In late 2003, while searching for support for her adult daughter’s treatment, Kathi Penn came across the national nonprofit
Epilepsy Foundation, which brought Tiffany Penn under its care. When a series of medications failed to control her life-long seizure disorder, a new therapy dubbed vagus nerve stimulation, or VNS, was recommended for her.
Vagus nerves are a pair of lengthy and meandering nerves — one on each side of the body — that runs from the brainstem through the neck and chest to the abdomen. It branches off to parts of the body, including the ears, voice box, lungs, heart, esophagus and stomach, and conducts motor impulses from the brain to these body structures to govern their reflex responses while supplying sensation to them.
The VNS therapy uses a device called the vagus nerve stimulator, which is a battery-powered generator surgically implanted under the skin on the left upper chest. It is connected to the left vagus nerve via a lead, which is a flexible wire tunneled under the skin. When the generator is activated, the device transmits electrical pulses through the vagus nerve to the brainstem, which then sends signals to other areas of the brain.
The device is programmed to send electrical signals to the brain at certain intervals throughout the day to preempt a seizure. If a patient senses the aura of an onset or has an attack during the interval, a magnet can be used to swipe across the implanted area to activate the stimulator to avert a seizure or stop an ongoing one.
“The device works like a pacemaker,” says Jeremy Slater, M.D., neurologist and associate professor at The University of Texas Health Science Center at Houston (UTHealth) Medical School and director of the
Texas Comprehensive Epilepsy Program at the Mischer Neuroscience Institute of the Memorial Hermann Healthcare System. “It’s not a cure for epilepsy, but it makes it harder for a patient to have seizures. It can make a lot of people’s lives better.”
Tiffany Penn says the two-hour VNS implant she received under general anesthesia in her early 20s in 2004, coupled with her continued medication, virtually put an end to her years of suffering.
“It was a relief. I was able to have a productive life again,” she says, noting that she still had a couple of
complex partial seizures after the surgery that lasted a few seconds each time. “I quickly got better and better.”
She completed the nurse aid program at Houston Community College and received enhanced training from a health vocational academy to start a job as a shift supervisor at an assisted-living facility for residents with Alzheimer’s disease in Sugar Land, Texas. And she resumed her full-time role as a mother.
But the battery of the device began to wane four years later, and her epileptic symptoms started to creep up. Her life was overtaken by seizures again when the battery was completely depleted.
Life reclaimed with new device
In 2013, Tiffany Penn was referred to Slater and Nitin Tandon, M.D., a neurosurgeon and associate professor in the Vivian L. Smith Department of Neurosurgery at UTHealth Medical School.
“When I first saw her, she wasn’t really able to function, especially in regards to taking care of her family. She was having a lot of seizures,” recalls Tandon, who also is director of Epilepsy Surgery at
Memorial Hermann-Texas Medical Center. “She couldn’t be left home alone, couldn’t drive and couldn’t have a job.”
After evaluation, Slater and Tandon decided on surgery to replace the defunct VNS device along with a new cocktail of antiepileptic medicines.
“It was a fairly simple procedure that took only about half an hour,” says Tandon, who performed the surgery to swap out the generator without having to replace the lead. Cyberonics, a medical technology company that developed the VNS therapy system, donated the new device with the help of the Epilepsy Foundation.
The longevity of the battery largely depends on factors such as how frequent the device is activated and how intense the electrical pulse is set based on the patient’s condition, says Justin Hohenstein, a Cyberonics clinical engineer.
“The life of a device can range from a year to about a decade depending on the uses,” Hohenstein says.
On her living room wall, Tiffany Penn posted instructions on using the VNS magnet for visitors.
“If I feel a seizure is coming, I can immediately swipe the magnet myself. But if it comes too quickly, and I’m knocked out before I get to use the magnet, anyone in the room can do it for me,” she says. “But I haven’t had to use it since the new implant.”
Brain surgery targets problems at the core
VNS is one of the therapies for epilepsy. People with epilepsy uncontrolled by medications — often called intractable or refractory epilepsy — may be candidates for direct surgical intervention in the brain.
“The first line of treatment is always medicine for most people with epilepsy,” Slater says. “Up to 70 percent of them respond to drugs. But of about 30 percent who don’t respond, about half of them are candidates for surgery.”
Resection is a more common surgical treatment that removes the brain tissue that causes seizures especially in focal epilepsy cases. Another type of surgery is aimed at disconnecting the nerve pathways responsible for the spreading of seizures particularly in generalized epilepsy.
Research shows that brain surgery can be a better option for a patient saddled with repeated seizures, given the impact of high doses of medication on the person’s physical, intellectual, social and emotional life.
Do’s and don’ts during a seizure
Immediately lay the person down on a flat surface to prevent a fall and away from sharp or pointed objects, source of fire or any place where the person can get injured.
