Characterizing perception of transcutaneous electrical stimulation on the external ear via psychometric functions

Abstract

Tinnitus is a condition where one has the perception of a sound, such as ringing or hissing, despite the absence of an external auditory stimulus.1 Tinnitus affects around 740 million people worldwide.2 For some, this perceived sound can be irritating, decreasing their quality of life. Despite this, few effective treatments exist for tinnitus, launching research into developing new techniques.3 Two new and promising treatment strategies are transcutaneous auricular vagus nerve stimulation (taVNS) and bimodal stimulation. Both have been shown to be effective, portable, and noninvasive.4,5 Both treatment options make use of paired electrical stimulation (e-stim) and sounds to induce therapeutic neuromodulation that alleviates tinnitus symptoms. A key element of e-stim is the intensity–the amount of stimulation delivered (referred to as e-stim level here). While there is a growing body of work on taVNS and bimodal stimulation, there remains no consensus on the optimal e-stim level for tinnitus treatment. In this project, we aimed to understand the variability of the perceptual threshold of e-stim in tinnitus participants.