Home-based Transcranial Stimulation in the Treatment of Patients With Refractory Chronic Pain

October 18, 2021 updated by: María Teresa Carrillo de la Peña, University of Santiago de Compostela

Brain and Pain (BaP): Understanding the Central Mechanisms of Pain to Improve Management of Patients With Refractory Chronic Pain

Refractory chronic pain represents a serious and limiting health condition which does not respond to standard pharmacological therapy. Thus, it emerges the necessity of new techniques to treat these group of diseases, such as the transcranial electrical stimulation (tES). This procedure induces a low-intensity electrical current through the scalp to modify the excitability of brain cells, thus facilitating changes in neural networks which may be dysfunctional in some chronic pain patients.

The main objective of this research is to test the efficacy of two tES techniques, differentiated by applying direct or alternant electrical current, to reduce the pain intensity and to increase pain thresholds of these patients. Besides, intervention is implemented at home for patients themselves thanks to a portable and convenient stimulator device, after one training session provided by technicians. Researches can supervise the compliance of the treatment remotely, as the stimulator has a permanent connection with their computers. A home-based approach means a more comfortable and accessible treatment alternative for patients, since they do not have to attend to clinics everyday to receive the stimulation; the advantages become even more relevant in the pandemic context, since the risk of being infected is radically minimized.

Despite the main purpose is to test the efficacy of tES to improve the pain suffered by patients, many other areas are considered as secondary end points for being intrinsically linked or affected by the disease, such as the interference in daily tasks provoked by pain, mood disorders (depression/anxiety), fatigue, life quality, physical functioning and sleep quality; these last two variables are measured with actigraph wristwatches, apart from specific questionnaires. Lastly, endogenous modulatory pain mechanisms are examined through sensory tests, namely Conditioned Pain Modulation and Temporal Summation of pain.

Study Overview

Status

Recruiting

Conditions

Detailed Description

This work aims to provide answers to the refractory chronic pain challenge. Pain is defined as refractory when multiple evidence-based biomedical therapies have failed to reach treatment goals that may include adequate pain reduction and/or improvement in daily functioning, even after appropriately assessing and addressing those psychosocial factors that could influence pain outcomes. In this sense, on the one hand, the study focus on detecting central biomarkers of pain modulation and processing which will contribute to improving knowledge of the mechanisms of pain chronification and the diagnosis procedure. On the other hand, given the low efficacy of pharmacological or non-pharmacological therapies for the patients studied, the efficacy of new therapeutic alternatives (tES) is explored. In short, the project will allow the transfer of knowledge to clinical practice in several aspects, such as diagnosis or treatment.

Therefore, the research aims to test the role of defective central pain modulation/processing as explanatory mechanisms for chronic pain. A second main objective is to test the efficacy of transcranial electric stimulation (tES) to modify dysfunction of central mechanism of pain, and to improve symptoms and quality of life in refractory chronic pain patients.

To achieve this, the investigators will select valid and reliable instruments to assess pain and comorbid symptoms in chronic pain patients and the most sensitive outcome measures to assess tES treatment efficacy. Sensory testing paradigms, namely Conditioned Pain Modulation, Temporal Summation of Second Pain and pain-related evoked potentials using electroencephalographic recordings, will act as biomarkers which are proposed to correlate with the severity of the chronic pain disease or some of their symptoms, and also as predictors of the treatment outcome.

Total sample includes 120 patients with refractory pharmaco-resistant pain, attended at the Pain Units of two Public Galician Hospitals (36 male, 84 female).

The study is expected to contribute to detection and preventive measures of future pain, and diagnosis of chronic pain disorders, improving prognosis and development of feasible patient-centered interventions, providing new directions for future research on pain.

Study Type

Interventional

Enrollment (Anticipated)

120

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

    • A Coruña
      • Santiago De Compostela, A Coruña, Spain, 15701
        • Recruiting
        • University of Santiago de Compostela
        • Contact:
        • Principal Investigator:
          • María Teresa Carrillo de la Peña, PhD, University teacher
        • Sub-Investigator:
          • Noelia Sanmartín Veiga, PhD Student
        • Sub-Investigator:
          • Alberto González Villar, PhD
        • Sub-Investigator:
          • Mónica Mayo Moldes
        • Sub-Investigator:
          • José Javier Carceller Ruíz
        • Sub-Investigator:
          • Pablo López País
        • Sub-Investigator:
          • Fátima Fernández Feijoó, BsC
        • Sub-Investigator:
          • J. Antonio Vázquez Millán, BsC
        • Sub-Investigator:
          • Antonio Gil Ugidos, PhD Student
        • Sub-Investigator:
          • Lara Rubal Otero, PhD Student

