The Effect of In-Ear and Behind-Ear Transcutaneous Auricular Vagus Nerve Stimulation on Autonomic Function: A Randomized, Single-Blind, Sham-Controlled Study.

Background/Objectives: Transcutaneous auricular vagus nerve stimulation (TaVNS) is a non-invasive method of electrical stimulation used to autonomic neuromodulation. Position and form of the electrodes are important for the effectiveness of autonomic modulation. This study was aimed to investigate the effect of TaVNS in-ear and behind-ear on autonomic variables. Methods: A total of 76 healthy participants (male: 40, female: 36) were randomized into four groups as in-ear TaVNS, behind-ear TaVNS, in-ear sham, and behind-ear sham. The TaVNS protocol included bilateral auricular stimulation for 20 min, 25 hertz frequency, a pulse width of 250 µs, and a suprathreshold current (0.13-50 mA). Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), and heart rate variability (HRV) were measured baseline and after stimulation. The parameters RMSSD (root mean square of consecutive differences between normal heartbeats), LF power (low-frequency), and HF power (high-frequency) were assessed in the HRV analysis. Results: HR decreased in the in-ear TaVNS after intervention (p < 0.05), but did not change in behind-ear TaVNS and sham groups compared to baseline (p > 0.05). SBP and DBP decreased and RMSSD increased in the in-ear and behind-ear TaVNS groups (p < 0.05), but did not change in sham groups compared to baseline (p > 0.05). There was no significant difference in LF and HF power after TaVNS compared to baseline in all groups (p > 0.05). SBP was lower and RMSSD was higher in-ear TaVNS than behind-ear TaVNS after intervention (p < 0.05). Conclusions: In-ear TaVNS appears to be more effective than behind-ear TaVNS in modulating SBP and RMSSD, but this needs to be studied in larger populations.

Comparison of the efficacy of auricular vagus nerve stimulation and conventional low back rehabilitation in patients with chronic low back pain.

BACKGROUND: In recent years, human and animal studies have provided increasing evidence that vagus nerve stimulation (VNS) can produce analgesic effects as well as alleviating resistant epilepsy and depression. Our study was designed to compare the efficacy of transcutaneous auricular vagus nerve stimulation with conventional low back rehabilitation in patients with chronic low back pain (CLBP). METHODS: Sixty patients with LBP were randomly divided into two groups. Group 1 received conventional rehabilitation and home exercise, and Group 2 received transcutaneous auricular VNS and home exercise. Both groups received treatment five days a week for three weeks. Trunk mobility (Modified Schober test, fingertip-to-floor test), muscle strength (CSMI-Cybex Humac-Norm isokinetic dynamometer and Lafayette manual muscle strength measuring device), trunk endurance, balance tests, Visual Analog Scale, Beck Depression Scale, Pittsburgh Sleep Quality Index, Oswestry Disability Index were evaluated. RESULTS: At the end of three weeks, within-group assessment results showed positive effects on mobility, functional status, depression and sleep in all groups (p < 0.05). Pain level, endurance time and flexion trunk muscle strength results showed more improvement in Group 2 (p < 0.05). Some parameters of isokinetic lower extremity quadriceps muscle strength and fall risk scores showed a significant improvement in Group 1 (p < 0.05). DISCUSSION: VNS has been observed to be more effective on pain, trunk muscle strength and endurance duration and sleep status. Auricular VNS may be included in the treatment of patients with CLBP in whom conventional physical therapy is inadequate or not applicable.

Effects of a single session of noninvasive auricular vagus nerve stimulation on sports performance in elite athletes: an open-label randomized controlled trial.

