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

Jones, Olivia; Schindler, Igor; Holle, Henning

Department of Psychology; Department of Psychology; Department of Psychology
Itch
2017

Journal article


Alternative title
The general labelled magnitude scale is more reliable in assessing acute itch intensity than the classic visual analogue scale
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.

Publisher
The University of Hull
Peer reviewed
No
Language
English
Extent
247 KB
Identifier
hull:14044

Journal

Journal title
Acta dermato-venereologica
Publication date
2017
Publisher
Society for Publication of Acta Dermato-Venereologica
DOI
10.2340/00015555-2584
ISSN (Print)
0001-5555
ISSN (Electronic)
1651-2057
Volume
97
Issue
3
Start page
375
End page
376
Notes

This is the authors' accepted manuscript of an article published in: Acta dermato-venereologica, 2017, v.97 issue 3.

Link
Published article
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