The Convergent Validity of Pain Drawings and Anatomic Checklists in Individuals With Chronic Pain

The assessment of the spatial characteristics of pain, such as location and extent, is essential in the clinical evaluation of pain, especially when managing patient's with chronic musculoskeletal pain. This study evaluated the convergent validity of pain drawings (PDs) and anatomic checklists (ACLs) in measuring pain location (PL) and pain extent (PE) in individuals with chronic musculoskeletal pain.

Twenty volunteers participated, each completing a PD and an ACL in a randomized order following standardized training. PDs were digitized and analyzed using a custom algorithm on a web platform. PL was categorized across 45 anatomic areas. PE was assessed using a region-weighted approach by means of the Margolis rating scale and a pixel-based method. Statistical analyses included Spearman rho and the Jaccard Index to compare the obtained PD metrics.

A strong correlation was found between PDs and ACLs for PE (Spearman rho=0.823), suggesting similar capabilities in quantifying the spatial distribution of pain. However, a significant discrepancy in PL measurements, with a mean Jaccard Index of 0.54, indicated poor agreement between methods.

These results highlight the non-interchangeability of these instruments for PL identification and underscore the importance of each tool's unique advantages and limitations. The study also highlighted the potential benefits of incorporating innovative pain metrics into current health questionnaires to enhance their clinimetric properties. These findings advocate for continued research with larger and more diverse patient cohorts to further validate PDs and ACLs and to explore additional psychometric properties for pain assessment.