Current clinical scales in multiple sclerosis (MS) are often complicated to administer, suffer from interrater variability and lack of uniform representation across grades, and are insensitive to progression at certain stages. Furthermore, they are not easily applied by neurologists and do not clearly differentiate among functional stages of MS. For these reasons, we developed Disease Steps to assess disability in MS. A total of 1,323 patients were classified using both Disease Steps and the Expanded Disability Status Scale (EDSS) for a total of 2,755 assessments. The Disease Steps scale consists of 0 = Normal; 1 = Mild disability, mild symptoms or signs; 2 = Moderate disability, visible abnormality of gait; 3 = Early cane, intermittent use of cane; 4 = Late cane, cane-dependent; 5 = Bilateral support; 6 = Confined to wheelchair; and U = Unclassifiable. Results demonstrate that raters could simply and quickly categorize patients using Disease Steps. Patients were uniformly distributed with Disease Steps, whereas a bimodal distribution occurred with the EDSS. On the EDSS, 40.3% of patients scored between 1.0 and 3.5 and 36.0% scored from 6.0 to 6.5, with only 6.9% of patients scoring between 4.0 and 5.5. For 60 patients seen by two neurologists, concordance between raters was excellent for Disease Steps (kappa = 0.8) but only moderate for the EDSS (kappa = 0.54). As a simple and reproducible measure of different functional steps of MS, Disease Steps can be used as a guide in therapeutic decision-making, following response to therapy, and in assessing disease progression.

Clinical assessment of outcome in multiple sclerosis (MS) patients is problematic since the disease can affect different aspects of the central nervous system and follow a variable course. Recently, we developed Disease Steps, a simple approach for evaluating disease progression. Previously, we found that Disease Steps was easy to use, had uniformly distributed scores and low inter-rater variability. Our current objective was to test the long-term use of Disease Steps together with the most widely utilized clinical outcome measure in MS, the Expanded Disability Status Scale (EDSS) in assessing clinical progression. Over 4 years, 804 patients were classified using both EDSS and Disease Steps. Each patient was assessed at least twice. Follow-up results included annual status and time-to-event analysis examining median staying times within a level of Disease Steps or EDSS. We found that the two scales behaved similarly and correlated strongly with each other. For both Disease Steps and EDSS, patients with milder levels of disability and relapsing-remitting disease demonstrated a higher likelihood of changing scores over time and shorter median staying times compared to more disabled, chronic progressive patients. These findings have important implications for patient selection in clinical trials and for the design of future measurements of clinical outcome in MS. Furthermore, Disease Steps may serve as a simple, practical tool for the nonspecialty neurologist to follow patients over time and serve as a guide in therapeutic decision making. Our findings further document the general progressive nature of MS when a large cohort is followed in an MS specialty clinic over time.

Multiple sclerosis lesions show a propensity for frontal and parietal white matter. Lesion burden in these areas was strongly associated with performance on tasks requiring sustained complex attention and working verbal memory. This relationship was consistent over a 4-year period, suggesting that disruption of frontoparietal subcortical networks may underlie the pattern of neuropsychological impairment seen in many patients with MS.