Blog #41: New Hope for Refactory Epilepsy

(This blog was originally posted on December 24, 2013)

 

 

Epilepsy is a brain disorder causing seizures. It affects 1 percent, or three million, of the American population. Only half of these people can control their seizures with anticonvulsant medications or with surgical removal of the offending brain area.  The treatment efforts in approximately 20-30 percent of people with epilepsy are not effective. A new device offers hope for those whose seizures originate in parts of the brain not amenable to surgical removal. It is not recommended in generalized epilepsy where no isolated seizure focus can be detected.

The U.S. Food and Drug Administration (FDA) approved an implantable neuro-stimulator in November, 2013. The device, called the RNS System (Neuropace, Inc.), is surgically implanted into the skull bone close to the site where the seizures are determined to originate.  Lead wire electrodes from this stimulator extend through the skull bone and are placed on, or sometimes in, the brain. The battery-powered stimulator monitors brain activity. When the onset of abnormal activity is detected, even before the person is aware of the oncoming seizure, the electrodes deliver stimuli that short-circuit the abnormal brain activity and normalize it before a seizure can manifest. The RNS System activates only when it detects seizure activity.

The FDA based its approval on clinical trials of the RNS System involving 191 patients with drug-resistant seizures. They were aged 18-70 and many had uncontrolled epilepsy for years. Half of this patient population had their stimulator turned on and the other half’s stimulator was kept off. After 3 months the average number of seizures per month in the group with the activated stimulator decreased a median of 34 percent. For the patients with the turned-off device, the median reduction in seizure frequency was only 19 percent.

Researchers were encouraged by the significant improved quality of life provided by the RNS System, even allowing many to safely drive vehicles.

The device is designed for people 18 and older whose epileptic seizure onset can be localized by various neurological testing, e.g., EEG and various brain scanning.

According to Neuropace president and CEO Frank Fischer, NeuroPace has done studies involving a total of 256 patients who were monitored for 2-9 years without any significant problems. Its batteries can last several years and be replaced in an out-patient clinic. The cost of the RNS System is still under evaluation.

 

 

Lance Fogan, M.D. is Clinical Professor of Neurology at the David Geffen School of Medicine at UCLA. DINGS is his first novel.