Diagnosis of AD

There are currently no specific tests that may positively confirm the diagnosis of AD. AD may be diagnosed on physical and neurological exams, and checking for signs of intellectual impairment through standard tests of mental function. For a diagnosis of AD, the criteria adapted from the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) include the following:

§  dementia established by examination and objective testing;

§  deficits in two or more cognitive areas;

§  progressive worsening of memory and other cognitive functions;

§  no disturbance in consciousness;

§  and onset between ages 40 and 90.

Absence of systemic disorders or other brain diseases, which could account for the deficits in memory and cognition, should also be ruled out. Diagnostics tests such as MRI and CT are also done to rule out medical causes of creased brain function. Definitive changes found in the brain of affected AD patients are microscopic and can be seen only when a sample of brain tissue is removed and examined, usually on autopsy.6^,13

Alzheimer disease is characterized primarily by a gradual onset of progressive symptoms, including:[i]

·         memory loss

·         changes in personality

·         noticeable decline in cognitive abilities (including speech and understanding)

·         loss of executive function (decision-making)

·         losses impairing activities of daily living (dressing, eating, toileting, etc.)

Annex 6.11.1 identifies sources for the differential diagnosis of AD. The actual diagnostic work-up for AD is very involved and requires several steps this includes an initial evaluation including a medical history, a mental status evaluation, a clinical examination, and laboratory tests.13

Alzheimer disease is the most common cause of dementia, however there are many disorders that can cause or simulate dementia. To appropriately diagnose for AD, other forms of dementia or diseases need to be ruled out.

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[i] http://www.alz.org/Health/Diagnose/overview.asp. Alzheimers Association. Diagnosis. Last Accessed July 27, 2004.