Long-term treatment that involves electrically stimulating the spinal cord has improved symptoms of Parkinson's disease in rats. Publishing the results of their study in the journal Scientific Reports, researchers from Duke Medicine are hopeful their findings could help human Parkinson's patients.
The team, led by Dr. Miguel Nicolelis, professor of neurobiology at Duke University, built on their own previous research, which showed that stimulating rats' spinal cords with electrical signals temporarily eased symptoms of the disease.
Parkinson's disease is a progressive neurological condition, which is caused by the loss of neurons that produce dopamine in the brain. It affects movement, control of muscles and balance, and it can also cause stiffness, eye problems and sleep problems, among many other symptoms.
"Finding novel treatments that address both the symptoms and progressive nature of Parkinson's disease is a major priority," says Dr. Nicolelis.
The current treatment for Parkinson's is a drug called L-dopa, and it works by replacing dopamine. However, the researchers say it can cause side effects and, over time, lose its effectiveness.
Another emerging therapy is deep brain stimulation. This works through an implant in the brain, which emits electrical signals. But the downside of this technique is that less than 5% of Parkinson's patients qualify for it because it is so invasive.
"We need options that are safe, affordable, effective and can last a long time," says Dr. Nicolelis. He adds that spinal cord stimulation could be the key.
Treatment could protect against loss, damage of neurons
Back in 2009, the Duke University team developed a device that they attached to the spinal cords of rodents that had depleted levels of dopamine.
By electrically stimulating the dorsal columns of rats' spinal cords, the researchers found motor skills improved.
Image credit: Duke University School of Medicine
The researchers showed that by sending electrical stimulation to the dorsal column - a sensory pathway that carries information from the body to the brain - the mice and rats no longer had slow, stiff movements, but rather, they appeared as healthy, active animals.
However, because research on this type of stimulation in animals has focused on short-term effects, the team wanted to look at the long-term effects this kind of treatment might yield in rats with Parkinson's symptoms.
So, for 6 weeks, the team applied electrical stimulation to the spinal cord dorsal columns in rats twice a week for 30 minutes.
During this longer-term study, the team saw a "significant improvement" in symptoms. These included improved motor skills and an about-face in severe weight loss.
Additionally, the stimulation was linked to better neuron survival and higher density of "dopaminergic innervation" in two brain regions controlling movement. The loss of this causes Parkinson's disease in humans, the researchers note.
They say their findings suggest that this electrical stimulation may protect against the loss or damage of neurons.
Other uses for dorsal column stimulation
A similar use of dorsal column stimulation is currently being used to lessen chronic pain syndromes in humans, says the team.
They find hope in other small-scale studies in humans that have shown how dorsal column stimulation may also help restore motor function in Parkinson's patients.
However, there is more work to be done, Dr. Nicolelis says:
"This is still a limited number of cases, so studies like ours are important in examining the basic science behind the treatment and the potential mechanisms of why it is effective."
The team is continuing their investigation into this technique and how it might help with other neurological motor disorders.
Medical News Today recently reported on a study that suggested vitamin D could prevent cognitive impairment in Parkinson's patients.