Parkinson's, the second most common neurodegenerative disease affecting around 160,000 people in Spain, continues to pose a significant challenge for Medicine. Despite the development of various treatments in recent years that improve some of the symptoms of the disease, a therapy to cure the disorder, which causes motor problems, sleep disturbances, and cognitive impairments, among other signs, has not yet been achieved.
In the quest to explain the causes of the disease, which limits the brain's dopamine availability, groups of researchers worldwide are involved, such as Hesheng Liu's team (Changping Laboratory, China), who this week published a new and interesting research pathway in Nature.
Scientists link the disease's development to alterations in a brain network identified for the first time in 2023. They suggest that directing therapies to this brain structure, called the somatocognitive action network (SCAN), associated with how cognition and action are integrated, can improve symptoms to a greater extent than current approaches.
According to neuroimaging tests conducted on over 800 patients from different centers in the US and China, individuals with the neurodegenerative disease exhibit hyperconnectivity between the SCAN area and subcortical regions of the brain, whose involvement with the disease was already known.
To further advance the research, scientists conducted a small trial with 36 patients. Half received non-invasive transcranial magnetic stimulation therapy in the SCAN area, while the rest received the same therapy in other brain areas previously associated with the disease. After two weeks of treatment, the first group showed a response rate of 56% compared to the 22% obtained by the second group.
According to Salvador Ventura, Professor of Biochemistry and Molecular Biology at the Autonomous University of Barcelona, this study "reinforces the idea that Parkinson's not only affects the 'movement center' but a broader neuronal circuit that coordinates action, motivation, and bodily functions, thus having both a 'physical and mental' component," as stated in comments to SMC Spain.
"In a way, the study suggests a possible paradigm shift both in diagnosis - using hyperconnectivity as a marker - and in Parkinson's treatment through neuromodulation. Targeting stimulation could significantly improve outcomes," he adds. However, Ventura cautions that "it is important to be cautious: at this point, it does not imply a cure or an immediate change in clinical practice. The practical message today is that this approach can help refine where to stimulate and design better clinical trials, but it does not yet alter standard care protocols."
"There will be no changes in clinical practice yet"
Jose A. Morales-García, a Parkinson's disease research scientist at the Complutense University of Madrid, points out that the study's contribution is mainly conceptual, as it "suggests that Parkinson's disease, known to produce motor and non-motor symptoms, involves the alteration of a broader brain network, the so-called 'somatocognitive action network,' which integrates movement, cognition, and bodily functions. This idea aligns well with previous clinical observations, such as the early presence of non-motor symptoms and the influence of cognitive factors on movement, now supported by direct experimental evidence."
However, he also notes that these results do not definitively establish a causal relationship between SCAN network hyperconnectivity and all Parkinson's symptoms. "There are no anticipated changes in standard clinical practice in Spain yet, but a promising avenue opens up for better personalizing treatments in the future."
Guglielmo Foffani, lead researcher and head of Neurophysiology at the CIEN Foundation, mentions that "although the study is undoubtedly very interesting and opens new research avenues," it does not justify claiming that Parkinson's disease is a somatocognitive action network disorder, "nor that this concept will double treatment efficacy in clinical practice."
According to the scientist, "further studies with other techniques will be necessary to confirm or refute the proposed hypothesis, as well as larger, independent trials with more rigorous designs before translating these ideas into standard clinical practice."