From Paper to Digital Applications of the Pain Drawing: Systematic Review of Methodological Milestones

Background In a pain drawing (PD), the patient shades or marks painful areas on an illustration of the human body. This simple yet powerful tool captures essential aspects of the subjective pain experience, such as localization, intensity, and distribution of pain, and enables the extraction of meaningful information, such as pain area, widespreadness, and segmental pattern. Starting as a simple pen-on-paper tool, PDs are now sophisticated digital health applications paving the way for many new and exciting basic translational and clinical applications. Objective Grasping the full potential of digital PDs and laying the groundwork for future medical PD apps requires an understanding of the methodological developments that have shaped our current understanding of uses and design. This review presents methodological milestones in the development of both pen-on-paper and digital PDs, thereby offering insight into future possibilities created by the transition from paper to digital. Methods We conducted a systematic literature search covering PD acquisition, conception of PDs, PD analysis, and PD visualization. Results The literature search yielded 435 potentially relevant papers, from which 53 methodological milestones were identified. These milestones include, for example, the grid method to quantify pain area, the pain-frequency maps, and the use of artificial neural networks to facilitate diagnosis. Conclusions Digital technologies have had a significant influence on the evolution of PDs, whereas their versatility is leading to ever new applications in the field of medical apps and beyond. In this process, however, there is a clear need for better standardization and a re-evaluation of methodological and technical limitations that no longer apply today.


Palmer [2]
-x x -First known description of pen-on-paper pain drawings (PDs). Visual inspection approach for differentiation of functional and organic pain based on symmetry. Melzack [19] x ---Encoding depth by letters E for external and I for internal. Generalization of PD to other sensations (eg, paresthesia). Mooney et al [20] x ---Use of symbols for different types of pain.

Ransford et al [21]
--x -Penalty point system for symbol-based PDs to diagnose somatization disorders from PD. Margoles et al [22] x x --Common body outline with 4 views with the goal of standardization. Use of colors for different kinds of pain. Toomey et al [23] -x x -Body region method to assess total sites of pain as a measure for widespreadness. Separate body outline for headaches. Margolis et al [24] --x -Lateralization score by subtracting left side score from right side score. Fordyce et al [25] --x -Using millimeter paper to measure pain area.

Gatchel et al [26]
--x -Grid method using transparent overlay to measure pain area in the body outline and surrounding space. Margolis et al [27] --x -Weighted body region method (by area).
Cummings et al [16] x -x -Comparison of patients' and doctors' PDs; number of clusters.
Udén et al [28] x x x -Sex-specific body outlines. Rating system for symbol-based PDs based on general impression. Hildebrandt et al [29] x -x -Arrows to indicate pain radiation. Showing major limitations of PDs as screening measure for psychological distress. Donelson et al [30] --x -Region-based calculation of centralization and peripheralization. Digitization of pen-on-paper PD using mouse on computer screen. North et al [9] -x x -Pixel-based PD analysis. Quantification of overlap for different sensations. PD acquisition via graphics tablet on computer screen. Sivik et al [34] --x -Frequency scoring for symbol-based PDs. Bryner [35] -x x -Comparison of pixel-based analysis and grid method. Digitization of pen-on-paper PD using graphics tablet. Escalante et al [36] --x -Methodology for analyses of McGill pain questionnaire PDs.

Parker et al [37]
--x -PDs as screening measure for psychological distress have major limitations irrespective of scoring method. Türp et al [38] x -x -Quantitative comparison of PDs with verbal reports of the chief complaint. Türp et al [39] --x -Quantitative assessment of dermatomal patterns using transparent overlay. Aló et al [4] -x --PD acquisition via pen on computer touch screen. Reigo et al [40] --x -Assessing bias in PD analysis caused by clinical knowledge of the patient. Toomingas [41] x -x -Grid-based calculation of centralization and peripheralization. Quantitative analysis of sex-related effects on PD outcomes. Sanders et al [42] -x x -Dermatome-based analysis using artificial neural networks. Digitization of pen-on-paper PD using video camera. Türp et al [43] x ---Pain intensity ratings of individual clusters. Ghinea et al [44] x -x -Using a geographic information system exploiting similarities of PDs and geographical maps. Bertilson et al [45] x ---Generalization of PD to discomfort drawing. Using saturation to encode pain intensity. Masferrer et al [46] x ---First detailed analysis of colored PDs.
Jaatun et al [7] -x --Detailed comparison of PDs acquired by tablet PC versus penon-paper and laptop-based PDs. Southerst et al [10] -x --Assessment of interrater reliability and intermethod reliability of digital and paper PDs. Spyridonis et al [56] x --x Use of virtual reality to visualize 3D PDs.
Tucker et al [57] x ---Calculation depth difference of pain from different sources.

Jaatun et al [58]
-x --Design guidelines for PD software apps for patients who are frail, very sick, or have cognitive impairments. Egsgaard et al [59] x x --Qualitative effects gender-specific body charts. Comparison of 2D and (pseudo-)3D body outlines. Zhang et al [60] --x -Automated assessment of discomfort drawings using machine learning. Boudreau et al [61] --x -Algorithm for the automatic identification of pain symmetry in PDs. Boudreau et al [62] --x -Principal component analysis to identify common pain patterns.

Shaballout et al [63]
--x -Automated calculation of pain widespreadness (widespread pain index). Wallace et al [64] --x -Compound score (Integrated Pain Quantification Index) to rate PDs based on number of noncontiguous painful areas, dermatome distance, and pain intensity.