- Parkinson’s disease is a degenerative neurological condition.
- Healthcare professionals have long used electrical stimulation to treat the symptoms of Parkinson’s disease, but there can be serious side effects with prolonged use.
- A recent study suggests that electrical stimulation delivered in short bursts to targeted locations may improve the longevity and effectiveness of the treatment.
The Parkinson’s Foundation estimates that more than 10 million people worldwide are currently living with Parkinson’s disease.
Parkinson’s disease is a neurological condition that worsens progressively. It is characterized by tremor, slowness of movement, and muscle stiffness.
The new study, which appears in the journal Science, investigates a way to improve deep brain stimulation in the treatment of Parkinson’s disease.
Treating Parkinson’s disease
Parkinson’s disease develops due to the progressive degeneration of neurons in a part of the brain called the substantia nigra. The death of these neurons results in a deficiency of the neurotransmitter dopamine.
The main treatment option for Parkinson’s disease is the drug levodopa. This medication is a dopamine replacement. However, it loses its effectiveness over time, and some people can develop motor complications as a result of using it.
Once drugs for Parkinson’s disease stop being effective, doctors may use high frequency deep brain stimulation to help reduce the symptoms.
Doctors now use electrical deep brain stimulation to treat a growing list of conditions, including dystonia, tremors and epilepsy, and obsessive-compulsive disorder.
In 1989, scientists successfully applied this technology for the first time to reduce the tremors associated with Parkinson’s disease. Since its initial clinical use, experts have further developed and refined the stimulation technique.
Some Parkinson’s disease symptoms respond well to this type of treatment. However, there are several downsides to electrical stimulation, including worsened depression, psychosis, and impulse-control disorders.
Additionally, symptoms that the treatment initially improves will return relatively quickly when the stimulation stops.
A new approach
Researchers at the Carnegie Mellon University in Pittsburgh based their recent study on previous work. The results of earlier studies indicate that optogenetic manipulation of certain targeted neurons can provide long lasting therapeutic effects in dopamine-depleted mice.
Optogenetics is a technique that enables scientists to activate or inhibit specific neuron activity through the use of light. Because optogenetics is still in its early stages in human disease models, the authors of this study chose to use a mouse model.
The researchers found that they could target specific neurons through brief bursts of electrical stimulation. By delivering stimulation in short bursts as opposed to continually applying it, they could target specific neurons.
These targeted treatments restored and maintained movement several hours after stimulation and provided long lasting therapeutic benefits in the laboratory mice.
Hope for the future
Dr. Brian Kopell, director of the Center for Neuromodulation at the Mount Sinai Health System in New York City, told Medical News Today that this study provides innovative options for possible future therapies for Parkinson’s disease.
“[The authors] noted that there is opportunity to modulate these circuits based on a dimension that is often overlooked,” said Dr. Kopell. “We tend to think mostly in terms of where to put the stimulation and not when to put the stimulation.”
In a companion editorial, the authors state, “The study by Spix et al. is an excellent example of ‘optogenetics-inspired’ [deep brain stimulation] and may pave the way to more robust [deep brain stimulation] approaches that ultimately can be translated to humans.”
However, it is important to note, as Dr. Kopell told MNT, that this study used a rodent model. So, until we see similar results in humans or nonhuman primates, we should try to curtail our excitement.
That said, the study authors hope that this treatment approach may be translatable to humans. If it is translatable to humans, it could represent a major therapeutic advance for the treatment of Parkinson’s disease.
They are confident that scientists will soon be able to test their burst stimulation protocol in people with Parkinson’s disease because the frequencies are within a range already approved for clinical use.
As they explain in their paper:
“Our burst [deep brain stimulation] protocol can be delivered through commonly used [deep brain stimulation] implants and falls within United States Food and Drug Administration [FDA]-approved stimulus frequencies, enabling immediate testing in [Parkinson’s disease] models across species, including [humans].”
The researchers conclude that the study demonstrates how fundamental knowledge about the organization and function of neurons within the brain can help healthcare professionals tune the specificity of electrical stimulation, “ultimately prolonging the therapeutic benefits of [deep brain stimulation] beyond those achieved with conventional methods.”
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