Emotional imagery alters symptom perception but not postural or respiratory behavior in individuals with chronic non-specific low back pain.

Chronic non-specific low back pain (CNSLBP) often coincides with alterations in postural behavior and respiration which contribute to pain. Increasing evidence suggests that emotions are closely related to postural behavior and respiration. Thereby, emotions can affect symptom perception processes in CNSLBP. This quasi-experimental study examined how emotions affect symptom perception, postural behavior, and respiration in individuals with (n= 40) and without (n= 40) CNSLBP using script-driven emotional imagery. Participants imagined three auditory scripts describing states of relaxation, hostile-resistance, and acceptance, while standing upright on an unstable support surface with their eyes closed. During each trial, postural behavior was assessed by center of pressure (CoP) and trunk muscle electromyography (EMG), and respiration by end-tidal carbon dioxide (PetCO₂). After each trial, participants self-reported bodily complaints. Emotion-induced differences in bodily complaints, CoP, EMG, and PetCO₂ were compared between individuals with and without CNSLBP using mixed models. When compared to healthy individuals, those with CNSLBP reported more bodily complaints during the hostile-resistance (p<0.0001; t=5.18) and acceptance script (p=0.002, t=3.93). Moreover, individuals with CNSLBP reported more bodily complaints during the hostile-resistance script compared to the acceptance (p=0.01; t=3.44) and relaxation (p<0.0001; t=6.56) script. Emotional imagery did not affect CoP, EMG, or PetCO2 in either group (all p>0.05). While imagining emotional scripts did not result in alterations in postural behavior or respiration, it did alter perceived bodily complaints. This highlights the significance of symptom perception processes in individuals with CNSLBP. PERSPECTIVE: Our article provides innovative insights into the processes of symptom perception in individuals with chronic non-specific low back pain, as merely imagining an emotional script affects the perception of bodily complaints.