Quantitative sensory testing and exercise-induced hypoalgesia protocols in low back pain: A scoping review

A significant driver of pain in individuals with low back pain (LBP) is alterations to endogenous pain modulation (EPM). EPM can be measured using quantitative sensory testing (QST), however; there are inconsistencies in the way QST has been implemented across the low back pain literature. The objective of this scoping review was to summarize protocols used to assess EPM using QST (pain pressure threshold (PPT), temporal summation (TS), conditioned pain modulation (CPM)) or exercise-induced hypoalgesia (EIH) in LBP. Databases Medline, Embase, CINAHL and AMED were searched on June 15, 2023, for articles that used QST or EIH protocols in LBP populations. Data was extracted on participants, study design, setting and details on QST and EIH protocols. Of the 221 studies included in the review, 196 used PPT, 62 used TS and 60 used CPM; only 5 studies investigated EIH. For all QST, there was high variability in the type of equipment, timing, trials, and testing location with many studies not reporting this information. There were 4 testing modalities used for TS, and 7 different test stimuli, and 3 different conditioning stimuli used across the studies for CPM. For CPM and EIH, PPT was the most common testing modality. There were 4 types of exercises used across the 5 EIH studies. This scoping review provides a summary of QST and EIH protocols in LBP that may be used as a guide for assessment in future studies. These results demonstrate a need for the development of standardized protocols and reporting guidelines. PERSPECTIVE: This article presents a summary of measures used to assess EPM in LBP. The results show the wide variability of protocols used in the literature. Future research should focus on creating standardized protocols, reporting guidelines and providing more guidance for researchers in selecting appropriate tests for their research questions.