Alzheimer’s disease (AD) is a type of progressive
deterioration of the structure and function of the brain. In the prodromal
stage, a person may function appropriately in his or her home and work
environment, and abnormalities in cognition may be apparent only on detailed
neuropsychologic testing. Eventually, cognitive deficits are noticeable.
A person with Alzheimer’s disease early on has difficulty with:
- short-term memory
- making lists
- keeping track of complicated appointments or social schedules
- organizing a vacation trip
- following directions using a map
- coordinating a multi-course holiday family dinner.
Later in the disease, there are often problems with long-term memory, mood, apathy, agitation, and abnormal motor activity (e.g.,
pacing). Affected people have trouble using appliances—first, complex ones, such as the car or dishwasher; later, the telephone; and lastly even table utensils.
Not every memory problem becomes dementia, and not
every cause of dementia is AD. Dementia means that there is a loss of memory and
at least one other aspect of cognition, such as abstract thinking, personality,
or executive (organizational) ability, and that the loss interferes with
function. Dementia cannot be diagnosed when a person becomes suddenly ill, such
as with a fever, infection, metabolic derangement, etc.
Alzheimer’s disease is the most common cause of dementia. However, stroke, alcohol, Parkinson’s disease, and other medical
conditions can cause dementia as well.
Alzheimer’s disease has both a genetic and an environmental component. The genetic component is very strong in those diagnosed
with AD in their 40s or early 50s. However, these represent a small fraction of the AD population. Most people with Alzheimer’s disease develop symptoms in
their 70s and 80s, and the genetic component is much weaker at this age. Only 50% of identical twins of older Alzheimer’s patients are diagnosed with
Alzheimer’s disease.
Health and environmental factors, such as mental and physical activity, and treatment of medical conditions such as hypertension and
diabetes play a strong role in postponing AD symptoms. Genetic testing for Alzheimer’s disease occurring after age 60 is not generally recommended.
Stages of Alzheimer’s disease
Prodomal: This stage is usually not diagnosed
because people in this stage are functioning at a high level. Occasionally, they
may report having more problems than usual with short-term memory, or
remembering names or where they placed their belongings. However, they balance
their checkbook, keep appointments, and continue to drive.