When is a change really A Change?

Symptoms fluctuate with MS. When is a change in function a significant change? Unfortunately, such assesments often rely on a neurologist's subjective impressions and guesswork. In this brief communication in Neurology, [Quantitative functional measures in MS: What is a reliable change?] the authors report on their attempts to develop a way to assess change in MS, and determine its significance. The authors assessed the reliability of quantitative functional tests on 5 consecutive days in 63 patients with MS, determining the range of measurement variability present when patients are clinically stable. Time to walk 25 feet and the 9-hole peg test varied by less than 20% of individual mean scores on repeated testing. They conclude a 20% change on these tests can be considered to be the threshold that reliably indicates a true change in function for an individual.