Mechanistic Study of Personalized rTMS in Chronic Pain

Official title

Building on Previous Evidence: A Mechanistic Clinical Trial of Personalized rTMS for Chronic Pain

Overview

Previous research has demonstrated that repetitive magnetic brain stimulation can be an effective adjunctive treatment for several conditions, including chronic pain. However, current stimulation protocols are typically standardized and do not account for individual variability in brain function. This uniform, one-size-fits-all approach results in only about 40% of patients experiencing meaningful clinical benefit, while the remainder show little to no improvement. To address this limitation, the present study will investigate how magnetic stimulation can be tailored to individuals with chronic pain. By analyzing each participant's brain signals prior to treatment, we aim to personalize stimulation parameters to better match individual neural characteristics and potentially enhance therapeutic outcomes. The design of this study builds directly on the findings of a previous clinical trial.

Detailed description

This study builds directly on previous clinical findings identifying four cortical targets-primary motor cortex (M1), anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC) and the posterior insula (PSI)-as exhibiting neurophysiological properties potentially useful for guiding individualized repetitive transcranial magnetic stimulation (rTMS) target selection. Earlier results demonstrated that chronic pain patients with low alpha-band intertrial coherence (ITC) over M1 were more likely to respond to stimulation of M1, whereas patients with high alpha-band ITC showed a greater likelihood of responding to stimulation of PSI, ACC or DLPFC. These findings suggest that specific electroencephalography (EEG) connectivity markers may help predict the cortical target most likely to provide therapeutic benefit for an individual patient.

Building on this evidence, the present trial will classify participants according to their pre-treatment transcranial magnetic stimulation-electroencephalography (TMS-EEG) connectivity profiles and assign treatment to the cortical region with the highest predicted probability of clinical response.

A total of 90 patients with chronic pain will be enrolled in a double-blind, randomized, two-parallel-arm clinical trial comparing the analgesic effects of individualized target selection with those of the standard rTMS protocol. Participants will be randomized 1:1 to:

* Individualized targeting, in which the rTMS site is selected based on each participant's TMS-EEG connectivity profile * Standard stimulation, representing the conventional rTMS approach for pain relief.

At baseline, participants will complete standardized questionnaires and undergo neurophysiological assessments, including single-pulse TMS-EEG for target classification. The induction phase will then begin, consisting of five consecutive daily rTMS sessions delivered Monday through Friday. Each session lasts 30 minutes, including 15 minutes of active stimulation.

The induction phase will be followed by a 7-week maintenance phase, during which participants receive one rTMS session per week (seven sessions in total). At the end of the maintenance phase, all outcome measures will be reassessed to evaluate treatment efficacy.

Interventions

• Device Classical repetitive trancranial magnetic stimulation to M1
  The rTMS intervention consists of 10-Hz rTMS. Thirty trains of ten seconds with an interval of twenty seconds between trains will be delivered, as traditionally performed. Each train includes 100 pulses, and the total number of pulses will be 3,000 given in 15 minutes.
• Device Personalized Target Arm
  The rTMS intervention consists of 10-Hz rTMS. Thirty trains of ten seconds will be delivered with an interval of twenty seconds between trains. Each train includes 100 pulses, and the total number of pulses will be 3,000 given in 15 minutes. The rTMS will be delivered to the optimal target

Primary outcome measures

• Pain intensity (Visual analogue scale) [Time frame: Visual analogue scale will be assessed before treatment, after 2 months, and again after 3 months. Responders are those with ≥30% pain reduction at the end of maintenance compared to average pain intensity the week before baseline assessment.]

Secondary outcome measures (4)

• Quality of life (EQ-5D) [Time frame: Quality of life changes will be investigated before the treatment, immediately after 2 months of treatment, and again after 3 months of treatment.]
• Patients' Global Impression of Change [Time frame: Patients' Global Impression of Change will be investigated before the treatment, immediately after 2 months of treatment, and again after 3 months of treatment]
• Short Brief Pain Inventory [Time frame: Short Brief Pain Inventory changes will be investigated before the treatment, immediately after 2 months of treatment, and again after 3 months of treatment.]
• Connectivity analysis [Time frame: Connectivity changes will be investigated before the treatment and immediately after 2 months of treatment.]

Eligibility criteria

Inclusion criteria

• Presence of chronic pain (present most of the days for more than 3 months).
• Pain with a mean pain intensity between 3-9 on a 0-10 pain scale (where 0 means no pain and 10 means the worst pain imaginable).
• Speak and understand English or Danish

Exclusion criteria

• Pregnant or breastfeeding
• Current uncontrolled major depression as the main diagnosis
• Current history of substance abuse
• Lack of ability to cooperate, to fully understand the protocol or any difficulty in filling out questionnaires (e.g., due to language or cognitive problems)
• Formal contraindications to TMS application (presence of epilepsy, cranial implanted ferromagnetic devices, e.g., intracranial neurostimulator or cochlear implants, tattoos with metal ink on the face or permanent make up with metal in the face )
• Unable to answer the "Transcranial Magnetic Stimulation Adult Safety Screen" screening questionnaire.
• Participation in other research protocols within 1 month before the inclusion.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Denmark · 1 center

• Aalborg University — Gistrup

Identifiers

NCT: NCT07266103 · N-20230076-4

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