facts for health--alzheimer's--frequently asked questions

Because changes seen in a brain scan may not be due to Alzheimer's disease (AD). Other causes of dementia may also produce changes in the brain images similar to those found in AD. Also AD, early on, may not produce any changes. Identifying the probable cause is important so that the most effective treatments or preventive measures can be used. Despite these issues, a brain scan may prove useful as part of a comprehensive evaluation for AD, particularly if it finds a treatable cause of dementia.

Believe it or not, the most important diagnostic tool in the evaluation of someone with possible AD is the history provided by the patient and, when possible, by someone who knows the patient well. Other important steps in a comprehensive diagnosis are physical and neurological exams, including simple tests of memory and other aspects of thinking, blood and urine tests, an electrocardiogram, and sometimes a detailed neuropsychological examination that provides highly specific measures of memory and thinking abilities.

Computerized tomography (CT) and magnetic resonance imaging (MRI) permit doctors to see and measure the brain's structures. These technologies are mainly useful in finding blood vessel abnormalities or other brain problems (such as tumors) that may be causing or contributing to dementia. Some of these problems may be reversible. Alzheimer's disease causes a progressive loss of brain tissue, most visible on the surface of the brain, but also obvious in some brain structures deeper in the brain. However, recognizable loss of brain tissue is usually seen only late in the course of AD. Currently, the American Academy of Neurology recommends either a CT or MRI scan in the initial evaluation of patient with dementia.

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) permit doctors to see how the brain is functioning. These studies of brain function may be helpful when the diagnosis is unclear. Unfortunately, these brain scans are seldom covered by medical insurance.

Are laboratory tests helpful?

Very helpful, though perhaps not in the way most people would think. There is no specific laboratory test for Alzheimer's disease. However, laboratory tests can help rule out other causes of dementia, and if other dementias are discovered, guide treatment in the right direction. For example, blood tests may show high blood sugar or high blood lipids (cholesterol) and a brain scan may show evidence of a stroke. An electrocardiogram may indicate an earlier heart attack or an abnormal heart rate or rhythm. These findings may lead to a diagnosis of vascular or multi-infarct dementia and to treatments that would reduce the risk of further brain injury due to interference with blood flow to the brain.

Alternatively, blood tests might show low levels of vitamin B₁₂ that cause a particular type of anemia that can produce dementia. The specific treatment for vitamin B₁₂ deficiency would involve periodic injections of vitamin B₁₂.

Could Alzheimer's disease be the wrong diagnosis?

It certainly could. Alzheimer's disease is a diagnosis made after excluding other causes of brain dysfunction. Getting the diagnosis right is important in selecting the most effective treatments. Please see the previous question — Are laboratory tests helpful? — for two examples of different treatments for different causes of non-Alzheimer's disease dementia.

Delirium is a medical disorder that involves confusion and memory difficulties that can be mistaken for dementia. Delirium usually has a rapid onset within hours or days rather than months or years as seen in dementia. The severity of delirium usually fluctuates dramatically during a 24-hour period, whereas changes in dementia severity are usually gradual unless delirium is superimposed on dementia. People who have delirium are often disoriented and confused about the date or their location. They can be hyperactive and agitated, or very sleepy, and may fluctuate between these states. Delirium is seen more commonly in older people, especially when they are in the hospital for surgery or medical problems. Delirium has many causes including reactions to medications, infection, head injury, kidney or liver problems, and abnormal levels of blood chemicals such as sodium. When a person with dementia has a sudden worsening of their memory or confusion, this should prompt a search for medical causes of delirium because they can often be treated rapidly and effectively.

What is early stage Alzheimer's disease?

In its mild or early stage, Alzheimer's disease (AD) may be overlooked both by individuals developing AD and by those around them. Lack of awareness may be an early AD symptom, although some are keenly aware of diminished memory and thinking abilities. Family and friends may ignore early symptoms hoping they will not progress or because they think nothing can be done to treat AD. Symptoms that should lead to early evaluation include:

It is possible that stress, busy schedules, worries or a recurrence of depression or another illness may explain some of these symptoms. A careful medical evaluation is indicated to sort through the possible explanations. Early treatment for all medical disorders is likely to preserve or improve functioning and relieve suffering for the patient and caregivers.

What is middle stage Alzheimer's disease?

Middle stage or moderate Alzheimer's disease (AD) involves a worsening of the symptoms of early AD, the appearance of new symptoms or both. Obvious impairment of comprehension and judgment often emerge. Dangerous behaviors (e.g., auto accidents if the person is still driving, physical aggressiveness, forgetting to turn off appliances or take medications) make it clear that something is seriously wrong. Other signs of AD progression include sleep pattern changes (more or less sleep and sleeping at odd times), trouble carrying out complex tasks (balancing a checkbook, planning dinner or putting together a puzzle) or obvious disorders of perception (hallucinations) or thinking (delusions). By this stage, evaluation is obviously necessary and has usually occurred. Treatment at this stage is still worthwhile.

What is late stage Alzheimer's disease?

The late stage or severe Alzheimer's disease (AD) involves further progression of the signs and symptoms of early and middle stage AD. It is important to search for correctable conditions, especially when a change is sudden. As severity increases, the person with AD can no longer provide self-care, often requiring help with personal activities of daily living such as dressing, eating and going to the bathroom. Memory is very poor or gone altogether. Ability to communicate and to feel and express appropriate emotions is further diminished or absent. Physical problems increase with incontinence of urine and/or feces, weakness, difficulty chewing and swallowing, and increased susceptibility to infections becoming common. In its end state, individuals may become bedridden or entirely dependent on others for all aspects of their care.

Did former President Ronald Reagan have Alzheimer's disease?