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NCT Number: NCT07432841

Personalized High-Definition tDCS Protocols for Chronic Pain Treatment

This study aims to examine the use of neurostimulation as a potential adjuvant treatment for chronic pain. Among neurostimulation techniques, transcranial direct current stimulation (tDCS) represents a promising, yet not fully exploited, option. Recent methodological advances allow for increased intensity and focality of its effects through personalized high-definition tDCS protocols (HD-tDCS), enabling targeted stimulation of specific brain regions involved in pain and analgesia processing, such as the dorsal anterior cingulate cortex (dACC).

Based on this evidence, the specific objective of the study is to investigate the effect of an innovative HD-tDCS protocol (personalized using structural and functional magnetic resonance imaging (fMRI)), with stimulation applied to the dACC. The experimental design involves randomly assigning 144 patients with chronic pain to three groups, who will undergo an intensive treatment (five sessions in the same week) with cathodal, anodal, or sham (placebo) HD-tDCS.

Patient recruitment and treatment will be equally distributed between sites located in Lombardy (IRCCS Maugeri-Pavia; University of Milano-Bicocca; n=72) and Palermo (IRCCS ISMETT-Palermo; University of Palermo; n=72).

The effects of neurostimulation will be: a) evaluated using self-reported measures of physical and social functioning (Brief Pain Inventory, BPI; primary outcome) before and after treatment, and at follow-up assessments at 3 weeks and 3 months; b) interpreted in relation to underlying neurophysiological changes, as revealed by the high spatial and temporal resolution provided, respectively, by fMR) and by transcranial magnetic stimulation-evoked potentials combined with electroencephalographic recording (TMS-EEG) before and after treatment (secondary outcome).

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Key information

Conditions

Chronic Pain Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Milano-Bicocca, Milan, Italy

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of chronic pain lasting for at least six months
  • Pain scores equal to or greater than 4 on Numerical Rating Scale (NRS) 0-10 on most days for the last 3 months
  • Pain unresponsive to conservative treatment such as pharmacological therapy and physiotherapy, and unresponsive to minimally invasive treatments such as peripheral nerve blocks or neuromodulation or steroid epidural injections, when appropriate
  • Age between 18 and 75
  • Stable pain levels and willingness not to modify any ongoing pain management therapies during the study period (1 week)

Exclusion criteria

  • History of seizure disorders
  • Active malignancy
  • Implanted medical devices and/or metallic implants in the head or neck region
  • Cranial abnormalities
  • Severe cognitive impairment (Montreal Cognitive Assessment (MoCA)<15.5)
  • Neurological or psychiatric conditions, or significant comorbidities, that may interfere with tDCS
  • Pregnancy
  • Incompatibility with MRI and/or TMS

Treatment and study plan

Anodal High-Definition transcranial Direct Current Stimulation

Device

Participants will receive 5 stimulation sessions in a week, with the HD-tDCS setup including 6 electrodes (3 anode + 3 cathode electrodes) delivering a total current of 2mA. The spatial configuration of the six electrodes is aimed to induce the maximum intensity of stimulation at the target stereotactic coordinate, based on the modeling of estimated distribution of electric fields.

The active stimulation lasts for 20 minutes.

Cathodal High-Definition transcranial Direct Current Stimulation

Device

Participants will receive 5 stimulation sessions in a week, with the HD-tDCS setup including 6 electrodes (3 anode + 3 cathode electrodes) delivering a total current of 2mA. The spatial configuration of the six electrodes is aimed to induce the maximum intensity of stimulation at the target stereotactic coordinate, based on the modeling of estimated distribution of electric fields.

The active stimulation lasts for 20 minutes. In cathodal sessions, polarity is reversed.

Sham (No Treatment)

Device

Participants will receive 5 stimulation sessions in a week, with the HD-tDCS setup including 6 electrodes (3 anode + 3 cathode electrodes) delivering a total current of 2mA. The spatial configuration of the six electrodes is aimed to induce the maximum intensity of stimulation at the target stereotactic coordinate, based on the modeling of estimated distribution of electric fields. In sham sessions, the duration is also 20 minutes but participants are unaware that the stimulation intensity gradually ramps down to 0 mA after 30 seconds and then ramps up again during the final 30 seconds.

Primary outcomes

  1. Reduction of perceived pain

    Time frame: Baseline; Up to 3 weeks; After 3 months

    We aim to assess the effect of a personalized (MRI-based) HD-tDCS protocol targeting dACC on clinical measures of perceived chronic pain. To this purpose, patients will be randomly assigned to 3 groups, each undergoing either cathodal, anodal or sham HD-tDCS treatment. Neurostimulation effects will be assessed with self-reported measures of perceived pain, collected via validated subjective functional questionnaires at 3 timepoints: before and after a 1-week (5 sessions) treatment, and at a 3 months follow-up assessment. The BPI score will be indeed considered the primary outcome measure for assessing the effect of HD-tDCS treatment, which will be deemed effective if a 30% reduction of pain intensity and interference on the BPI will be reached. The same statistical approach will be applied to the other clinical scales administered. In case of normality violations, data will be analyzed by means of non-parametric tests.

Secondary outcomes

  1. Change in pain-related neural sensitivity measured with fMRI and TMS-EEG

    Time frame: Baseline; Up to 3 weeks

    Participants will undergo both fMRI and TMS-EEG sessions at the two main timepoints (pre- and post-treatment). For both techniques, data will be collected during a) resting-state (cross-fixation); b) observation of pain-related/unrelated facial expressions and bodily stimulations (Jauniaux et al., 2019). The T1-weighted MRI image collected on the pre-treatment session will be used for personalized targeting/modeling of HD-tDCS electric fields, and for neuronavigation in TMS-EEG sessions.

Sponsors and collaborators

Lead sponsor

Istituti Clinici Scientifici Maugeri SpA

Other

Collaborators

  • IRCCS ISMETT Palermo
  • University of Milano Bicocca
  • University of Palermo

Registry information

Official study title

Innovative Neuromodulation Treatments for Chronic Pain: Assessing and Predicting the Effects of Personalized High-Definition Protocols for Transcranial Direct Current Stimulation (HD-tDCS)

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Feb 25, 2026
Registry last updated
Feb 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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