MS Glossary



Ageusia is the loss of taste functions on the tongue, which means you lose the ability to distinguish what is sweet, sour, bitter, or salty.


Allodymia is a high sensitivity to touch, resulting in intense pain even with minimal contact, and refers specifically to a painful response to a normally innocuous stimulus. Allodymia is a specific type of dysesthesia, which is the abnormal sense of touch.


Any substance that triggers the immune system to produce an antibody; generally refers to infectious or toxic substances, e.g. viruses or bacteria, or the small molecules that form part of these microorganisms.


Astrocytes are star-shaped cells found in the brain and spinal cord. They perform many functions, including biochemical support of cells that form the blood–brain barrier, provision of nutrients to the nervous tissue, and play a role in the repair and scarring process of the brain and spinal cord following traumatic injuries.


The incoordination and unsteadiness that result from the brain’s failure to regulate the body’s posture and the strength and direction of limb movements. Ataxia is most often caused by disease activity in the cerebellum (the part of the brain at the back of the skull).


A wasting away or decrease in size of a cell, tissue, or organ of the body because of disease or lack of use.


An antibody produced by the body’s immune system which target the body’s own cells, which it mistakenly recognizes as a threat.


Autoimmune processes or autoimmunity is when the immune system mistakenly attacks healthy cells and tissues.

Autologous Haematopoietic Stem Cell Transplant (AHSCT)

Autologous Haematopoietic Stem Cell Transplant refers to a treatment scheme where a patient’s haematopoietic (or blood) stem cells are isolated from their bone marrow, before their immune system is removed either by chemotherapy or whole body irradiation. The patient’s own haematopoietic stem cells are then reintroduced back into their body to rebuild the immune system.


A nerve fibre that carries information from the nerve cell body to another nerve cell or muscle fibre.


B cells

B cells also known as B lymphocytes, are a type of white blood cell in the immune system. B cells are important for ‘policing’ the human body for foreign substances. In particular, B cells are responsible for the production of antibodies and cytokines (chemical signals that circulate around the body), they are also important for presenting foreign substances (antigen presenting) to the rest of the immune system.

Babinski Reflex

The Babinski Reflex is often used to test MS, normally when stimulated with a blunt instrument the toes natural respond by pointing downwards, in newborns and some people with nerve damage the big toe points up and the toes splay outwards, this latter reaction is known as the Babinski reflex and may indicate an issue in the brain or the CNS.


The word biomarker is short for biological markers. Biomarkers are measurable indicators of a biological process. Biomarkers can usually be measured through external testing such as tests of blood, urine or other body fluids such as cerebrospinal fluid (CSF) or can be measured by scans or other physical tests. Often the term biomarker is used to describe indicators which are observable during disease, or a factor which may predict disease onset. Biomarkers may also been used during clinical trials to determine whether treatment being tested is working.

Bladder dysfunction

MS attacks the central nervous system, which controls the normal functions of the body, including controlling the bladder. Bladder dysfunction is a breakdown in the communication between nerves and the bladder.

Blood-brain barrier

The blood-brain barrier is a selective barrier that separates the circulating blood from the fluid that surrounds the tissue of the brain and spinal cord.

Brain Fog

A common symptom of MS is brain fog, or brain haze. It is a term used to describe the forgetfulness, trouble concentrating, and confusion.

Brain tissue

Brain tissue refers to any cells or connective tissue that make up the brain. Brain tissue is further subdivided into two categories, grey matter or white matter. The grey matter is the part that contains the main body of the nerve cells, and the white matter is mainly made up of axons or the projections that nerves cells use to connect and communicate with other nerve cells.


Central nervous system

The central nervous system refers to the brain, spinal cord and optic nerves. It is named the central nervous system because it integrates information it receives from all of our senses, and coordinates and influences the activity of all the parts of the body.

Clinically Isolated Syndrome (CIS)

Clinically Isolated Syndrome is diagnosed when a person has only experienced a single episode of neurologic symptoms (such as visual blurriness, numbness, tingling and weakness of the limbs).  It is caused by inflammation and/or loss of the myelin sheath that covers the nerve fibres. It can be associated with future development of MS, but is not always associated with the development of MS. A diagnosis of MS can only be made if a person has experienced two or more attacks occur separated by time (for example 2 months) and affecting different parts of the central nervous system.


The central nervous system (CNS) refers to the brain, spinal cord and optic nerves. It is named the central nervous system because it integrates information it receives from all of our senses, and coordinates and influences the activity of all the parts of the body.

Cognitive Impairment

Cognitive Impairment is the noticeable decline in memory, learning, language, thinking or judgment, and memory. AKA as brain fog.


A permanent shortening of the muscles and tendons adjacent to a joint, which can result from severe, untreated spasticity and interferes with movement around the joint.

