. tDCS applies a weak, direct current to the brain via electrodes on the scalp and is thought to cause brain cells to change their firing rate.

Two completely noninvasive techniques are the subject of active study: transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). Both are painless and safe and do not require surgery. To date, most of this research has been in adults.

Transcranial magnetic stimulation (TMS)

TMS uses a small but powerful electromagnet to apply an electrical current to specific brain areas. It is currently being used experimentally at Boston Children’s by neurologist Alexander Rotenberg, MD, PhD. So far, the research is very encouraging and suggests that one type of TMS, called low-frequency repetitive TMS (rTMS), can calm down an over-excited brain and may suppress focal seizures.

TMS is safe enough to be used in the doctor’s office. Children are usually awake during TMS and seated comfortably. Most, even young children, handle TMS well, and side effects are minimal. Clinical trials are ongoing at Boston Children’s to test the anti-epileptic potential of rTMS, particularly for temporal lobe epilepsy.

While the Food and Drug Administration has not specifically approved TMS for treatment in children, a diagnostic TMS device that helps identify brain regions critical for language or motor function is approved for all ages and can be used to help neurosurgeons plan epilepsy surgery. TMS is also being investigated as a way of measuring brain excitability and inhibition and perhaps predicting a patient’s response to an anti-epileptic intervention.

Transcranial direct current stimulation (tDCS)

tDCS is another brain stimulation technology that applies a weak, direct current to the brain via scalp electrodes to increase or decrease excitability in selected areas. tDCS may be helpful in suppressing seizures, and Dr. Rotenberg will soon be testing it as a treatment for focal seizures in a two-year trial.

Like TMS, tDCS is safe and most children tolerate it well. Unlike the large TMS machines, tDCS devices are often portable and can run on nine-volt batteries. tDCS does not yet have FDA approval for any clinical application, but a fast-growing body of research supports the use of tDCS for neuropsychiatric disorders, and there is much popular interest in using it for cognitive enhancement.

Still other noninvasive methods, such as transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS), are evolving fast, though it’s too soon to know if they will have a place in epilepsy care. Like TMS and tDCS, these techniques can potentially change brain function with minimal side effects.

Brain stimulation for children?

Adapting brain stimulation to children requires special considerations that take into account the biology of children’s developing central nervous systems. As we begin offering brain stimulation to children with epilepsy and other disorders, we are carefully tracking its safety and efficacy. The tools get better every year, and we’re hopeful that noninvasive brain stimulation will help increase treatment options for drug-resistant epilepsy. Stay tuned!

Did you know?

Brain stimulation is not new. In the 1st century AD, the Roman physician Scribonius Largus treated headaches by applying electric torpedo fish to the head. In the 20th century, electroconvulsive therapy was developed to treat drug-resistant depression, vagus nerve stimulation to treat drug-resistant epilepsy, and deep brain stimulation to treat symptoms of Parkinson’s disease.