Dementia is a general term that is used to describe losses in memory and other intellectual abilities, which are serious enough to interfere with daily life. The most common form of dementia is Alzheimer's disease, which accounts for most (50 to 70 percent) cases of dementia, but not all cases. A more recent term, “Mild Cognitive Impairment”, is describes a loss of intellectual function that is not sufficiently severe enough to interfere with daily function.
The greatest known risk factor for Alzheimer’s disease is increasing age, and the majority of people with Alzheimer's disease are 65 years of age and older.
However, Alzheimer's disease is not a normal part of aging, nor is it just a disease of old age. Up to 5 percent of people with the disease have an early-onset (also known as younger-onset), which often appears when someone is under the age of 65.
Alzheimer's disease very gradually worsens over time. In its early stages, memory loss is the primary symptom and is mild, but with late-stage Alzheimer's disease, individuals lose a wide range of intellectual abilities and can have difficulties with just carrying on a conversation.
Alzheimer's disease is the sixth leading cause of death in the United States. People with Alzheimer's disease live an average of eight years after their symptoms become noticeable to others, but survival with the disease can range from three to 20 years, depending on age and other health conditions.
Alzheimer's disease has no current cure, but treatments are available for the symptoms Alzheimer’s disease. Although current treatments cannot stop Alzheimer's disease from progressing, they can temporarily slow the worsening of symptoms and improve the quality of life for people with the disease and their caregivers.