March 21, 2009
Studies Show New Methods Of Dealing With Parkinson’s
A new study from researchers at Stanford University is providing new insights into how deep-brain stimulation works to treat people who suffer from Parkinson's disease.
Researchers found that the largest effect in "Parkinsonian" rodents occurs not by stimulating cells in the subthalamic nucleus, but by stimulating the neural wires, called axons, that connect directly to it from areas closer to the surface of the brain.
"Pointing to these axons that converge on the region opens the door to targeting the source of those axons. This insight leads to deeper understanding of the circuit and could even lead to new kinds of treatments," said Karl Deisseroth, associate professor of bioengineering and of psychiatry and behavioral sciences.
"Because these axons are coming from areas closer to the brain's surface, new treatments could perhaps be less invasive than deep-brain stimulation."
Deisseroth's team used an approach called "optogenetics" to genetically engineered specific types of cells, or neurons, in the subthalamic nucleus regions of different rodents to become controllable with light.
A blue-colored laser pulse makes the neurons more active, while a yellow laser light suppresses activity.
In another study, also published in the March 20 edition of the journal Science, researchers spoke of promising results with a device that is implanted on the spinal cord.
Researchers studied the effects of the device, which applies electrical stimulation to the dorsal column, in 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 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."
Researchers observed improved movement speeds within 3.35 seconds and notably reduced low-frequency seizures in the rats that were depleted of dopamine to recreate the effects of Parkinson's.
Additionally, "the animals were 26 times more active when the device was used without additional medication," researchers told AFP.
"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 Miguel Nicolelis of Duke University Medical Center.
Parkinson's is a movement disorder that primarily affects people over the age of 50. It can cause muscle rigidity, tremors a slowing of physical movement and a loss of movement in some cases.
An estimated 1.5 million Americans suffer from Parkinson's disease.
On the Net: