Modifying lumbar fexion pain thresholds in patients with chronic low back pain through visual‑proprioceptive manipulation with virtual reality: a cross‑sectional study

Abstract

Study design Cross-sectional study. Background Movement-evoked pain may serve as a protective response infuenced by visual-proprioceptive cues signaling potentially threatening movements. This study aimed to assess the impact of manipulating visual-propri‑ oceptive feedback using virtual reality (VR) during lumbar fexion on movement-evoked pain thresholds. Addition‑ ally, we explored whether individuals with elevated pain, kinesiophobia, and catastrophizing were more susceptible to visual-proprioceptive manipulation. Methods Fifty participants with non-specifc chronic low back pain (cLBP) were included. We assessed lumbar fexion-evoked pain thresholds alongside pain levels, pain interference, kinesiophobia, and catastrophizing. Partici‑ pants performed lumbar fexion movements in three conditions: (1) without VR (control, F), (2) with a virtual illusion shortening the perceived arm length by 20% (understated condition, F−), and (3) with a virtual illusion elongating arm length by 20% (overstated condition, F+). Range of motion (ROM) was measured using an electro-goniometer. One-way ANOVA with Bonferroni post-hoc tests examined diferences among conditions, and three two-sample t-tests explored whether individuals with higher pain, kinesiophobia, and catastrophizing were more afected by visual-proprioceptive manipulation. Results Understating the fexion task (F−) led to a 5% increase in movement compared to the control (P=0.04; 95% CI [0.6%, 10.7%]) and a 7% increase compared to the overstated condition (F+) (P<0.001; 95% CI [2.6%, 11.6%]). Additionally, individuals with higher pain levels and pain interference, exhibited a more pronounced response to the understated condition (F−). Conclusions Manipulating visual-proprioceptive feedback through VR signifcantly infuenced pain thresholds during lumbar fexion in cLBP patients. The understated condition (F−) extended pain-free movement, delaying pain onset. Furthermore, pain intensity and interference modulated susceptibility to visual feedback manipula‑ tion. These fndings enhance our understanding of how visual-proprioceptive feedback infuences pain perception