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Suffering a chronic pain condition of non-cancer nature. Those patients who report chronic pain even after overcoming an oncological process are suitable to participate, but only if they have received the definitive medical discharge and have been free from radiotherapy/chemotherapy for at least twelve months.
  • Adult subjects (18-65 years old).
  • Subjects able to provide informed consent to participate in the study and to self-report pain.
  • Existing chronic pain which reaches an intensity of at least 4 on a 0-10 Numeric Rating Scale (NRS) on average over the past 3 months prior to enrolment.
  • Pain intensity of at least 5 on a 0-10 NRS over the week prior to enrolment.
  • Diagnosis of pharmaco-resistance to analgesic drugs across the WHO ladder.
  • Pharmacological regimen have kept stable for at least two months previous to the enrolment, and it must not suffer modifications during the whole research period.

Exclusion Criteria:

  • Chronic pain derived from current cancer disease.
  • Pregnant women or women in fertile age not having efficacious contraception during the whole period of the study.
  • History of alcohol or drug abuse within the past 6 months as self-reported.
  • Suffering from unstable medical conditions (e.g., uncontrolled diabetes, uncompensated cardiac issues, heart failure or chronic obstructive pulmonary disease).
  • Intracranial ferromagnetic devices or implanted stimulator (basal ganglia stimulator, vagus nerve stimulation).
  • Antecedents of, or active epilepsy.
  • History of neurosurgery, psychiatric diseases other than anxiety or depression, traumatic brain injury with loss of consciousness, and/or cortical lesions.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Transcranial direct current stimulation (tDCS)
Fifteen stimulation sessions applied with a daily frequency during an uninterrupted period of time which comprises just over two weeks. Current intensity of 2mA is applied during 20 minutes at the left M1, with anodal electrode placed in C3 and cathodal in FP2, following the International 10-20 EEG System. Ramp-up and ramp-down comprises 15 seconds at the beginning and end of the stimulation period.

By applying a low current over the cortex through the scalp, this technique can excite or inhibit the neural activity, thus modulating brain processes like pain perception and inducing relatively sustained changes in cortical excitability and neuroplasticity.

Home-based transcranial electrical stimulation device consists of a custom headgear with fixed electrode sites and built-in cabling made for a simplistic setup for tDCS/tACS stimulation. Systems are equipped with strict dose control feature that provide reliable control over the intensity and timing of stimulation, turning these devices into a feasible and safe clinical alternative. The equipment is specifically designed for easy and simplistic self-setup and allows the researchers to remotely check the position of electrodes and also monitor the stimulation session.

Other Names:
  • Transcranial direct current stimulation
  • Transcranial alternant current stimulation
Active Comparator: Transcranial alternant current stimulation (tACS)
Fifteen stimulation sessions applied with a daily frequency during an uninterrupted period of time which comprises just over two weeks. Two electrodes will be placed at F3 and F4 and connected together for 10-Hz tACS (or the frequency which shows best sensitivity or specificity), and one electrode at Pz will be the return electrode. This setting is used to stimulate the somatosensory cortical region. Stimulation will last for 20 minutes, with a ramp-up and ramp-down of 15 seconds at the beginning and end of the session.

By applying a low current over the cortex through the scalp, this technique can excite or inhibit the neural activity, thus modulating brain processes like pain perception and inducing relatively sustained changes in cortical excitability and neuroplasticity.

Home-based transcranial electrical stimulation device consists of a custom headgear with fixed electrode sites and built-in cabling made for a simplistic setup for tDCS/tACS stimulation. Systems are equipped with strict dose control feature that provide reliable control over the intensity and timing of stimulation, turning these devices into a feasible and safe clinical alternative. The equipment is specifically designed for easy and simplistic self-setup and allows the researchers to remotely check the position of electrodes and also monitor the stimulation session.

Other Names:
  • Transcranial direct current stimulation
  • Transcranial alternant current stimulation
Placebo Comparator: Sham stimulation
The electrode montage will be either the tDCS (for half of the participants) or the tACS montage (for the other half), and we will just apply the current at the ramps terms, but no current in the interval between the ramps which practically comprises the whole session. As for the two other group, fifteen sham stimulation sessions will be daily scheduled in a non-interrupted period of two weeks.

