Researchers at Duke are exploring the long-term effects of spinal cord stimulation in improving symptoms of Parkinson’s disease.
Caused by the progressive loss of neurons that produce dopamine, the disease impairs muscle control, movement and balance. This study, led by Miguel Nicolelis, founder of the Duke Center for Neuroengineering and Anne W. Deane professor of neurobiology, found that dorsal column stimulation promotes normal activity of neurons impaired by Parkinson’s. The team tested a control group, a group of rats injected with 6-hydroxydopamine to mimic the symptoms of Parkinson’s, and a Parkinsonian group treated with spinal cord stimulation. At the end of the experiment, the treated Parkinsonian group demonstrated improvements in motor systems, body weight and the integrity of dopaminergic pathways.
"These findings are key because they suggest there is not only an acute effect of spinal cord simulation, but also a long-term efffect derived from the regular use of it, and that this long-term effect could be even more effective than the acute one," said Romulo Fuentes, research director at the Edmond and Lily Safra International Neuroscience Institute of Natal and an author on the study.
Fuentes added that this type of spinal cord stimulation works by circulating an electrical current through the electrodes implanted along the spinal cord’s dorsal surface, activating the fibers that convey sensory information to the brain.
“We think that spinal cord stimulation can disrupt or decrease the intensity of oscillatory activity apparent in Parkinsonism, bringing the brain activity patterns closer to those of a healthy state,” Fuentes said.
Amol Yadav, a doctoral candidate in biomedical engineering and President of Graduate and Professional Students Council, stated that one of the main challenges of this study was innovating previous electrode designs and surgical procedures to make sure the electrode implant was stable for a longer duration.
“It was also hard to objectively quantify some of the Parkinson’s symptoms such as posture and gait,” Yadav wrote in an email Thursday . “We had to develop a novel technique using custom algorithms in order to quantitatively measure these symptoms.”
Parkinson’s is currently a disease with no cure, and despite the potential that this new method offers, a treatment option that either arrests or prevents the loss of dopaminergic neurons is still needed, Yadav added. DCS, however, is a major stepping stone, providing an alternative to treatments such as pharmacological symptomatic treatment and neuromodulation.
“Pharmacological symptomatic treatment through the chemical L-Dopa can lead to long-term complications,” Yadav said. “Neuromodulation through deep brain stimulation is also effective but is only available to less than 5 percent of Parkinson’s patients due to its invasive and risky nature.”
He added that DCS is cheaper, safer and could be employed at an early stage of the disease’s development.
Researchers have already applied the method to a small number of patients with Parkinson’s, as well as chronic pain syndrome, in France, Japan, Italy and the United States, Yadav said. Reports state that patients experienced alleviation of Parkinsonian symptoms with spinal cord stimulation. The team plans to test this approach in patients diagnosed only with Parkinson’s in the near future.
Fuentes added that researchers are continuing to explore if the stimulation can be applied to other diseases associated with neurological dysfunction.
“We think it is possible,” Fuentes said. "It is plausible that spinal cord stimulation can be applied to other motor disorders as well.”
Miguel Nicolelis could not be reached for comment because he is out of the country.