Dementia is a collective term used to describe various symptoms of cognitive decline, such as forgetfulness. It is a symptom of several underlying diseases and brain disorders.

Dementia is not a single disease in itself, but a general term to memory, communication, and thinking.

While the likelihood of having dementia increases with age, it is not a normal part of aging.

An analysis of the most recent census estimates that people aged 65 years or older in the United States were living with Alzheimer's disease in 2010. The Alzheimer's Association estimates that:

  • just over a tenth of people aged 65 years or more have Alzheimer's disease
  • this proportion rises to about a third of people aged 85 and older
  • Alzheimer's accounts for 60-80 percent of all cases of dementia

This article discusses the potential causes of dementia, the various types, and any available treatments.

Fast facts on dementia

  • there are an estimated 47.5 million dementia sufferers worldwide
  • one new case of dementia is diagnosed every 4 seconds
  • dementia mostly affects older people but is not a normal part of aging

Dementias can be caused by brain cell death, and neurodegenerative disease - that happens over time - is associated with most dementias.

However it is not known if the dementia causes the brain cell death, or the brain cell death causes the dementia.

But, as well as progressive brain cell death, like that seen in Alzheimer's disease, a head injury, a stroke, or a brain tumor, among other causes.

  • Vascular dementia (also called multi-infarct dementia) - resulting from brain cell death caused by conditions such as cerebrovascular disease, for example, stroke. This prevents normal blood flow, depriving brain cells of oxygen.
  • Injury - post-traumatic dementia is directly related to brain cell death caused by injury.

Some types of - particularly if repetitive, such as those received by sports players - have been linked to certain dementias appearing later in life. Evidence is weak, however, that a single brain injury raises the likelihood of having a degenerative dementia such as Alzheimer's disease.

:

  • Prion diseases - for instance, CJD (Creutzfeldt-Jakob disease).
  • HIV infection - how the virus damages brain cells is not certain, but it is known to occur.
  • Reversible factors - some dementias can be treated by reversing the effects of underlying causes, including medication interactions, depression, vitamin deficiencies, and thyroid abnormalities.

The first step in testing memory performance and cognitive health involves standard questions and tasks.

Research has shown that dementia cannot be reliably diagnosed without using the standard tests below, completing them fully, and recording all the answers; however, diagnosis also .

Cognitive dementia tests

Today's cognitive dementia tests are widely used and have been verified as a reliable way of indicating dementia. They have changed little since being established in the early 1970s. The abbreviated mental test score has, which include:

Each correct answer gets one point; scoring six points or fewer suggests cognitive impairment.

The General Practitioner Assessment of Cognition (GPCOG) test includes an added element for recording the observations of relatives and caregivers.

Designed for doctors, this sort of test may be the of a person's mental ability.

The second part of the test probes someone close to the patient and includes six questions to find out whether the patient has:

If the test does suggest memory loss, standard investigations are then recommended, including routine blood tests and a CT brain scan.

Clinical tests will identify, or rule out, treatable causes of memory loss and help to narrow down potential causes, such as Alzheimer's disease.

The mini-mental state examination () is a cognitive test which measures:

The MMSE is used to help diagnose dementia caused by Alzheimer's disease and also to rate its severity and whether drug treatment is needed.