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RNS device helps patients with epilepsy

Photos by Matt Haas

January 2016

Dr. Christopher Anderson

A device slightly smaller than the human thumb has the potential to dramatically change the lives of people who have epilepsy.

Responsive neurostimulation (RNS) is a computer device that, when implanted into the brain, monitors brain waves 24 hours a day, can detect when a seizure is about to begin and sends a signal to stop the seizure.

"When RNS sees a pattern in the brain waves that looks like the beginning of a seizure, it fires back with an electrical stimulation to disrupt that abnormal rhythm from continuing," says Dr. Christopher Anderson, associate professor of neurology and medical director of the epilepsy monitoring unit at Froedtert & the Medical College of Wisconsin.

RNS treats patients who suffer seizures in multiple parts of the brain. While surgery is an option for some of those patients, others have seizures in areas of the brain (speech center, e.g.) where surgery is not safe.

RNS is not a substitute for medication, but rather a patient-friendly complement to medication.

"Patients with severe epilepsy can be on two, three, four or even more anti-seizure medicines, and they all have side effects," Anderson says. "At high doses, that can be disabling in terms of quality of life. RNS works in conjunction with medication but doesnt have any side effects on cognition or speech or injuries to any of the other organs."

After the device is implanted, a patient is given a laptop computer with a wand, which when held up to the head transmits recent brain wave activity through the scalp. The data is downloaded onto an Internet server where physicians who can change the detection settings by using another wand can examine it.

"At first, wed check with the patient every couple of weeks to change the parameters on the device to essentially tweak it to their exact seizure type," Anderson says. "But as months to years go by with the device, hopefully we can set the ideal settings for them and leave it alone."

Three RNS implant surgeries have been performed at Froedtert with encouraging results. "Our earliest patient was done in July," Anderson says. "His seizure frequency is reduced clearly, his quality of life is better. Hes become more active and actually got a job for the first time in several years."

The technology developed for RNS opens a range of possibilities for treating other brain-related illnesses.

"People probably will develop similar devices for all kinds of neurological and psychiatric diseases," Anderson says. "Its just figuring out what the target is for each condition."



This story ran in the January 2016 issue of: