Alzheimer's disease (AD) is a type of progressive deterioration of the structure and function of the brain. In its earliest stage, a person may function appropriately in his or her home and work environment, and problems with brain function may be apparent only on detailed neuropsychologic testing. Eventually, brain function problems 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

Prodromal: 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.

People compensate by giving themselves more time to adapt and perhaps by writing reminder notes. Some people may become anxious about their memory deficits. There is no specific treatment except for lifestyle.

Mild: In this stage, cognitive deficits are noticeable in demanding situations. The key to diagnosing mild dementia is that function at home or work is impaired, although slightly. Affected people begin to need help with complicated tasks such as planning a party or handling finances. They may have problems remembering life events (hospitalizations, medical conditions, educational/job milestones), have trouble concentrating, and may have trouble traveling, particularly to unfamiliar places.

Most people in the mild stage have no problem with familiar faces, are not disoriented with respect to time, and can usually travel to familiar places. However, people with Alzheimer's tend to back away from dealing with difficult or challenging situations. Their mood may be a bit "flat." Most are not aware of the extent of their deficits. They may say they have the same memory problems everyone else their age has, but they really do not understand the extent of their loss.

Many persons with mild Alzheimer's disease may still be driving. They should be encouraged not to drive. If they insist, they should be evaluated by a driver rehabilitation specialist to assess their driving risks. They might get therapy to improve their driving ability and lower their risks. Medicare covers an Occupational Therapy evaluation for certain diagnoses, such as stroke or lack of coordination. If Medicare does not cover it for you in your region of the country, consider an evaluation by a private driving school from an instructor who is certified in driver rehabilitation.

Moderate: People in the moderate stage of Alzheimer's require assistance. They need help choosing proper attire and may need help putting clothes on in the right order. Kitchen safety (e.g., fire from an unattended pot on the stove) may be an issue, and appliances such as the stove may need to be disabled. If still driving, they should be persuaded to "retire" from driving. They also may not be able to manage their medications or finances safely.

While there is some disorientation with time, such as remembering that the Cold War followed World War II, people with moderate dementia can still remember major information about themselves, their families, and others. There may be delusional behavior, depression, apathy, or anxiety as the disease progresses.

Moderately severe: As memory loss progresses, a person may not consistently recognize his or her children or spouse, or may confuse them with other family members. Functionally, the person loses skills in dressing, bathing, and then toileting. Urinary incontinence and, later, fecal incontinence occur. Sleep is often disturbed.

Severe: The person's speech ability becomes limited to about half dozen words, and eventually, intelligible vocabulary decreases to a single word. He or she has lost or will lose the ability to walk, sit up, smile, and eventually hold up his or her head. The brain now appears unable to tell the body what to do. The person may sit on the toilet, having forgotten how to move his or her bowels, or may be incontinent prior to reaching the toilet.

A person with severe dementia will hold food in his or her mouth, having forgotten how to swallow. Weight loss, aspiration, and bedsores may occur as the disease progresses. Hospice care may be appropriate at this time for comfort and palliation.