How does a neurologist diagnose Multiple Sclerosis?

The diagnosis of Multiple Sclerosis, known as the disease of a 1,000 faces due to the diversity of its symptoms, is very complex and usually requires a certain time.

In this brief guide we are going to answer the question ‘’How neurologist diagnose ms?’’ We will define what Multiple Sclerosis is, its causes, symptoms and we will explain the role of the neurologist in the diagnosis of this disease.

How does a neurologist diagnose Multiple Sclerosis?

A neurologist diagnoses Multiple Sclerosis by evaluating studies such as magnetic resonance imaging (MRI), spinal taps, evoked potentials, and blood tests.

Multiple sclerosis (MS) is the most common of the inflammatory diseases that damage the covering of the nerve fibers (myelin) of the Central Nervous System (CNS).

Multiple sclerosis preferentially involves the destruction of the myelin sheath of nerve fibers, although the nerve fibers themselves (axons) are also damaged in the central nervous system.

It affects the brain and spinal cord in a disseminated way, with a certain predilection for optic nerves, white matter of the brain, brainstem and spinal cord.

The signs and symptoms of multiple sclerosis vary greatly depending on the extent of the damage to the nerves and which of the nerves are affected. Some people with severe multiple sclerosis may lose the ability to walk completely, while others may experience long periods of remission without any symptoms.

Multiple Sclerosis: Diagnose

Multiple sclerosis (MS) can be a difficult disease to diagnose as it manifests itself in different ways and the wide range of accompanying symptoms often coincides with those of other conditions.

For this reason, doctors must perform different tests that help them rule out other conditions and determine if the patient meets the criteria for diagnosing MS.

Currently the basic “rule” for making a diagnosis of Multiple Sclerosis requires that the following two conditions be met:

  1. That there’s objective evidence of at least two areas of myelin loss, or demyelinating lesions, appearing in two distinct neurological areas separated in time. This means that the lesions have occurred in different places and at different times within the brain, spinal cord, or optic nerve.
  2. That other diseases that can cause similar neurological symptoms have been objectively ruled out

These two conditions, called the McDonald Criteria, made it possible in 2005 to agree on medical practice in the diagnosis of Multiple Sclerosis and establish an earlier diagnosis of the disease.

However, it can take months to obtain such a diagnosis, since sometimes the tests must be repeated several times in order to gather the necessary information in different areas and at different times.

All this without taking into account the fact that, if the affected person comes to the consultation with an outbreak, when it remits without an established diagnosis, sometimes it takes years for other symptoms or another attack to appear that confirms that the disease is suffered.

To confirm the diagnosis of Multiple Sclerosis, two types of tests are needed:

1. Physical exam

2. Diagnostic tests

  1. Review of the clinical history

The neurologist will ask many questions about health problems and symptoms, now and in the past, to better understand the patient’s health and identify any other problems that may explain their symptoms.

The neurologist will ask many questions about health problems and symptoms, now and in the past, to better understand the patient’s health and identify any other problems that may explain their symptoms.

The doctor might ask, for example:

  • When did you start experiencing symptoms?
  • Have the symptoms been continuous or occasional?
  • How severe are the symptoms?
  • Is there something that seems to be improving the symptoms?
  • Is there something that seems to be making my symptoms worse?
  • Does anyone in your family have Multiple Sclerosis?

What can the patient ask the doctor, among other things:

  • What is the most likely cause of my symptoms?
  • What kind of tests do I need to have?
  • Do they require any special preparation?
  • Is this disease usually temporary or chronic?
  • Will my illness progress?
  • What treatments are available?
  • I have other health problems. What is the best way to control them together?
  1. Physical exam

The neurologist performs a detailed examination to assess the symptoms that the patient presents and the state of his neurological system, looking for changes, weakness, irregularities in vision, strength of the extremities (hands or legs), balance and coordination, speech and reflexes.

  1. Diagnostic test

Blood test

It allows to rule out other pathologies that can cause similar symptoms, such as AIDS or Lyme disease.

Magnetic resonance imaging (MRI)

This technique uses a powerful magnetic field and radio waves to obtain cross-sectional images of the brain and spinal cord, which can detect the small areas of inflammation and scarring in the brain typical of MS.

It should be noted that although magnetic resonance imaging can be helpful in diagnosing MS, it’s not always conclusive, especially during the early stages of the disease. Therefore, your results should be compared with symptoms and physical evaluation.

Evoked potentials

This test consists of placing electrodes on the scalp to measure the electrical response of the central nervous system (CNS) to a stimulus.

For example, to analyze visual evoked potentials, a pattern of light and dark squares similar to a checkerboard pattern that alternate on a screen is used, and to evaluate auditory brainstem evoked potentials, click sounds are used with headphones.

An abnormal pattern or slowing of electrical impulses in certain nerves suggests malfunction of the nerves, probably due to damage to myelin. Between 70 and 90% of patients who have been diagnosed with multiple sclerosis show abnormal results on these tests.

In fact, evoked potentials often detect other abnormalities that were not seen on neurologic examination. Also, because these tests measure brain and spinal cord function, they supplement the information about brain structure that MRI provides.

Lumbar puncture

It’s an analysis of a sample of cerebrospinal fluid (CSF), which performs the function of cushioning the brain and spinal cord, to evaluate the abnormalities that occur in patients with MS. CSF is removed by inserting a needle into the lower back, a procedure that is performed under local anesthesia.

The most common CSF abnormality found in 80-90% of MS patients is an increase in the number of cells and proteins of the immune system (immunoglobulins), suggesting inflammation or a strong immune response.