Controlled study

An experiment or clinical trial in which two groups are used for comparison purposes. This includes drug trials where one groups of participants are given a substance or treatment whereas the other group (the control group) are not, or are given a mock treatment.


Messenger chemicals produced by immune cells, to influence the activity of other cells.



The process where the protective myelin sheath which surrounds nerve fibres is attacked and destroyed during an active phase of MS.

Disease Modifying Drugs

Disease Modifying Drugs (DMD) or Disease Modifying Therapies (DMT) are treatments which slow down or reduce the damage caused by MS, as opposed to symptom modifying treatments which work to control the symptoms.


Short for deoxyribonucleic acid, DNA constitutes the chemical basis for genes, the basic units of heredity.

Double-blind clinical study

A study in which none of the participants nor examining doctors, know who is taking the test drug and who is taking control agent (also known as a simulated medication or placebo). The purpose of this research design is to avoid inadvertent bias of the test results.


Dysathria is a reduced control of the speech muscles resulting in slurred speech. It is often associated with damage to the nervous system.


Dysesthesia is an unpleasant abnormal sense of touch. It can present as pain – Allodymia, but it may also present as abnormal response to touch such as burning, wetness, itching, electric shock, pins and needles, and can affect any body part.


Dysmetria is the lack of coordination of movement, and is a subtype of ataxia. Dysmetria is characterised by when the limb undershoots or overshoots the intended position. It is sometimes described as an inability to judge distance or scale.


Dysphagia is problem swallowing, which can be a symptom of MS resulting from loss of control over the muscles controlling the pharynx or oesophagus (the tube leading from the mouth to the stomach), or loss of sensation of the pharynx, leading to disruption to the swallowing mechanism.


Dysphonia is the weakness or spasticity of the muscles that control the voice, resulting the issues with producing the voice. This can include issues with pitch control and hoarseness of the voice amongst other symptoms.



Encephalomyelitis is inflammation of the brain and spinal cord, a characteristic of MS.


A flareup or relapse is a period of worsening symptoms that can either be new symptoms or the return or worsening of existing ones.

Expanded Disability Status Scale (EDSS)

The EDSS is a scoring system for quantifying the impairment brought on by MS. It includes measurements assessing weakness of limbs, tremor, speech and swallowing difficulties, numbness, bowel and bladder function and visual function amongst others. It is a scale from 0 to 10, where 0 = no impairment, 10 = the greatest severity.

Experimental Autoimmune Encephalomyelitis (EAE)

EAE is an animal model where the mice develop an MS-like illness (an autoimmune demyelination disease), where the animal’s immune system is deliberately made to target the nerve myelin sheath. Mice with EAE are the most common laboratory model of MS used in research.



Is a feeling of constant tiredness or weakness and can be physical, mental or a combination of both. It is distinct from and more debilitating than general feelings of sleepiness or physical tiredness. Fatigue is the most commonly reported symptom of MS.


A flareup or relapse is a period of worsening symptoms that can either be new symptoms or the return or worsening of existing ones.

Food and Drug Administration (FDA)

The Food and Drug Administration is an American government agency which is responsible for regulating and supervising the use of medications and medical devices. One of its roles is to certify medications. Medications are typically submitted to either the FDA or the European equivalent the European Medicines Agency (EMA) before they being submitted to the Australian equivalent known as the Therapeutic Goods Agency (TGA).


Gd Lesions (GAD)

Gd is an abbreviation for Gadolinium, a chemical which is sometimes injected into a person’s blood during an MRI. Gadolinium normally cannot pass from the bloodstream into the brain, however during an MS relapse the blood brain barrier is disrupted, allowing gadolinium to enter into the brain where it enters MS lesions, creating a bright spot on an MRI. It is therefore used to identify ‘active’ lesions in the brain to distinguish them from old lesions (scars) or repairing lesions.


A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, encode instructions to make molecules called proteins.

Genetic Susceptibility

Genetic susceptibility or genetic risk or predisposition is an increased likelihood of developing a particular disease based on an individual’s genetic makeup.  It may be determined by just one gene or by a combination of many genes.


Glial cells, sometimes called simply glia, are non-neuronal cells that provide support and protection for neurons in the central and peripheral nervous systems.



Hypogeusia is a reduction in ability to detect sweet, sour, bitter, or salty tastes.



MS can disrupt the nerve signalling between the central nervous system and the bladder, disrupting the control of the movement of urine, causing urine to leave the body at any stage.


Inflammation is when the immune system acts to defend the body against invading microbes or to heal damaged tissue. In the skin, inflammation is typically associated with redness, heat, swelling and pain.

Interferon-Beta (IFN-β )

Is a type of interferon. Interferons are signalling molecules (cytokine) that are found naturally in the body. They are released by cells in response to the presence of foreign objects. Interferon beta can also be manufactured as a drug and is used as a treatment for MS; it is thought act to reduce MS symptoms by modulating inflammatory signals.


