How Is Ataxia Diagnosed?
It is sometimes difficult to get a diagnosis of the specific type of ataxia, as there are many different conditions that can seem very similar.
A neurologist may need to do extensive tests to find out exactly what a patient has and this can take time.
Patient history: This usually involves a doctor asking questions to help identify whether the ataxia is caused, for example, by a tumour or alcohol poisoning.
Brain scans: Magnetic resonance imaging (MRI) brain scans can give an image of the cerebellum and other parts of the brain that show whether they are damaged. The scans can sometimes be used to distinguish between multiple sclerosis and ataxia.
Family history: This helps to determine whether the patient has an inherited type of ataxia. If their parents and grandparents also have/had ataxia then it is likely that the patient has an autosomal dominant inherited ataxia. If the parents are not (or were not) affected but more than one child has ataxia, it suggests that the condition is inherited recessively. Even if no one else in the family is affected, this does not necessarily mean that the ataxia is not inherited.
Genetic tests: These are available for some types of inherited ataxia and involve taking a blood sample. If the result is positive, then it can generally be considered a definite diagnosis.
If the results are negative for all these tests, this may mean that it is a type of inherited ataxia for which the gene has not been found, or that a test is not yet available. Sometimes your blood sample may be stored for a long time so that, if there are advances in research and new tests become available, further tests can be done. For more information, take a look at Genetic Alliance UK's Frequently Asked Questions on Genetic Tests booklet. You can also look at our Taking part in research page for current opportunities available for people with undiagnosed ataxia.
Other laboratory tests: These may include testing for vitamin E levels in the blood or to see whether a patient has a genetic condition such as abetalipoproteinemia or familial isolated vitamin E deficiency. People with these conditions have low levels of vitamin E, and this can be treated with vitamin E supplements and a specialised diet. Another condition that can be treated is gluten ataxia.
Pre-symptomatic genetic testing
If you are a close relative of someone with a known inherited ataxia and you do not show any signs of ataxia, it is possible to have a genetic test for yourself. The chance of developing ataxia or being a carrier depends on how the ataxia is inherited (as described above).
The decision to have a test or not is a very personal one and can be a difficult one to make. Some people prefer to have all possible information in advance, in order to plan for the future. Others may prefer not to know unless there is a cure. Test results can have a range of long-term consequences, affecting everything from whether or not to have a family to the ability to get insurance. Support in making this decision is available from clinical geneticists who are experienced in talking to people about these issues.
Tests are only generally available for adults (ie people over 18 years old), but this may vary depending on individual circumstances. For more specific advice, talk to your doctor.
The results of a genetic test can bring up some difficult questions and concerns about the future, so it is often useful to see a genetic counsellor or clinical geneticist before testing goes ahead; to talk about what the potential results might mean. If the neurologist suspects it is an inherited condition, they may make a referral for genetic counselling. This provides an opportunity to discuss what a diagnosis could mean for the person with ataxia and their family.
A doctor or neurologist can arrange a referral to a regional genetic centre (where genetic services are available) to explain the tests and the implications of the test results. Specialist Ataxia Centres also offer genetic counselling to their patients. For a full list of regional genetic centres in the UK contact the Genetic Alliance.