Eye movements during visual search for emotional faces in individuals with chronic headache

Background Attentional biases for pain-related information have been frequently reported in individuals with chronic pain. Recording of participants' eye movements provides a continuous measure of attention, although to date this methodology has received little use in research exploring attentional biases in chronic pain. The aim of the current investigation was to explore the specificity of attentional orienting bias using a novel visual search task while recording participant eye movement behaviours. This also allowed for the investigation of whether attentional biases for pain-related information exist in the presence of multiple stimuli competing for attention. Methods Twenty-three participants with chronic headache and 24 pain-free, healthy control participants were engaged in a visual search task where pain, angry, happy and neutral faces were used as both target and distractor stimuli. While completing this task, participants' eye movements were recorded. Results Supporting the adopted hypothesis, participants with chronic headache, relative to healthy controls, demonstrated a significantly higher proportion of initial fixations to target pain expressions when the pain expressions were presented in displays containing neutral-distractor faces. No significant differences were found between groups in the time taken to fixate target pain expressions (localization time). Conclusions Individuals with chronic headache show facilitated initial orienting towards pain expressions specifically when used as targets in a visual search task. This study adds to a growing body of research supporting the presence of pain-related attentional biases in chronic pain as assessed via different experimental paradigms, and shows biases to exist when multiple stimuli competing for attention are presented simultaneously.