An injection or infusion of medicines into the fluid filled canal in the spinal cord or the fluid that surrounds the spinal cord. This allows the medicine to directly reach the cerebrospinal fluid that bathes the spinal cord and brain. It is sometimes used to deliver anesthetics or pain relief medicines or certain types of chemotherapy. This drug delivery method allows certain drugs to reach the brain without being stopped or blocked by the ‘[blood brain barrier]’ – the blood brain barrier is a barrier that lines the blood vessels in the brain and spinal cord that selectively allows only certain cells and chemicals through to protect the brain.


An injection or infusion of medicines directly into a vein in the body. This drug delivery method allows drugs to reach the body that would otherwise be digested or broken down if given as a pill or tablet. It also allows higher doses of medicines to be delivered straight into the blood stream.



A lesion is an area of abnormal tissue or scarring (sclerosis) of the brain tissue or spinal cord due to a previous inflammatory attack. In MS these are typically detected during life by magnetic resonance imaging (MRI). They can also be seen in post mortem tissue using specialised tissue staining and microscope techniques.

Lumbar puncture

A lumbar puncture is a diagnostic test for multiple sclerosis that involves removing and analysing a sample of cerebrospinal fluid (CSF), the fluid that surrounds the brain and spinal cord within the skull and backbone. It is also known as a spinal tap. The fluid is then examined to see whether there is a higher than normal white blood cell count and/or higher levels of antibodies (also known as oligoclonal bands due to the test carried out on the fluid).


Lymphocytes are cells of the immune system. They are small cells found in the blood that circulate through the body looking for foreign objects/microorganisms. They further subgroup into two major groups B-lymphocytes and T-lymphocytes.


Magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) is a medical imaging procedure. It uses a magnetic field and radio waves to take pictures of the inside of the body. It is particularly useful to collect pictures of soft tissue such as the brain or spinal cord which can reveal tell-tale MS scars (lesions) on the brain or spinal cord.


Microglia are a special type of immune cell located throughout the brain and spinal cord. They help in defending the brain and spinal cord from infection by engulfing and digests debris, foreign substances, microbes and if needed can attract other cells in the immune system to mount a full response.

MS Hug

MS Hug is a band of tight pain around your torso that can range from dull and achy to sharp and burning. The pain can sometimes make it hard to breathe, giving it the nickname "MS girdle."


Myelin is a white fatty substance that surrounds the axon of some nerve cells. The myelin sheath forms an electrically insulating layer. It is essential for the proper electrical conduction of nerve signals along nerve axons. The production of the myelin sheath is called myelination.



Neurodegeneration is a term to describe the loss of function of neurons, or nerve cells in the brain or spinal cord.

Neurodegenerative Disease

Neurodegenerative Disease is an umbrella term which covers conditions which are characterised by progressive nervous system dysfunction.


Neurology is the branch of medicine concerned with the study and treatment of disorders of the nervous system.

Neuromyelitis optica (NMO)

Neuromyelitis optica (NMO), also known as Devic's syndrome, is a diverse condition consisting of the simultaneous inflammation and demyelination of the optic nerve (optic neuritis) and the spinal cord (myelitis). While MS and NMO are similar, they are considered to be different diseases due to the specific regions under inflammatory attack in NMO. In NMO it known that the immune system targets a protein called AQP4 whereas the target in MS is unknown.


Neurons or nerve cells are specialised cells which are electrically excitable. They process and transmit information through electrical and chemical signals. They are the core component of the nervous system which includes the brain, the spinal cord and peripheral nervous system.


Nocturia is the need to wake and pass urine at night. Waking up once during the night is considered normal. Nocturia is a when the night-time urination occurs more frequently.

Normal appearing white matter or Normal appearing grey matter

Areas of the brain that appear normal under standard MRI conditions but look abnormal when pulsed with specific radiofrequencies (known as magnetization transfer MRI). These areas can occur in white matter regions or grey matter regions. Why the normal appearing areas appear in the brain is unknown, but they can be used to help predict the course of the disease.


Oligoclonal bands

Oligoclonal bands are bands of antibodies that are seen in a patient's blood serum, or cerebrospinal fluid (CSF) is analysed. They are an important indicator in the diagnosis of MS. More than 95% of all patients with multiple sclerosis have permanently observable oligoclonal bands.


The cell in the central nervous system that makes myelin.

Optic nerve

The nerve that transmits signals from the light sensitive layer at the back of the eye (the retina) to the brain.

Optic neuritis

Inflammation of an optic nerve, causing blurred vision or other visual disturbances.



Paresthesia refers to a burning or prickling sensation that is usually felt in the hands, arms, legs, or feet, but can also occur in other parts of the body.

