Tools for Diagnosing Multiple Sclerosis
To diagnose multiple sclerosis (MS), neurologists rely on a person’s medical history, the neurologic exam, and a variety of laboratory tests to help confirm the diagnosis and rule out other medical conditions, such as:
Infections such as Lyme disease, syphilis, and HIV/AIDS
Inflammatory diseases such as systemic lupus erythematosus or other causes of vasculitis
Metabolic problems such as vitamin B12 deficiency or certain genetic disorders
Diseases of the spine
Certain types of tumors
All these conditions and more are running through your doctor’s mind as he or she tries to find an explanation for your symptoms. Visit the National MS Society for more information about the diagnostic process.
MS diagnostic: Review of medical history
The neurologist’s ability to piece together the evidence of a diagnosis is only as good as the information that he or she is given. Calling ahead to see if the neurologist would like records sent before the visit is a good idea.
If not, bring all your medical records and test results with you, and be prepared to answer a lot of questions about past and present complaints, relevant family history, the places you’ve traveled, your use of alcohol or drugs, any medications you take, and any allergies you may have to medications or the environment. This information is valuable in three ways:
It helps the neurologist rule out other problems (for example, a virus contracted while visiting another part of the world, neurologic problems resulting from substance abuse, and side effects from medications).
It lets the neurologist know whether you have any family history of MS or other autoimmune diseases.
It can indicate whether you have ever experienced any symptoms — no matter how mild or fleeting — that may be indicative of MS. Examining your history is one of the primary ways the neurologist has for identifying past MS relapses.
For example, suppose Susie goes to her neurologist complaining of numbness and tingling down her right side that began about a week ago. When taking her history, the neurologist finds that Susie experienced an episode of blurred vision when she was a teenager. The blurred vision passed after a few days, and no one gave it another thought. However, for the doctor, these separate events suggest a diagnosis of MS.
The point is, don’t show up empty-handed for your appointment with the neurologist. He or she can take your history and examine you, but can’t give you any definitive information or even know what tests to recommend without reviewing your records, including previous test results and other doctors’ findings.
MS diagnostic: Neurologic exam
The neurologic exam is an important tool both for diagnosing MS and for assessing disease progression over time. Understanding the components of this examination is important because you’re likely to experience all or some of them many times over the course of the disease. During the neurologic exam, the doctor will evaluate both your symptoms and signs of MS.
Symptoms are the problems or changes you’re reporting. Because every person experiences and describes symptoms differently, they’re always very subjective. This subjectivity doesn’t make the symptoms less important; it just means that the neurologist has to rely on your experience of them to try and get a handle on what the problems may be and how severe they are. Examples of symptoms include problems with vision, walking, fatigue, bladder or bowel control, and so on.
On the other hand, signs are more measurable and objective pieces of evidence that you may have never even noticed, including involuntary eye movements, altered reflexes, or evidence of spasticity (tightness) in your legs.
The neurologic exam usually evaluates the following:
Functioning of the cranial nerves: The neurologist evaluates the 12 individual nerves in your head that control the senses, such as vision and touch, and activities related to talking and swallowing.
The neurologist can check for damage in your optic nerve by testing your visual acuity using an eye chart, and by looking through an ophthalmoscope to examine the head of the optic nerve (the optic disc). A pale optic disc may indicate earlier damage to the nerve even if you don’t remember ever experiencing any problem with your vision.
The doctor also checks for double or blurred vision (by evaluating your eye movements), abnormal responses of the pupils, and other signs of neurologic damage. He or she also assesses the movements of your tongue and throat, evaluates the strength of your facial muscles, and checks for reduced or altered sensations in your face.
Strength and coordination: The neurologist may evaluate your strength by pushing on your arms and legs and asking you to resist the pressure. You may also be asked to squeeze his or her hand as hard as you can to determine your level of strength.
To evaluate your coordination, the neurologist may ask you to do the following:
Walk down the hall so he or she can assess your speed and stability.
Stand and move the heel of one foot up and down the opposite leg (which is often called the heel-knee-shin test).
Walk on your heels and then on your toes.
Walk a tandem gait by placing the heel of one foot directly against the toe of the other foot in alternating fashion.
Touch his or her finger and then your nose many times rapidly (called the finger-to-nose test), first with the eyes open and then with them closed.
Sensation: The neurologist may evaluate your position sense by asking you to close your eyes and describe where your hands and feet are in space. He or she may test your vibration sense by placing a tuning fork against various parts of your body. The doctor may also use very gentle pinpricks or a cotton ball at various points on your arms or legs to check for changes in sensitivity to touch.
Reflexes: The neurologist may check your reflexes (at the ankle, knee, and elbow) to see if they’re equal on both sides of your body. Testing for the Babinski reflex (named after the French neurologist Josef Babinski) is also important because this abnormal sign in anyone more than one year old is always an indication of damage in the central nervous system.
To do this test, the doctor runs a blunt instrument down the side of your foot from the heel to the little toe. The normal response to this stimulus is to curl your toes (as generally happens whenever a person’s foot is tickled). The abnormal (Babinski reflex) response, which is common in MS, is for your toes to fan upward and outward.
The presence of Lhermitte’s sign: To determine if you have this neurologic sign (named after Jean Lhermitte, another French neurologist), the neurologist may ask whether you ever experience a sudden, fleeting, electric-like shock or buzzing sensation down your body or limbs when you bend your head forward. Your neurologist can use this neurologic sign to confirm damage in your CNS. Even though Lhermitte’s sign can occasionally occur for other reasons, it’s generally caused by MS.
The neurologist probably will do this kind of in-depth exam only during your initial visit. Unless you’ve experienced a major change in your symptoms or you’re participating in a clinical trial (research study) of some kind, he or she will most likely do an abbreviated version of the exam during subsequent check-ups, focusing primarily on any new problems you may have.