Analysis of the Analgesic Mechanism of TENS-WAA During Non-anesthetized Colonoscopy Using EEG-fNIRS System

First Affiliated Hospital of the Chinese People's Liberation Army Naval Medical University

Status: Enrolling

Conditions: Colonoscopy; Pain

Treatments: Device: Using an electrical stimulation device to relieve pain during colonoscopy

Study type: Interventional

Funder types: Other

Identifiers

NCT06813703

CHEC2025-006

Details and patient eligibility

About

This study is a single-center, randomized controlled trial aiming to evaluate the analgesic mechanism of Transcutaneous Electrical Nerve Stimulation based on Wrist-Ankle Acupuncture (TENS-WAA) during unsedated colonoscopy using EEG-fNIRS technology to assess neural activity in brain regions associated with pain perception. Sixty patients aged 18-75 years, with stable cardiopulmonary function and a baseline visual analog scale (VAS) pain score <3, will be enrolled and randomly allocated into the intervention and control groups. The intervention group will receive TENS stimulation based on the Wrist-Ankle Acupuncture theory 10 minutes before the colonoscopy, with a frequency of 2 Hz and adjustable current intensity ranging from 1 to 9 mA. The control group will receive minimal-intensity sham stimulation under identical conditions. All participants will wear EEG-fNIRS devices to monitor neural activity in key pain-related brain areas, including the prefrontal cortex, anterior cingulate cortex, motor cortex, and parietal cortex. Primary outcomes include EEG-fNIRS data, while secondary outcomes are VAS scores at the four colonic bends, colonoscopy duration, and the correlation between EEG-fNIRS signals and pain perception. Statistical analyses will include multivariable linear regression, generalized estimating equations, and mixed-effects models to investigate the analgesic effects and neural mechanisms of TENS-WAA. This study seeks to provide innovative pain management strategies for patients undergoing unsedated colonoscopy and further explore the neuroregulatory potential of TENS-WAA technology.

Enrollment: 60 estimated patients

Sex: All

Ages: 18 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

1. Inclusion Criteria:

   • Patients undergoing unsedated colonoscopy are eligible for inclusion in this study.
   • Aged 18 to 75 years.
   • Meeting the requirements for colonoscopy, with good cardiopulmonary function and stable vital signs.
   • A pre-procedural Visual Analog Scale (VAS) pain score of less than 3.

2. Exclusion Criteria:

   • Participants with speech or cognitive impairments.
   • Those with acute anal or rectal stenosis, acute perianal or rectal infections, acute diverticulitis, or active inflammatory bowel disease.
   • Women who are menstruating, pregnant, or breastfeeding.
   • Patients with active tuberculosis, hemophilia, or advanced malignant tumors.
   • Individuals with sensory disturbances, implanted pacemakers or defibrillators, or ankle skin ulcers.
   • Those who have used sedatives or analgesics either long-term or within the past 24 hours.
   • Individuals with any condition that interferes with EEG-fNIRS signal acquisition, such as cranial abnormalities, implanted metal or electronic devices, epilepsy, or neurological disorders.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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60 participants in 2 patient groups, including a placebo group

Electrical stimulation group

Experimental group

Description:

According to the WAA theory, the selected Lower Zone 1 (LZ1) and Lower Zone 2 (LZ2) are defined as follows: LZ1 is located between the medial Achilles tendon and the medial malleolus, while LZ2 is positioned at the central inner edge of the ankle joint, near the posterior border of the tibia. Two electrode pads will be placed on each LZ1 and LZ2 of both legs, totaling eight electrode pads. The TENS-WAA device will be set to a frequency of 2 Hz, a pulse width of 500 μs, and a continuous waveform. Participants in the stimulation group will receive electrical currents at their maximum tolerable intensity below the pain threshold.

Treatment:

Device: Using an electrical stimulation device to relieve pain during colonoscopy

control group

Placebo Comparator group

Description:

Participants in the control group will have the electrodes placed in the same positions as those in the stimulation group, with identical electrical stimulation frequency and pulse width settings. However, the current intensity will be set to the minimum level.

Treatment:

Device: Using an electrical stimulation device to relieve pain during colonoscopy