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Tests and diagnosis
By Mayo Clinic staffTo be diagnosed with Lewy body dementia, you must have experienced a progressive decline in your ability to think, as well as two of the following:
- Fluctuating alertness and thinking (cognitive) function
- Repeated visual hallucinations
- Parkinsonian symptoms
In addition, one or more of the following features are considered supportive of the diagnosis of Lewy body dementia:
- REM sleep behavior disorder, a condition in which people act out their dreams during sleep
- Autonomic dysfunction, which involves instability in blood pressure and heart rate, poor regulation of body temperature, sweating, and related symptoms
No single test can diagnose Lewy body dementia. Instead, doctors diagnose your condition through ruling out other conditions that may cause similar signs and symptoms. Tests may include:
Neurological and physical examination
As part of your physical examination, your doctor may also check for signs of Parkinson's disease, strokes, tumors or other medical conditions that can impair brain function as well as physical function. The neurological examination may test:
- Reflexes
- Eye movements
- Balance
- Sense of touch
Assessment of mental abilities
A short form of this type of test, which assesses your memory and thinking skills, can be done in less than 10 minutes in your doctor's office but is generally not useful in distinguishing Lewy body dementia from Alzheimer's disease. Longer forms of neuropsychological testing can take several hours, but these tests help identify your condition.
Your results are then compared with those of people from a similar age and education level. This can help distinguish normal from abnormal cognitive aging, and may help identify patterns in cognitive functions that provide clues to the underlying condition.
Blood tests
Simple blood tests can rule out physical problems that can affect brain function, such as vitamin B-12 deficiency or an underactive thyroid gland.
Electroencephalogram (EEG)
If your confusion comes and goes, your doctor may suggest an EEG. This test can help determine if your symptoms may be caused by seizures or Creutzfeldt-Jakob disease, a rare, degenerative brain disorder that leads to dementia. This painless test records the electrical activity in your brain via wires attached to your scalp.
Brain scans
Your doctor may order an MRI, PET or CT scan to check for evidence of Alzheimer's disease, stroke or bleeding, and to rule out the possibility of a tumor.
Your doctor may order a sleep evaluation to assess for REM sleep behavior disorder or an autonomic function test to look for signs of heart rate and blood pressure instability.
- NINDS Dementia with Lewy bodies information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/dementiawithlewybodies/dementiawithlewybodies.htm. Accessed Jan. 18, 2013.
- Hake AM, et al. Clinical features and diagnosis of dementia with Lewy bodies. http://www.uptodate.com/home. Accessed Jan. 18, 2013.
- Hake AM, et al. Epidemiology, pathology, and pathogenesis of dementia with Lewy bodies. http://www.uptodate.com/home. Accessed Jan. 18, 2013.
- Diagnosis. Lewy Body Dementia Association. http://www.lbda.org/content/diagnosis. Accessed Jan. 31, 2013.
- Hake AM, et al. Prognosis and treatment of dementia with Lewy bodies. http://www.uptodate.com/home. Accessed Jan. 18, 2013.
- Symptoms. Lewy Body Dementia Association. http://www.lbda.org/content/symptoms. Accessed Feb. 1, 2013.
- Neurological diagnostic tests and procedures. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/misc/diagnostic_tests.htm. Accessed Jan. 28, 2013.
- Shadlen MF, et al. Evaluation of cognitive impairment and dementia. http://www.uptodate.com/home. Accessed Feb. 1, 2013.
- Dementia: Hope through research. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/dementias/detail_dementia.htm. Accessed Jan. 18, 2013.
- Communication and Alzheimer's. Alzheimer's Association. http://www.alz.org/care/dementia-communication-tips.asp. Accessed Feb. 4, 2013.
- Creating a daily plan. Alzheimer's Association. http://www.alz.org/care/dementia-creating-a-plan.asp. Accessed Feb. 4, 2013.
- Press D. Treatment of behavioral symptoms related to dementia. http://www.uptodate.com/home. Accessed Feb. 4, 2013.
- Sleep issues and sundowning. Alzheimer's Association. http://www.alz.org/care/alzheimers-dementia-sleep-issues-sundowning.asp. Accessed Feb. 4, 2013.
- Buettner LL, et al. Animal-assisted therapy for clients with dementia. Journal of Gerontological Nursing. 2011;37:10.
- Being a healthy caregiver. Alzheimer's Association. http://www.alz.org/care/alzheimers-dementia-healthy-caregiver.asp. Accessed Feb. 4, 2013.
- Respite care. Alzheimer's Association. http://www.alz.org/care/alzheimers-dementia-caregiver-respite.asp. Accessed Feb. 4, 2013.
- Caregiver stress. Alzheimer's Association. http://www.alz.org/care/alzheimers-dementia-caregiver-stress-burnout.asp. Accessed Feb. 4, 2013.
- U.S. News best hospitals 2012-2013. U.S. News & World Report. http://health.usnews.com/best-hospitals/rankings. Accessed Jan. 18, 2013.
- Smith GE (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 28, 2013.
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