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Diagnosis of Alzheimer’s disease
Assessment of a patient with Alzheimer’s disease, usually
involves a team of doctors consisting of a neurologist, psychiatrist and neuro-psychologist,
assisted by a radiologist and a
pathologist. Assessment involves a series of steps and can take several days
to complete. There is no single test which confirms or excludes Alzheimer’s
disease.
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Steps in the diagnosis of Alzheimer’s disease
There are three steps in the diagnosis of Alzheimer’s
disease:
Step 1: Documentation of loss of intellectual
function.
Step 2: Documentation that the loss of
intellectual function is disabling the patient in daily activities.
Step 3: Exclusion of other
causes of loss of intellectual function.
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Step 1: In evaluating a patient,
the physician will need to check if there is a substantial deterioration in
the intellectual function of the aged person relative to his/her previous
status, who otherwise seems to be in good physical
condition. In medical terms, it is necessary to seek evidence of ‘dementia’.
Doctors will administer neuropsychological tests to check
various components of intellectual function. Examples of such tests are the Fuld Object Memory Test in which patients are shown 10
objects and then asked to memorize this list of objects and repeat it to the
examiner. An average healthy adult should be easily able to recall 7-8
objects. However, patients of Alzheimer’s disease can recall only one or two
objects. Another neuropsychological test is the Boston Naming Test in which
subjects are shown various objects and asked to name them. Most healthy
people can easily name these objects, while patients with Alzheimer’s disease
have trouble naming even such simple objects as a comb or a pen. Similarly,
there are neuropsychological tests for speech, calculation, problem-solving
and judgement. Based on the results of these tests,
loss of intellectual functions can be documented.
Step 2: The doctor needs to ensure that the loss of
intellectual functioning is severe enough to disable the person in activities
of daily living. Patients of Alzheimer’s disease are extremely disabled in
function. When loss of intellectual function is so severe that it leads to
disabilities, conditions for Step 2 in the diagnosis of Alzheimer’s disease
are met.
Step 3: In the diagnosis of Alzheimer’s disease, it is
important to exclude other causes of loss of intellectual function. For this
purpose, doctors will take a detailed history of the patient’s illness from
their relatives, then conduct a comprehensive
medical, neurological and neuropsychological examination. Blood tests and
X-ray tests, such as CT scan and MRI scan, will help to exclude conditions
such as thyroid disease, brain tumour or stroke. In
Alzheimer’s disease, CT and MRI scans show a shrinking of the brain. This is
medically referred to as "cortical atrophy".
If Alzheimer’s disease is diagnosed, the family should
collectively decide on several issues of management or treatment of the
patient as well as on the patient’s rights, aspirations and legal interests.
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