With the use of functional MRI (fMRI), researchers have been able to study the mechanism underlying visual hallucinations in Parkinson’s disease. Their main finding: these visual hallucinations may be triggered by disconnections of brain areas involved in attention and visual processing.
The disconnected brain areas seen on fMRI may be valuable in predicting the development of visual hallucinations in patients with Parkinson’s disease, according to the study published in the journal Radiology.
The researchers used resting-state fMRI to examine the connectivity between brain areas. The connectivity was measured in 15 patients with visual hallucinations, 40 patients without visual hallucinations, and 15 healthy controls by calculating the level of synchronisation between activation patterns of different brain areas.
The results showed that in all the patients with Parkinson’s disease, multiple brain areas communicated less with the rest of the brain as compared to the control group. Notably, in patients experiencing visual hallucinations, several additional brain areas showed this decreased connectivity with the rest of the brain — especially in areas that are important in maintaining attention and processing of visual information.