Bacteria in the mouth and gut may play a significant role in the progression of cognitive decline in Parkinson's disease, according to a study.

Specific changes in the gut microbiome have been associated with the shift from mild memory issues to dementia, a common and distressing symptom of the disease.

While Parkinson's is currently very difficult to diagnose in its early stages, these changes in the microbiome could potentially act as early warning signs of Parkinson's, said the researchers from King's College London.