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A-Z, the medical jargon associated with MS


Getting the diagnosis of Multiple Sclerosis (MS) is terrifying.  Understanding what that means for your future and sorting through the different treatment options is daunting.  What makes matters worse is that the people who are trying to help you in your journey-your doctors, nurses, support groups, pharmacist- are using words that are unfamiliar to you.  Medical jargon is a foreign language.  We have compiled some terms often used when discussing MS to help you become part of the dialogue.


Aphasia- Impairment of the ability to communicate-speaking, understanding, and writing

Ataxia Clumsy voluntary movements usually used to to describe  difficulty with walking and balance due to poor muscle control

Atrophy- A decrease in size of an organ or tissue (in MS this would occur in the brain or spinal cord) which results from damage to or death and resorption of cells.

AutoimmuneWhen the immune system makes antibodies against normal cells of the body.  In MS, the attack is against the coating of the nerve cells (axons).

Axon- the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells

Brainstem- the trunk of the brain, which connects the brain above to the spinal cord below. It consists of the medullapons, and midbrain.

Central Nervous System -the brain plus the spinal cord

Cerebrum- The largest part of the brain which is divided into two hemispheres, or halves. Different parts of the cerebrum control different functions, such as motor, sensory, memory, speech, thought, and emotions.

Cerebellum- The portion of the brain in the back of the head between the cerebrum and the brain stem. The cerebellum controls balance for walking and standing, and other complex motor functions.

CIS (Clinically Isolated Syndrome)- one form of MS in which there has been only one clinical flare

Cognitve Impairment- disturbance of how one thinks, understands, and processes information

CT Scan (Computed Tomography Scan)-an imaging test using a series of X-rays to show tissue, bone, and blood vessels.  It is not as sensitive for MS lesions but must be used when patients have metal in their bodies, making using the preferred MRI scan dangerous.

Demyelination- Stripping of the coating  (myelin) of the nerve cells.

Disability- a physical or psychological condition that limits a person’s ability to function normally.

Diplopia- Double vision.

DMT (Disease-Modifying Therapy)- MS therapeutic medications that slow the progression of the disorder.  They do not cure the disease.

Dysarthria- Difficulty speaking clearly, including slurring and increased pauses.  

Dysphagia- Difficulty swallowing. MS is one of the causes of dysphagia.

Dysphasia –unclear articulation of speech that is otherwise linguistically normal due to brain disease or damage.

EDSS (Expanded Disability Status Score)- the calculated disability score for MS patients on a scale of 1 to 10 that reflects the degree of disability

Flare- A new episode of MS symptoms that is different in clinical symptoms and location in the brain or spinal cord.

Gait -The quality of the way one walks.  In MS this can be affected by weakness, motor control, imbalance, and stiffness.

Immune System- A complex network of organs, cells, and proteins that defends the body against infection.

Immunocompromised- People with a weakened immune system.  This may be an intentional weakening by medications to reduce the damage done by a dysfunctional attack of the body’s cells by its own immune system.

Infusion- Fluids or medications delivered to the body through a needle inserted into a vein, typically in the arm.

JC virus- A common virus affecting up to 90% of the population without significant illness. It remains “asleep” in brain tissues.  When a patient becomes immunocompromised, including by DMT, which are used to treat MS, it can cause a serious brain infection called progressive multifocal leukoencephalopathy (PML).

Lesion- an abnormality on MRI or CT scans reflective of MS damage.

Lhermette’s sign- an electric shock-like sensation that occurs on flexion of the neck.  Its occurrence suggests damage to the cervical spine, and in MS, it suggests a cervical demyelinating lesion.

Lumbar puncture– Another term for Spinal Tap.

MRI (Magnetic Resonance Imaging)-  This is the most common way to diagnose MS. Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. MRIs are very useful for examining the brain and spinal cord.

MS (Multiple Sclerosis)-  An immune-mediated disease in which the body’s immune system mistakenly attacks myelin in the brain and spinal cord.

Myelin- The protective coating around the axons which allows for quicker transmission of signals and information.  In MS, it is the target for antibody attack by a misguided immune system. Damage to the myelin is the hallmark of the disease.

Nystagmus- Involuntary jerking movements of the eyes, either up and down or side to side.  It often causes dizziness and difficulty walking

Oligoclonal Bands (OCB)- Inflammation-related proteins found in the cerebrospinal fluid (CSF) which surrounds the spinal cord.  The presence of OCB supports the diagnosis of MS.

Optic Neuritis-  Inflammation of the optic nerve which exits the back of the eye and causes temporary or permanent visual loss in that eye.  This is often the presenting symptom of MS.

Plaques- Another word for MS-related lesions on MRI or CT scan.

PML (Progressive multifocal encephalopathy)- A potentially fatal infection of the brain that occurs when an inactive JC virus is awakened by immunosuppression. 

Pseudobulbar Affect- outbursts of uncontrolled or inappropriate laughing or crying which affect 10% of MS patients.

RIS (Radiographically Isolated Syndrome)- MRI changes with white matter lesions which are diagnostic for MS but without known clinical symptoms.

RRMS (Relapsing Remitting MS)- The most common form of MS (85% of MS patients) in which acute flares are followed by periods of no clinical worsening (remission).  Patients do not always regain all the function lost during an acute flare.

Sclerosis- Scarring of affected tissue

SPMS (Secondary Progressive MS)- A type of MS that starts as RRMS but becomes a steady clinical decline without distinct flares.

Spasticity- A stiffening and tightness of muscles that cause pain and difficulty walking.  In MS, this commonly occurs due to the damage in the brain and spinal cord.

Spinal tap– A diagnostic procedure during which a needle is introduced into the fluid-filled space surrounding the spinal cord.  Examination of the fluid can help confirm the diagnosis of MS.

Steroids- Medications given to reduce inflammation in the nervous system and other areas of the body.  They are given to MS patients when new symptoms arise to cause a rapid improvement.

Vertigo- A form of dizziness that is characterized by a spinning sensation of the patient or of the world around them. In MS this is caused by involvement of the brainstem or cerebellum.

White Matter -the tissue of the brain and spinal cord that appears paler when inspected by the naked eye consisting mainly of nerve fibers (axons) that have myelin coating, called myelin sheaths.


BeCare MS Link can help you track the progress of your own disease and offers information to help you become an active driver of your treatment.

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