The causes of the symptoms of Parkinson’s disease are still poorly understood, but there are hints that the brain naturally compensates for a decrease of dopamine by slowing down its activity and causing weak motor activity. An early-stage study at Johns Hopkins University has demonstrated that electrical brain stimulation may be an effective option for helping to reduce some of the symptoms of Parkinson’s.
The research involved twenty Parkinson’s patients who performed various tasks with their arms with and without mild electrical brain stimulation. The findings showed that the stimulation temporarily improved how Parkinson’s patients used their weaker side compared to their stronger one. The team behind the study believes that while a lack of dopamine makes activity seem more difficult for the brain, providing an external electric current promotes the neurons to fire more willingly.
From the study abstract in The Journal of Neuroscience:
We used an isometric task in which patients produced a goal force by engaging both arms, but were free to assign any fraction of that force to each arm. The patients preferred their less-affected arm, but only in some directions. This preference was correlated with lateralization of signal-dependent noise: the direction of force for which the brain was less willing to assign effort to an arm was generally the direction for which that arm exhibited greater noise. Therefore, the direction-dependent noise in each arm acted as an implicit cost that discouraged use of that arm. To check for a causal relationship between noise and motor cost, we used bilateral transcranial direct current stimulation of the motor cortex, placing the cathode on the more-affected side and the anode on the less-affected side. This stimulation not only reduced the noise on the more-affected arm, it also increased the willingness of the patients to assign force to that arm. In a 3 d double-blind study and in a 10 d repeated stimulation study, bilateral stimulation of the two motor cortices with cathode on the more-affected side reduced noise and increased the willingness of the patients to exert effort. This stimulation also improved the clinical motor symptoms of the disease.
Study in The Journal of Neuroscience: Altering Effort Costs in Parkinson’s Disease with Noninvasive Cortical Stimulation…
Source: Johns Hopkins…