By applying a low current over the cortex through the scalp, this technique can excite or inhibit the neural activity, thus modulating brain processes like pain perception and inducing relatively sustained changes in cortical excitability and neuroplasticity.

Home-based transcranial electrical stimulation device consists of a custom headgear with fixed electrode sites and built-in cabling made for a simplistic setup for tDCS/tACS stimulation. Systems are equipped with strict dose control feature that provide reliable control over the intensity and timing of stimulation, turning these devices into a feasible and safe clinical alternative. The equipment is specifically designed for easy and simplistic self-setup and allows the researchers to remotely check the position of electrodes and also monitor the stimulation session.

Other Names:
  • Transcranial direct current stimulation
  • Transcranial alternant current stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Self-reported pain intensity
Time Frame: Pre-treatment measure is the average of pain intensity of fifteen days previous to treatment; whereas the post-treatment measure is the average of fifteen days after treatment have finished
Participants must evaluate the intensity of their pain using an online version of a Numerical Rating Scale of eleven points (0-10), so that the higher the score is, the worse the pain is.
Pre-treatment measure is the average of pain intensity of fifteen days previous to treatment; whereas the post-treatment measure is the average of fifteen days after treatment have finished

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Global severity of chronic pain syndrome
Time Frame: Participants will complete MPI one or two days before the treatment onset, and one or two days after treatment ending.
Composed index about the gravity of the chronic pain condition, taking into account several parameters as social and professional limitations due to pain, frequency and intensity of pain crisis, among others. The severity of chronic pain syndrome is assessed with global and subscales scores of Multidimensional Pain Inventory (MPI). Higher scores are indicative of worse health condition.
Participants will complete MPI one or two days before the treatment onset, and one or two days after treatment ending.
Pressure pain threshold
Time Frame: Pressure pain thresholds will be assessed in face-to-face laboratory sessions, which would take place one or two days before the treatment onset and one or two days after treatment ending.
Pressure pain threshold is defined as the minimum force necessary to induce pain in the participant, measured using a manual algometer and operationalized in kPa.
Pressure pain thresholds will be assessed in face-to-face laboratory sessions, which would take place one or two days before the treatment onset and one or two days after treatment ending.
Heat pain threshold
Time Frame: Heat pain thresholds will be assessed in face-to-face laboratory sessions, which would take place one or two days before the treatment onset and one or two days after treatment ending.
Heat pain threshold is stablished as the temperature, measured in degrees Celsius, at which participant starts to feel pain, using a thermal stimulator.
Heat pain thresholds will be assessed in face-to-face laboratory sessions, which would take place one or two days before the treatment onset and one or two days after treatment ending.
Interference in daily living caused by pain
Time Frame: Pain interference will be assessed in face-to-face laboratory sessions, which would take place one or two days before the treatment onset and one or two days after treatment ending.
Subscales of Multidimensional Pain Inventory (MPI) are used to evaluate whether patients usually leave undone or are not capable to do some daily activities and tasks due to the pain they suffer from. The test consists of a numerical rating scale of seven points (0-6), so that the higher the score is, the more pronounced is the interference due to pain.
Pain interference will be assessed in face-to-face laboratory sessions, which would take place one or two days before the treatment onset and one or two days after treatment ending.
Life quality
Time Frame: Life quality will be assessed one or two days before the treatment onset and one or two days after treatment ending.
General health status considering physical, emotional and social functionality, as well as physical and mental health. Life quality is measured using the Short Form-36 Health Survey (SF-36). Higher scores are indicative of better health condition.
Life quality will be assessed one or two days before the treatment onset and one or two days after treatment ending.
Physical condition and functioning
Time Frame: Estimations about daily energy expenditure, based on sedentary and activity bouts are recorded with wristband actigraphs which participants must wear during the whole research period.
Involvement and time-spent in physical activities or exercises.
Estimations about daily energy expenditure, based on sedentary and activity bouts are recorded with wristband actigraphs which participants must wear during the whole research period.
Sleep quality and disturbances
Time Frame: Participants will complete PQSI at two time-points, this is, one or two days before the treatment onset and one or two days after treatment ending.
