Facts About Dementia: Overview

Did You Know

Some loss of mental ability is normal with age; however, a decline in thinking ability that cannot be explained by aging alone may be due to a syndrome called Mild Cognitive Impairment (MCI). MCI can affect one or more areas of thinking (cognition), such as memory, speech, or decision making. Half of individuals with MCI will go on to get dementia.

Symptoms of MCI are often subtle and can be mistaken for normal age-related decline. Individuals with MCI often have balance and coordination problems that are not part of normal aging. (Gauthier et al, 2006) You can learn more about MCI here.


Watch a video that introduces dementia (2 minutes long)

What is Dementia?

Dementia a disorder of the brain that affects how well it works. It affects millions of people, mostly older adults. Dementia is sometimes mistakenly considered to be one disease, but it is actually a group of diseases that affect people in many different ways. Just as there are different types of heart disease or cancer, there are different types of dementia. Dementia includes Alzheimer's disease, vascular dementia, Lewy body dementia, alcohol-induced dementia, and others. Alzheimer's disease is the most common type of dementia.

What are the Symptoms of Dementia?

People with dementia often have problems with their memory and with completing daily activities, such as making dinner or paying bills. Mood swings and personality changes are other common symptoms of dementia. While some people with dementia may demonstrate all of these symptoms, others may have only some of them. The symptoms that a person develops depend on the type of dementia.

How Many People Have Dementia?

The chance of developing dementia increases with age. However, dementia is not a natural process of aging and it does not affect everyone. For example, less than 2% of people ages 65-69 have dementia (Alzheimer's Disease International, 2008). The percentage of people with dementia in the US illustrates the increasing prevalence of dementia with advanced age:

  • 5% of those age 71-79
  • 24% of those age 80-89
  • 37% for those age 90 and over

(Plassman et al, 2007).

Nearly 15 million people non-professional caregivers are helping care for an estimated 5.4 million people with Alzheimer's disease (Marcus, 2011).

How Long does Dementia Last?

Dementia is a progressive disease - meaning that it gets worse over time - that usually starts later in life and lasts for the rest of a person's life. Unfortunately progressive dementia currently has no cure and the symptoms are not reversible and lead to permanent damage. Eventually, people with these conditions are unable to care for themselves. The disease process is often described in universally recognized "stages" of dementia. Persons with dementia increasingly need help with cooking, cleaning, paying bills, bathing, walking, and with all activities of daily living.

There are some treatable forms of dementia-like symptoms that are often completely reversible. This condition is usually referred to as delirium. Causes include infection, depression, alcoholism, medication effects and interactions, and poor nutrition; treatment involves addressing the underlying condition.

View References Alzheimer's Disease International. The prevalence of dementia worldwide. 2008. Available at: http://www.alz.co.uk/adi/pdf/prevalence.pdf. Retrieved June 30, 2009.

Plassman BL et al. Prevalence of Dementia in the United States: The Aging, Demographics, and Memory Study. 2007; 29:125-132. Available at: http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ArtikelNr=000109998&Ausgabe=233821&ProduktNr=224263&filename=000109998.pdf. Retrieved June 30, 2009.

Marcus Mary B. Alzheimer's Carries Heavy Toll on 15M Unpaid Caregivers. 2011. Available at: http://www.usatoday.com/yourlife/health/medical/alzheimers/2011-03-15-alznumbers15_ST_N.htm. Retrieved June 13, 2011.
Alzheimer's Society (United Kingdom)
This website, developed in Great Britain, includes links to a variety of online resources about dementia, including fact sheets and "A-Z" of dementia. There are also links to resources for those living with dementia, their caregivers, and health professionals.
National Institute of Neurological Disorders and Strokes
This webpage includes a paragraph that explains that dementia is not a specific disease, and that many disorders are associated with dementia, as well as links to a number of webpages that answer many other specific questions about dementia.
Alzheimer's Association
This article discusses the prevalence of Alzheimer's disease, and the increased risk among African Americans for Alzheimer's disease and Vascular dementia due to a higher presence of certain risk factors. An introduction section is provided describing the risk of Alzheimer's disease among African Americans, as well as a section on warning signs, brain health, and the Alzheimer's Association Alzheimer's Early Detection Alliance.
Alzheimer's Association
This resources page, also available in Spanish, offers information about Latinos and Alzheimer's, including links to articles on why Latinos are at risk for Alzheimer's disease, diagnosis, treatments, and other resources.
CBS News
This article discusses the estimated prevalence of dementia in the U.S., from the results of a recent study. The article notes that 14% of a nationally representative sample of people over age 71 had dementia, and 10% had Alzheimer's disease.