Effects of Transcutaneous Stimulation of the Auricular Branch of the Vagus Nerve in Older Adults
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 12
- 试验地点
- 1
- 主要终点
- HRV
研究概览
简要总结
The autonomic nervous system consists of two branches, the sympathetic and the parasympathetic, which must work in balance. Its functioning can be measured indirectly by heart rate variability, which is the time between heartbeats, which is not constant. The more it varies, the greater the role of the parasympathetic branch, and vice versa. However, with age, an imbalance can occur and the parasympathetic branch can play a lesser role, resulting in less heart rate variability (the times between heartbeats become more similar).
The aim of this study is to know if electrical stimulation in the ear can improve the balance between the two branches of the autonomic nervous system in older adults, comparing two different locations of application. The main questions to answer are:
Does applying electrical stimulation to a specific area of the ear improve the balance of the autonomic nervous system? Does it also help improve hand tremors, balance, concentration, saliva production, and voice quality?
详细描述
Electrical stimulation (ES) of the nervous system, also denominated as neuromodulation, has been investigated for diverse conditions as cardiovascular diseases, chronic pain and psychiatric conditions. It is unknown which locations and parameters can be more effective and better tolerated. The transcutaneous ES is a non-invasive technique which has fewer side-effects than subcutaneous vagus nerve stimulation.
The aim of this study is to analyze the acute effects of transcutaneous ES on autonomic nervous modulation by heart rate variability (HRV) and heart frequency (HF) in older adults who perceive themselves as healthy, comparing two different locations for the ES, before and after a battery of motor, cognitive and other tests.. In addition, the tolerance to the current and the side-effects will be compared.
Once the participants have given their informed consent and had been checked for exclusion criteria, are invited to an experimental session. Subjects will be advised to refrain from caffeine or alcohol for 12 h and vigorous exercise for at least 24h prior to the intervention. The volunteers will be randomized by sex to begin with one of two electrode locations: cymba concha and cavum concha at the left ear (active session); or scapha and lobule at the left ear (sham-session). These two interventions will be denominated as Transcutaneous Vagus Electrical Nerve Stimulation (t-VNS) and Sham Transcutaneous Vagus Electrical Nerve Stimulation (sham t-VNS). Allocation concealment, stratified by sex, will be ensured as the person will choose a piece of paper with the assignment coded with numbers (real/placebo) from a bag containing all the coded options that only the person applying the stimulation will see and understand (coded) The stimulation location will be wiped down with alcohol and the minimum intensity, at which the stimulus is perceived, will be registered. Subsequently, the intensity will be increased until reaching the discomfort threshold, and then decreased to a strong but well-tolerated sensation.
At the beginning of the intervention, the different tests will be explained to the participant, the chest strap will be placed, its synchronisation with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a belt.
After 10 minutes, the pre-stimulation assessment will be carried out. At the beginning of each session, participants will be allowed to try each one to familiarise themselves with it. At the end of the session, the stimulation will be applied and the variables will be measured in the same order during the actual electrical stimulation or placebo, as appropriate.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Double (Participant, Investigator)
盲法说明
The volunteers will be randomized by sex to begin with one of two electrode locations: cymba concha and cavum concha at the left ear (active session); or scapha and lobule at the left ear (sham-session). These two interventions will be denominated as Transcutaneous Vagus Electrical Nerve Stimulation (t-VNS) and Sham Transcutaneous Vagus Electrical Nerve Stimulation (sham t-VNS). Allocation concealment, stratified by sex, will be ensured as the person will choose a piece of paper with the assignment coded with numbers (real/placebo) from a bag containing all the coded options that only the person applying the stimulation will see and understand (coded). The researcher analysing the results does not know whether condition 1 or 2 corresponds to the placebo or active location.
入排标准
- 年龄范围
- 65 Years 至 80 Years（Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Non-smokers aged 65 to 80, with BMI from 18.5 to less than 30, who consider themselves healthy and are able to maintain their balance for at least 1 minute without assistance, living in A Coruña (Spain), with a 50% allocation to each sex
排除标准
- •systolic blood pressure above 160 mm Hg and diastolic blood pressure above 100 mm Hg,
- •previous vagotomy, history of syncope in the last two years, or lack of reliable reading in heart rate variability
- •presence of chronic pain (migraine, back, neck, shoulder, etc.) or being diagnosed with or receiving treatment for malignant, cardiovascular disease (excluding hyperlipidaemia and hypercholesterolaemia), respiratory, neurological or autonomic, metabolic (e.g. diabetes), osteoarticular of autoimmune origin (e.g. arthritis), psychiatric or history of treatment with antidepressants or anxiolytics
- •impaired cognitive level
- •presence of any contraindication or difficulty in applying TENS: pacemaker, defibrillator or any implanted electronic device, apprehension of electric current, burns or irritated skin or allergic reaction or any alteration in the area that prevents the electrode from being placed on the left ear;
- •previous application of electrical stimulation to the ear
研究组 & 干预措施
Active tVNS
While acclimatization of the participant (10 minutes) the different tests will be explained, the chest strap will be placed, its synchronization with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a fanny pack.
