Assessment of Chronic Pain: Domains, Methods, and Mechanisms

Abstract

Accurate classification of chronic pain conditions requires reliable and valid pain assessment. Moreover, pain assessment serves several additional functions, including documenting the severity of the pain condition, tracking the longitudinal course of pain, and providing mechanistic information. Thorough pain assessment must address multiple domains of pain, including the sensory and affective qualities of pain, temporal dimensions of pain, and the location and bodily distribution of pain. Where possible, pain assessment should also incorporate methods to identify pathophysiological mechanisms underlying the pain. This article discusses assessment of chronic pain, including approaches available for assessing multiple pain domains and for addressing pathophysiological mechanisms. We conclude with recommendations for optimal pain assessment.

Perspective: Pain assessment is a critical prerequisite for accurate pain classification. This article describes important features of pain that should be assessed, and discusses methods that can be used to assess the features and identify pathophysiological mechanisms contributing to pain.

Keywords: Pain assessment; neuropathic pain; pain intensity; pain mechanisms; quantitative sensory testing.

Figure 1

Heuristic Model of Pain Assessment. This model depicts the two major goals of pain assessment: 1) assessment of pain burden, and 2) assessment of pain mechanisms. On the left side of the figure are depicted the domains of pain burden that should be measured. These measures primarily fulfill the goal of assessing pain burden (as indicated by the solid arrows), but some of these domains can also provide information regarding pain mechanisms (as indicated by the dashed arrows). The right side of the figure displays several common and emerging methods for assessing pain mechanisms (as indicated by the solid arrows). QST=quantitative sensory testing.