The following is a summary of the “Are we ready to define cognitive worsening in MS? How different cutoffs detect future cognitive worsening after six years of follow-up,” published in the January 2023 issue of Multiple Sclerosis and Related Disorders by Damasceno, et al.
Several MS clinical studies have included cognitive evaluation, although it is unclear how to define cognitive advancement, and new data raises doubts about the utility of a 4-point threshold on the SDMT at the individual level. Their goal was to examine cognitive performance trends over time by employing a variety of thresholds. About 6 years’ worth of data on verbal and visual memory and information processing speed were studied in a group of 42 relapsing-remitting MS patients and 30 controls. Change thresholds of 10% and 20% across all tests, as well as 4- and 8-point changes, were set in stone (SDMT).
Regression models determined that a one standard deviation (SD) shift should serve as the relative threshold. Comparisons of the distributions of “worsening,” “stability,” and “improvement” indicated poor concordance rates across the cutoffs (p<0.001 for most comparisons). Little sensitivity to predict eventual cognitive worsening was shown when patients were first diagnosed with deteriorating using predefined cutoffs, despite the fact that most patients improved on all cognitive tests.
Applying the relative cutoff resulted in a significantly lower number of individuals showing subsequent improvement. Many patients who show cognitive improvement are misclassified due to the use of fixed cutoffs. Most patients initially classified as deteriorating showed subsequent improvement. Instead, the performance was better with the relative cutoff. These findings raise questions regarding the accuracy of our current definitions of cognitive decline, particularly at the individual level.
Source: sciencedirect.com/science/article/abs/pii/S2211034822009063
