Multiple Sclerosis Society of Canada


Medical history and a neurological exam are fundamental to the diagnostic process of MS. Magnetic Resonance Imaging (MRI), evoked potentials and occasionally lumbar puncture, are tests that may be useful in confirming when a diagnosis of MS is suspected. A diagnosis of MS must include evidence of disease activity separated in time (lesions that formed at different points in time) and space (lesions in at least two separate areas of the CNS). Sometimes this means that it can take a little while for a diagnosis to be confirmed. 

It is important to remember that there is no one test that can be used to diagnose MS. The diagnosis of MS is one made only once other potential causes for symptoms have been ruled out.

Learn more about MRI, EP and LP

Magnetic Resonance Imaging (MRI)

MRI is a medical imaging technique commonly used in radiology to visualize the internal function and structure of the body. In MS, the MRI can provide pictures of the areas of damage (lesions) in the central nervous system, caused by MS, and can also reveal whether there is loss of brain volume.

Evoked Potentials (EP)

EP is a test that measures the speed of nerve impulse conduction in the pathways of the central nervous system. In MS, nerve impulse conduction is slowed related to the myelin damage, and EP’s can record this slowing. There are three types of EP: visual, auditory, motor and sensory.

Lumbar puncture (LP)

Sometimes known as a spinal tap, LP can be helpful when other investigations are negative. A small needle is inserted at the base of the spine and a small amount of the cerebrospinal fluid (CSF) is collected to test for the presence particular proteins (antibodies), called oligoclonal bands, which are known to be present with inflammation in the CNS.

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