If you talk with families, many will share that getting a diagnosis for one specific form of LBD, called dementia with Lewy bodies (DLB), was a challenge. Sometimes the diagnosis is delayed because the symptoms made DLB look like another disorder for a while. Or, especially in the early stage, not all symptoms are evident at the first few doctor’s appointments.
Thankfully, over the past decade research has revealed that certain test results are highly linked to both the clinical symptoms of DLB and the presence of Lewy bodies in the brain at autopsy. For the first time, physicians can rely on both symptoms and ‘biomarkers’ (biological signs of disease) to help make the diagnosis. This means healthcare professionals can now diagnose DLB with greater confidence, even when fewer symptoms are present.
“There is now a consensus among experts on DLB that certain symptoms, specifically REM sleep behavior disorder, and tests results, formal sleep study and brain and cardiac imaging, are highly predictive for the presence of Lewy bodies in the brain at autopsy. For this reason, the consensus criteria have been updated to include these findings and now provide guidance to clinicians trying to diagnose DLB,” stated James B. Leverenz, MD, chair of LBDA’s Scientific Advisory Council.
The new criteria were established when researchers gathered for the 2015 International Dementia with Lewy Bodies (DLB) Conference. Their goal was to update the criteria last revised in 2005. Leading the effort was Prof. Ian McKeith of Newcastle University and member of LBDA’s Scientific Advisory Council.
There are now several ways the DLB diagnosis can be made – on the presence of symptoms alone, or on the presence of fewer clinical symptoms plus a biomarker test result that suggest the presence of Lewy bodies in the brain.
Diagnosing DLB on Clinical Symptoms Alone
- Dementia is required, which simply means a decline in thinking skills that interferes with everyday life. In early DLB memory may be relatively normal in comparison to Alzheimer’s disease. Instead, a person with DLB experiences problems with other cognitive skills, which may need a neuropsychologist for assessment:
- Paying attention
- Reasoning and problem solving, called executive function
- Understanding how objects relate in three-dimensional space, called visuospatial skills.
- At least two of the following clinical symptoms are required:
- Delirium-like fluctuating cognition: unpredictable changes in thinking, attention and alertness
- Repeated visual hallucinations
- REM sleep behavior disorder (which may appear long before the dementia)
- Parkinsonism, specifically slowed movements, tremor when limbs are at rest, and muscle rigidity
DLB also has other symptoms that “support” a diagnosis, but are not so common that they help make the diagnosis. Two new “supportive” symptoms added to this list are the loss of smell and excessive daytime sleepiness.
Diagnosing DLB Clinical Symptoms Plus Biomarkers
- Dementia plus one of the core clinical symptoms (fluctuating cognition hallucinations, REM sleep behavior disorder, parkinsonism)
- At least one of the following biomarker test results
- Brain scans (SPECT or PET) indicates a reduction in brain cells that produce dopamine
- MIBG myocardial scintigraphy reveals reduced communication of the cardiac nerves
- A formal sleep study confirms the presence of REM sleep behavior disorder
Members of the LBDA’s Scientific Advisory Council who were co-authors on the paper include lead author, Ian G. McKeith, plus Bradley F. Boeve, Dennis W. Dickson, Daniel Weintraub, James Galvin, John E. Duda, Tanis J. Ferman, Douglas Galasko, Jennifer G. Goldman, Kejal Kantarci, Daniel I. Kaufer, James B. Leverenz, Carol Lippa, Andrew B. Singleton, Debby Tsuang and Kenji Kosaka.
The article was published online in the journal Neurology on June 7, 2017. The International DLB Consortium was supported by The National Institute on Aging, National Institutes of Neurological Disorders and Stroke, the Lewy Body Dementia Association, the Lewy Body Society, Alzheimer’s Association, Acadia Pharmaceuticals, Axovant Sciences, Banner Health, GE Healthcare, and Lundbeck.