Transcutaneous auricular vagus nerve stimulation improves working memory in temporal lobe epilepsy: A randomized double-blind study.

Abstract

This study investigated the impact of transcutaneous auricular vagus nerve stimulation (taVNS) on working memory (WM) in refractory temporal lobe epilepsy (rTLE) and the underlying mechanisms. In this randomized double-blind study, 28 rTLE patients were subjected to an active or sham taVNS (a/s-taVNS) protocol for 20 weeks (a-taVNS group, n = 19; s-ta VNS group, n = 9). Patients performed visual WM tasks during stimulation and neural oscillations were simultaneously recorded by 19-channel electroencephalography. Compared with the baseline state, reaction time was significantly shorter after 20 weeks of taVNS in the a-taVNS group (p = 0.010), whereas no difference was observed in the s-taVNS group (p > 0.05). The power spectral density (PSD) of the theta frequency band in the Fz channel decreased significantly after a-taVNS during WM-encoding (p = 0.020), maintenance (p = 0.038), and retrieval (p = 0.039) phases, but not in the s-taVNS group (all p > 0.05). Neural oscillations during WM were altered by taVNS and WM performance was improved. Alterations in frontal midline theta oscillations may be a marker for the effect of taVNS on cognitive regulation.