tvns, transcutaneous vagus nerve stimulation, vagus nerve, memory, short-term memory, long-term memory

Background: Altered vagal modulation is associated with dementia and cognitive decline. Vagus nerve stimulation has been proven effective in the treatment of a variety of neuropsychiatric disorders, but its effect on memory remains unexplored.In this pilot study we, therefore, aimed to investigate the effect of long-term transcutaneous vagus nerve stimulation (tVNS) on memory performance.Methods: Drawing on perliminary data from a single-blind randomized placebo-wait list controlled study, 13 healthy individuals aged 20-59 years were randomly assigned to 1 of 2 groups: active tVNS and sham tVNS. Memory performance was evaluated before and after 14 days of active or sham stimulation (4 hours/day) by a standardized memory test (RAVLT). Change in immediate memory, overal short-term memory and long-term memory between the pre- and post- intervention measurements were calculated for each participant. Mann Whitney U test and r as an Effect Size (ES) index were used to statistically test differences in pre-post change in memory performance between the groups.Results: Compared with the sham group, participants in the tVNS group showed statistically significant improvement in immediate memory (p = .006; ES = .540) and overal short-term memory (p = .005; ES = .547) with a large effect size. There were no differences in long term memory between the groups (p = .940; ES = .015).Conclusions: Preliminary results suggest beneficial effects of tVNS on some aspects of memory performance.