The pre-stimulation assessment will be carried out (from 10 to 40 minutes after initiating the session). Participants will be allowed to try each one to familiarize themselves with it. All the tests will be performed (tremor, saliva, Flanker, balance, voice, Heart Rate Variability- HRV). At the end of this first part, the stimulation will be applied at the left ear in the area innervated by the vagus nerve (concha and cymba concha),and all the variables will be measured again in the same order during the actual electrical stimulation, after a new HRV measurement (from 45 to 75´). Then, the last HRV measurement will be taken and the participant will be asked about tolerance, the occurrence of adverse effects, and blinding.
干预措施: Active location tVNS (Device)
Sham tVNS
At the beginning, the different tests will be explained, the chest strap will be placed, its synchronization with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a fanny pack.
Next, the pre-stimulation assessment will be carried out. Participants will be allowed to try each one to familiarize themselves with it. All the tests will be performed (tremor, saliva, Flanker, balance, voice, Heart Rate Variability- HRV). At the end of this first part, the stimulation will be applied at the left ear in the area not innervated by the vagus nerve (scapha) and all the variables will be measured in the same order during the sham electrical stimulation, after a new HRV measurement. Then, the last HRV measurement will be taken and the participant will be asked about tolerance, the occurrence of adverse effects, and blinding.
干预措施: Sham Comparator (Device)
结局指标
主要结局
HRV
时间窗: Change from pre-tVNS (baseline= post initial battery of tests, about minute 35 after initiating the session) and during tVNS (post second battery of tests, 5 minutes before the end of the session, about minute 70)
Heart Rate Variability (HRV) using Kubios app and H10 polar heart rate monitor chest strap, in periods of 5 minutes: * Frequency domain; ratio LF/HF power will be calculated along with normalised LF/HF where baseline values will set to 1; Low frequency (LF, referred to HRV frequency band 0.04-0.15 Hz); High frequency (HF = HRV frequency band 0.15-0.4 Hz); absolute powers of LF, and HF bands (ms2); normalized power (powers of LF and HF bands in normalised units, %) * Time domain: RR (mean values of RR intervals in ms) ; SDNN (Standard deviation of RR intervals); RMSSD (Root mean square of successive RR interval differences, in ms) * Non-linear methods: the poincaré plot short term variability (SD1, ms); the poincaré plot long term variability (SD2, ms). * Global measures: Stress Index (SI), square root of Baevsky's stress index; Parasympathetic nervous system (PNS) index
次要结局
- HRV(Change from pre-tVNS (baseline = post initial battery of tests, about minute 35 after initiating the session) and initial tVNS (5 minutes after setting the intensity of tVNS, about 45 minutes after initiating the session))
- Hand tremor(Change from pre-tVNS (baseline= initial battery of tests, about minute 10 to 15 after initiating the session) and during tVNS (post = second battery of tests, about 50 to 55 minutes after after setting the intensity of tVNS))
- Balance test(Change from pre-tVNS (baseline= post initial battery of tests, from minute 25) and during tVNS (post second battery of tests = from minute 65))
- Salive(Change from pre-tVNS (baseline= initial battery of tests, from minute 15 to 20 after initiating the session) and during tVNS (post second battery of tests, about 55 to 60 minutes after after setting the intensity of tVNS))
- Flanker test(Change from pre-tVNS (baseline= initial battery of tests, about 20 minutes after initiating the session) and during tVNS (post second battery of tests = 60 minutes after initiating the session))
- Voice(Change from pre-tVNS (baseline= post initial battery of tests, from minute 35) and during tVNS (post second battery of tests = from minute 75 after initiating the session))
- Tolerance(Immediately after the intervention (around the 80th minute after the start of the session))
- Adverse effects(Immediately after the intervention, and after 48 hours of ending it)
研究者
Alicia Martínez Rodríguez
Lecturer; Faculty of Physical Therapy. Researcher; Psychosocial Intervention and Functional Rehabilitation Group
Universidade da Coruña