Mayo Clinic Health Manager

Get free personalized health guidance for you and your family.

Get Started

Free

E-Newsletter

Subscribe to receive the latest updates on health topics. About our newsletters

  • Housecall
  • Alzheimer's caregiving
  • Living with cancer

Tests and diagnosis

By Mayo Clinic staff

Memory loss and other dementia symptoms have many causes, so diagnosis can be challenging and may require several doctor visits. Diagnosis involves a number of tests.

Medical history and physical exam

  • Medical history. The doctor will ask about how and when symptoms began and about any health issues that may help identify the cause of the problem, for example diabetes, high blood pressure or a family history of dementia.

    In addition, the doctor may request information from your caregiver or family member to find out whether your concerns represent a change from your earlier level of functioning.

  • Physical examination. A physical exam helps your doctor rule out treatable causes of dementia and identify signs of stroke or other disorders that may cause similar symptoms. It also helps your doctor determine the best course of treatment. As part of an exam, your doctor may collect urine or blood samples, check blood pressure and review what medications you're using.

    This examination can also help identify signs of other illnesses, such as heart disease, diabetes or thyroid abnormalities and any medication side effects, which can overlap with dementia.

Cognitive and neuropsychological tests
Anyone screened for dementia needs his or her cognitive function evaluated. A number of tests measure orientation, general intellectual skills, academic skills, language skills, spatial skills, attention, memory, reasoning and judgment. The goal is to determine whether dementia is present, how severe it is and what part of the brain is affected.

Neurological evaluation
This part of the examination evaluates balance, sensory function and reflexes to identify conditions that may affect the diagnosis or are treatable with medication.

Brain scans
A look at your brain can help your doctor identify strokes, tumors or other problems that can cause dementia. Alzheimer's disease changes brain structure over time and can also be seen with a brain scan. Several types of scans are used.

  • CT and MRI scans. The most common imaging techniques for identifying dementia are computerized tomography (CT) and magnetic resonance imaging (MRI). A CT scan is an X-ray technique that produces images of your body that show internal structures in cross section. MRI is a technique that uses a magnetic field and radio waves to create detailed images of the organs and tissues in your body. These scans help identify brain-size changes, strokes and other problems such as excess fluid in the brain (hydrocephalus) or bleeding on the surface of the brain (subdural hematoma).
  • Electroencephalogram (EEG). Using electrodes placed on your scalp, your doctor can detect and record patterns of electrical activity and check for abnormalities. If found, these abnormalities can indicate cognitive dysfunction, a condition common in people with moderate to severe Alzheimer's disease. An EEG may also detect seizures, Creutzfeldt-Jakob disease and other disorders associated with dementia.

Laboratory tests
A variety of lab tests can help rule out other conditions, such as kidney failure, that can contribute to symptoms. Treatable medical conditions are often associated with dementia. Medication and other treatments can improve many symptoms and quality of life.

Tests that help identify treatable medical conditions include:

  • A complete blood count (CBC) to rule out anemia
  • A blood glucose test to rule out diabetes
  • Blood tests to estimate kidney function, to estimate liver function and to measure vitamin B-12 levels
  • A blood or urine screen to identify drugs or alcohol
  • Cerebrospinal fluid analysis (spinal tap) to rule out brain infections
  • Analysis of thyroid and thyroid-stimulating hormone levels to rule out hypothyroidism

Psychiatric evaluation
This examination may be performed to determine whether depression or another psychiatric disorder is contributing to symptoms.

Treatments and drugs Preparing for your appointment
References
  1. Chertkow H. Diagnosis and treatment of dementia: Introduction. Canadian Medical Association Journal. 2008;178:316.
  2. Feldman HH, et al. Diagnosis and treatment of dementia: 2. Dementia. Canadian Medical Association Journal. 2008;178:825.
  3. Dementia: Hope through research. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/dementias/detail_dementia.htm#1318919213. Accessed Jan. 3, 2009.
  4. National Institute on Aging. Frontotemporal dementia: Growing interest in a rare dementia. http://www.nia.nih.gov/Alzheimers/Publications/FTDreprint.htm. Accessed Jan. 11, 2009.
  5. Ersek M, et al. Tube feeding decisions for people with advanced dementia. The AGS Foundation for Health in Aging. http://www.healthinaging.org/public_education/pef/tube_feeding.php. Accessed Jan. 24, 2009.
  6. Dementia Guidelines for Early Detection, Diagnosis and Management of Dementia. New York, N.Y.: The American Geriatrics Society. http://www.americangeriatrics.org/products/positionpapers/aan_dementiaPF.shtml. Accessed Jan. 24, 2009.
  7. Farlow M. Moderate to severe Alzheimer disease — definition and clinical relevance. Neurology. 2005;65(suppl):S1.
  8. Hsiung G-YR, et al. Genetics and dementia: Risk factors, diagnosis, and management. Alzheimer's & Dementia. 2007;3:418.
  9. Patterson C, et al. General risk factors for dementia: A systematic evidence review. Alzheimer's & Dementia. 2007;3:341.
  10. Fuhrer R, et al. Exploring sex differences in the relationship between depressive symptoms and dementia incidence: Prospective results from the PAQUID study. Journal of the American Geriatric Society. 2003;51:1055.
  11. Wang H-X, et al. Late-life engagement in social and leisure activities is associated with a decreased risk of dementia: A longitudinal study from the Kungsholmen project. American Journal of Epidemiology. 2002:155:1081.
  12. Barberger-Gateau P. Diet and risk of dementia or cognitive decline. Alzheimers & Dementia. 2008;4(suppl):T181.
  13. Xu W-L, et al. Mid- and late-life diabetes in relation to the risk of dementia: A population-based twin study. Alzheimers & Dementia. 2008;4(suppl):T119.
  14. Biessels GJ, et al. Risk of dementia in diabetes mellitus: A systemic review. The Lancet Neurology. 2006;5:64.
  15. Kramer A, et al. Inflammation and Alzheimer's disease: Possible role of periodontal disease. Alzheimer's & Dementia. 2008;4;242.
  16. Tyas SL, et al. Risk factors for Alzheimer's disease: A population-based, longitudinal study in Manitoba, Canada. International Journal of Epidemiology. 2001;30:590.
  17. Hogan DB, et al. Diagnosis and treatment of dementia: 4. Approach to management of mild to moderate dementia. Canadian Medical Association Journal. 2008;179:787.
  18. Hogan DB, et al. Diagnosis and treatment of dementia: 5. Nonpharmacologic and pharmacologic therapy for mild to moderate dementia. Canadian Medical Association Journal. 2008;179:1019.
  19. Dementia. Alzheimer's Association. http://www.alz.org/alzheimers_disease_dementia.asp. Accessed Feb. 8, 2009.
  20. Steps to diagnosis. Alzheimer's Association. http://www.alz.org/alzheimers_disease_steps_to_diagnosis.asp#physexam. Accessed Feb. 9, 2009.
  21. Haan MN, et al. Homocysteine, B vitamins, and the incidence of dementia and cognitive impairment: Results from the Sacramento area Latino study on aging. The American Journal of Clinical Nutrition. 2007;85:511. http://www.ajcn.org/cgi/reprint/85/2/511. Accessed Feb. 9, 2009.
  22. Alternative treatments. Alzheimer's Association. http://www.alz.org/alzheimers_disease_alternative_treatments.asp#Coenzyme_Q10. Accessed Feb. 9, 2009.

DS01131

April 17, 2009

© 1998-2009 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "EmbodyHealth," "Reliable tools for healthier lives," "Enhance your life," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.

Print Share Reprints

Text Size: smaller largerlarger