Pain assessment using physiological responses/markers in different types of pain: a scoping review

Figures

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  Fig. 1. Flow diagram illustrating the search strategy based on PRISMA-ScR guidelines. The figure presents the flow of information through the different stages of the systematic review. It summarizes the number of records identified by the search strategy, the screening steps applied, and the reasons for exclusion, leading to the final set of studies included.

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  Fig. 2. Trends in the Use of Physiological Signals for Pain Assessment Research from 2014 to 2024. The figure illustrates the publication trends on the use of physiological signals in pain assessment over the past decade. Individual categories represent specific physiological signals, while the “Others” category includes all signals reported in the literature that were not assigned to a predefined group. The polynomial line labelled “Poly. (Total)” depicts the overall trajectory of publications addressing pain assessment with physiological signals during this period.

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  Fig. 3. Schematic representation of the PPG waveform. The figure shows a schematic of the characteristic morphology of a photoplethysmography waveform.

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  Fig. 4. Search strategy implemented. The figure illustrates the search strategy used for the systematic review. Three categories of terms were combined: pain, assessment, and physiological signals. Terms for pain and assessment were restricted to article titles, while physiological signals were searched in titles, abstracts, and keywords. The dollar sign in “Signal$” indicates truncation, allowing the inclusion of variations such as “signal” and “signals”.