Medical History and Neurologic Exam
The physician takes a careful history to identify any past or present symptoms that might be caused by MS and to gather information about birthplace, family history and places traveled that might provide further clues. The physician also performs a variety of tests to evaluate mental, emotional and language functions, movement and coordination, balance, vision, and the other four senses. In many instances, the person’s medical history and neurologic exam provide enough evidence to meet the diagnostic criteria. Other tests are used to confirm the diagnosis or provide additional evidence if it’s necessary.
MRI is the best imaging technology for detecting the presence of MS plaques or scarring (also called lesions) in different parts of the CNS. It can also differentiate old lesions from those that are new or active. The diagnosis of MS cannot be made solely on the basis of MRI because there are other diseases that cause lesions in the CNS that look like those caused by MS. And even people without any disease — particularly the elderly — can have spots on the brain that are similar to those seen in MS. Although MRI is a very useful diagnostic tool, a normal MRI of the brain does not rule out the possibility of MS. About 5% of people who are confirmed to have MS do not initially have brain lesions on MRI. However, the longer a person goes without brain or spinal cord lesions on MRI, the more important it becomes to look for other possible diagnoses.
Visual Evoked Potential (VEP)
Evoked potential (EP) tests are recordings of the nervous system’s electrical response to the stimulation of specific sensory pathways (e.g., visual, auditory, general sensory). Because damage to myelin (demyelination) results in a slowing of response time, EPs can sometimes provide evidence of scarring along nerve pathways that does not show up during the neurologic exam. Visualevoked potentials are considered the most useful for confirming the MS diagnosis.
Cerebrospinal Fluid Analysis
Analysis of the cerebrospinal fluid, which is sampled by a spinal tap, detects the levels of certain immune system proteins and the presence of oligoclonal bands. These bands, which indicate an immune response within the CNS, are found in the spinal fluid of about 90-95% of people with MS. But because they are present in other diseases as well, oligoclonal bands cannot be relied on as positive proof of MS.
While there is no definitive blood test for MS, blood tests can rule out other conditions that cause symptoms similar to those of MS, including Lyme disease, a group of diseases known as collagen-vascular diseases, certain rare hereditary disorders, and AIDS.
This procedure involves drawing off a sample of fluid from around the spine and testing for abnormalities that can indicate MS.