Diagnostic Terms to Understand

The path to MS diagnosis can be a long and confusing one. There are many new words and phrases that you might encounter. Below are some of the most common, along with their definitions.

Diagnostic terms for MS

Central nervous system: The brain and spinal cord. Also called the CNS. The nerves of the CNS are affected by MS. These are different from the nerves of the peripheral nervous system (PNS).

Cerebrospinal fluid (CSF):Fluid that surrounds the brain and spinal cord. It is typically colorless and contains proteins and glucose (sugar). CSF provides cushioning and nutrients to the CNS.

Cranial nerves: Twelve pairs of nerves that control most functions of the head and neck. Many of these (like the nerves involved in vision, speech, or swallowing) may be affected in MS.

Demyelination:Myelin is the protective layer around nerves that allows them to communicate with one another and function normally. In MS, the body mistakenly attacks healthy myelin, preventing nerves from functioning correctly. This process is called demyelination.

Dissemination in space: A diagnostic requirement of MS. In order to have MS, a person needs to have multiple separate areas of the CNS affected. Different clinical symptoms or imaging findings can indicate different areas of the CNS are involved.

Dissemination in time: A diagnostic requirement of MS. In order to have MS, a person needs to have damage across different time points. Clinical symptoms that occur at different times (typically at least 30 days apart) or lesions that appear to be various ages on imaging can fulfill this requirement.

Evoked potentials: Tests used to detect damage to sensory nerve pathways before symptoms have developed. These include visual, hearing, and touch pathways.

Gadolinium: A type of contrast used during magnetic resonance imaging (MRI) scans to help highlight areas of inflammation. Often abbreviated Gd.

Lesion: An area of inflammation seen on CNS imaging that may be caused by MS-related damage. Newer lesions are bright on imaging, while older lesions are darker.

Lumbar puncture: A procedure used to collect a sample of CSF. It involves inserting a needle into the spine and drawing out a small amount of fluid for analysis in a lab.

Magnetic resonance imaging (MRI): A type of imaging used to look for MS damage in the brain and spinal cord. It uses magnetic fields rather than traditional radiation.

McDonald Criteria: A set of guidelines that can be used to determine whether a person has MS. These take into account the type and timing of symptoms, imaging findings, and CSF studies. The criteria can help a doctor determine whether a person has MS-related findings that are disseminated in space and time.

Neurological exam: A physical examination focused on the neurological system. Involves testing motor nerves, sensory nerves, cranial nerves, reflexes, coordination, and more.

Neurologist: A doctor who specializes in diagnosing and treating disorders of the nervous system. Often the health professional who will make the diagnosis of MS.

Oligoclonal bands: Also called O-bands. A specific type of protein that may be found in the CSF that can help lead to a diagnosis of MS.

Primary-progressive MS: A type of MS that involves a continuous slow worsening of symptoms rather than different periods of relapses and improvements.

Relapsing-remitting MS: The most common type of MS. Characterized by periods of worsening symptoms called relapses followed by at least a partial recovery. Relapses and recoveries continue in a cyclic manner.

Secondary-progressive MS: MS that begins as relapsing-remitting but develops into a more progressive form of MS later on. Sudden worsening of symptoms may still occur, but overall, the condition is steadily progressing rather than having periods of improvement.

Symptom history: A detailed history of all signs and symptoms a person is experiencing during the MS diagnosis process. This includes the type of symptoms present, frequency, changes, and more.

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Written by: Casey Hribar | Last reviewed: June 2021.