Many people mistakenly use dementia as a synonym for Alzheimer's Disease. This use of the word is inaccurate; "dementia" is an umbrella-like term that refers to any brain syndrome that causes multiple cognitive deficits. In other words, saying someone has "dementia" is similar to saying that someone has a fever; you are not specifying the exact cause of the symptoms.

A person with dementia can experience all sorts of problems, including:

  • Impaired Memory (especially the ability to remember recent events and newly learned facts)
  • Impaired Language Skills (decreased ability to communicate to others and understand what is being communicated)
  • Impaired Orientation (not knowing who one is, where one is, and/or what time it is)
  • Impaired Judgment (impaired ability to make decisions regarding personal, interpersonal, financial, and/or medical affairs)
  • Impaired Executive Functioning (impaired ability to plan and carry out daily tasks and make decisions).

Dementia can be caused by one medical condition or by multiple medical problems. Most dementias are caused by one of the following:

  • Alzheimer's Disease, which accounts for 50-70% of all dementia cases
  • Vascular Disease, which accounts for 15-20% of all dementia cases and includes strokes (disruptions in the blood supply to the brain) and transient ischemic attacks (TIAs, or mini strokes)
  • Lewy Body Disease, which accounts for up to 20% of all dementia cases

We will concentrate most of our discussion on dementia due to Alzheimer's Disease, Vascular Disease, and Lewy Body Disease because these conditions are most common. However, there are other medical conditions worth mentioning that can also cause dementia (at a much lower rate). They include HIV/AIDS, head trauma, Parkinson's Disease, Huntington's Disease, Pick's Disease, Creutzfeldt-Jakob Disease, normal pressure hydrocephalus, and Wernicke-Korsakoff Syndrome. Each is discussed in the following section.