This test is particularly useful in diagnosing patients who experience a slow and progressive decrease in their functions without exacerbation pictures; that is, people with primary progressive multiple sclerosis, especially when no abnormalities are detected in the MRI images of the brain.

Cerebrospinal fluid evaluation can also be used to exclude infections difficult to distinguish from multiple sclerosis.

Is there a treatment for Multiple Sclerosis?

There’s no vaccine for Multiple Sclerosis. Since the first treatment for Multiple Sclerosis was authorized in Europe in 1995, new pharmacological therapies have emerged to modify the course of the disease.


These modifying treatments don’t cure MS or relieve symptoms (in fact, the effects of these drugs on the disease may not be seen immediately), however, they can modify its course and reduce the number of flare-ups and lesions on MRI. Brain magnetic, and delay the increase in disability.

The decision to begin disease-modifying treatment is personal and must be individualized in each case. Also, a treatment that works for one person may not work for another.

The specialists in Multiple Sclerosis – based on the information obtained through the original clinical studies and other data obtained later – affirm that starting treatment early is associated with a better evolution.

If you are considering starting disease-modifying treatment, it’s important to consider:

  • The benefits / risks for each person with MS
  • The characteristics of MS in each case (type of MS, outbreaks and their impact, etc.)
  • Side effects that may appear
  • The mode and frequency of administration and monitoring
  • The impact on daily life: the emotional impact that starting a long-term drug therapy may have on the person, the impact on lifestyle, personal preferences

Treatment is generally started with first-line drugs, such as interferon beta and glatiramer acetate, which reduce the rate of flare-ups and new lesions. These TMEs act on different aspects of the immune system without causing immunosuppression, so they are generally quite safe.

If the expected response doesn’t occur, then the neurologist usually prescribes one of the second-line drugs, such as tysabri and gilenya, which are more effective, but can have certain adverse effects.

Disease-modifying treatments control neuroinflammation in the early stages of the disease, which affects neurodegeneration in the long term.

Outbreak treatment

A worsening, the appearance of new symptoms, or the reappearance of symptoms that have been experienced in the past, lasting from 24 hours to several days or weeks, may indicate the presence of a flare, relapse or exacerbation of MS. An outbreak is usually accompanied by inflammation or demyelination in the central nervous system (CNS), either in new or old places.

In case the attack is mild and brief, the specialist may consider that it does not require treatment.

If the symptoms are severe or continue to get worse, the health neurologist may prescribe a corticosteroid treatment to:

  • Reduce inflammation that causes demyelination
  • Shorten the duration of the outbreak
  • Accelerate recovery from a relapse

Corticosteroids can be administered intravenously or orally. They are powerful drugs that have side effects, and that is why they are usually indicated for the shortest possible periods. Recovery from flare-ups may require the help of rehabilitation in many cases.

There is insufficient evidence that long-term corticosteroid treatment slows the progression of disability in people with MS.

So, how does a neurologist diagnose Multiple Sclerosis?

People with multiple sclerosis (MS) often face many uncertainties at different stages of the disease. After the diagnosis, it’s very important to have information about multiple sclerosis, since its development is different in each person.

For example and according to different estimates, around a third of people with multiple sclerosis will have little or no progression of disability. The effects of pharmacological treatment and different therapies are another of the issues that generates more uncertainty.

People with MS have the right, if they so wish, to receive accurate, recent and relevant information to make informed decisions. And they not only affect the disease, but also on personal life planning decisions. For this to happen, it’s necessary to offer quality information to patients.

In short, patients with multiple sclerosis need quality information. It’s important to have rigorous and verified information to be able to face the disease with confidence and optimism. 

The relationship with the professionals who serve us must be positive. The more information they have, the more personalized the treatment can be. The doctor-patient relationship must be excellent. Professionals are good allies to face this disease.

FAQS: How does a neurologist diagnose Multiple Sclerosis?

How does a doctor diagnose multiple sclerosis?

A doctor diagnoses multiple sclerosis using Magnetic Resonance Imaging. This technique detects abnormal tissue in nerve fibers.

Can neurologist diagnose MS?

Yes, neurologists are the specialists in charge of diagnosing Multiple Sclerosis, since they are the specialists of the nervous system.

Can MS be diagnosed with a nerve conduction test?

Yes, in fact, it is the best option of all. If your doctor observes irregularities in the MRI study, you should have a nerve conduction study.

What are the four stages of MS?

Clinically isolated syndrome (CIS)
Relapsing-remitting MS (RRMS) 
Primary progressive MS (PPMS)
Secondary progressive MS (SPMS).

When should you suspect multiple sclerosis?

People should consider the diagnosis of MS if they have one or more of these symptoms: Tingling and numbness. Pain and spasms Weakness or fatigue Balance problems or dizziness.

In this brief guide we answered the question ‘’How neurologist diagnose ms?’’ We defined what Multiple Sclerosis is, its causes, symptoms and we will explain the role of the neurologist in the diagnosis of this disease.

If you have any questions or comments please let us know!


Sospedra, M., & Martin, R. (2005). Immunology of multiple sclerosis. Annu. Rev. Immunol., 23, 683-747.

Poser, C. M., Paty, D. W., Scheinberg, L., McDonald, W. I., Davis, F. A., Ebers, G. C., … & Tourtellotte, W. W. (1983). New diagnostic criteria for multiple sclerosis: guidelines for research protocols. Annals of Neurology: Official Journal of the American Neurological Association and the Child Neurology Society, 13(3), 227-231.

Trapp, B. D., Peterson, J., Ransohoff, R. M., Rudick, R., Mörk, S., & Bö, L. (1998). Axonal transection in the lesions of multiple sclerosis. New England Journal of Medicine, 338(5), 278-285.