Lewy bodies are also found in the brains of people with Parkinson’s disease and may be the most common cause of Dementia in the late-stages of the disease. They first appear in different parts of the brain in each condition and, in Parkinson’s, the symptoms these protein deposits produce are subtly different to those caused in DLB. It is thought that Lewy bodies form in Parkinson’s as a defence mechanism when cells become threatened by chemical changes in the brain.
In Parkinson’s early symptoms are usually to do with movement (e.g. Tremor, Stiffness, Bradykinesia), and dementia may appear later. In DLB the dementia is an initial and defining feature.
It has been estimated that around 75% of people with DLB will also develop symptoms of Parkinson’s, whilst around 40% start by showing signs of Parkinson’s and then go on to develop dementia.