Transcutaneous Electric Nerve Stimulation (TENS) for Vagal Modulation

Not Applicable

Terminated

Conditions: Functional Gastrointestinal Disorders

Interventions: Device: TENS Unit

Registration Number: NCT05987813

Lead Sponsor: Virginia Commonwealth University

Brief Summary: This study is to determine if the auricular microstimulator produces the expected increase in HRV.

Detailed Description: The aim of this proposal is to determine if utilizing an affordable tool like microstimulation utilizing a transcutaneous electric nerve stimulator (TENS) unit and applying the stimulation to the ear though an ear clip does improve vagal modulation. This can be easily done at home by utilizing the microstimulation for 2 hours/day and measuring vagal modulation before and after. Previous research investigating this had participants use the unit for 2 hours as well (Chelimsky et al., 2019), however the data from this study was inconclusive, and therefore this study aims to demonstrate effectiveness of the unit usage on heart rate variability (HRV).

Although functional gastrointestinal disorders (FGID) affect 10%-20% of children and adolescents. 1-3 the pathophysiology remains unknown. The multiple current hypotheses include visceral hypersensitivity, altered brain-gut connections, dysbiosis, genetic and epigenetic factors, and increased gut permeability among others. 4 Since the vagus nerve links the brain to the gut, many studies of adult subjects have evaluated the cardiovagal modulation in this group of disorders. The cardiovagal modulation can be measured by heart rate variability (HRV). HRV evaluates the heart rate fluctuation over a period of time. HRV is considered a reliable tool to look at parasympathetic function, baroreflex function, and parasympathetic to sympathetic balance.5, 6 High-frequency (hf) HRV is a marker of vagal modulation. The low-frequency (lf) HRV probably reflects cardiac autonomic outflow from the baroreflex or parasympathetic regulation, rather than sympathetic modulation, although this is still being discussed.6, 7

A meta-analysis of adult subjects with irritable bowel syndrome (IBS) showed decreased cardiovagal modulation.8 One study compared children aged 7-10 years of age with functional abdominal pain or IBS to healthy subjects. They found no difference in cardiovagal and cardiac sympathetic modulation.9 However, a study of young adolescents with different chronic pain syndromes, including chronic abdominal pain, showed decreased cardiovagal modulation.10 These findings are similar to those in many adult syndromes with chronic pain, such as chronic pelvic pain,11 complex regional pain syndrome,12 fibromyalgia,13 and chronic neck pain.14

Although future research would aim to investigate vagal modulation in those specifically with FGID, for preliminary data purposes we are testing the unit's effects on heart rate variability regardless of having/not having an FGID diagnosis.

Recruitment & Eligibility

Status: TERMINATED

Sex: Female

Target Recruitment: 8

Inclusion Criteria

Female
12 - 21 years old
Either diagnosed OR not diagnosed with chronic idiopathic nausea, functional abdominal pain, dyspepsia and/or irritable bowel syndrome.
English speaking

Exclusion Criteria

Patients who are unable to stand upright during the heart rate variability recording
Patients with a known bleeding disorder
Patients with swollen, infected, inflamed, or other skin eruptions on outer ear
Patients with epilepsy
Patients with any implanted cardiac pacemaker or defibrillator
Patients with serious arterial circulatory problems in the lower limbs
Patients with abdominal or inguinal hernia
Patients who are pregnant
Any unstable medical condition, such as renal disease, uncontrolled diabetes, etc.
Requires new medication during the 4 weeks of the study that may affect the gastrointestinal symptoms, vagal modulation or immune response.
Practices over 1 hour of aerobic activity a day
Daily practice of abdominal breathing (yoga)

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Non-FGID	TENS Unit	Patients without a FGID
FGID	TENS Unit	Patients with a FGID

Primary Outcome Measures

Name	Time	Method
Change in High-frequency Heart Rate Variability (hfHRV) at 4 Weeks	Assessed at baseline and 4 weeks.	Determine if microstimulation over a 4 week period results in improvement in hfHRV power. Average hfHRV power was calculated at baseline and 4 weeks. The change in average hfHRV power in milliseconds squared from baseline to 4 weeks was calculated for each participant. The average change for each group is reported.
Rate of Compliance With Daily TENS Usage	Assessed daily for duration of study (4 weeks) via self-report recording journal.	Determine the compliance rate of adolescents utilizing a microstimulator. Compliance rate calculated as number of minutes unit was used (summed from all self-report daily recording journals) divided by 3360 (the total number of minutes the unit could have been used if the participant used it for 2 hours daily for 4 weeks). The rate average for each group is reported.