Dementia With Lewy Bodies
The Second Most Common Cause of Dementia Behind Alzheimer’s Disease
Aug 23, 2008
The buildup of insoluble aggregates of specific proteins, or their fragments, in the brain is a common hallmark of several neurodegenerative diseases. In Alzheimer’s disease, amyloid deposits develop earliest in regions of the brain important for memory formation. In Dementia with Lewy Bodies (DLB), fragments of the protein alpha-synuclein accumulate in regions of the brain that are important to movement control and to memory. Dementia with Lewy Bodies can be misdiagnosed as Alzheimer’s disease.
What Is Alpha-Synuclein
The protein alpha-synuclein has been linked to the formation of Parkinson’s disease and is believed to be involved in Multiple System Atrophy. While the exact function of alpha-synuclein remains a mystery, it has been linked to increases in oxidative stress in cells. In the case of Parkinson’s disease, there have also been identified specific chemically modified forms of this protein in affected brain tissue.
What Are the Symptoms of DLB
Degeneration in DLB can cause damage to regions of the brain important to memory and to motor function. Like Parkinson’s disease, patients with DLB can exhibit slowness of movement and rigidity, but they also can show memory disorders and visual hallucinations, as well as striking fluctuations in attentiveness. Because of the risk of making hallucinations much worse with certain medications that are used quite successfully to treat symptoms in patients with Alzheimer’s disease, it is important to diagnose DLB correctly. Sometimes this differentiation is difficult.
Are There Any Treatments for DLB
While there are not any cures, the symptoms seen in patients suffering from DLB can be ameliorated to a certain extent with the use of specific drugs that work in other neurodegenerative disorders. Cognitive symptoms can sometimes be helped by using drugs that inhibit the enzyme acetylcholinesterase such as rivastigmine and donepezil. In some cases, motor symptoms may be lessened with the use of drugs for Parkinsonism such as levodopa.
How Common Is DLB
Dementia with Lewy Bodies represents approximately 20% of all diagnoses of dementia in the United States which translates to approximately 800,000 cases. However, as with many neurodegenerative diseases there can be overlap between symptoms and pathologic findings. For instance, Lewy Bodies can also be found at autopsy in neurons in patients with Alzheimer’s disease and with Parkinsonism. And as is true for many things, there is likely to be a continuum of both symptoms and pathological findings in many different types of neurodegenerative diseases.
For additional information, see the DLB page at the NINDS website of the US National Institutes of Health and the Lewy Body Dementia Association.