OBJECTIVES: The purpose of this study was to investigate the efficacy of noninvasive auricular vagus nerve stimulation (AVNS) on sports performance. METHODS: The intervention group (n = 30) received a single session of AVNS, while the control group (n = 30) received a single session of sham AVNS. Pre- and post-treatment isometric quadriceps muscle strength, heart rate, lower extremity balance, and grip strength were measured. RESULTS: It was ascertained that the differences in heart rate (-0.73 pulse/min, p = 0.032) and modified Star Balance Test scores (anterior 2.72 cm, p = 0.000, posterolateral 3.65 cm, p = 0.000 and posteromedial 2.43 cm, p = 0.000) before and after AVNS were significant in subjects in the experimental group. The results of the one-way ANOVA analysis show that the differences obtained in all measurement parameters are not statistically significant (p > 0.05). Considering the partial eta squared (η2) obtained from the measurements, a small descriptive effect in favor of experimental group was obtained for the quadriceps strength (0.016) and anterior balance (0.054) measurements. CONCLUSION: This study demonstrates that a single AVNS session compared to sham AVNS shows a modest benefit though not statistically significant improvement in athletic performance. Single-use of AVNS seems not effective in improving athletic performance. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov identifier NCT05436821.

The effect of transcutaneous auricular vagus nerve stimulation on cycling ergometry and recovery in healthy young individuals.

BACKGROUND: It is aimed to examine the potential benefits and effects of the use of transcutaneous auricular vagus nerve stimulation (VNS) for sporting purposes on recovery, fatigue, and sportive performance level. METHODS: In this study, 90 people between the ages of 18-23 were participated. They were randomly divided into three groups as bilateral sham, unilateral left, and bilateral VNS. A 4-day protocol was applied to the participants. Cycling exercise was performed with maximum performance for 30 min under the same watt load. Pulse, systolic and diastolic blood pressure, distance, pain, fatigue, lactic acid level, and autonomic nervous system were evaluated. RESULTS: Within the groups, there was a statistically significant difference between the data (p < .05) except for the distance covered parameter. When we compare the groups, in addition to the distance traveled in all groups, there is no statistically significant difference in the 1st day 1st measurement and 2nd measurement data of all parameters (p > .05 When we compared the data according to days, there was a statistically significant difference between bilateral stimulation (BS) and unilateral stimulation, only pain and fatigue levels (p < .05). CONCLUSION: In our study, we saw that BS application gave positive results in reducing pain and fatigue due to cycling exercise compared to other applications. Similar results were obtained when we evaluated the data on a daily basis. We believe that VNS will be beneficial in reducing pain and fatigue, especially during and after the competition halftime.

The effects of transcutaneous auricular vagus nerve stimulation on visual memory performance and fatigue.

Objectives: This study aims to investigate the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on visual memory performance and fatigue in healthy individuals. Patients and methods: Between April 10, 2022 and May 25, 2022, a total of 60 physical therapy and rehabilitation students (27 males, 33 females; mean age: 20.6±1.6 years; range, 18 to 24 years) were included in the study. The individuals were divided into two groups as the experimental group (n=30) and the control group (n=30). The experimental group received taVNS, mobile device supported games, and low-medium intensity aerobic exercises, while the control group received mobile device supported games and aerobic exercises. The personal information form was applied to all participants. The level of fatigue was measured using a computer-based evaluation and Fatigue Severity Scale (FSS) to analyze the visual memory performance. Results: All parameters used to evaluate visual memory performance showed a significant difference, while the FSS scores showed no significant difference (p>0.05). Only one sub-parameter in the control group was significantly different, while none of the other sub-parameters or FSS scores were significantly different (p>0.05). There was a significant difference between the two groups in terms of two of the visual memory sub-parameters, although no significant difference was found for the results of one parameter and the FSS (p>0.05). Conclusion: Our study results show that taVNS can produce positive effects on visual memory performance, although it does not apparently affect fatigue.

The effect of auricular vagus nerve stimulation on electroencephalography and electromyography measurements in healthy persons.

