An incidence cohort consisting of 308 Multiple Sclerosis patients was followed up repeatedly during at least 25 years of disease.

A number of clinical factors were analyzed with respect to their validity in assessing the long-term prognosis.

Of the onset characteristics, the type of course was the most important, with Primary/Progressive patients experiencing a much more severe course.

In patients with an acute onset, low onset age, high degree of remission at first exacerbation, symptoms from Afferent Nerve fibers and onset symptoms from only one region:

As compared with polyregional symptoms of the Central Nervous System, were factors significantly associated with a favorable long-term prognosis.

Of all factors known 5 years after onset, the most important favorable prognostic factors were:
• Low number of affected Neurological Systems
• Low Neurological Deficit Score
• High degree of remission from the last bout

Objective
To assess whether the level of Multiple Sclerosis (MS) -related disability in the Olmsted County population has changed over a decade, and to evaluate how the rate of initial progression to moderate disability impacts further disability.

Methods
The Minimal Record of Disability (MRD) measured impairment, disability, and handicap for the 2000 (n = 201) prevalence cohort.

The authors compared these results with the 1991 (n = 162) cohort; 115 patients were in both cohorts.

The authors assessed retrospectively intervals at which Expanded Disability Status Scale (EDSS) scores of 3 (moderate disability), 6 (cane), and 8 (wheelchair) were reached.

Results
The distribution of the 2000 EDSS and MRD scores were not significantly different from the 1991 distribution.

The median time from MS diagnosis, for the entire cohort, to EDSS scores of 3 and 6 was 17 and 24 years, respectively.

At 20 years after onset, only 25% of those with Relapsing/Remitting MS had EDSS scores > or =3. The median time from diagnosis to EDSS score of 6 for the Secondary and Primary/Progressive groups was 10 and 3 years, respectively.

Rate of progression from onset or diagnosis to EDSS score of 3 did not affect the rate of further disease progression.

However, once an EDSS score of 3 was reached, progression of disability was more likely, and rate of progression increased.

Conclusions
The distribution of Multiple Sclerosis disability in the Olmsted community has remained stable for 10 years.

Progression of disability for patients with Relapsing/Remitting Multiple Sclerosis or Secondary/Progressive Multiple Sclerosis may be more favorable than reported previously.

Once a clinical threshold of disability is reached, rate of progression increased.