Identifying reliable change in tactile temporal thresholds in multiple sclerosis: test-retest reliability

Background Tactile temporal thresholds are typically significantly higher (ie, prolonged) in multiple sclerosis (MS) patients when compared to controls and increase significantly during relapses, probably reflecting integrity of conduction across a portion of the corpus callosum. As part of an ongoing validation study of tactile temporal thresholds, the test-retest reliability of these thresholds was examined in patients with MS. Methods Tactile temporal thresholds were measured in 61 MS patients during two separate test sessions within three weeks. Test-retest reliability and the standard error of measurement were calculated. The threshold of change in tactile temporal thresholds in MS patients that would correspond to real change beyond measurement error with 95% certainty was also calculated. Results The test-retest reliability of this measure of tactile temporal thresholds was 0.93. The threshold indicating change beyond chance or measurement error with 95% certainty was 19 ms. Conclusions This measure of tactile temporal thresholds has excellent test-retest reliability and a change of greater than 19 ms is highly likely to represent real change. This measure is promising as a precise, reliable outcome measure in MS.