If you visit your GP with neurological symptoms that cannot be explained, they may consider the possibility of MS. If your initial symptoms are not too severe, your GP may not take any immediate action. However, if you have another period of symptoms (relapse), your GP should refer you to a neurologist, who specialises in conditions of the central nervous system. If the neurologist believes that you may have MS, you should be given an explanation of what will happen next. Before a final diagnosis of MS can be made, you will normally undergo a number of tests. The neurologist will then assess your test results against set diagnostic criteria to determine if you have MS.

Diagnostic tests

Neurological examination
Your neurologist will ask you lots of questions about past symptoms and problems - this is known as 'history taking'. It helps the neurologist get a better picture of you and can help identify any other problems that may explain current symptoms. A physical examination checks for abnormalities in nerve pathways involved in movement, reflexes or sensation. Your neurologist will look for changes or weaknesses in your eye movements, leg or hand coordination, balance, sensation, speech or reflexes. Whilst a neurologist may strongly suspect MS at this stage, a diagnosis would not be given until other positive test results confirm MS.

Magnetic Resonance Imaging (MRI)
An MRI scanner uses a strong magnetic field to create a detailed image of your brain and spinal cord. It is very accurate and can pinpoint the exact location and size of any damage or scarring in your myelin (lesions). MRI scans confirm the diagnosis in over 90 per cent of people with MS. To get the image of a person's brain and spinal cord they must lie down and enter a small tunnel in the centre of the MRI scanner. The process takes between 10 and 30 minutes and is painless.

Evoked potentials
This involves testing the time it takes for your brain to receive messages. Your neurologist will place small electrodes on your head to monitor your brain waves responding to what you see or hear. This is a painless procedure. If myelin damage has occurred, messages to and from your brain will be slower.

Lumbar puncture
This is sometimes called a spinal tap. It involves a needle being inserted into the space around your spinal cord, under local anaesthetic. A small sample of the fluid that flows around the brain and spinal cord, called cerebrospinal fluid, is then taken and tested for abnormalities. People with MS often have antibodies in this fluid, showing that the immune system has been at work in the central nervous system. This test is not carried out as often as it used to be and tends only to be used where a diagnosis of MS has not been confirmed by other tests. People commonly report headaches following a lumbar puncture. This is a recognized side effect and your neurologist can advise on how best to manage this.

Other tests
To rule out conditions that mimic MS, other tests may also be completed: blood tests to reveal certain antibodies and inner ear tests to check your balance.  

Diagnostic Criteria

Although the criteria say it is possible to clinically diagnose MS without any tests, they recommend that investigations are carried out so test results can provide further evidence of MS.

Diagnosis of relapsing remitting MS rests on:

• two relapses, separated by more than 30 days OR


• one relapse and an MRI scan three months later that shows new lesions

To determine if a person has secondary progressive MS, they must have:

• had relapses in the past


• shown a steady increase in disability for at least six months, whether or not they continue to have relapses

Primary progressive MS is diagnosed if there have been no previous relapses and if there is:

• a progression of disability over at least a year


• an MRI scan that shows lesions consistent with MS


• evidence of MS detected by examining the spinal fluid collected during a lumbar puncture (this is the only situation where a lumbar puncture is needed to diagnose MS).
 

Results

After assessment, you will be given one of the following diagnoses:

• You have MS


• You have possible MS. This may happen if your tests are not clear. For example, your symptoms and spinal fluid test suggest MS, but there are no lesions visible on the MRI scan.


• You do not have MS
 

Last Updated

Last updated by MS Society Information Team, October 2004. Reviewed by Dr Alasdair Coles, MS Society Medical Advisor.