A small device implanted on the spinal cord could one day offer a better way to treat Parkinson's disease, according to a study released Thursday showing success in trials on mice and rats.
"This work addresses an important need because people living with Parkinson's disease face a difficult reality -- (the drug) L-Dopa will eventually stop managing the symptoms," said lead author Romulo Fuentes of Duke University Medical Center.
"Patients are left with few options for treatment, including electrical stimulation of the brain, which is appropriate for only a subset of patients."
Parkinson's is a motor system disorder which primarily affects people over the age of 50 and can lead to such severe trembling, stiffness and loss of balance that patients have trouble walking, talking or performing basic tasks.
The device applies electrical stimulation to the spinal cord's dorsal column, which is a main pathway for carrying tactile information from the body to the brain.
When it was turned on, the slow, stiff movements of mice and rats depleted of dopamine in order to mimic the effects of Parkinson's were replaced with the active behavior of healthy animals.
Improved movement was typically observed within 3.35 seconds, the study published in the peer-reviewed journal Science found.
The stimulation also reduced the low-frequency seizures often seen in patients with Parkinson's disease and observed in the dopamine-depleted mice and rats.
The researchers tested mice at rats with varying levels of stimulation and doses of dopamine replacement drugs to determine the most effective pairing.
The animals were 26 times more active when the device was used without additional medication. When coupled with medication, only two doses were needed to produce movement compared to five doses when the medication was used by itself.
"If we can demonstrate that the device is safe and effective over the long term in primates and then humans, virtually every patient could be eligible for this treatment in the near future," said senior author Miguel Nicolelis of Duke University Medical Center.
The device will likely mirror similar spinal cord stimulator technology currently used to treat chronic pain if it is approved for use on Parkinson's patients, Nicolelis said.
Small leads are implanted over the spinal cord and then connected to a small, portable generator capable of producing mild electrical currents.
The generator used in the trial period is external but would be implanted below the skin for permanent treatment.
The Duke team is currently working with neuroscientists in Brazil to test the procedure on primates, and with researchers in Switzerland to translate the findings into clinical practice.