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Chandrakanta Das, 87, of Mississauga, has been diagnosed with early-stage Alzheimer disease. (Peter Power/Peter Power/The Globe and Mail)
Chandrakanta Das, 87, of Mississauga, has been diagnosed with early-stage Alzheimer disease. (Peter Power/Peter Power/The Globe and Mail)

Q&A

Your dementia questions answered Add to ...

MEDICAL ISSUES

Q: What is the difference between Alzheimer's and dementia?

A: The word dementia is derived from the Latin words " de" meaning "apart" and " mens" - a derivative of " mentis" or "mind".

Literally, the word means the body being separated from the mind. In medical terms dementia is the progressive deterioration in cognitive function - the gradual loss of the ability to process thought.

Alzheimer is a brain disease characterized by abnormal deposits (plaques) in the brain of a protein fragment, beta-amyoloid, and twisted strands (tangles) of the protein tau. One of the principal symptoms of Alzheimer is dementia. But there are many other conditions that cause dementia.

Q: Am I correct that there are 20 categories of dementia and one of them is Alzheimer's?

A: There are dozens of diseases that affect the brain and can cause dementia; the most common - and best-known - is Alzheimer's. Vascular dementia, caused by interruption of blood flow to the brain (mini-strokes), is also common. Lewy bodies dementia, frontotemporal dementia, Pick's disease, Parkinson's disease and Creutzfeldt-Jakob disease are other brain diseases whose principal symptom is dementia. While dementia usually grows worse over time, some forms are reversible: normal pressure hydrocephalus (known commonly as water on the brain) can be treated by installing a shunt that drains fluid from the brain.

Q: Is delirium the same thing as dementia?

A: Delirium is a sudden state of confusion and disorientation. It is similar to dementia because there is a loss of cognitive skills, but it is not a permanent condition. Delirium, which is very common in frail seniors, is almost always caused by a medical problem, such as a drug reaction, an infection, a heart problem or a stroke. Delirium is not a dementia per se, but often occurs in people with dementia.

Q: As I understand it, Alzheimer is a disease that starts early in life (often 55 to 60) and patients degenerate a lot faster than those with general dementia, which starts later (in the 70s and 80s). Is that correct the elderly suffer from dementia and not Alzheimer's?

A: Dementia can occur at any age, for a host of reasons (see above), but it is far more likely in older persons. In fact, the rate of dementia doubles every five years after 65 - from about 2.5 per cent among 65-year-olds to over 40 per cent in 90-year-olds.

     The most common cause of dementia at all ages is Alzheimer's disease. But vascular dementia is also quite common among older seniors, due to the high rate of stroke.

     You are quite correct to point out, however, that when a person has early-onset dementia (before 60, sometimes as young as 40) they tend to deteriorate much more quickly. But again, most cases of early-onset dementia are caused by Alzheimer's.

Q: Is senility the same thing as dementia?

A: Senility is just an old-fashioned word for dementia. But senility also implies that loss of cognitive function is a normal part of aging. It is not. We know now that dementia is caused by specific changes to the brain and while those conditions are more likely in old age, they are not caused by aging.

Q: How is a person diagnosed with dementia?

A: Despite the amazing advances made in neurosciences, diagnosing dementia still consists principally of detective work. There are six main steps leading to diagnosis: taking a patient's history; interviewing a caregiver or family member; physical examination; brief cognitive tests; basic laboratory tests and; in some cases, imaging tests like a MRI.

Because a diagnosis is rarely urgent, these steps are usually carried out over a series of visits. The physician is looking for three main things: a clinical diagnosis (dementia or not), a probable cause (i.e. a history of head trauma), and to identify any treatable related conditions (such as high blood pressure causing mini-strokes).

People complaining of memory loss will undergo brief cognitive tests. The most common is the Mini-Mental State Examination (MMSE), a 30-question test that takes about 10 minutes. Various functions are tested, including arithmetic, memory and orientation; for example, patients are asked to do a clock-drawing.

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