What Are the Different Forms of Dementia?

Although commonly perceived as a distinctive disorder, dementia is not a single specific disease. Instead, the descriptive term refers to several conditions that cause the brain to change, precipitating a range of symptoms that can adversely impact a person's ability to carry out normal tasks. Moreover, while some forms of dementia become progressively more debilitating, other types are treatable and even reversible.

Features

There are numerous symptoms that help indicate the presence of dementia. For example, sufferers are unable to complete tasks that require mental alertness or accuracy, such as solving problems and performing everyday activities such as driving and getting dressed. Individuals with dementia might also be unable to control their emotions and have personality changes, hallucinations or behavioral issues such as agitation. Health care professionals only diagnose dementia when there is no loss of consciousness and at least two brain functions--for example, language and perception--are impaired.

Types

According to the United States' National Institute of Neurological Disorders and Stroke, the different types of dementia fall into several categories. For instance, cortical dementia is related to damage to the brain's cortex, which leads to issues with language, memory, socializing and thinking; subcortical dementia is associated with damage in the brain below the cortex, producing problems with emotions, memory and movement; progressive dementia becomes gradually worse and slowly reduces cognitive skills; primary dementia isn't caused by another disease; and secondary dementia results from a physical injury or disease.

Progressive Dementias

Well-known progressive dementias that grow worse as time passes include Alzheimer's disease, which occurs when the brain cells, or neurons, are slowly destroyed over a period of seven to 10 years; Frontotemporal dementia caused by deteriorated nerve cells in the brain's frontal and temporal lobes; Lewy body dementia, which results from abnormal protein clusters in the brain; and Vascular dementia arising from brain damage because of to malfunctioning arteries. Alzheimer's disease, the most frequent kind of dementia, strikes 10 percent of Americans older than age 65 and almost 50 percent of seniors older than age 85.

Reversible Dementias

At the opposite end of the spectrum from progressive dementias are those varieties that are reversible with treatment. Such dementias usually emerge after incidents such as anoxia (when organs are deprived of oxygen, such as during an asthma attack and strangulation), dehydration and improper nutrition, infections and immunity problems, and poisoning.

Dementia-Related Disorders

Many medical conditions produce symptoms of dementia, as well, such as Huntington's disease, a hereditary disorder that causes the brain and spinal cord's nerve cells to degenerate; HIV (human immunodeficiency virus), which destroys brain cells as it advances toward AIDS; and dementia pugilistica stemming from repeated trauma to the head. Certain disorders that negatively impact movement, including Parkinson's disease, are also linked to dementia symptoms.