Pain assessment in cognitively impaired and unimpaired older adults: a comparison of four scales

The purpose of the study was to compare the psychometric properties of four established pain scales in a population of hospitalized older adults (mean age, 76 years) with varying levels of cognitive impairment. Patients made ratings of current pain three times/day for 7 days. They also made retrospective daily, weekly, and bi-weekly ratings of usual, worst, and least pain levels over a 14-day period. Ratings were made on four different scales, varying in numeric and verbal demands: a five-point verbal rating scale, a seven-point facts pain scale. a horizontal 21-point (0-100) box scale, and two vertical 21-point (0-20) box scales (measuring pain intensity and pain unpleasantness). The accuracy, reliability, construct validity, postdictive validity. and bias susceptibility of each scale were evaluated. The horizontal 21-point box scale emerged as the best scale with respect to both psychometrics and validity, regardless of mental status. Pain intensity did not vary as a function of mental status. Retrospective estimates of pain varied by mental status: a combination of usual/worst pain was best for cognitively impaired patients, while a combination of usual/least pain was best for unimpaired patients. These findings support the use of the 21-point box scale for pain assessment in older patients, including those with mild-to-moderate cognitive impairment. They also support the ability of older, cognitively impaired patients to rate pain reliably and validly. (C) 2001 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.