Effects of Trancutaneous Auriculotemporal Nerve Stimulation

University of Gran Rosario12 enrolled

Overview

Neuromodulation works by either actively stimulating nerves, causing the alteration or modulation of nerve activity by delivering electrical agents directly to a target area. Transcutaneous auricular vagus nerve stimulation is a noninvasive therapy that has demonstrated positive effects in a wide range of conditions. The auricular branch of the vagus nerve is stimulated by electrical pulses in the skin of the ear (cymba conchae). Knowledge about the effects of trigeminal nerve stimulation has increased considerably in recent decades, demonstrating great potential as a therapeutic tool. However, to date, no studies have evaluated the effects of transcutaneous auriculotemporal nerve stimulation (tANS). Therefore, the aim of this study will be to compare the effects of two types of tANS on nociceptive processing in asymptomatic volunteers.

This study will be a randomized, double-blind, crossover pilot clinical trial. Its objective is to compare the immediate effects of two types of transcutaneous auriculotemporal nerve stimulation (tANS) applied to the auricular helix on nociceptive processing in asymptomatic volunteers. Outcome measures will include pressure pain threshold, temporal summation of pain, and conditioned pain modulation. Adverse effects and treatment tolerance will also be recorded. Eligible participants will be randomly assigned to one of two groups: Group 1: tANS using transcutaneous electrical nerve stimulation (TENS) Group 2: tANS using electrical stimulation (ES) Each intervention will be administered 72 hours apart at the University of Greater Rosario (Rosario, Argentina). Outcomes will be assessed both before and after each treatment. All assessments will be conducted by a physical therapist blinded to group allocation.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Eligibility

Sex: ALLMin age: 18 YearsMax age: 35 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Subjects of both sexes, aged 18 to 35 years; * No symptoms or history of disease in the craniofacial region; * No symptoms of chronic pain in any body region. Exclusion Criteria: * History of surgery, trauma to the craniofacial region or cancer; * Systemic disease (e.g., rheumatic disease); * Neurological and/or psychiatric disorders; * Altered sensation (e.g., hipo or hypersensitivity); * Current pregnancy or menstrual cycle * Intake medication (e.g., centrally acting); * Prior experience with electrical stimulation treatment; * Intense physical activity, use of stimulants and/or analgesics in the previous 24 hours; * Acute sleep disruptions (e.g., recent sleep deprivation); * Inability to understand the informed consent document.

Outcomes

Primary Outcomes

1. Change in Pressure Pain Threshold

The Pressure Pain Threshold (PPT) will be measured through a pressure algometer in 2 different sites bilaterally; 1) temporomandibular joint and 2) thenar eminence. At each site, 3 measurements will be made with an interval of 30 seconds, and the mean will be registered. To determine the PPT, the pressure will be increased at a rate of approximately 1 kg/second and patients will be asked to raise their arm the moment the pressure begins to change to a sensation of pain, at which point, the evaluator will stop pressing. PPT values will be expressed in kg/cm2. The PPT will be determined as the arithmetic mean of the three measurements. A higher score means a better result.

Time frame: Pre-intervention and post-intervention with a 72 hours washout period, between groups

Change in Temporal Summation of Pain

Temporal Summation of Pain (TSP) will be induced using a pressure algometer. For TSP, 10 consecutive pressure pulses will be elicited using the PPT (obtained before). For each pulse of the TSP procedure, the pressure will increase at a rate of 1 kg/second until the PPT is reached, where it will remain for one second before being released. The pressure pulses will be repeatedly performed with an interval between stimuli of one second. Participants will be instructed to assess the pain intensity of the first and tenth pressure pulses according to the numeric pain rating scale (NPRS). The TSP score will be obtained by subtracting the first NPRS score from the last score. The higher the TSP score, the more efficient the nociceptive signaling for the brain.

Time frame: Pre-intervention and post-intervention with a 72 hours washout period, between groups

Change in Conditioned Pain Modulation

For Conditioned Pain Modulation (CPM), cold water immersion will be used as the conditioning stimulus (CS) and the PPT as the test stimulus (TS). The participant will immerse their non-dominant hand in a cold water bath at approximately 4°C (±0.5°C) until they reach their maximum pain tolerance or 2 minutes after the start of the immersion, at which point they will remove their hand. The TS will be taken before and immediately after the CS (three PPT measurements). Differences between the PPT values before and after the CS will be considered as CPM values. A greater difference in score indicates more efficient descending inhibition.

Time frame: Pre-intervention and post-intervention with a 72 hours washout period, between groups

Secondary Outcomes

Adverse Effects And Tolerance

Participants will be asked about the presence of adverse effects immediately and 72 hours after the stimulations (e.g., itching or skin irritability at the electrode placement site) and their assessment of which stimulation was best tolerated (using the numerical pain rating scale).

Time frame: Time Frame: Immediately and 72 hours after the interventions.

Effects of Trancutaneous Auriculotemporal Nerve Stimulation

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes