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\'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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
80
The stimulation parameters were set to a burst pulse wave with a frequency of 20Hz, 200μs,5s ON-5s OFF,and a burst frequency of 2000Hz. Electrodes were attached to the tragus and cymba conchae of the left ear,the screen of the device displays slow breathing guidance video at 0.1Hz, while the device delivered stimulation during the 5 seconds of exhalation.
Without slow breathing guidance video on the stimulation device,the stimulation parameters were set to a burst pulse wave with a frequency of 20Hz, 200μs,5s ON-5s OFF,and a burst frequency of 2000Hz. Electrodes were attached to the tragus and cymba conchae of the left ear
Xidian University
Xi'an, Shaanxi, China
Sleep diary indicators after two weeks of treatment
Sleep latency, sleep efficiency, wake time after sleep onset, number of wake times after sleep onset, and total sleep time were used as the primary outcome measure in the sleep diary.
Time frame: Sleep diaries were collected daily for five weeks, but changes in sleep diary data were assessed after one week baseline, two weeks of treatment, and two weeks of follow-up.
Changes in heart rate variability
Heart rate variability(HRV) were analyzed to evaluate the mean peak interval (MeanRR) of the RR and three commonly used measures of autonomic nervous function: the root mean square sum of the difference between adjacent normal heartbeat intervals (RMSSD), the percentage of adjacent NN differences greater than 50ms in the total number of sinus heart beats (PNN 50%), and high frequency power (aHF).
Time frame: Heart rate variability will be assessed twice within five weeks:at baseline,and after two weeks of treatment.
Changes in heartbeat evoked potential
Heartbeat evoked potential(HEP) is the electrical activity of the brain at a specific moment in the heart cycle, which is synchronized with the R wave of the heart's electrical signals and can be measured by recording the electrical activity of the brain at a specific point in time within the heartbeat cycle. HEP represents an electrophysiological marker of cortical processing of incoming cardiovascular information.
Time frame: Heartbeat evoked potential will be assessed twice within five weeks:at baseline,and after two weeks of treatment.
Changes in ISI scores
The Insomnia Severity Index (ISI) is utilized to assess the severity of insomnia and its impact on physical health, daily function, and quality of life. This scale includes seven items, with a total scoring range from 0 to 28. Higher scores denote more severe insomnia. The change in ISI score will be determined by subtracting the baseline score from the score at each subsequent time point.
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Time frame: ISI will be assessed three times within five weeks: at baseline, after two weeks of treatment, and two weeks of follow-up.
Changes in PSQI scores
The Pittsburgh Sleep Quality Index(PSQI) assessed the sleep quality of the participants in the last 1 month, which was composed of 19 self-rated items and 5 other rated items, in which the 19th self-rated items and 5 other rated items did not participate in the score. The 18 self-rated entries that participate in the scoring can be combined into seven sections. They were: sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disorders, hypnotic drug use and daytime dysfunction. Each part is scored from 0 to 3, and the cumulative score of each part is divided into PSQI total score, ranging from 0 to 21, and the higher the score, the worse the sleep quality
Time frame: PSQI will be assessed three times within five weeks: at baseline, after two weeks of treatment, and two weeks of follow-up.
Change in PHQ-9 scores
The Patient Health Questionnaire-9 (PHQ-9) encompasses nine items, each representing a different facet of depressive symptoms. The total score ranges from 0 to 27, with higher scores indicating more severe depressive symptoms. The change in PHQ-9 score will be determined by subtracting the baseline score from the score at each subsequent time point.
Time frame: PHQ-9 will be assessed three times within five weeks: at baseline, after two weeks of treatment, and two weeks of follow-up.
Change in GAD-7 scores
The Generalized Anxiety Disorder Scale (GAD-7) is used to assess the emotional state of patients. The Generalized Anxiety Disorder Scale (GAD-7) comprises seven items, with a total possible score ranging from 0 to 21. An elevated score suggests a more pronounced level of anxiety. The change in GAD-7 score will be determined by subtracting the baseline score from the score at each subsequent time point.
Time frame: GAD-7 will be assessed three times within five weeks: at baseline, after two weeks of treatment, and two weeks of follow-up.
Change in FFS scores
The Flinders Fatigue Scale(FFS) consists of seven entries that measure various fatigue characteristics (e.g., frequency, severity) experienced during the past two weeks. Six items were presented in Likert form, with responses ranging from 0(not at all) to 4(very serious). The total score is calculated by the sum of all the items. The total score of the scale ranges from 0 to 31 points, and the higher the score, the more serious the fatigue degree of patients.
Time frame: FFS will be assessed three times within five weeks: at baseline, after two weeks of treatment, and two weeks of follow-up.