High definition tDCS of the left dorsolateral prefrontal cortex modulates nonlinear HRV in high test anxiety individuals

Prior neurostimulation research has underscored the importance of the left dorsolateral prefrontal cortex (DLPFC) in the modulation of autonomic nervous system responses, with activation of this region significantly enhancing heart rate variability (HRV) - a key indicator of autonomic flexibility. High test anxiety (HTA) individuals often demonstrate diminished HRV in evaluative scenarios, signalling reduced physiological adaptability to stress. This study investigates the effects of offline high-definition transcranial direct current stimulation (HD-tDCS) targeting the left DLPFC on nonlinear HRV measures in individuals with high levels of test anxiety. Two experiments were conducted: Experiment 1 measured HRV in 23 HTA participants before and after HD-tDCS application. Experiment 2 replicated the tDCS protocol with 24 participants with low test anxiety (LTA). Significant enhancement in nonlinear HRV post-HD-tDCS was observed in HTA group, whereas no notable changes were reported in HRV among LTA group. These results indicate that HD-tDCS targeting the left DLPFC may be an effective intervention for managing test anxiety, as it appears to improve autonomic regulation in individuals experiencing high anxiety levels.