Reliability and validity of the Faces Pain Scale with older adults

Abstract

Background The Faces Pain Scale (FPS) is effective with older adults in clinical assessment of pain intensity. The 0–10 numerical rating scale (NRS) has universally adapted for assessment of pain intensity. The commonly used versions of the FPS have six, seven or nine faces. Objectives We proposed an 11 face modified version of the McGrath nine face FPS to compare with the 0–10 NRS without the mathematical translation. The psychometric properties of the proposed version were also investigated in a sample of Korean older adults. Design This study employed methodological research design. Settings and participants A sample of 31 older adults was recruited through local senior citizen centers to examine the construct validity and the test–retest reliability. For the concurrent validity testing, a sample of 85 older adults with chronic pain was recruited through a general hospital and an oriental medical hospital. Methods The construct validity was examined by determining if the subjects perceive the FPS as representing pain and they agree on the rank of each face. The test–retest reliability was examined at a 2-week interval. The concurrent validity was examined by using the NRS and the Visual Analogue Scale (VAS). Results Subjects perceived the 11 FPS as a pain measure, and the subjects’ agreements in the rank ordering of the faces were almost perfect (Kendall's W = . 93 , p < . 001 ). Cohen's kappa of .61 ( p < . 001 ) for test–retest reliability was acceptable in the cognitively intact subjects. Concurrent validity measured by the correlation between the FPS and the NRS ( r = . 73 , p < . 001 ) and the VAS ( r = . 73 , p < . 001 ) was supported. Conclusions These results supported the appropriateness of the 11 FPS for use with the older adults in clinical practice to measure pain intensity. Additionally, this study provided cross-cultural evidence to evaluate usefulness of the FPS.