Benchmarks of meaningful impairment on the MSFC and BICAMS.

BACKGROUND: Cognitive and motor abilities in multiple sclerosis (MS) are typically quantified using reliable, consensus standard tests validated in the MS population. While these performance measures are associated with vocational disability in parametric analyses, translation of raw scores into anchors reflecting clinically relevant, functional impairment requires further research. OBJECTIVE: To examine performance-based motor and cognitive outcomes among definitive anchors that designate varying degrees of functional impairment, thereby establishing benchmarks for score interpretation. METHODS: We evaluated MS patients and healthy controls, all undergoing a brief test battery. Outcomes were derived from the MS Functional Composite (MSFC) and the Brief International Cognitive Assessment for MS (BICAMS). Functional impairment anchors were (1) disability benefits, (2) employed with negative work events, and (3) employed without problems. RESULTS: All measures yielded statistically significant differences across all levels of work status, after accounting for the effects of age and education. Benchmark values distinguished the functional impairment groups. When evaluated in combination, the Timed 25-Foot Walk and the Symbol Digit Modalities Test were the most robust predictors of functional decline. CONCLUSION: We have established benchmark scores for popular motor and cognitive tests that are associated with specific degrees of impairment in work status.

Latent profile analysis of regression-based norms demonstrates relationship of compounding MS symptom burden and negative work events.

OBJECTIVE: We endeavored to clarify how distinct co-occurring symptoms relate to the presence of negative work events in employed multiple sclerosis (MS) patients. Latent profile analysis (LPA) was utilized to elucidate common disability patterns by isolating patient subpopulations. METHOD: Samples of 272 employed MS patients and 209 healthy controls (HC) were administered neuroperformance tests of ambulation, hand dexterity, processing speed, and memory. Regression-based norms were created from the HC sample. LPA identified latent profiles using the regression-based z-scores. Finally, multinomial logistic regression tested for negative work event differences among the latent profiles. RESULTS: Four profiles were identified via LPA: a common profile (55%) characterized by slightly below average performance in all domains, a broadly low-performing profile (18%), a poor motor abilities profile with average cognition (17%), and a generally high-functioning profile (9%). Multinomial regression analysis revealed that the uniformly low-performing profile demonstrated a higher likelihood of reported negative work events. CONCLUSIONS: Employed MS patients with co-occurring motor, memory and processing speed impairments were most likely to report a negative work event, classifying them as uniquely at risk for job loss.