Dementia

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Overview, Causes, & Risk Factors

Disorders that cause dementia include conditions that impair the vascular (blood vessels) or neurologic (nerve) structures of the brain. Some causes of dementia are treatable. These include normal pressure hydrocephalus, brain tumors, and dementia due to metabolic causes and infections. Unfortunately, most disorders associated with dementia are progressive, irreversible, and degenerative.

The two major degenerative causes of dementia are Alzheimer's disease (the progressive loss of nerve cells without known cause) and vascular dementia (loss of brain function due to a series of small strokes). The two conditions often occur together, and vascular dementia may speed the progression of Alzheimer's disease. Neither condition can be diagnosed definitively until autopsy.

Dementia may be diagnosed when two or more brain functions are impaired. These functions include language, memory, visual-spatial perception, emotional behavior or personality, and cognitive skills (such as calculation, abstract thinking, or judgment). Dementia usually appears first as forgetfulness. Other symptoms may be apparent only with neurologic examination or cognitive testing.

Dementia progresses slowly from decreased problem solving and language skills to difficulty with ordinary daily activities to severe memory loss and complete disorientation with withdrawal from social interaction.