title: Relative and absolute reliability of a vertical numerical pain rating scale supplemented with a faces pain scale after stroke.
abstract: BACKGROUND
  Pain is a serious adverse complication after stroke. The combination of a vertical numerical pain rating scale (NPRS) and a faces pain scale (FPS) has been advocated to measure pain after stroke.
  
  
  OBJECTIVE
  This study was conducted to investigate whether an NPRS supplemented with an FPS (NPRS-FPS) would show good test-retest reliability in people with stroke. The relative and absolute reliability of the NPRS-FPS were examined.
  
  
  METHODS
  A test-retest design was used for this study.
  
  
  METHODS
  Fifty people (>3 months after stroke) participating in an outpatient occupational therapy program were recruited through medical centers to rate current pain intensity twice, at a 1-week interval, with the NPRS-FPS (on a scale from 0 to 10). The relative reliability of the NPRS-FPS was analyzed with the intraclass correlation coefficient for determining the degree of consistency and agreement between 2 measures. The standard error of measurement, the smallest real difference, and Bland-Altman limits of agreement were the absolute reliability indexes used to quantify measurement errors and determine systematic biases of repeated measurements.
  
  
  RESULTS
  The relative reliability of the NPRS-FPS was substantial (intraclass correlation coefficient=.82). The standard error of measurement and the smallest real difference at the 90% confidence interval of the NPRS-FPS were 0.81 and 1.87, respectively. The Bland-Altman analyses revealed no significant systematic bias between repeated measurements for the NPRS-FPS. The range of the limits of agreement for the NPRS-FPS was narrow (-2.50 to 1.90), indicating a high level of stability and little variation over time.
  
  
  CONCLUSIONS
  The pain intensity of the participants ranged from no pain to a moderate level of pain.
  
  
  CONCLUSIONS
  These findings suggest that the NPRS-FPS is a reliable measure of pain in people with stroke, with good relative and absolute reliability.
authors.affiliation: L. Chuang, PT, PhD, Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, and Healthy Ageing Research Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Li-ling
authors.initials: LL
authors.lastname: Chuang
authors.forename: Ching-yi
authors.initials: CY
authors.lastname: Wu
authors.forename: Keh-chung
authors.initials: KC
authors.lastname: Lin
authors.forename: Ching-ju
authors.initials: CJ
authors.lastname: Hsieh
mesh_terms: D005149:Facial Expression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D011594:Psychometrics; D015203:Reproducibility of Results; D020521:Stroke / Q000150:complications* / Q000503:physiopathology*; D000071939:Stroke Rehabilitation