How Is MS Diagnosed?
How Is MS Diagnosed?
The diagnosis of MS is often difficult because many of its symptoms are similar to (or mimic) the symptoms of other illnesses. Therefore, no single test is 100% conclusive. Several tests and procedures are needed for a complete diagnosis. They include:
MEDICAL HISTORY: The physician will require the patient’s general medical history, including a description of any suspected signs or symptoms of MS and when they occurred.
NEUROLOGICAL EXAMINATION: A neurologist will examine an individual for specific abnormalities in the nerve pathways. During the examination, the doctor will look for abnormal changes in eye movement, limb co-ordination, strength, balance, sensation, speech and reflexes. When MS is suspected, further tests will be scheduled to eliminate other possibilities.
EVOKED POTENTIAL TESTS: These tests measure the time it takes for the brain to receive and interpret messages (Nerve Conduction Velocity). In short, it shows how quickly a person’s nervous system responds to certain stimulation. There are separate tests for sight, hearing and motor function. In order, they are:
VER – Visual-evoked response
BAER – Brainstem auditory-evoked response
SER – Somatosensory-evoked response
These tests measure the speed of nerve conduction and can detect lesions not always shown on an MRI. They are not invasive or painful.
MAGNETIC RESONANCE IMAGING (MRI): This scan, using a magnetic field, produces very detailed pictures of the brain and spinal cord. It shows any existing areas of sclerosis (lesions or plaques). This is the only test where the lesions can be seen, but it cannot be regarded as conclusive. MRI, along with evidence from medical history, neurological examination and other tests, are considered significant in confirming the diagnosis of MS.
Note: MRI is a very important tool used in clinical trials to assess the value of new therapies. This is due to its ability to measure changes in disease activity in the brain and spinal cord.
LUMBAR PUNCTURE: A small amount of cerebrospinal fluid (the fluid which flows around the brain and spinal cord) is withdrawn and tested. In people with MS, patterns formed by proteins in the fluid are examined. These patterns can show changes that match up with the presence of inflammation. The proteins in people with established MS (about 90%) form a particular pattern when an electrical current is passed through them. Consequently, this test is often ordered when MRI results are inconclusive.
Two basic criteria are required to confirm MS:
1. Tests show at least two areas of the nervous system are affected.
2. At least two separate relapses (exacerbations) have occurred a month or more apart.
Obviously, making a definitive MS diagnosis can be very difficult. Some people may be diagnosed with “possible MS” or “probable MS” until a definite diagnosis can be reached. Although a diagnosis of MS can be shocking, most patients continue to lead productive and relatively normal lives.