Diagnosing MS

No single test can confirm or rule out a MS diagnosis. Rather, your neurologist uses a combination of tests and exams, in addition to a thorough look at your medical history to determine whether or not you have the disease. Your neurologist will look for signs consistent with a MS diagnosis across all the information collected and will also use this information to rule out other possible causes of your symptoms.

If someone has had problems with MS over a period of years, it is relatively easy to diagnose the disease. It becomes more difficult if you have had relatively little trouble or if you are in the first stages of the illness, when MS cannot actually be diagnosed with any certainty: it is only after new symptoms have appeared (relapsing remitting MS) or when there is a gradual increase in the severity of symptoms (progressive forms of MS) that the diagnosis can be made with much more certainty.

If you think you may have MS, it is important you see a doctor as quickly as possible as early MS treatment can help even if you don’t have visible symptoms of MS. That’s because the disease often progresses silently, causing nerve damage before you’re even aware of any problems.

There are treatments available to help slow progression of disability and reduce the number of flare-ups (relapses), even if you have had only one episode and have an MRI consistent with MS. If you have had only one episode of MS symptoms, you may be told to wait until you have a second episode before returning for further tests. This is due to the fact that your doctor may not be able to accurately diagnose your condition until a second episode occurs.

Medical history

This is extremely important to help your doctor make a multiple sclerosis diagnosis. Remember, the more information you give, such as family history, symptoms and duration of symptoms, the better.

Neurological exam: Your neurologist will examine your vision, balance, coordination, reflexes, and muscle strength, as well as your ability to feel pain, temperature and touch.

Diagnostic tests

There are several tests your doctor will use to reach a diagnosis. These are:

Magnetic Resonance Imaging (MRI)

A Magnetic Resonance Image (MRI) is a non invasive test that uses a strong magnetic field and radio waves to produce computerized images (scans) of your brain and spinal cord. MRI is one of the most important tests used to diagnose multiple sclerosis because it can show brain lesions and scars and/or any defects in the white matter associated with the disease.

Spinal fluid test

Also known as a lumbar puncture or spinal tap, helps your neurologist see if the fluid (cerebrospinal fluid or CSF) surrounding your central nervous system shows signs of MS. A long, thin needle is inserted between two bones in the lower spine to extract a sample of the colourless fluid. A laboratory examines the sample to see if it contains elevated levels of immune system cells that are often seen in PwMS.

There are lots of rumours about how painful this particular examination can be. In practice it seems to be less fearsome (with hindsight!)

About 20% of all those who undergo this examination get headaches and dizzy spells, but these usually clear up after a few hours.

Evoked potentials

One or more tests can be used in addition to an MRI to make a diagnosis. Evoked potential tests are used to measure how fast your brain responds to sensory input, such as flashing lights, sounds or electrical stimulation. The examiner places wires on your scalp over the areas of the brain involved in receiving sensory information. Then the examiner provides specific sensory input for testing.

For example, you may hear a series of clicks, be asked to look at a screen with a checkerboard pattern, and be given mild electrical stimulation to your legs. The wires on your scalp record how fast your brain receives the sensory input. If the brain response is slower than normal, it can be an indication that the myelin in your brain or spinal cord has suffered inflammation or damage due to multiple sclerosis.

A VEP (Visual Evoked Potential) examination checks the speed at which the optic nerve transmits signals. The person being examined is asked to look at a pattern on a TV screen. Wires stuck to the back of the head can measure very accurately how fast the optic nerve transmits messages.

For the SEP (Somatosensory Evoked Potentials) examination, the patient is given few weak electric shocks in the ankle or wrist. Again the speed of transmission of the messages is recorded through wires taped to the back of the head.

The BAEP (Brainstem Auditory Evoked Potentials) examination uses the same methods (sound stimulus, wires taped to the head) to measure how quickly messages are transmitted along the nerves of the ears and in part of the brain.

The MEP (Motor Evoked Potentials) examination shows how the motor system (the system controlling bodily movement) is working. For this examination a magnet is placed above the head. When the magnet is turned on it causes a very brief tension in the arm or leg muscles. The speed at which the muscles react to the magnetic stimulus (which is transmitted through the brain and along the spinal cord) can be accurately measured with this technique.