Authors:
Kristie S. Nix, EdD
Lynn B. Clutter, MSN
Donna L. Wong, PhD
University of Tulsa and
University of Oklahoma, Tulsa, Oklahoma
The use of facial expressions provides a self-report method for measuring both pain intensity and affect in children as young as 3 years of age. Although the FACES Pain Rating Scale (Wong & Baker, 1988) was developed to measure pain intensity, the instructions include affective words (happy, sad, feeling). This study investigated the influence of the original instructions with a revised set without affective words on children's pain scores. The study also explored the scale's construct validity by comparing pre- and post-injection scores.
A convenience sample of 100 English-speaking children ages 4 and 5 years who received injected vaccines were randomly assigned to Group 1 (original instructions) or Group 2 (revised instructions). Children rated their pain with the FACES before and after the injection(s).
For each instruction group, age, sex, race (white and nonwhite), and number of injections (1 vs 2) were found to have no significant effect on the mean pre-injection score, the mean post-injection score, and the mean difference between post- and pre-injection scores. Statistical analysis also showed that the three mean scores for Group 1 did not differ significantly from the corresponding mean score for Group 2. However, the mean post injection score was found to be significantly higher than the mean pre injection score for each group, with t(110) = 5.07, p<0.0005 for Group 1 and t(86) = 5.720, p<0.0005 for Group 2. Since some children chose pre-injection scores other than zero (no pain), the proportion of these children in Group 1 (10/56) was compared to those in Group 2 (10/44) using the binomial distribution. The difference was not statistically significant, indicating that the scale probably taps both the sensory and affective components of the pain experience independent of the instructions.
These findings support that use of the FACES and its original instructions with affective words measures the same concept of pain in children as instructions without affective words. Since pain is expected to increase after an injection, the scale demonstrated validity in its ability to measure this change. No child had any difficulty using the instrument.
Wong, D.L. & Baker, C.M. (1988). Pain in children: comparison of assessment scales. Pediatric Nursing 14, 7-17.
March 15, 2002
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