Mixed evidence for transcutaneous vagal nerve stimulation to improve the extinction and retention of fear.

Abstract

We tested whether stimulating the auricular branch of the vagus nerve (transcutaneous VNS; tVNS) accelerates fear extinction and reduces spontaneous recovery of fear.

Automatic Detection of Target Engagement in Transcutaneous Cervical Vagal Nerve Stimulation for Traumatic Stress Triggers

“…As for HRV, this measure does not have a continuous nature and requires a long-term clean recording to compute a single number based on the variability in R-R intervals. An auricular stimulation study noted changes in HRV with long-term recordings [10], while some studies did not note changes in HRV [17, 51].…”

“…Second, this study did not have continuous blood pressure recordings, hence we could not use blood pressure-related measures except pulse arrival time (PAT) obtained from ECG and PPG, which is a measure related to both continuous blood pressure and cardiac contractility [56]. Nevertheless, analyses on the effects of auricular or cervical stimulation on cardiovascular and autonomic function have produced mixed outcomes throughout many studies that use basic vital signals such as HR, HRV, or BP [10, 17, 18, 21, 23, 51], hence these basic measures are not likely to be sufficient for monitoring stimulation presence. Lastly, in the current study, we obtained a transmissive PPG signal that requires the photodiode (PD) and light emitting diode (LED) combination to be at the opposite sides of the skin.…”

“…acute psychological stress was also studied: taVNS was shown to improve subjective fear and worry responses [17][18][19]. The newer and less common approach, tcVNS, was shown to decrease serum cytokines, and improve cardiac vagal tone [20,21].…”

“…Favorable outcomes have been reported for migraine [12], epilepsy [13], major depression [14, 15], posttraumatic stress disorder [16]. Pairing taVNS with acute psychological stress was also studied: taVNS was shown to improve subjective fear and worry responses [17-19]. The newer and less common approach, tcVNS, was shown to decrease serum cytokines, and improve cardiac vagal tone [20, 21].…”