Assessing acute itch intensity : general labelled magnitude scale is more reliable than classic visual analogue scale

Jones, O; Holle, Henning; Jones, Olivia; Schindler, Igor

Abstract

The reliable measurement of itch intensity is crucial, both in research as well as clinical contexts. For example, when the reliability of a measurement scale is unknown, it is impossible to determine whether a patient has changed sufficiently to be confident that the change is beyond that which could be attributed to measurement error (1). One factor that might influence the reliability of measurements is the type of rating scale used to assess itch intensity. Previous research (2-4) has documented the retest reliability of different rating scales for assessing chronic itch intensity. However, a retest reliability analysis of rating scales for acute experimental itch, induced using substances such as histamine or cowhage, is currently lacking. Here, we compare the test-retest reliability of three rating scales commonly used for this purpose. First, we considered the visual analogue scale in its classic form (cVAS), where participants indicate itch intensity on a line ranging from 0 (no itch) to 100 (the most intense itch imaginable). Second, we included a variant of the VAS, where an additional ‘Scratch Threshold’ marker is set at 33% (tVAS,5), defined as itching strong enough to be scratched (6). Finally, we considered the general Labelled Magnitude Scale (gLMS,7), where participants judge the magnitude of itch on a line with quasilogarithmically placed labels of “no sensation” at 0, “barely detectable” at 1, “weak” at 6, “moderate” at 17, “strong” at 35, “very strong” at 53 and “strongest imaginable sensation” at 100. Thus, all three scales have an identical range, but differ in the type and number of verbal labels provided.

Citation

Jones, O., Holle, H., Jones, O., & Schindler, I. (2017). Assessing acute itch intensity : general labelled magnitude scale is more reliable than classic visual analogue scale. Acta Dermato-Venereologica, 97(3), 375-376. https://doi.org/10.2340/00015555-2584

• Acceptance Date: Nov 17, 2016
• Online Publication Date: Nov 21, 2016
• Publication Date: Jan 1, 2017
• Deposit Date: Nov 17, 2016
• Publicly Available Date: Nov 21, 2016
• Journal: Acta dermato-venereologica
• Print ISSN: 0001-5555
• Electronic ISSN: 1651-2057
• Publisher: Society for Publication of Acta Dermato-Venereologica
• Peer Reviewed: Not Peer Reviewed
• Volume: 97
• Issue: 3
• Pages: 375-376
• DOI: https://doi.org/10.2340/00015555-2584
• Keywords: Dermatology; General Medicine
• Public URL: https://hull-repository.worktribe.com/output/445303
• Publisher URL: https://www.medicaljournals.se/acta/content/abstract/10.2340/00015555-2584
• Additional Information: This is the authors' accepted manuscript of an article published in: Acta dermato-venereologica, 2017, v.97 issue 3.