The N2pc component as a neural index of early attention allocation among adults with chronic musculoskeletal pain.

Abstract

Recent evidence from event-related potentials (ERPs) has identified N2 posterior contralateral (pc) amplitudes as a neural marker of early attention allocation. The N2pc has been used to evaluate attention biases (ABs) in samples with anxiety-based problems, but its utility has yet to be considered among persons with chronic pain, another group theorized to display ABs that perpetuate their difficulties. To address this gap, we assessed N2pc responses of adults with chronic pain (N=70) and pain-free controls (N=70) during a dot-probe task comprising painful-neutral and happy-neutral facial expression image pairs. Analyses indicated that (1) larger N2pc amplitudes were elicited by both painful and happy expressions compared to complementary neutral expressions in each sample, (2) the chronic pain sample displayed larger N2pc amplitudes during exposure to both painful and happy expressions than controls did and (3) no group differences were evident for N2pc latencies. Overall N2pc results reflected general biases in early allocation of attention towards affectively valenced expressions rather than pain-specific ABs among chronic pain cohorts. SIGNIFICANCE: Although numerous researchers have examined pain-related attention biases, these data are based exclusively upon behavioural measures of attention such as reaction times and eye movements. Drawing from relevant event-related potentials research, this study is the first to evaluate and identify differences in orienting of attention between adults with chronic pain and pain-free controls based on N2 posterior contralateral (pc) amplitudes which provide a neural index of early attention allocation.