Transcutaneous auricular nerve stimulation modulates the functional connectivity of the descending pain modulation system and reward network in patients with chronic low back pain

This study aims to examine the modulatory effects of transcutaneous auricular vagus nerve stimulation (taVNS) on Chronic low back pain (cLBP). 70 cLBP patients were recruited and randomized into taVNS or transcutaneous greater auricular nerve stimulation (tGANS) group. Both interventions were administered by participants themselves after initial training (five times/week for four weeks). Magnetic resonance imaging (MRI) data were collected at baseline and after 4-week interventions. Seed-based static and dynamic functional connectivity (sFC and dFC) were performed to investigate the modulation effects on descending pain modulation system and reward network using the periaqueductal gray (PAG) and ventral tegmental area (VTA) as seeds. 51 patients (taVNS: n ​= ​25; tGANS: n ​= ​26) completed the study. Within-group comparisons showed a significant improvement in pain-related outcomes for both groups. Between-group comparisons revealed no significant differences. FC analysis showed that both taVNS and tGANS can increase the PAG - postcentral gyrus sFC. The taVNS is associated with increased PAG - amygdala and PAG - paracentral gyrus and decreased PAG – medial frontal cortex sFCs compared to tGANS. The present study suggest that both taVNS and tGANS can alleviate cLBP through distinct yet overlapping pathways. Our findings underscore the potential of auricular nerve stimulation as a telehealth solution for cLBP and other chronic pain conditions.