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

Analysis of the Analgesic Mechanism of Transcutaneous Electrical Nerve Stimulation Based on Wrist-ankle Acupuncture Theory During Non-anesthetized Colonoscopy Using Electroencephalogram-Functional Infrared Spectroscopy System

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.

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.