A recent study out of Duke University found that ongoing spinal cord stimulation could improve symptoms of Parkinson’s disease. The report also showed that the treatment could safeguard nerve cells from further damage.
The study, published in Scientific Reports, explained how scientists used a technology called dorsal column stimulation (DCS) to help rats with a similar disease regain control of their movements.
A Parkinson’s Breakthrough?
Dr. Miguel Nicolelis, a neurobiology professor at the Duke University School of Medicine, applied DCS to the rats’ spinal cords. His team did it twice a week for a half hour for six weeks.
The researchers found that the rats’ motor skills improved, and the stimulation reversed weight loss associated with Parkinson’s. It also helped brain cells survive and new dopamine neurons to grow in two areas of the brain that control movement.
Parkinson’s disease is a result of losing neurons that make the chemical dopamine. It impairs a person’s muscle control, balance, and overall movement. A dopamine-boosting drug called levodopa or L-dopa, is the standard treatment, though it can become less effective over time.
Researchers have also stimulated the brain directly, known as deep brain stimulation (DBS), to treat Parkinson’s disease, as well as epilepsy, memory loss, chronic pain, Tourette syndrome, and stroke patients.
But DCS is less invasive, Nicolelis said.
To perform DBS, doctors implant electrodes in the patient’s brain, said Dr. Ritesh Ramdhani, an assistant professor of neurology at the Icahn School of Medicine at Mount Sinai. The wires are then connected through the body to a pacemaker-like device in the chest during an outpatient operation. Doctors can then send electric currents to the brain. The frequency and intensity are tailored to the person’s needs. The person controls the device, which has a battery life of about five years.
“It’s a symptomatic treatment,” Ramdhani said. He said that DBS is not a cure for Parkinson’s, but there is mounting evidence that the treatment is “modulating abnormal motor circuitry.”
“Stimulation doesn’t cure the symptoms themselves,” added Dr. Andre Machado, a physician at the Cleveland Clinic.
Exactly how the treatment works is still being researched, Ramdhani said, but it seems to have better effects than past treatments that killed nerve tissue. Instead, he said DBS can jam abnormal nerve firing patterns.
Another upside of DBS: It helps doctors reduce a person’s medication amounts.
“Typically, our patients can significantly reduce the amount of medications they take,” Machado said.
Who’s a Candidate for Nerve Stimulation?
DBS works for people who have tremors that do not always respond to medication. It also helps with motor fluctuations, slowness, and rigidity. It’s not ideal for those with dementia, uncontrolled psychiatric problems, or walking problems. Fewer than 5 percent of people with the disease are good candidates for DBS.
DBS is not the initial treatment option when a person is first diagnosed, Ramdhani said.
“We don’t look at DBS early in the disease,” he said. In fact, it’s often deployed six or seven years into the disease progression. In the past, doctors didn’t use the technology until about a decade after diagnosis. Now, they are finding better results when it is used sooner.
To determine who can receive treatment, Machado said his organization gathers a committee to evaluate each person.
“In general, we’re offering this for patients that already have advanced Parkinson’s,” he said. In many cases, the disease was initially well managed but the neurologist eventually turned to DBS in order to improve the person’s quality of life. DBS also can help during the late stages of life.
“We’re now seeing 10 years after, that the results are still good,” Machado said.
“Now that we know that it’s possible and safe … we are exploring how it may help many, many other disorders,” he added.
Electrode Stimulation Approved for Obesity, Too
Electrode stimulation could also be a breakthrough for treating obesity. The Food and Drug Administration (FDA) recently approved the Maestro Rechargeable System, which involves surgically implanting electrodes that interact with a rechargeable electrical pulse generator.
The generator sends pulses to the abdominal vagus nerve, which sends signals to the brain when the stomach feels full.
The device is aimed at adults with a body mass index (BMI) of at least 35. Ideal candidates have not had weight loss success on a diet and exercise program, and have at least one other condition related to obesity, such as type 2 diabetes.
In a study of the device, scientists put 233 patients with BMIs higher than 35 into two groups. The experimental group had activated devices; the control group did not. More than half of the people in the experimental group dropped around 20 percent of their excess weight. And 38.3 percent shed a quarter of their excess weight. The FDA is requiring further research to make sure the device is safe over the long term.
According to the Mayo Clinic, vagus nerve stimulation can also treat epilepsy and depression, and it is being evaluated to treat symptoms of migraines, multiple sclerosis, and Alzheimer's disease.