well, there's no clear demarkation... no border that is crossed, so it's usually hard to tell.

the way it was explained to me was "rearview mirror diagnosis"

I used to have relapses like clockwork, one or two a year, with obvious new symptoms, but as the years rolled past, there was less and less "full remission" and more and more pile-up of "residual deficits"

particular symptoms began lasting for years, and not remitting, or only partially remitting, and instead of *weeks* (like I remember flares lasting back in the late '80s) flares may resolve very slowly, taking months to settle down into the "new normal" (naturally, your mileage may vary... )

for me, the 2002 flare which involved my right side, only halfway went away, leaving my right hand feeling like I'm wearing a thick glove, .

the neuro said that eventually, there's less and less room to rebuild neural-signal pathways AROUND the damaged area of the myelin sheath.

but remember, I've had MS for almost 21 years now, so this was fully expected, and calmly planned for.

here's the brutally blunt numbers and percentages:

After 5–15 years of relapses and recovery, the relapses start to dwindle in frequency, and disease symptoms worsen during and between attacks. These changes may take months or even years to notice, and then only in hindsight. No tests or imaging studies can absolutely confirm the onset of SPMS, but a diagnosis is generally based on the history of worsening MS over the course of a year in a patient who previously had clear relapses and recoveries. About 50% of individuals who begin with RRMS have SPMS within 10 years, and 90% within 25 years.

http://www.neura.net/channels/1.asp?...e=&cps=0&cpp=0

I remember being very unhappy with hearing this answer back in 1994, because it's so vague and uncertain, and what I *wanted* was certainty and clarity...

my neuro told me... "Well, my dear" (he was an elderly gentleman, so I let him get away with THAT, lol!) "There IS no clarity in life, just go ahead and do what you CAN, and live your life the best you can..."

so, I followed his advice, and most days are full of good, if I *LOOK* for it, and *FOCUS* on it, instead of getting bogged down in carp.