Objectives: Auricular vagus nerve stimulation (VNS) is a non-invasive treatment modality. Opinions that it can be used in the treatment of various clinical problems have gained importance in recent years. In this study, it was aimed to lay the groundwork for the use of the auricular VNS in different ears. Methods: Healthy individuals (n = 90) were divided into three groups: unilateral left (n = 30), unilateral right (n = 30), and bilateral (n = 30) auricular VNS. Electroencephalography (EEG) and electromyography (EMG) measurements were performed before and after auricular VNS (10 Hz, 300 µs, 20 min) for a single session. Results: An increase in wrist extensor muscles activation was detected on the contralateral side of the auricular VNS application side. It has been observed that there is a general decrease in the power of high-frequency waves and an increase in the power of lower-medium frequency waves in various parts of the brain. Conclusion: Our findings suggest that the projection of the auricular VNS in the central nervous system may also affect the corticospinal tracts.

Acute Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Hand Tremor in Parkinson's Disease: A Pilot Study of Case Series.

Objectives: The aim of this study is to investigate the effects of non-invasive vagus nerve stimulation (VNS) on tremor in Parkinson's disease (PD). Methods: This single-center, prospective, and implementation study with before-after design included five participants diagnosed with PD. Auricular VNS was applied to each participant 3 times on different days. VNS was applied to the participants as the right ear, left ear, and bilateral ear. The cardiovascular parameters of the participants were evaluated with Kubios HRV Standard and tremor with UPDRS tremor subscale and smartphone application before and after the intervention. Results: Significant decrease in diastolic blood pressure (p=0.043) was found in participants who underwent bilateral auricular VNS. Although there was no significant change in the UPDRS tremor subscale, decreases in the maximum tremor amplitude in the x (p=0.043) and y (0.014) planes were detected in the measurements made with the smartphone application. Conclusion: In this study, a decrease in the tremor amplitude measured in the 3D plane with auricular VNS was found in patients with PD.

Chiropractic Care and Quality of Life Among Office Workers With Nonspecific Pain: A Cross-Sectional Study.

Objective: The aim of this study was to evaluate the quality of life by a self-administered World Health Organization Quality of Life short version survey (WHOQoL-BREF) among office workers with nonspecific pain receiving chiropractic care in Istanbul, Turkey. Methods: This cross-sectional study included 77 office workers (age interval, 18-65) with nonspecific neck, thoracic, back and/or extremity pain who underwent chiropractic care. Two weeks later, the quality of life was evaluated by a self-administered WHOQoL-BREF. The Numeric Pain Scale to evaluate the perceived pain was administered to all of the participants in the beginning and at the end of the study. Group-level changes on WHOQoL-BREF total score and subdimensions were compared according to descriptive data of office workers. The significance level was set at P ≤ .05. Results: WHOQoL-BREF scale scores after chiropractic care (mean ± standard deviation) were 71.21% ± 7.91% (total score), 81.49% ± 14.43% (general health), 80.38% ± 10.49% (physical health), 73.16% ± 11.68% (psychological), 70.41% ± 12.43% (social), and 65.58% ± 10.91% (environment). Numeric Pain Scale scores decreased in a statistically significant way when compared with baseline (P ≤ .05). The descriptive statistical analysis of WHOQoL-BREF dimensions revealed that women had significantly higher scores than men, the 18-to-35 age group had higher scores compared with the 50-to-65 age group, and those married had significantly higher scores than those who were not married (P ≤ .05). Conclusion: The findings of our study suggest that chiropractic care had positive effects on the quality of life of office workers.

The Impact of Auricular Vagus Nerve Stimulation on Pain and Life Quality in Patients with Fibromyalgia Syndrome.

