I have to wonder if I'm SPMS at this point. I was diagnosed about 7 years ago, but my first "official" exacerbation was maybe 5 years before that. My first exacerbation was several days of numbness around my upper lip, cheek, and side of my nose. A spot maybe as big a a 50-cent piece. That's all.
Virtually none of my initial symptoms were sudden or huge. Instead, they were fatigue, imbalance, strange sensory stuff, "brain cramps", heat sensitivity, etc. I've had a few pseudo-exacerbations, where the same symptoms kind of flare up--usually due to stress or other physical problems.
For the past 5 or 6 years, no new symptoms, just the same ones getting slowly worse. Every time I go to the vet (what I call the neuro), he asks me about my symptoms and I say, "A little bit worse. Not a lot worse, but worse." Every time.
If someone hadn't seen me for 5 years, she would probably notice that I've gone downhill, but not fallen over the cliff. I have more pain, my balance is worse, my muscles spasm more, it takes more effort to climb steps, I tire more easily, I venture less far from home. A lot of the things I can't/don't do anymore are due to the ever-increasing fatigue.
I've not had anybody other than my daughter comment about my seeming "worse". Nothing surprises me that people say, and when somebody says something dumb, I try to think of all the dumb things that I'VE blurted out.

I cringe when I remember.
I can still walk, drive, see, and have rare moments when I can get the Jeopardy questions before the contestants. But when I stand beside the me of 7 years ago, I've surely progressed.