Your symptoms sound very similar to myself.
All my previous MRI scans show no new lesions or active lesions at all, even since being diagnosed 5 years ago, yet my legs are far far weaker than 12 months ago, even 6 months ago, my hands feel “gloved” all the time and my walking is far far worse than it has been since being diagnosed.
The neuro has said its “possibly” a transition to SP.
I was put on steroids a few months ago as the neuro suspected a possible relapse, but personally I dont think it was a relapse because the symptoms had worsened slowly over a matter of time, probably first starting 18 months ago, then gradually got worse over 12 months then the last 6 months, not suddenly like a relapse would usually do.
I’m due another MRI next month so maybe that will reveal something new.
I think Sue is spot on with old nerve damage causing “new” symptoms or gradual worsening.
Once the lesions have done there damage, then they are there for good.
Things may settle but the nerves within that area of damaged mylen will always be a problem.
I think it’s that constant scaring/lesions around those nerves that slowly pushes you towards SP, even with or with out a relapse.