Updated 27 October 2007
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The assessment of Alzheimer disease might begin with a memory screening test in
a primary care doctor's office, followed by a referral to a neurologist, neuropsychologist,
geriatric psychiatrist, or other specialist with expertise in the diagnosis of Alzheimer
disease. The diagnostic process involves determining whether symptoms fit the diagnostic
criteria, and ruling out other possible causes of dementia symptoms. A close family
member or companion of the patient should be included in the clinical interview
to help assess the reliability of the patient's own reports and to supply information
to the physician if the patient is too impaired. Interviews with close companions
are essential for diagnosing early-stage disease and mild cognitive impairment.
The Quality Standards Subcommitte of the American Academy of Neurology published
Practice Parameter: Early Detection of Dementia: Mild Cognitive Impairment (An Evidence-Based
Review) [.pdf] in May 2001, in recognition of the increased risk among persons
with mild cognitive impairment for developing dementia.
A helpful summary of diagnostic criteria and screening tests is available from the
American Academy of Family Physicians (Early Diagnosis of Dementia, by Santacruz and Swagerty). The
typical picture of an Alzheimer patient involves:
- a progressive decline in memory function
a gradual retreat from, and frustration with, normal activities
Many additional clinical signs have been described and all of these occur
more than ten percent of the time and include (in roughly decreasing order):
- agitation or irritability
- aggression (verbal>physical)
- sleep disturbance
- aberrant motor behavior
- social withdrawal
- decreased appetite (+/- weight loss)
- hallucinations (visual>auditory>>tactile,olfactory)
Many other disorders can mimic the symptoms of Alzheimer's
(see Disorders that can mimic Alzheimer's). The clinical traits/ histories
that might lead one to exclude a diagnosis of pure Alzheimer's disease include:
- Extremely rapid onset (from normal to incapacitated in less than three years) or
onset before age 55 (may indicate a rare, familial form of Alzheimer)
- Preponderance of movement symptoms (Parkinson/Lewy Body diseases, Huntington disease,
or other rarer diseases)
- Impaired eye movements (progressive supranuclear palsy, multiple sclerosis,Wernicke's)
- Reports of temporary blindness, widely fluctuating symptoms, or focal neurological
signs (cerebrovascular disease).
- History of alcoholism (Korsakoff psychosis) or drug abuse (drug-induced delirium).
- History of AIDS (AIDS dementia)
- History of depression, psychosis, head trauma, seizures, diabetes, neurosyphilis,
vasculitis, and tumors
See Tests for a description of the standard
medical workup used to diagnose Alzheimer's.
A brain autopsy is recommended to confirm a diagnosis.
See Consensus Recommendations for the Postmortem Diagnosis of Alzheimer's Disease
for current pathology criteria.
See the Alzheimer's Association working group's Consensus Report on MRI and PET imaging for diagnosis of dementias