A study has shown that long-term stimulation of the spinal cord is effective in treating induced Parkinson’s disease symptoms in rats. Previous studies have shown short-term improvements in Parkinson-like symptoms during spinal cord stimulation.
But this is the first time that such a treatment has been shown to have lasting effects, potentially offering a safe, effective and durable alternative to current treatments, according to the study’s lead author, Miguel Nicolelis.
Parkinson’s disease is a progressive neurological condition that affects around one in five hundred people. It is caused by the loss of nerve cells from a part of the brain important for movement. This leads to reduced levels of a chemical called dopamine, resulting in symptoms including shaking, problems with walking and, in the later stages of the disease, dementia.
The condition is usually treated by replacing the lost dopamine using a drug called Levodopa. The effectiveness of this treatment, however, generally breaks down with time. Another possible treatment is deep brain stimulation (DBS). This involves placing electrodes connected to a pulse generator deep inside the brain to stimulate activity. But DBS is not possible in all cases of the disease.
“The number of patients who can take advantage of this therapy is small, in part because of the invasiveness of the procedure,” Nicolelis said.
In the study, Parkinson-like symptoms were induced in the rats, followed by twice-weekly treatment with spinal cord stimulation for six weeks. This led to a significant improvement in the symptoms; the rats showed improved motor function and reversal of severe weight loss following treatment. The researchers also saw better survival of nerve cells in the part of the brain affected by Parkinson’s disease in the treated rats compared with untreated ones.
Early small-scale clinical trials have shown that the acute benefits of spinal cord stimulation previously observed in rats can also be seen in humans. The researchers at Duke University, North Carolina, where the study took place, are hopeful that chronic treatment could also prove effective. Discussing the implications of the research, Nicolelis said: “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.”