When is
dementia
NOT
dementia?
We were recently asked an interesting question about dementia at a community presentation. How do we know for sure that someone with dementia, has dementia? Or when is dementia not really dementia? A great question! We thought you might want to know the answer too. Read on …
What’s normal memory loss?
Dementia is not dementia when the memory loss experienced is associated with normal aging. Some level of cognitive decline accompanies normal aging. For example, mild memory changes and changes in memory processing (storing and retrieving information) are common. These changes do not usually impact on overall independence.
What’s not normal?
Some people experience more than normal cognitive decline with aging. They may experience mild cognitive impairment (MCI) and/or mild behavioural impairment (MBI). While some people with MCI and/or MBI eventually develop dementia, most people do not develop dementia and either stay the same or improve over time.
What is MCI?
MCI is memory impairment above and beyond that experienced with normal aging. People with MCI usually maintain their independence. MCI is common in people aged 60 and over (15 – 20% have MCI). People with MCI have a risk for developing dementia that is three to five times greater than people without MCI. Worldwide each year, around 8 – 15% of people with MCI progress to having dementia.
What is MBI?
MBI was first defined in 2016 and occurs alone or in addition to MCI. MBI involves marked changes in behaviour or personality which cannot be explained medically, in people without dementia, which persist for 6 months or more. Independence is usually maintained. MBI occurs from age 50 onwards. The incidence of MBI is unknown. People with MBI have an increased risk of dementia; however, the rate of progression is not known.
What is dementia?
Dementia is not a specific disease. The term dementia describes a wide range of symptoms associated with a decline in memory or other thinking skills, severe enough to impact on a person’s independence. Dementia is caused by several diseases that affect the brain. The most common is Alzheimer disease, which accounts for 60 to 80 percent of all cases of dementia.
How is dementia diagnosed?
Australian guidelines state that the diagnosis of dementia should include a comprehensive assessment and a basic dementia screen. Assessment involves:
- History taking from the person suspected to have dementia and a person who knows the person well
- A physical examination and mental state examination
- Cognitive (thinking) testing
- A medication review to identify & minimise use of drugs/OTC products that may affect cognitive functioning
- Consideration of other causes that may cause similar signs and symptoms
What does the basic dementia screen involve?
The basic screen includes routine blood and urine tests to investigate anemia, electrolytes, renal and liver function, Vitamin B12, folate levels, thyroid function and infection. Additional tests may be ordered as required (eg syphilis, HIV; chest X-ray; electrocardiogram; brain scans (eg MRI); lumbar puncture).
What does cognitive testing involve?
Cognitive tests, such as the Mini Mental State Examination, evaluate cognitive functions (eg memory, problem solving, language). They help diagnose dementia, assess mood and diagnose depression (which can cause symptoms similar to those of dementia). Doctors undertake initial cognitive screening and refer to a neuropsychologist (a psychologist specialising in assessment and measurement of cognitive function) for more extensive testing if required.
When is dementia diagnosed?
Dementia is suggested when there is strong agreement between the person’s history and their cognitive & mental state examination results. Occasionally the history may suggest cognitive impairment while the results of the cognitive and mental state examination are normal (in mild dementia, high intelligence/educational level, in depression, or rarely, informants have misrepresented facts). Alternatively, the cognitive & mental state examination may suggest a cognitive impairment and the family/patient deny problems. In these instances, it’s possible the person has a confusional state (eg delirium), very low intelligence or education, or the person or family do not recognise the cognitive problems.
So, when is dementia not dementia?
A number of conditions present with dementia-like symptoms and some of these are treatable/reversible. These include normal memory loss associated with aging, MCI or MBI, or MBI plus MCI concurrently. Other conditions include cerebrovascular disease (eg stroke), delirium, depression, vitamin deficiency, certain infections, metabolic disorders and side effects from drugs. For example, brain-imaging may rule out brain tumours, infarcts (dead areas of brain tissue due to stroke) and hydrocephalus (fluid on the brain) which may cause dementia like symptoms.
Further Reading
Alexander M & Larson EB. Up to Date. Patient education: Dementia (including Alzheimer disease) (Beyond the Basics). Literature review current through: Aug 2017. This topic last updated: Mar 21 2017. [Accessed Sep 18 2017].
https://www.uptodate.com/contents/dementia-including-alzheimer-disease-beyond-the-basics?view=print
Alzheimer’s Association International Conference. July 16-20, 2017, London, England.
PRESS RELEASE New Concept – Mild Behavioural Impairment (MBI) – and Checklist of Symptoms Could Support Earlier Alzheimer’s/Dementia Diagnosis.
https://www.alz.org/aaic/releases_2016/sun_445_ET.asp
Sullivan MG. Clinical Neurology News. CONFERENCE COVERAGE. Checklist captures new predementia diagnosis of mild behavioral impairment
http://www.mdedge.com/clinicalneurologynews/article/111088/alzheimers-cognition/checklist-captures-new-predementia
Alzheimer’s Australia. Tests used in diagnosing dementia.
https://www.fightdementia.org.au/national/about-dementia/how-can-i-find-out-more/tests-used-in-diagnosing-dementia