Don’t try to open and put things in the person’s mouth or pull the person’s tongue out because the person have mouth movements such as the appearance of biting the tongue. Most seizures will stop on their own within a minute.
Call 911 if the person is having a seizure for the first time, or when a grand mal seizure lasts more than 2 minutes, or if the person is turning blue or not breathing.
Source: Nitin Tandon, M.D.
widely cited study published in The New England Journal of Medicine in August, 2001, scientists compared the effect of brain surgeries on 40 patients with epilepsy at the temporal lobe — a brain area behind the temple and above the ear — and that of drug therapies for 40 other patients with the disease one year into the study. Fifty-eight percent of the surgical patients but only 8 percent of those treated with medications were found to be seizure-free.
Tests currently used
Although science doesn’t fully explain why people develop epilepsy, there are numerous conditions known to trigger the disease, Tandon points out.
“Some of the common causes include brain injury, scars from a brain injury, tumors in the brain, structural abnormality during brain formation, or abnormal vascular anatomy,” Tandon says.
Genetic predisposition and stroke are also among the top factors, Slater adds.
“If you’ve had more than one seizure, the first thing to do is to make sure your family doctor or neurologist refers you to an epilepsy specialist for accurate diagnosis,” Tandon says.
The evaluation of epilepsy includes an electroencephalogram (EEG) to measure electrical activity related to seizures, and a brain magnetic resonance imaging (MRI) scan to look for malformations of brain development, possible tumor or scarring in the brain.
Anatomical imaging of the brain isn’t enough to determine if a patient is a candidate for brain surgery. Scans such as positron emission tomography, or PET, explores metabolic activity, while single photon emission computed tomography, or SPECT, identifies blood flow patterns. In addition, magneto-encephalography, or MEG, is used to localize abnormal activity as well as map neurological function, while the Wada test explores the language and memory functions.
Leaps in technology
Innovative technologies for diagnosing and treating epilepsy also have come to the fore in recent years. At Memorial Hermann-Texas Medical Center, Tandon and his team of colleagues from UTHealth Medical School have been pioneering the use of laser ablation and stereoelectroencephalogram — SEEG — in severe, complicated epilepsy cases.
SEEG is a diagnostic tool to assess electrical activity both on the surface and in the depth of the brain while a patient is having a seizure. With SEEG, electrodes are implanted into the brain tissue through incisions made in the skull.
During laser ablation, a surgeon inserts a laser probe into the brain through holes 3.2 millimeters in diameter drilled in the skull. Guided by real-time MRI-generated thermal imagery that precisely pinpoints the brain areas where seizures originate, laser beams are delivered through the probes to destroy the targeted bad brain tissue.
“SEEG and laser ablation revolutionized the way we diagnose and treat epilepsy,” says Tandon, noting that traditional brain surgery, called craniotomy, involves opening the skull.
SEEG and laser ablation are not only less invasive, but their precision is unmatched by conventional tools, he adds.
“Many people have to live with epilepsy for so long because they’re afraid to have their heads cut open. Now we can do this with just tiny little cuts, and we can tackle almost every kind of epilepsy case,” he says.
The era of automation
More recently, robotic technology has been integrated into SEEG, resulting in an automated tool dubbed ROSA. Developed by the French company MedTech and first introduced to North America in 2011, the instrument features a robotic arm with high dexterity for precise 3-D mapping of where seizures begin in the brain. This allows the surgeon to accurately place electrodes into the brain.
Tandon, who is among the first in North America to use robotic SEEG in his work at Memorial Hermann-TMC, says the innovative tool vastly cuts operating time while providing solid stability to the patient’s head during the surgery for precise electrode implantation.
With the electrodes implanted, the patient typically stays in the hospital for a week to be monitored and evaluated for seizures before Tandon and his team determine the optimal treatment plans, including laser ablation for those deemed to be good candidates. A rocket scientist received laser ablation in January after a prior evaluation using robotic SEEG, Tandon says.
“He was having 30 seizures a day before the procedure, and is now back at work, free of seizures and doing great,” Tandon says. “People with epilepsy can and should enjoy a high level of functioning in life.”
Though not a candidate for brain surgery, Tiffany Penn says VNS works for her “just as beautifully.”
“It doesn’t cure epilepsy, but it allows me to have a normal life and be fully present in my kids’ lives,” she says.
She’s also found fulfillment in spreading the message of hope.
In March, she joined in the National Walk for Epilepsy in Washington, D.C., sponsored by the Epilepsy Foundation, to help raise awareness and funds for the fight against the disorder. In June, she was invited to share her experience at a symposium on epilepsy and the VNS therapy for nursing professionals in Chicago.
“I want to encourage health professionals to step up to make a difference in the lives of people with epilepsy,” she says. “I want everyone to know how powerful it is for someone like me to live normal and see hope.”