Transcutaneous auricular vagal nerve stimulation improves functional dyspepsia with sleep disturbance via enhanced vagal activity: a randomized controlled trial.

BACKGROUND

Functional dyspepsia (FD) is often comorbid with sleep disturbance. Transcutaneous auricular vagal nerve stimulation (taVNS) is a new and non-invasive therapeutic option. This study aimed to investigate its effects and possible mechanisms on FD with sleep disturbance.

METHODS

This was a prospective, single-center, single-blind, and randomized controlled trial. Fifty-four FD patients with sleep disturbance were randomly divided to receive 4-week taVNS or transcutaneous non-vagal nerve stimulation (tnVNS). The primary outcomes included Nepean Dyspepsia Index Symptom (NDIS) and Pittsburgh Sleep Quality Index (PSQI). The secondary outcomes were composed of Nepean Dyspepsia Index Quality of Life (NDIQOL), Hamilton Anxiety (HAMA), Depression (HAMD), autonomic functions, gastric slow waves, gastric accommodation, and serum melatonin.

RESULTS

Compared with tnVNS: (1) taVNS resulted in a lower NDIS and PSQI scores ( P < 0.05); it also reduced HAMD and HAMA scores but increased NDIQOL score ( P < 0.05). (2) taVNS increased the percentage of normal gastric slow waves (NSW%), the maximum tolerable volume, the serum melatonin level, and the high-frequency (HF, reflecting vagal activity) component in the fasting state ( P < 0.05). In taVNS group, the HF in the fasting state was positively correlated with the NSW% and the melatonin level.

CONCLUSION

taVNS is effective and safe for the treatment of FD with sleep disturbance. The effect may be attributed to the dual neuromodulating effects of taVNS on both the gut and the brain via enhanced vagal activity.