Dementia isn’t just one condition - it’s a term that refers to symptoms that cause a decline in mental ability that interferes with daily life. Alzheimer's is the most common type of dementia and accounts for 60 to 80 percent of cases.

In addition to Alzheimer's, some of the other things that can cause dementia include previous or new brain infections, a bad head injury, stroke or multiple sclerosis. There are some treatable conditions that can produce similar symptoms to dementia, such as thyroid disease, vitamin deficiencies, mental illness or sleep disorders.

To have dementia, at least two of these core mental functions must be significantly impaired: memory, visual perception, reasoning and judgment, ability to focus or problem-solve and language and communication.

There isn’t one test to diagnose dementia. A physician will usually do a physical examination, ask health history questions, test memory and recommend a blood test, MRI or CT scan. He or she will probably double check symptoms and answers with a loved one as well.

Dementia treatment may include medications to slow progression, but they’re not a cure. Counselling, family support and social programs can help people and their loved ones deal with dementia.