Alzheimer's and Other Types of Dementia
Dementia (dih-MEN-shuh) is a general term for the loss of memory and other intellectual abilities serious enough to interfere with daily life. Alzheimer’s is the most common form of dementia. Today we estimate that 5 million Americans have Alzheimer’s. That includes 12 percent of those over age 65 and nearly 50 percent of those aged 85 and older.
Because 70 percent of those with Alzheimer’s live at home, the impact of the illness extends to millions of family members, friends, and caregivers.
Other Types of Dementia
Alzheimer’s disease accounts for 60 to 70 percent of cases of dementia. Other disorders that can cause memory loss, confusion, and other symptoms associated with dementia include:
Vascular or multi-infarct dementia, often considered the second most common form, refers to impairment caused by reduced blood flow to parts of the brain. The most common type is what used to be called “multi-infarct dementia,” in which a series of very small strokes block small arteries. Individually, these strokes are too small to cause major symptoms, but, over time, their combined effect becomes noticeable.
Symptoms of vascular dementia can be similar to Alzheimer’s disease. They include problems with memory, confusion, and difficulty following instructions. In some cases, the impairment associated with vascular dementia can occur in “steps” rather than in the slow, steady decline usually seen in Alzheimer’s.
Mixed dementia is a condition in which Alzheimer’s disease and vascular dementia occur together. Some experts believe that this combination is also very common.
Parkinson’s disease affects control of movement, resulting in tremors, stiffness, and impaired speech. Many individuals with Parkinson’s also develop dementia in later stages of the disease. Drugs for Parkinson’s can help steadiness and muscle control, but have no effect on dementia symptoms.
Dementia with Lewy bodies often starts with wide variations in attention and alertness. Individuals affected by this illness often experience visual hallucinations as well as muscle rigidity and tremors similar to those associated with Parkinson’s disease.
Physical injury to the brain caused by an automobile accident or other significant trauma can damage or destroy brain cells, and cause symptoms of dementia such as behavioral changes, memory loss and other cognitive difficulties.
Huntington’s disease is an inherited, progressive disorder that causes irregular movements of the arms, legs, and facial muscles, personality changes and a decline in the ability to think clearly.
Creutzfeldt-Jakob disease (CJD) (CROYZ-felt YAH-kob) is a rare, rapidly fatal disorder that impairs memory and coordination, and causes behavior changes. Recently, “variant Creutzfeldt-Jakob disease” (vCJD) was identified as the human disorder believed to be caused by eating meat from cattle affected by “mad cow disease.”
Frontotemporal dementia or Pick’s disease is another rare disorder that may sometimes be hard to distinguish from Alzheimer’s. Personality changes and disorientation often occur before memory loss.
Normal pressure hydrocephalus (NPH) is caused by a buildup of fluid in the brain. The cause of most cases is unknown. Symptoms include difficulty walking, memory loss and inability to control urine. NPH can sometimes be corrected with surgery to drain the excess brain fluid.
Mild Cognitive Impairment (MCI)
Although a person may have a noticeable difficulty with memory or other thinking skills, a doctor may determine the person does not meet criteria for being diagnosed with Alzheimer’s or another form of dementia. Some doctors use the term mild cognitive impairment (MCI) to describe this situation.
Research has shown that individuals with MCI have an increased risk of progressing to Alzheimer’s disease over the next few years, especially when their main area of difficulty involves memory. But a diagnosis of MCI does not always mean the person will develop Alzheimer’s.
