A new MS diagnosis comes with a stack of unfamiliar vocabulary — often spoken quickly, in a clinic, when you are not in a state to absorb any of it. The terms on this page are the ones that come up in the very first conversations: what kind of MS you have, what the scans show, and what the doctors are looking for before they commit to a diagnosis. None of these definitions are medical advice; they are just plain-language translations so you can follow along.
5 terms in this topic
Multiple Sclerosis
Multiple sclerosis (MS) is a condition where the immune system mistakenly attacks the protective coating around nerves in the brain and spinal cord. That coating, called myelin, he...
Relapsing-Remitting MS (RRMS)
Relapsing-remitting MS is the most common form of MS. People with RRMS have flare-ups of new or worsening symptoms (relapses) followed by periods of partial or full recovery (remis...
Clinically Isolated Syndrome (CIS)
Clinically isolated syndrome is a first episode of neurological symptoms that lasts at least 24 hours and looks a lot like MS. It might be optic neuritis, numbness, or weakness. So...
McDonald Criteria
The McDonald Criteria is the checklist doctors use to decide if a person has MS. It combines symptoms, MRI findings, and sometimes spinal fluid results to show that nerve damage ha...
Lesion
A lesion is a patch of nerve damage in the brain or spinal cord that shows up on an MRI. In MS, lesions are spots where the protective coating around nerves has been inflamed or in...
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Reviewed by the MS Buddy editorial team. Not medical advice — always consult your care team.