Pharmaceutical Benefits Advisory Committee (PBAC)

The PBAC is an independent expert body appointed by the Australian Government. It is made up of doctors, health professionals, health economists and consumer representatives.  Its primary role is to recommend whether medications should be subsidised on the Pharmaceutical Benefits Scheme.

Physical therapy or physiotherapy

Physical therapy is a therapy using mechanical force and movements, in an effort to remediate impairments and promote mobility.

Pilot study

An initial study, often with fewer samples or participants, designed in order to determine the effects and results of a drug, procedure or observation and decide whether further larger studies are warranted.


Progressive multifocal leukoencephalopathy (PML) is a rare and usually fatal viral disease. It is caused by a virus called the JC virus which is normally controlled by the immune system, but in people whose immune systems are compromised by either disease or by medications which suppress the immune system, the virus can cause progressive damage to the brain.

Primary Progressive Multiple Sclerosis (PPMS)

Primary Progressive Multiple Sclerosis affects about 10-15% of people with MS. PPMS is characterised by a progressive worsening of symptoms and disability without periods of recovery or remission.


Proteins are large biomolecules made up of amino acids. They perform a vast array of functions within living organisms. Proteins are the functional units encoded by genes; they are the ‘components’ of the living machinery in our cells.



A flareup or relapse is a period of worsening symptoms that can either be new symptoms or the return or worsening of existing ones.

Relapsing-remitting multiple sclerosis (RRMS)

Relapsing-remitting multiple sclerosis is the most common form of MS; it is characterised by flare-ups of the neurological symptoms of MS, also known as relapses or attacks, followed by periods of recovery or remission.


A remission is a lessening in the severity of MS symptoms or even their temporary disappearance.


Remyelination is the process in which oligodendrocytes (specialised cells in the central nervous system) recreate new protective myelin sheaths to surround nerve fibres.


Secondary Progressive Multiple Sclerosis (SPMS)

Secondary Progressive Multiple Sclerosis is a secondary phase of relapsing remitting MS; it follows an initial period of relapsing-remitting MS. SPMS is characterised by a progressive worsening of symptoms (accumulation of impairments) over time, with no obvious signs of remission.


Spasticity refers to the feeling of stiffness or involuntary muscle spasms. It can range from relatively mild with a feeling of tightness in the muscles, to very severe with large uncontrollable spasms.

Stem cell

The human body is made up of different kinds of specialised cells such as muscle cells, nerve cells, fat cells and skin cells. All specialised cells originate from stem cells. A stem cell is a cell that is not yet specialised, and specialises into a specific cell type. Stem cells can be further separated into categories depending on whether they have started the specialisation process, for example haematopoietic stem cells are cells which can give rise to all the different haematopoietic cells.


T cells

T cells also known as T lymphocytes, are a type of white blood cell in the immune system. T cells can be further divided into subcategories, including T Helper Cells, Cytotoxic T cells, and Memory T cells. Together they help form a full immune response against invading objects or microorganisms.

T1 and T2 Lesions

T1 and T2 are technical terms applied to different MRI methods used to generate magnetic resonance images. Specifically, T1 and T2 refers to the time taken between magnetic pulses and the image is taken. These different methods are used to detect different structures or chemicals in the central nervous system. T1 and T2 lesions refers to whether the lesions were detected using either the T1 or T2 method. A T1 MRI image supplies information about current disease activity by highlighting areas of active inflammation. A T2 MRI image provides information about disease burden or lesion load (the total amount of lesion area, both old and new).

Therapeutic Goods Agency (TGA)

The Therapeutic Goods Agency is the Australian government agency which is responsible for regulating and supervising the use of medications and medical devices in Australia. Medications are typically submitted to the American FDA (Food and Drug Administration) or the European Medicines Agency (EMA) before being submitted to the TGA.

Trigeminal Neuralgia

Trigeminal Neuralgia is pain of the nerve (trigeminal nerve) responsible for sensation in the face and motor functions such as biting and chewing. It can manifest in multiple forms including severe, sudden, shock like pain in one side of the face but can include burning and other unpleasant feelings.


Uhthoff’s Phenomenon

Uhthoff's phenomenon (also known as Uhthoff's syndrome, Uhthoff's sign, and Uhthoff's symptom) is the worsening of MS symptoms when the body gets overheated, whether it be from hot weather, exercise, fever, or saunas and hot tubs.



Vertigo is the feeling that your surroundings are spinning even if you’re standing still. It is a balance issue commonly associated with MS and its interruption of nerve signals.

Vitamin D

A group of vitamins, important for the absorption of calcium, iron, magnesium, phosphate and zinc. Vitamin D is predominantly generated in the body when the skin is exposed to sunlight, with smaller amounts being derived from foods such as liver and fish oils.

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