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Dementia Overview (cont.)

Is there a test for dementia?

There is no specific test for dementia. However, dementia may be diagnosed if at least two of the following core mental functions are significantly impaired, according to some researchers:

  • Memory
  • Communication/language
  • Attentiveness/focus on a problem or subject
  • Reasoning/Judgment
  • Visual perception

In some people, the signs and symptoms of dementia are easily recognized; in others, they can be very subtle. A careful and thorough evaluation is needed to identify their true cause.

  • The individual's health-care professional will conduct a detailed medical interview to develop a picture of the symptoms. The interview will address the symptoms and when they began, the person's medical problems now and in the past, family medical problems, medications, work and travel history, and habits and lifestyle.
  • Family members, especially those who live with the affected person, will also be asked about his or her symptoms.
  • The review of medications is very important, especially for seniors, who are more likely to take several medications and to experience side effects.
  • A thorough physical examination will look for evidence of illness and dysfunction that might shed light on what is causing the symptoms.
  • This evaluation is designed to identify reversible, treatable causes of dementia symptoms.
  • At any point in the evaluation or treatment, the person with dementia may be referred to specialists in conditions of older people (geriatricians), in brain disorders (neurologists), or in mental disorders (psychiatrists).

An assessment of dementia symptoms should include a mental status evaluation. This evaluation uses various "pencil and paper," "talking," and physical tests to identify brain dysfunction. A more thorough type of testing, performed by a psychologist, is called neuropsychologic testing.

  • Mental status examination or neuropsychological testing pinpoints the nature and measures the severity of the person's mental problems. This can help give a more accurate diagnosis of the problems and, thus, can help in treatment planning.
  • Testing includes noting the individual's appearance, mood, anxiety level, and experience of delusions or hallucinations.
  • Dementia testing assesses cognitive abilities such as memory, attention, orientation to time and place, use of language, and abilities to carry out various tasks and follow instructions, but there is no definitive test for dementia.
  • Reasoning, abstract thinking, and problem solving are also tested.

Lab tests may be used to identify or rule out possible causes of dementia.

  • Routine blood tests include a complete blood cell (CBC) count, blood chemistry, liver function tests, thyroid function tests, and vitamin B levels (especially folic acid and vitamin B-12), ammonia level, and detection of drugs of abuse.
  • Other blood tests (for example, syphilis and HIV testing, levels of intoxicating drugs, arterial blood gases [in hypoxia], specific hormone tests like thyroid function tests, or measurement of heavy metals) are used only when a person is at high risk for specific conditions.
  • Urine tests may be needed to assess blood abnormalities further, to detect certain drugs, or to rule out certain kidney and metabolic disorders.
  • Cerebrospinal fluid testing may be necessary to rule out brain infections, brain tumors, and hydrocephalus with elevated fluid pressure. A sample of the fluid is obtained by a procedure called a lumbar puncture (spinal tap), in which a long needle is inserted between two vertebrae of the spine at the lower back.

In some cases, imaging studies of the brain may be necessary to detect conditions such as normal pressure hydrocephalus, brain tumor, or infarction or bleeding in the brain.

  • CT scan is usually adequate, although MRI may be used if greater detail is needed.
  • Single-photon emission CT (SPECT) imaging detects blood flow in the brain and is used in some medical centers to distinguish Alzheimer's disease from vascular dementia.
  • Electroencephalography (EEG) is not an imaging study but a recording of the electrical activity in different parts of the brain. It is used in people who are having seizures but may help diagnose other disorders as well.
Medically Reviewed by a Doctor on 6/20/2016

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Read What Your Physician is Reading on Medscape

Delirium, Dementia, and Amnesia »

Delirium, dementia, amnesia, and certain other alterations in cognition are subsumed under more general terms such as mental status change (MSC), acute confusional state (ACS), or organic brain syndrome (OBS).

Read More on Medscape Reference »


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