Senior Health

Understanding Dementia

For the Caregiver

What is dementia?

Dementia is a general term for impaired memory, language, problem-solving and other thinking abilities that interfere with daily life. The most common cause of dementia is Alzheimer's disease.

What is Dementia?

Que es Demencia?

Dementia is not a single disease. Instead, it covers various medical conditions–including Alzheimer's disease. Disorders in the "dementia" category are those caused by abnormal brain changes. In addition to a decline in thinking abilities, dementia also leads to changes in the following areas:

  • Behavior
  • Feelings
  • Relationships

Alzheimer's disease is the most common cause of dementia –accounting for 60-80% of cases. The second most common cause is vascular dementia, which results from microscopic bleeding and blood vessel blockage in the brain. The correct term for individuals who experience multiple types of dementia is "mixed dementia". Other conditions can cause symptoms of dementia, including thyroid problems and vitamin deficiencies. However, some of these are reversible.

Note that dementia is often incorrectly referred to as "senility" or "senile dementia", which reflects the incorrect belief that severe cognitive decline is a typical part of aging.

Information provided by the Alzheimer's Association:

What is Alzheimer's Disease?

Alzheimer's disease is the most common cause of dementia–a general term for memory loss and other cognitive abilities that interfere with daily life. Alzheimer's accounts for 60-80% of dementia cases. Unfortunately, Alzheimer's is not a universal part of aging. However, increasing age is the most significant known risk--and most individuals with Alzheimer's are 65 and older (though there is younger-onset Alzheimer's as well).

Because Alzheimer's is a progressive disease, it worsens over time. In its early stages, individuals experience mild memory loss. But by the time it progresses to late-stage Alzheimer's, they lose the ability to converse with others and respond to their environment. On average, a person with Alzheimer's lives four to eight years after diagnosis, though they can live up to 20 years.

Fortunately, Alzheimer's is at the forefront of biomedical research. As a result, researchers are working to understand how Alzheimer's affects the brain and develop subsequent treatments for it.

Information provided by the Alzheimer's Association. For more information, please visit:

The Alzheimer's Association

Founded in 1980, the Alzheimer's Association is the leading voluntary health organization in Alzheimer's care. Call 800-272-3900 for around-the-clock support or check out the links below for additional information: