Maintaining validity of neuropathic pain screening tools over time: challenges and opportunities

Background Significant efforts are made to validate screening tools at the time of development. This paper outlines the challenge in maintaining validity of neuropathic pain (NP) screening tools alongside advances in how NP condition is defined, diagnosed, and classified. To illustrate this, the validity of the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) was critiqued in relation to advances in knowledge of NP. Methods This narrative review used a systematic literature search to identify content validity (including tool development) and criterion validity studies of the LANSS. Content validity (including face validity) was critiqued using a subset of COSMIN standards. Criterion validity was critiqued using a subset of QUADAS-2 standards. Results Twelve papers were identified (nine pertain to criterion validity and three pertain to both content and criterion validity). Content validity studies with patients provided limited evidence of the tool’s relevance and comprehensibility. At face value, two items may no longer be relevant to NP. Six of 12 criterion validity studies may no longer be applicable (included patients who would no longer be classified with NP and/or the diagnostic assessment is outdated); six remaining studies reported variable results (sensitivity 22–86%, specificity 37–100%). Conclusion Additional content validity testing of the LANSS is warranted to determine if the tool is relevant and comprehensible, and to determine whether revisions are needed to reflect the current state of knowledge of NP. Screening tool validity is not static over time; validation is a continuous process that may include tool revision.