Patients with severe epilepsy can have seizures every day – sometimes waking up on the floor, not knowing what happened. For about 1 in 3 epilepsy patients, drugs are of no help. An implanted vagus nerve stimulator can sometimes control seizures, but often not. Surgically removing the excitable brain tissue can be curative, but often, too many areas of the brain are involved to effectively remove the entire seizure focus. Or the area causing the seizures is too close to a vital brain area – say, a memory or motor area – making surgery too risky.
Alex Rotenberg, a neurologist in Children’s Hospital Boston’s epilepsy program, has been having success with an experimental technique for this kind of disabling, treatment-resistant epilepsy. Known as repetitive transcranial magnetic stimulation (rTMS), it has helped a small number of patients with no other good options for controlling their seizures.
Cleared in 2008 by the Food and Drug Administration to treat patients with major depression, rTMS involves placing a very strong magnet over the patient’s scalp. The magnet generates a powerful, fluctuating magnetic field that induces small electrical currents inside the brain. It’s completely non-invasive.
Rotenberg has used rTMS off-label to treat about 15 patients with drug-resistant seizures, with about a 50 percent success rate. “In epilepsy, the problem is excessive brain excitability,” he says. “It turns out that if we stimulate the brain, perhaps once per second, that stimulation reduces brain excitability. If the seizure focus is close to the brain surface, we sometimes see a reduction in seizures.”
Some patients have been able to go seizure-free for long periods. Responders must come to Children’s every 2 to 3 months for maintenance treatments, since rTMS’s effects last only several weeks to a few months.
With support from the Epilepsy Therapy Project and the Epilepsy Foundation, Rotenberg will soon launch a clinical trial in patients with treatment-resistant temporal lobe epilepsy (TLE). This form of epilepsy — accounting for nearly 20 percent of all epilepsy and some 70 percent of all drug-resistant focal epilepsy — affects a deeper brain area that so far hasn’t responded to conventional rTMS.
“The conventional device does not penetrate much below the surface of the skull,” says Rotenberg. “We had to wait for a specialized rTMS device that can penetrate deep enough to reach the temporal lobes.”
That device, called H-Coil (Brainsway Ltd.), is being shipped to Rotenberg from Israel. It’s already marketed for the treatment of major depression and other neuropsychiatric symptoms, and is in clinical trials for indications as wide ranging as Alzheimer’s disease, stroke and schizophrenia, autism and smoking cessation, with a benign safety profile.
If rTMS works as well as hoped for TLE, it could rapidly move to commercialization for epilepsy treatment. As the price of the device goes down, Rotenberg believes rTMS will be available in community medical practices within several years, and thus more accessible to the patients who so desperately need it.