The purpose of this study is to explore whether high-definition transcranial direct current stimulation (HD-tDCS) could augment effectiveness of attentional bias modification (ABM) on pain perception, and to explore the potential neuroimaging mechanism by functional infrared spectroscopy (fNIRS).
This randomized, single-blind, parallel-controlled trial randomized 46 healthy volunteers into two groups: active HD-tDCS combined with ABM group and sham HD-tDCS combined with ABM group. The pressure pain threshold (PPT), cold pain threshold, cold pain tolerance, pain intensity, pain unpleasantness and attentional bias were measured before and after the intervention. fNIRS was used to monitor cerebral hemodynamic responses while receiving repeated cold pain stimulation task.
Compared with sham HD-tDCS group, active HD-tDCS combined with ABM training significantly increased PPT at the ventral midpoint of the forearm (z = -3.142, P= 0.002) and quadriceps femoris (t = 2.912, P = 0.006), and decreased pain unpleasantness rating (z = -2.237, P = 0.025). However, there was no significant improvement in pain attentional bias after intervention.
Active HD-tDCS combined with ABM training can boost the analgesic impact of ABM training, reducing the unpleasantness of pain ratings. This analgesic effect might be linked to alterations in prefrontal cortex activation. Nevertheless, this effect may not be influenced by altering the direction of pain attention bias.
This study suggests that combining tDCS with ABM may enhance pain management by improving attentional control and modulating brain networks involved in pain processing. These findings could lead to more effective, non-pharmacological interventions for chronic pain, offering a promising alternative to traditional pain treatments.
attentional bias modification
pain
