BioPsychoSocial Assessment Tools for the Elderly - Assessment Summary Sheet Test: Visual Analogue Pain Rating Scale (VAS)   Year: 1974 Domain: Biological Assessment Tool Category: Pain Variations/Translations: N/A Assessment Setting: Clinical Method of Delivery: Self-administered Description: VAS provides a simple way to record subjective estimates of pain intensity. A VAS is a line that represents the continuum of the symptom to be rated. The scale, conventionally a straight line 10cm long (horizontal or vertical), is marked at each end with labels that indicate the range being considered. For instance, Huskisson’s version used “pain as bad as it could be” at one end and “no pain” at the other. Descriptive terms may be placed along the line, such as “severe,” “moderate,” or “mild.” Scoring/Interpretation: There are several ways to score the VAS. The distance of the respondent’s mark from the lower end of the scale, measured in millimeters, forms the basic score ranging from 0 to 100. Alternatively, a 20-pt grid can be superimposed over the line to give a categorical rating. A 30mm change represents patients’ perceptions of a clinically important reduction in pain. Time to Administer: Approximately 30 seconds Availability: Technique described in several articles. Software: N/A Website: N/A Quantitative/Qualitative: Quantitative Validity (Quantitative): A correlation of 0.75 between VAS printed vertically and a 4-pt descriptive scale rating pain as slight, moderate, severe, or agonizing. Correlations between vertical and horizontal scales ranged from 0.89 to 0.91. VAS are more sensitive to change than are verbal rating scales and so require smaller sample sizes. The comparison with numerical rating scales is less clear. Effect size for VAS is 1.58. Reliability (Quantitative): Test-retest reliability was 0.99. Test-retest reliability with literate and nonliterate participants found VAS to be more reliable (0.94) in literate vs nonliterate groups (0.71). In a study of geriatric patients, the Spearman retest correlation was 0.78 for VAS, whereas the numerical rating scale was 0.82. References: Huskisson, E.C. (1974). Measurement of pain. Lancet, 2, 1127-1131. Comments: Some patients have difficulty with the VAS, mainly elderly or less educated respondents who have trouble grasping the metaphor of the continuum represented by the VAS.