A team of researchers at the Research Institute of the Hospital de la Santa Creu i Sant Pau – IIB Sant Pau, together with scientists at École Polythecnique Fédérale de Lausanne (EPFL), describe the brain network responsible for minor hallucinations in Parkinson’s disease. Scientists developed a robotic device that allows the induction of hallucinations and the study of the brain networks that are involved. The study, which has been published in Science Translational Medicine, shows the relationship of such hallucinations in the context and progression of Parkinson’s disease, which could be relevant for early diagnostic.
Researchers at theInstitut de Receca de l’Hospital de la Santa Creu i Sant Pau – IIB Sant Pau in collaboration with scientists at the École Polythecnique Fédérale de Lausanne (EPFL) have described the brain network responsible for minor hallucinations in Parkinson’s disease and its possible relation with the progression of the disease.
A team led by Jaume Kulisevsky, director of the Parkinson disease and movement disorders research group at IIB Sant Pau and of the socalled Unit at the Neurology Service of the Hospital de la Santa Creu i Sant Pau, and by Olaf Blanke, principal investigator at EPFL in Geneva, has desenvoled a robotic device that allows the induction of hallucinations in healthy subjects and Parkinson disease patients. By combining this robot with MRI imaging, scientists have been able to study the brain networks involved in hallucinations. They identified these networks and confirmed that are the same ones related to major hallucinations in Parkinson disease, which are one of the most disturbing non-motor symptoms for these patients.
Hallucinations that were not considered but could be significant
Parkinson’s disease is the second neurode
Parkinson’s disease is the second most prevalent neurodegenerative disease worldwide after Alzheimer’s and affects primarily the elderly. It is a progressive neurodegenerative disease that has been traditionally defined as a movement disorder, characterized by tremor, rigidity and slowness of movement. But many patients also suffer from a wide array of symptoms that are not associated with movement and some may go on to suffer from mental symptoms like psychosis, depression, apathy, cognitive decline and even dementia. Hallucinations are frequent in the disease but only major hallucinations were considered real symptoms in the past.
Did you ever felt a presence behind you? Did you ever felt someone else in an empty room? Or maybe, have you ever seen animals or other things quickly passing by next to you? These kind of events are named minor hallucinations. They are very frequent in Parkinson’s disease, becoming more and more frequents as the disease progresses, even they are also present amongst the 5-10% of healthy population.
“In the past, we did not consider these hallucinations a symptom. They were attributed to medication or maybe they were not reported because many patients are hesitant to report them, and questions remain about the neurobiology at play. Our research group already identified the key role of these hallucinations in Parkinson’s disease and now, with this new paper we can conclude that the brain networks behind them are the same that will later cause major hallucinations. Thus, it can be a powerful indicator of the progression of this disease as well as of cognitive damage,” explains Jaume Kulisevsky, principal investigator at IIB Sant Pau and co-corresponding author of the paper published in Science Translational Medicine.
Practical implications
The study, which has been done with healthy individuals and with Parkinson’s disease patients at the Hospital de Sant Pau in Barcelona, and in other hospitals in Switzerland and France, confirms the funcional basis of the hallucinations phenomena and it could be a good marker to study the disease progression. The expertise of the Kulisevsky group on these kind of events and their previous work about the key role of minor hallucinations in Parkinson’s disease as a pre-motor symptom, as well as the description of the attention networks and visual connectivity in the brain, contributed the use this new device as a tool for a better understanding and diagnostic of Parkinson’s disease.
As in other neurodegenerative diseases, it is important to focus in early detection and in the identification fo new targets to develop treatments in order to stop the progression of the disease.By combining this robot with MRI imaging, scientists have been able to study the brain networks involved in hallucinations and to determine its level of severity and damage.
Reference: Bernasconi et al., Sci. Transl. Med., 13, eabc8362 (2021) 28 April 2021. 10.1126/scitranslmed.abc8362
