‘Disability-Relevant’ Pain Assessment: The Inclusion of Movement-Evoked Pain

Background: Studies investigating the role of pain severity as a determinant of disability have been mixed. Even when a significant relation is found, pain severity rarely accounts for more than 10-20% of the variance in measures of disability. Recent findings suggest that a more ‘disability-relevant’ approach to pain assessment is required. Indeed, research has begun to examine the dynamic changes in ‘movement-evoked pain’ in individuals with persistent pain conditions. Movement-evoked pain refers to pain that is experienced in response to a physical challenge. Study 1 examined the degree to which measures of spontaneous and movement-evoked pain measures accounted for shared or unique variance in functional disability associated with whiplash. Study 2 examined whether movement-evoked pain could be observed in healthy individuals following induction of delayed onset muscle soreness (DOMS), as well as the attenuating effects of high-frequency transcutaneous electrical stimulation (TENS).

Methods: In Study1, 142 whiplash-injured participants performed a canister-lifting, whereby spontaneous and movement-evoked measures of pain were collected. In Study 2, DOMS was induced in 56 healthy participants. Twenty-four hours later, participants performed the canister-lifting task with either Active or Placebo TENS.

Results: In Study 1, it was found that measures of movement-evoked pain accounted for significant unique variance in self-reported disability, beyond the variance accounted for by spontaneous pain measure. In Study 2, movement-evoked pain was observed in roughly 25% of participants, and TENS attenuated the effects of movement-evoked pain.

Conclusions: Sensitivity to movement-evoked pain might interfere with successful recovery following musculoskeletal injury and may represent a key target for rehabilitation interventions.