Impact of Auricular Vagal Neuromodulation Therapy on Depression in Long COVID Patients: A Group Assignment Study

Abstract

The vagus nerve (VN) is a crucial link between autonomic function, chronic inflammation, and depression. The study measured effects of a 10-day Nurosym Auricular Vagus Nerve Therapy on patients with long COVID syndrome. Patients experienced a significant 48% reduction in Beck Depression Scale scores, along with notable improvements in inflammatory biomarkers and gastrointestinal symptoms. These findings suggest that enhancing vagal tone with Nurosym effectively reduces inflammation and depressive symptoms, highlighting its potential as a therapeutic intervention for depression related to autonomic dysfunction and chronic inflammation.

Background and aims

The study aimed to investigate the effectiveness of Auricular Vagus Nerve Therapy in relieving depression symptoms in patients with post-viral syndrome. Depression is associated with changes in the autonomic nervous system, particularly characterised by increased sympathetic activity and/or decreased parasympathetic activity, characterised with reduced vagal tone. Disturbed vagal tone, often seen in people experiencing stress-induced inflammation or chronic infections, can disrupt the activity of the nervous system. This imbalance not only exacerbates inflammatory responses, but also contributes to gut inflammation and the pathogenesis of depression. Additionally, chronic infections may compromise the integrity of the intestinal barrier, exacerbating depressive symptoms.

Methods

Patients underwent Nurosym stimulation for 10 consecutive days, with sessions lasting 35 minutes each. Clinical assessments were conducted before the first stimulation (day 0), after 5 sessions (day 5), and after 10 sessions (day 10), followed by a 7-day post-stimulation assessment. The clinical measures included scores on the Beck Depression Score. The Beck Depression Score is a widely used self-report questionnaire designed to measure the severity of depression symptoms.

Results

Enhancement of vagal tone through Nurosym stimulation significantly activated the gut-brain axis, leading to a reduction in inflammatory cytokines and the alleviation of depressive and gastrointestinal symptoms.

The data presented in the study demonstrate a statistically significant 48% reduction in Beck Depression Scale scores from baseline (D0) to day 10 (D10) (p<0.05). Moreover, there was a noteworthy 185% improvement in IL-1ra levels compared to the median baseline and the median at visit 3. Patients also experienced an amelioration in the reduction of gastric symptoms by the end of the treatment period (D10).

Conclusion

Research on the Nurosym device demonstrates its efficacy in normalising the functioning of the vagus nerve by enhancing vagal tone and reducing inflammatory responses through modulation of the cholinergic pathway and inhibition of pro-inflammatory cytokine release. These mechanisms, identified in multiple studies, are believed to play a crucial role in the pathogenesis of depressive symptoms. The significant improvements observed in Beck Depression Inventory scores not only underscore the device's positive impact on overall mental health but also imply a protective effect against behaviours associated with depression.