Lewy body disease

Lewy body disease is a term that incorporates both Parkinson’s disease and dementia with Lewy bodies, which share similarities in the ways by which they both damage the brain at the cellular level and in the symptoms a person may experience. Lewy bodies are microscopic structures that can be seen inside some of the brain cells of people diagnosed with both Parkinson’s disease and dementia with Lewy bodies. The Lewy body is composed of a protein called alpha-synuclein that, for reasons that are not understood, becomes disrupted and tangled. It is not known whether Lewy bodies represent the primary cause of the disease, but the gradual loss of brain cells results in changes in movement, thinking and behaviour.

Lewy body disease includes three overlapping disorders:

• Parkinson’s disease, which is diagnosed by the presence of significant movement symptoms including slowness, muscle stiffness and tremor.
• Parkinson’s disease dementia, which is diagnosed when a person develops dementia symptoms after having at least 12 months of established Parkinson’s disease. The progression from Parkinson’s disease to Parkinson’s disease dementia can be slow.
• Dementia with Lewy bodies, a prominent feature of which is the presence of dementia symptoms at least 12 months before the development of the significant movement symptoms that are prominent in Parkinson’s disease. These movement symptoms are known as ‘Parkinsonism symptoms’ but not everyone who has dementia with Lewy bodies will develop them and not everyone will be diagnosed as having Parkinson’s disease.

Reference and further information: dementia.org.au