Gray Matter In pop culture, “gray matter” is a quirky way of referring to the brain or intellect. In medicine, it refers to the darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites. Other Terms Expanded Disability Status Scale (EDSS) A neurological exam to help assess the MS care needed. Fatigue More than just tiredness, fatigue often strikes thanks to MS. Flare-up When MS symptoms reappear after a quiet period. Foot Drop The clue’s in the name, but what’s the link to MS? View More