Study of the Effects of Transcutaneous Auricular Vagus Nerve Stimulation Combined with Slow Breathing on Insomnia

The study recruited college students with insomnia disorders and applied transcutaneous auricular vagus nerve stimulation(taVNS) combined with slow breathing. The main aims of the study are: 1) to explore the role of this novel and effective physical therapy technique of taVNS combined with slow breathing in regulating insomnia; 2) to investigate the relationship between the synergistic effect of taVNS and slow breathing on interoceptive indicators and their therapeutic effects.

This study conducted a randomized controlled clinical trial with an intention to enroll 80 insomnia participants. Participants were randomly assigned in a 1:1:1:1 ratio to four groups:1）taVNS combined with slow breathing group；2）taVNS with normal breathing group；3）slow breathing with sham taVNS group；4）normal breathing with sham taVNS group.The study included a one-week baseline period, a two-week treatment period, and a two-week follow-up period. During the 2-week treatment period, 20 minutes of continuous treatment was performed every evening. The stimulation parameters were set to 20Hz, 200μs, 5s ON-5s OFF and a burst frequency of 2000Hz. For taVNS combined with slow breathing group,after preparing the skin, electrodes were attached to the tragus and cymba conchae of the left ear,and under the guidance of the device\&#39;s video, the participants were instructed to perform six slow and relaxed breaths per minute (0.1Hz), while the device delivered stimulation during the 5 seconds of exhalation.For taVNS with normal breathing group,without video guidance on the device, the participants breathed freely while receiving normal taVNS intervention.For slow breathing with sham taVNS group,the participants followed the video instructions to perform slow breathing while wearing the stimulation electrodes, but the device only outputted stimulation for one minute.For normal breathing with sham taVNS group,the device outputted stimulation for only one minute, and the participants breathed normally. EEG and ECG data were collected before and after the 2-week treatment, and scale data were collected before and after the treatment as well as at the end of follow-up. Sleep diaries were recorded throughout the 5-week period.

Eligibility Criteria:
Inclusion Criteria:

1. Age over 18 years;
2. Meet the definition of insomnia in the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-V)；
3. Has not received any psychotropic drug treatment；
4. PSQI(Pittsburgh Sleep Quality Index) score\>7；
5. ISI(Insomnia Severity Index) score≥11；
6. Signed informed consent form;
7. Ability and willingness to comply with the study requirements.

Exclusion Criteria:

1. There are learning or working hours that affect the circadian rhythm;
2. There is abuse of alcohol, nicotine, or other substances;
3. Pregnancy, breastfeeding, or plans to become pregnant;
4. Damage or allergy to the selected stimulation site;
5. Clinically diagnosed mental disorders and other medical conditions;
6. Currently taking stimulant, hormone, or other medications that may cause insomnia and are not suitable for discontinuation.