Dementia is Not a Specific Disease

Many people are under the impression that Alzheimer's disease (AD) and Dementia are different conditions. In fact, AD is a type of Dementia. In addition to AD, Dementia also includes types such as vascular Dementia, Frontotemporal Dementia, and Dementia with Lewy bodies.

Many people, particularly those who are very old, have mixed Dementia or Dementia that is caused by more than one kind of brain disease.

There Are Many Types of Dementia

AD is currently considered the most common kind of Dementia. Current estimates suggest that Alzheimer's disease represents approximately 60% of the Dementia burden. Although scientists have found various genetic and environmental factors that may increase the likelihood of having AD, age is the most important risk factor. The estimated prevalence of AD increases with age, from less than 8% in people 58–69.9 years of age to 65.2% in those over 90 years of age.

Vascular Dementia, accounting for 5 to 10% of all Dementia cases in the US, is the second most common age-related Dementia. Unlike the gradual progression of AD, the onset of vascular Dementia symptoms is often abrupt and may occur when a heart attack or a stroke dramatically reduces blood flow to or through the brain.

Vascular Dementia can also have a slow progression. This happens when the cumulative damage of transient ischemic attacks - often called TIAs - causes many small areas of brain damage and, eventually, noticeable symptoms. The descriptive name “multi-infarct Dementia” is the term healthcare providers use to describe this kind of vascular Dementia. Multi-infarct Dementia is the most common type of vascular Dementia.

Each type of Dementia has specific signs and symptoms. For example, memory loss, confusion, and difficulty in performing tasks that were once familiar and easy are early symptoms of AD. In contrast, the early symptoms of frontotemporal lobe degeneration (FTD) are poor coordination, tremors, and difficulty in using and understanding written and spoken language. Memory loss is another aspect of FTD but occurs much later in the course of the disease. Ultimately, however, memory loss is a symptom that all forms of Dementia have in common.

Examples of other types of Dementia include Dementia resulting from Traumatic Brain Injury (TBD); Wernicke-Korsakoff Syndrome (WKS); Normal Pressure Hydrocephalus (NPH); Chronic Traumatic Encephalopathy (CTE); Creutzfeldt-Jakob Disease (CJD), and others.

Content Contributor: Janet Yagoda Shagam, Ph.D., is a freelance medical and science writer and the author of "An Unintended Journey: A Caregiver's Guide to Dementia", available through Amazon. Please visit our Author's page to learn more and find this title.

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