Background & Aims
When children are able to verbally self-report their pain experience, subjective pain ratings are the method preferred for pain assessment in clinical care and pain research. Among the available rating scales, the 11-point numerical rating scale (NRS-11) is frequently used, well researched and recommended for use in children from the age of 6 years (Birnie et al. 2019). Yet, research shows that agreement between children’s subjective pain ratings and parents’ or health care professionals’ judgements of children’s pain is moderate (e.g. Zhou et al. 2022). Additionally, in adults, subjective pain ratings on supposedly unidimensional scales are known to be highly idiosyncratic (Williams et al. 2000). Aim of the present study was, therefore, to investigate the understanding and use of the NRS-11 in children aged 7-14, with particular attention to intra- and interindividual differences in underlying dimensions used to label the single NRS points and how they are used when having acute pain.
Methods
So far 25 children [10 girls; age: M = 9.24 years (SD = 1.83)] have participated in an already piloted interview, which was distributed to two days with an interval of about 7 days.
On the first day, children were asked to label as many 11 NRS points as possible using their own descriptors and related to their own pain experiences. On the second day, about 7 days later, children were asked to re-assign their own descriptors from the first day to the NRS points and, additionally, descriptors taken from the literature as distractors. Children also underwent a cold pressor test (10° C) to induce acute pain. Their task was to keep the hand as long as possible in the water. To assess their pain experience, they were prompted to report their pain on a blank NRS-11 at regular intervals (after 10s, 30s, 60s, 90s, 120s, 180s). Maximum duration of hand immersion was 180s.
Results
Regarding the anchors, 20 children labelled the upper anchor using words referring to the intensity (e.g. very big, rather, intolerable), and 21 labelled the lower anchor as “no pain”. However, 4 children labelled it as “very little pain”. Four children extended the anchors (e.g. because worse things could happen). Many children (n=19) labelled all points, most (n=18) chose related labels for neighbouring NRS points, some combined several points into one (e.g. 5-7). All children used sensory attributes for describing the NRS points. Additionally, particularly older children used further descriptors referring to situational context, motor aspects, vegetative symptoms, and consequences of pain.
Agreement between day 1 and 2, measured by Cohen’s Kappa, was significant only for the lower anchor (? = .762) with a positive trend for the midpoint and the upper anchor.
During the CPT most children found the NRS-11 easy to use, but related their ratings to perceived changes in temperature.
Conclusions
The results show considerable interindividual variance among children when using the NRS-11, particularly with regard to type of descriptors used for their pain experiences. Not surprisingly, older children used more categories to describe pain, most likely due to their longer experience with pain and their level of cognitive development.
Intraindividually, agreement between labels and descriptors used on both interview days was low except for the lower anchor which, however, was relabelled by 4 children as “little pain”. Further, use of the NRS-11 during acute pain showed that children relied on specific contextual information to give their rating. Taken together, these findings indicate that children rely on specific and distinct cues from their personal experiences to construct meaning of the NRS, resulting in considerable variance both inter- and intraindividually.
References
Birnie, Kathryn A.; Hundert, Amos S.; Lalloo, Chitra; Nguyen, Cynthia; Stinson, Jennifer N. (2019): Recommendations for selection of self-report pain intensity measures in children and adolescents: a systematic review and quality assessment of measurement properties. In: Pain 160 (1), S. 5–18. DOI: 10.1097/j.pain.0000000000001377.
Williams, Amanda C. de; Davies, Huw Talfryn Oakley; Chadury, Yasmin (2000): Simple pain rating scales hide complex idiosyncratic meanings. In: Pain 85 (3), S. 457–463. DOI: 10.1016/S0304-3959(99)00299-7.
Zhou, Huaqiong; Albrecht, Matthew A.; Roberts, Pam A.; Porter, Paul; Della, Phillip R. (2022): Consistency of pediatric pain ratings between dyads: an updated meta-analysis and metaregression. In: Pain reports 7 (5), e1029. DOI: 10.1097/PR9.0000000000001029.