What Is Alzheimer's Disease?

Understanding Your Body

Understanding Your Body provides easy-to-understand explanations of body systems and disease conditions. This material can be used for patient education, life sciences curriculum development, or to enhance public understanding of general health concepts. Permission for such use is not required, but citation as to source is requested. The information provided is derived from Consumer Versions of Clinical Practice Guidelines, sponsored by the Agency for Health Care Policy and Research, from 1992 to 1996.

Alzheimer's disease is the most common form of dementia. It proceeds in stages over months or years and gradually destroys memory, reason, judgment, language, and eventually the ability to carry out even simple tasks.

Dementia is a medical condition that interferes with the way the brain works. Symptoms include anxiety, paranoia, personality changes, lack of initiative, and difficulty acquiring new skills.

Besides Alzheimer's disease, some other types or causes of dementia include: alcoholic dementia, depression, delirium, HIV/AIDS-related dementia, Huntington's disease (a disorder of the nervous system), inflammatory disease (for example, syphilis), vascular dementia (blood vessel disease in the brain), tumors, and Parkinson's disease.

Delirium is a state of temporary but acute mental confusion that comes on suddenly. Symptoms may include anxiety, disorientation, tremors, hallucinations, delusions, and incoherence. Delirium can occur in older persons who have short-term illnesses, heart or lung disease, long-term infections, poor nutrition, or hormone disorders. Alcohol or drugs (including medications) also may cause confusion.

Delirium may be life-threatening and requires immediate medical attention.

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Current as of November 2007
Internet Citation: What Is Alzheimer's Disease?: Understanding Your Body. November 2007. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/patients-consumers/prevention/understanding/bodysys/edbody9.html