A Study on the Efficacy of Dual-Carrier-Frequency Transcranial Alternating Current Stimulation Modulating the Hippocampus for the Treatment of Chronic Non-Specific Low Back Pain

Condition(s) studied

Investigational drug(s) / intervention(s)

Dual-carrier-frequency transcranial alternating current stimulation: Dual-carrier-frequency transcranial alternating current stimulation is based on the interference principle. Two pairs of carrier-frequency alternating currents with slightly different frequencies are applied to the scalp. After intracranial superposition, the nonlinear response of biological tissues generates a low-frequency envelope-modulated electric field in deep brain regions. This interference electric field oscillates periodically at the difference between the two carrier frequencies, enabling entrainment and modulation of neuronal rhythms in deep structures. This distinguishes it from conventional transcranial electrical stimulation, in which electric field intensity decays exponentially with depth, predominantly affecting superficial cortical layers and having limited efficacy in modulating deep nuclei. In terms of safety, this technique is a non-invasive stimulation method. Adverse effects are limited to mild tingling or itching at the electrode contact sites, indicating favo

Transcranial electrical stimulation (tES): Cortical electrical stimulation is a neuromodulation technique in which electrodes are placed on the surface of the cerebral cortex or over the dura mater to deliver weak electrical currents for direct modulation of local neuronal electrical activity. By either exciting or inhibiting neuronal firing in specific cortical regions, it can regulate functional brain networks and is commonly used in studies on brain function mapping, neurorehabilitation, and pain modulation.

Study summary

This is a single-center, randomized, double-blind, sham-controlled trial evaluating dual-carrier-frequency transcranial alternating current stimulation targeting the hippocampus in 60 patients with chronic non-specific low back pain. Participants will be randomized into four groups: active stimulation, active stimulation with iTBS, superficial stimulation control, and sham control. All groups will receive standard rehabilitation. The intervention is 20 minutes per session, 5 sessions weekly for 2 weeks (10 sessions total).

The primary objective is to assess improvements in pain intensity (VAS) and emotional symptoms (anxiety, depression) at week 2. Exploratory objectives include examining functional connectivity changes between the hippocampus and prefrontal/sensory cortices using fMRI, MEG, and fNIRS, and correlating these with clinical improvements.

Outcomes include VAS (primary), McGill Pain Questionnaire, HAMA, HAMD, ODI, CSI, PSQI, and objective measures (brain imaging, EEG, EMG). Assessments occur at baseline (T0), post-first stimulation (T1), mid-treatment (T2), treatment end (T3), and 2-week follow-up (T4).

Linear mixed-effects models will be used for analysis with multiple comparison correction. This study aims to provide evidence for hippocampal-targeted neuromodulation in chronic non-specific low back pain.

Eligibility

Primary outcome measure(s)

• Visual Analogue Scale (VAS) — Pre-enrollment (T0), immediately after the first intervention (T1), mid-intervention (T2), end of the 2-week intervention (T3), and 2-week follow-up (T4)
  A 100-mm visual analogue scale is used, with "0" indicating no pain and "10" indicating the worst possible pain; the subject marks the current pain level on the scale, and the distance (mm) from the left end is measured as the VAS score

Trial sites (1)

More Qilu Hospital of Shandong University trials in China

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