People with memory loss and their families are often frustrated with the difficulties doctors have in making a firm diagnosis. This is especially true when dementia with Lewy bodies (DLB) is suspected, perhaps because there are symptoms other than dementia and the symptoms can vary by person and by day.
The main symptom of DLB is progressive dementia, but symptoms can also include:
- Vivid hallucinations
- Noticeable fluctuation in attention and alertness
- Parkinsonism [physical symptoms such as stiffness, tremors and problems with coordination]
- REM sleep behavior disorder, in which people physically act out dreams
- Extreme sensitivity to antipsychotic medications used to treat hallucinations.
Even specialists have a hard time diagnosing Lewy body dementias, explains Joseph Friedman, M.D., Professor of Clinical Neuroscience at Alpert Medical School at Brown University, Director of the NeuroHealth Parkinson's Disease and Movement Disorders Center in Warwick, Rhode Island and member of the Lewy Body Dementia Association’s Scientific Advisory Council.
“Unless the patient has the classic features of Lewy body dementia,” he says, “it is impossible to reliably distinguish it from Alzheimer’s. If the patient has symptoms of REM sleep behavior disorder, however, the diagnosis is highly likely to be DLB.” Researchers are still working to refine diagnostic criteria for both DLB and a related disease, Parkinson’s Disease with Dementia [both are considered Lewy body dementias].
It’s especially hard for doctors to diagnose Lewy body dementia because Alzheimer’s, vascular dementia, “normal” aging and some medicines can also cause the physical symptoms associated with these disorders, Dr. Friedman says.
In addition, the overlapping symptoms among Alzheimer’s, vascular dementia, and Lewy body dementias can reflect the pathologies found in the brain at autopsy: the brains of people with dementia often have a mixture of Alzheimer’s, vascular, Lewy body and other pathologies.
As with Alzheimer’s, researchers hope to find a biomarker that will indicate whether a person has a Lewy body disorder. Biomarkers are substances or characteristics that indicate the presence of a disease. They might be found in bodily fluids such as blood, or on brain scans showing abnormal proteins. To help researchers share information about potential biomarkers, the Lewy Body Dementia Association is organizing a biomarker symposium in Miami in late 2009.
If diagnosis is so difficult, why bother? Why does it matter whether you or a family member has Alzheimer’s, Lewy body dementia or some other dementia? I’ll talk about this in Part 3 of this series.