Far field potentials from brain stem after transcutaneous Vagus nerve stimulation: optimization of stimulation and recording parameters

Abstract

The method of vagus somatosensory evoked potentials (VSEP) was introduced to easily measure the activity of vagus brain stem nuclei. In Alzheimer's disease, this measure was characterized by longer latencies as compared to controls while amplitudes did not show statistical significant differences at frontal and central recording sites. Therefore, the influence of stimulation and recording parameters on amplitudes of VSEP were systematically examined. In 20 healthy participants, VSEP measurement was done by electrical stimulation of the cutaneous representation of the vagus nerve in the external auditory channel and recording of VSEP over the scalp. The optimum stimulation intensity is 8 mA without perception of pain. There is no effect of stimulation side or gender. Maximum VSEP amplitudes are detected at bipolar recordings comprising the electrode T4 without statistically significant differences of latencies, wave shape and polarity. Thus, recordings of future examinations should be performed at 8 mA including this temporal electrode position. The reason for focussing on brain stem evoked potentials is that recent work has accumulated evidence for this area being involved in early phases of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Improved methodological knowledge may facilitate the assessment of this non-invasive and cost-effective method in the early diagnosis of neurodegenerative disorders.

Vagus nerve somatosensory evoked potentials in Parkinson’s disease

“…The available evidence suggests that VN-SEP represents far field potentials of brainstem activity from vagus nuclei that can be elicited upon electrical stimulation of its auricular branch [8]. The present study disclosed significantly longer latencies in PD patients compared to controls, which may point to disease-related dysfunction of the sensory part of the vagus nerve (as part of the nucleus N. spinalis n. trigemini).…”

Transcutaneous Vagus Nerve Stimulation: A Promising Method for Treatment of Autism Spectrum Disorders

“…Functional neuroimaging and neurochemical studies have also shown that tVNS on the afferent branch of vagus nerve can activate multiple brain areas involved in social and emotional regulation (Manta et al, 2009; Polak et al, 2009; Frangos et al, 2015). These activation patterns evoked by tVNS are similar to brain activity changes evoked by traditional VNS (Chae et al, 2003; Kraus et al, 2013; Frangos et al, 2015; Fang et al, 2016).…”

Electrical Stimulation of the Vagus Nerve Dermatome in the External Ear is Protective in Rat Cerebral Ischemia

“…It has been suggested that stimulation of the dermatome corresponding to the auricular branch of the vagus nerve (Arnold’s nerve) in the external ear may be a non-invasive alternative to cVNS (Fig. 1) [5–8]. This is the region where the familiar “ear-cough reflex” can be elicited upon cutaneous stimulation and the dermatome is quite similar between rats and humans [9,10].…”