Transcutaneous Vagus Nerve Stimulation Modulates EEG Microstates and Delta Activity in Healthy Subjects

Author: Lorenzo Ricci1, Pierpaolo Croce2, Jacopo Lanzone1, Marilisa Boscarino1, Filippo Zappasodi2,3, Mario Tombini1, Vincenzo Di Lazzaro1, Giovanni Assenza1
1 Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy.
2 Department of Neuroscience, Imaging and Clinical Sciences, G. d'Annunzio University of Chieti-Pescara, 66100 Chieti, Italy.
3 Institute for Advanced Biomedical Technologies (ITAB), G. d'Annunzio University of Chieti-Pescara, 66100 Chieti, Italy.
Conference/Journal: Brain Sci
Date published: 2020 Sep 25
Other: Volume ID: 10 , Issue ID: 10 , Pages: E668 , Special Notes: doi: 10.3390/brainsci10100668. , Word Count: 216

Transcutaneous vagus nerve stimulation (tVNS) is an alternative non-invasive method for the electrical stimulation of the vagus nerve with the goal of treating several neuropsychiatric disorders. The objective of this study is to assess the effects of tVNS on cerebral cortex activity in healthy volunteers using resting-state microstates and power spectrum electroencephalography (EEG) analysis. Eight male subjects aged 25-45 years were recruited in this randomized sham-controlled double-blind study with cross-over design. Real tVNS was administered at the left external acoustic meatus, while sham stimulation was performed at the left ear lobe, both of them for 60 min. The EEG recording lasted 5 min and was performed before and 60 min following the tVNS experimental session. We observed that real tVNS induced an increase in the metrics of microstate A mean duration (p = 0.039) and an increase in EEG power spectrum activity in the delta frequency band (p < 0.01). This study confirms that tVNS is an effective way to stimulate the vagus nerve, and the mechanisms of action of this activation can be successfully studied using scalp EEG quantitative metrics. Future studies are warranted to explore the clinical implications of these findings and to focus the research of the prognostic biomarkers of tVNS therapy for neuropsychiatric diseases.

Keywords: EEG; delta activity; microstates; power spectrum; transcutaneous vagus nerve stimulation.

PMID: 32992726 DOI: 10.3390/brainsci10100668