Is an application developed for the iPad to measure pain using a Visual Analogue Scale (VAS) accurate, reliable and valid?

Question: Is an application developed for the iPad to measure pain using a Visual Analogue Scale (VAS) accurate, reliable and valid?

Design: Accuracy was tested using an observational study design. Reliability and validity were tested using a crossover RCT design.

Participants: One researcher collected accuracy data (101 data points). Twenty two community dwelling older adults were then recruited to test reliability and validity. Intervention: Each participant completed eight VAS (four iPad and four paper) in a randomised order.

Outcome measures: Accuracy was determined by physically measuring iPad scale on screen and comparing it to the results from the programme. Reliability was tested using intraclass coefficients (ICC) (95%CI), and validity tested using Bland-Altman graphs (measuring bias and limits of agreement) and correlations to describe the relationships.

Results: Accuracy was high resulting in means±SD 48.4±27.3 and 48.8±27.5 for paper and iPad respectively. Reliability for both tools was excellent with iPadVAS (ICC, 95%CI) (0.90 0.82 to 0.95) and paperVAS within individual (0.96.92 to 98). Linear regression demonstrated a strong relationship (R 2=0.904). There was a small negative bias towards the iPad (-2.6 ±5.0) with limits of agreement (95%CI) from -12.4 to 7.1.

Conclusion: The iPadVAS for Pain provides an efficient way of collecting data and is accurate and reliable in healthy older adults.