The purpose of this study is to evaluate the impact of auricular vagus nerve stimulation, applied in conjunction with an exercise treatment program, on pain and life quality in patients with fibromyalgia syndrome (FMS). To achieve the study objectives, 60 female patients between the ages 18 and 50, with diagnosed FMS according to the American College of Rheumatology (ACR) 2010 diagnostic criteria, were randomly divided into 2 groups of 30. The first group was assigned 20 sessions of a home-based exercise program, while the second group was assigned 20 sessions of auricular vagus nerve stimulation and 20 sessions of a home-based exercise program. Patients were assessed before and after the treatments using the Visual Analog Scale (VAS) for pain, Beck Depression Scale for depression, Beck Anxiety Scale for anxiety, Fibromyalgia Impact Questionnaire (FIQ) for functional evaluation, and Short Form-36 (SF-36) for life quality. In this randomized controlled trial, comparisons within the groups revealed that both groups had statistically significant improvements in pain, depression, anxiety, functionality, and life quality scores (p < 0.05), while comparisons across the groups revealed that the group experiencing the vagus nerve stimulation had no statistically significant differences between the baseline scores, except for those of SF-36's subparameters of physical function, social functionality, and pain. In fact, comparisons across the groups after the interventions revealed that the group experiencing the vagus nerve stimulation had better scores but not statistically significant. From analysis of this data, we observed that vagus nerve stimulation in FMS treatment did not give additional benefit together with exercise, except for three subparameters of SF-36. It was identified that further studies which separately investigate the effects of vagus nerve stimulation and exercise on FMS with longer follow-up periods and an increased number of patients are needed.

Efficacy of dry needling in patients with myofascial temporomandibular disorders related to the masseter muscle.

OBJECTIVE: This randomized, single-center clinical trial aimed to compare the efficacy of superficial dry needling (SDN) and deep dry needling (DDN) in patients with myofascial temporomandibular disorder (MTMD) related to the masseter muscle.Methods: Forty patients showing MTMD with trigger points in the masseter muscle were randomly assigned to groups. Dry needling of the masseter muscle was performed once per week for three weeks. Pressure pain threshold (PPT) measurements, visual analog scale scores, and maximal jaw opening were assessed.Results: Both patient groups showed significant pain reduction, but the SDN group showed significantly better pain reduction. The PPT measurements obtained in the follow-up examinations at three and six weeks were significantly better than the values in SDN and DDN groups.Discussion: SDN showed better pain-reduction efficacy in patients with MTMD. Further research with a larger size sample and a longer follow-up period will help elucidate the benefits of SDN.

Evaluation of the Sympathetic Skin Response to the Dry Needling Treatment in Female Myofascial Pain Syndrome Patients.

BACKGROUND: The aim of this study was to evaluate sympathetic nervous system (SNS) activity following dry needling (DN) treatment, by using the sympathetic skin response (SSR) method in female patients diagnosed with myofascial pain syndrome (MPS). METHODS: Twenty-nine MPS patients with trapezius muscle pain and 31 healthy subjects were included in this study. During a single treatment session, DN treatment was applied into trigger points, for a duration of 10 minutes. Healthy patients were subjected to SSR in weeks 1 and 4; whereas the patient group was subjected to SSR 1 week prior to their treatment and in the first, second, third and fourth weeks following the completion of their treatment. RESULTS: We found diminished latency on both sides. A significantly high algometer measurement (P < 0.05) was observed in the control group. DN treatment was effective in diminishing the visual analog scale (VAS) (P < 0.001), pressure pain threshold (PPT) (P < 0.01), and SSR (P < 0.001). No SSR change was detected in the healthy group after the follow-up period (P > 0.05). CONCLUSION: DN is an effective treatment in MPS and trigger point (TP). This original study is the first to deal with the SSR in MPS and weekly SSR trailing, requiring further investigation to solidy findings.

Peripheral facial nerve paralysis after upper third molar extraction.

Peripheral facial nerve paralysis (PFNP) after mandibular interventions has been reported in the literature. In most cases, paralysis begins immediately after the injection of the mandibular anesthesia, and duration of facial weakness is less than 12 hours. However, there are few documented cases of PFNP after maxillary dental or surgical procedures. A variety of mechanisms have been associated to PFNP, including viral reactivation, demyelination, edema, vasospasm, and trauma. The purpose of this presentation was to report a rare case of facial paralysis that occurred after an upper third molar extraction. The cause of the PFNP and the importance of the multidisciplinary approach in the management are emphasized.