Go to the Globe and Mail homepage

Jump to main navigationJump to main content

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 ...

As a rule of thumb, a score of 18 to 26 (out of 30) means mild dementia, 10 to 18 moderate dementia and under 10 severe dementia.  

Q: Is there a blood test or a biological test for diagnosing dementia?

A: There is no simple blood test to detect dementia. However, there are a number of diagnostic tests that can reveal if a person if their brains have tell-tell signs of Alzheimer's and other brain diseases. The tests - many of which are used only for research purposes - include PET scans of the brain and spinal-fluid analysis that can detect signs of the distinctive plaques and tangles that are characteristic of Alzheimer's. Similarly, MRIs can detect shrinkage of the hippocampus, a part of the brain involved in memory.

Testing for genetic risk factors associated with the disease has been available for years. If someone carries two copies of a gene called apoE4, one from each parent, they are nine times more likely to get Alzheimer's; one copy makes them three times more likely.

Testing, however, poses an ethical dilemma because there are very few effective treatments. Genetic tests are done principally on people with a strong family history, particularly with early-onset dementia.

Q: And how do they know what kind of dementia a person has?

A: The only way a definite diagnosis can be done is with an autopsy, after death, which is not very practical.

     However, there are certain characteristic symptoms of various brain diseases that help distinguish between them. The memory loss (remembering names and recent events in particular), confusion and disorientation that people associate with Alzheimer's occur with most brain diseases.

     But with frontotemporal dementia, for example, a person will have real difficulty with language and often abrupt personality change; with Lewy Bodies dementia, patients have visual hallucinations; while Parkinson's is characterized by muscle rigidity and tremors.

Q: What causes dementia? Are heavy metals a factor?

A: There is no single cause of dementia and, generally speaking, there is no single cause for the various brain diseases that cause dementia.

     The hallmark of Alzheimer is beta-amyloid plaques and tau tangles, but it is not clear why they occur. Genetics plays a role, and so too does lifestyle and environment. What scientists are searching for are triggers so they can de-activate them and prevent damage.

The theories are many: environmental toxins, infections, and lack of insulin. It is a fairly common belief that aluminum and products that contain traces like cooking pots and antiperspirants cause Alzheimer's, but there is no real scientific evidence for those theories.

In some cases though, the cause of dementia is more clear.

With vascular dementia, the interruption of blood flow to the brain kills cells, leading to loss of brain function. In new variant Creutzfeldt-Jakob disease, the prion causing the brain damage is believed to be transmitted when a person consumes beef from an animal with bovine spongiform encephalopathy (mad cow disease).

Q: What is the link between alcohol consumption and dementia?

A: There is type of dementia that occurs as the result of long-term excessive drinking. The formal name is Wernicke-Korsakoff syndrome, but it is more commonly called alcohol dementia.

Alcoholics often suffer from malnutrition, and Warnicke-Korsakoff syndrome occurs in those with thiamine (vitamin B1) deficiency, also known as beriberi. The symptoms are very similar to Alzheimer's, but sufferers tend to be affected at a relatively young age.

Alcohol can also be a problem for those already suffering from dementia. It is not uncommon for patients with dementia to undergo personality changes and they can unexpectedly become heavy drinkers. Depression is also common in patients with dementia, and that can lead to inappropriate use of alcohol.

Single page

Follow us on Twitter: @picardonhealth, @ErinAnderssen

In the know

Most popular video »

Highlights

More from The Globe and Mail

Most Popular Stories