Ask Well: Is Dementia the Same as Alzheimer’s Disease?

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Dementia is a general term for a set of symptoms that includes severe memory loss, a significant decline in reasoning and severely impaired communication skills; it most commonly strikes elderly people and used to be referred to as “senility.” Alzheimer’s disease is a specific illness that is the most common cause of dementia.

Though many diseases can cause dementia, Alzheimer’s accounts for 60 percent to 80 percent of dementia cases, “which is why you’ll often hear the terms used interchangeably,” said Heather Snyder, the senior director of medical and scientific operations for the Alzheimer’s Association. She said the question comes up frequently because patients may receive an initial diagnosis of dementia followed by an evaluation that yields the more specific diagnosis of Alzheimer’s disease, and they may be confused.

The second most common form of dementia is vascular dementia, which is caused by a stroke or poor blood flow to the brain. Other diseases that can lead to dementia include Huntington’s disease, Parkinson’s disease and Creutzfeldt-Jakob disease. Some patients may have more than one form of dementia.

Dementia is caused by damage to brain cells. In the case of Alzheimer’s disease, that damage is characterized by telltale protein fragments or plaques that accumulate in the space between nerve cells and twisted tangles of another protein that build up inside cells.

In Alzheimer’s disease, dementia gets progressively worse to the point where patients cannot carry out daily activities and cannot speak, respond to their environment, swallow or walk. Although some treatments may temporarily ease symptoms, the downward progression of disease continues and it is not curable.

But some forms of dementia are reversible, which is why it’s important to be evaluated by a physician early on. Vitamin deficiencies, thyroid problems, brain tumors, depression, excessive alcohol use, medication side effects and certain infectious diseases can cause reversible forms of dementia.

Another treatable form of dementia is a condition known as normal pressure hydrocephalus, which is caused by a buildup of cerebrospinal fluid in the brain that can be relieved by surgically implanting a shunt to drain off excess fluid. This type of dementia is often preceded or accompanied by difficulty walking and incontinence.