Tests Used
In order for Dementia to be diagnosed correctly it is required that a number of different tests and assessments be carried out. These currently include:
- A review of personal history including education and employment.
- A review of medical history.
- A full assessment of the persons mental abilities.
- A range of tests, including blood tests to rule out other possible causes of symptoms, such as a vitamin B deficiency.
- Imaging scans, such as a CT scan or Magnetic Resonance Imaging (MRI) scan, to provide information about the physical state and structure of the brain.
- A review of any medication the person may be taking, in order to rule out the possibility that it is contributing to the symptoms present.
Some of these tests will be carried out by the GP and others will be carried out by specialist such as a neurologist or a psychiatrist experienced in dealing with Dementia.
Assessment of Mental Abilities
There are many types of questionnaires that can be used to test a person's mental capabilities but the most widely used questionnaire is The Mini Mental State Examination (MMSE). This is used to assess a number of mental abilities that include:
- Short and long term memory.
- Attention span.
- Concentration.
- Language and communication skills.
- Ability to plan.
- Ability to understand instructions.
The MMSE cannot be used as a sole method for diagnosing Dementia, but it is useful for assessing the level of mental impairment that a person with Dementia may have.
- A score of 25 or above is considered normal.
- A score of 18 to 24 indicates mild to moderate impairment.
- A score of 17 or below indicates serious impairment.
These scores are affected by education. Some people who cannot read or write well may always score less than 25, but they may not have Dementia. Other people with a higher level of education, may have a higher score but still have Dementia.
Imaging Scans
Imaging scans can check if there are any underlying problems with the brain, such as a brain tumor, that could help explain the symptoms. Imaging scans can also identify changes in the appearance of the brain that may indicate Dementia. Several types of imaging scans can be used in the diagnosis of Dementia.
Computerised Tomography
A Computerised Tomography (CT) scan can take a series of X-ray images of the brain. The images are fed into a computer to build up a detailed 3D image of the inside of the brain.
Magnetic Resonance Imaging (MRI)
A Magnetic Resonance Imaging (MRI) scan may be used as an alternative to a CT scan.
MRI scans can help determine whether:
- There is any shrinkage to the outer layer of the brain.
- There is any evidence of changes to the blood vessels.
- There are any blood clots that might have resulted in Vascular Dementia.
The test will also show whether other conditions, such as a brain tumor, are causing Dementia related symptoms.
Single Photon-Emission Computed Tomography (SPECT)
A Single Photon-Emission Computed Tomography (SPECT) scan may be recommended if doctors are unsure as to whether a person has Alzheimer's Disease, Fronto-Temporal Dementia or Vascular Dementia.
A SPECT Scan is similar to a CT scan, but the scanner used for a SPECT scan is able to take moving pictures of the blood flow within the brain. The results show if the blood flow in the brain is abnormal, which can often be used to help diagnose the type of Dementia.
Further Tests
There are additional tests that can be used to rule out other conditions that could be responsible for the patient's symptoms.
A Full Blood Count
A full blood count can be used to assess general health and check for a range of disorders, including anaemia and infection. A blood sample will usually be taken from a vein in the arm using a needle and syringe. This test can also be used to check for a range of other illnesses.
Blood Glucose Test
A Blood Glucose Test can be used to find out whether the blood glucose level is normal, or whether the symptoms might be caused by undiagnosed diabetes.
Urine Analysis
Urine analysis is used to diagnose diabetes, or problems with the kidneys. During the test, the person will be asked to pass a small sample of urine into a sterile container. This is then sent off to the laboratory for testing.
Measurement of Thyroid Hormones
A measurement of thyroid hormones may be taken in order to screen for thyroid disorders, including an underactive thyroid (Hypothyroidism) and an overactive thyroid (Hyperthyroidism).
Measurement of Vitamin B12 Level
A test to check whether the symptoms are caused by a lack of vitamin B12. However, if you do have a B12 deficiency, it is still possible that you may also have Dementia.
