Non-invasive vagus nerve stimulation significantly improves quality of life in patients with persistent postural-perceptual dizziness

Abstract

Persistent postural-perceptual dizziness (PPPD) is one of the most common causes of chronic vestibular disorders, with a substantial portion of the affected patients showing no significant improvement to standard therapies (i.e., pharmacotherapy, behavioral psychotherapy). Patients with PPPD have been shown to have a significant comorbidity with anxiety disorders and depression. Further, these patients show an activation of the autonomic nervous system resulting in symptoms such as nausea, increase of heart rate, and sweating. Based on the comorbidities and the activation of the autonomic nervous system, we addressed the question whether non-invasive vagus nerve stimulation (nVNS) might be a treatment option for these patients. In this prospective study we, therefore, applied nVNS to patients with treatment-refractory (to the standard therapy) PPPD. The stimulation protocol was similar to previous studies in patients with cluster headache and consisted of stimulations during exacerbations or acute attacks of vertigo, but also with regular stimulations in the morning and evening as prophylactic treatment. Results showed that non-invasive vagus nerve stimulation significantly improved quality of life, as measured by the EQ-5D-3L (p = 0.04), and depression, as measured by the HADS-D (p = 0.002), in the nVNS group, but not in the age- and sex-matched group with standard of care (SOC) treatment. Moreover, in the pooled analysis (additional 4 weeks of stimulation also in the SOC-group), less severe vertigo attacks/exacerbations (p = 0.04), a decrease in total postural sway path as measured by posturography (p = 0.02), as well as tendentious less anxiety (p = 0.08), occurred after stimulation. These data imply that short term nVNS is a safe and promising treatment option in patients with otherwise refractory PPPD.

Keywords: Non-invasive vagus nerve stimulation (nVNS); Parasympathetic nervous system (PSNS); Persistent postural-perceptual dizziness (PPPD); Quality of life (QOL); Sympathetic nervous system (SNS); Total postural sway.