Sleep habits of participants and the degree in which they perceive that sleep as restorative. Sleep quality is measured using the Pittsburgh Sleep Quality Index (PSQI), a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. Higher scores are indicative of poorer sleep quality.
Participants will complete PQSI at two time-points, this is, one or two days before the treatment onset and one or two days after treatment ending.
Sleep quality and disturbances
Time Frame: Wristband actigraph are given to patients fifteen days before the treatment onset, so sleep habits are monitorized since that moment, until fifteen days after treatment have finished
Sleep habits of participants, as total sleep time. This sleep parameter is measured using the data recorded for wristband actigraphs which participants must wear during the whole research period.
Wristband actigraph are given to patients fifteen days before the treatment onset, so sleep habits are monitorized since that moment, until fifteen days after treatment have finished
Pain unpleasantness
Time Frame: Pre-treatment measure is the average of pain unpleasantness obtained from fifteen daily assessments previous to treatment; whereas the post-treatment measure is the average obtained from the fifteen days after treatment have finished
Affective component of pain, which refers to the discomfort or distress which pain provokes in patients. Participants must evaluate the discomfort produced by pain using an online version of a Numerical Rating Scale of eleven points (0-10), so that the higher the score is, the more stressful the pain is.
Pre-treatment measure is the average of pain unpleasantness obtained from fifteen daily assessments previous to treatment; whereas the post-treatment measure is the average obtained from the fifteen days after treatment have finished
Mood disorders
Time Frame: Participants will complete HADS at two time-points, this is, one or two days before the treatment onset and one or two days after treatment ending.
Depressive and anxiety symptomatology which can concur with chronic pain conditions. Mood alterations are measured using the Hospital Anxiety and Depression Scale (HADS). Higher scores are indicative of a worse mood state.
Participants will complete HADS at two time-points, this is, one or two days before the treatment onset and one or two days after treatment ending.
Anxiety
Time Frame: Pre-treatment measure is the average of anxiety levels obtained from fifteen daily assessments previous to treatment; whereas the post-treatment measure is the average obtained from the fifteen days after treatment have finished
General anxiety level are evaluated with a daily frequency using an online version of a Numerical Rating Scale of eleven points (0-10), so that the higher the score is, the higher the anxiety level is.
Pre-treatment measure is the average of anxiety levels obtained from fifteen daily assessments previous to treatment; whereas the post-treatment measure is the average obtained from the fifteen days after treatment have finished
Fatigue
Time Frame: Fatigue is registered with a daily frequency since the fifteen days before the treatment onset, until fifteen days after treatment ending. Participants will complete the MFIS at two time-points, this is, one or two days before and after treatment.
Tiredness which may result in difficulties to perform physical or psychological tasks. Fatigue and its consequences are measured using the Modified Impact Fatigue Scale (MFIS). Numerical Rating Scales of eleven points (0-10) are also used to assess daily fatigue levels. In both cases, higher scores are indicative of a greater fatigue.
Fatigue is registered with a daily frequency since the fifteen days before the treatment onset, until fifteen days after treatment ending. Participants will complete the MFIS at two time-points, this is, one or two days before and after treatment.
Caregiver burden
Time Frame: Caregivers are invited to a face-to-face interview with researchers one or two days before the treatment onset and one or two days after treatment ending.
Stress levels which are subjected the caregivers of chronic pain patients are evaluated through the Zarit Burden Interview (ZBI) to assess if tES treatment means a reduction in burden derived from caring tasks. Higher scores are indicative of a more pronounced caregiver burden.
Caregivers are invited to a face-to-face interview with researchers one or two days before the treatment onset and one or two days after treatment ending.
Global satisfaction with treatment and self-perceived improvement
Time Frame: Participants will evaluate their satisfaction with treatment a few days after it had finished.
Patients are asked to rate their satisfaction with the tES treatment and whether they believe it has helped to improve their health status, using an ad-hoc designed questionnaire.
Participants will evaluate their satisfaction with treatment a few days after it had finished.

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Endogenous pain inhibition response
Time Frame: CPM procedure will be performed at two time-points, this is, one or two days before and after treatment, in order to assess if tES treatment is capable of restoring any dysfunction in this inhibitory pain network.
Inhibitory pain system will be assessed through the Conditioned Pain Modulation (CPM) paradigm, which consists of the reduction of the pain provoked by a given noxious stimulus (i.e., test stimulus) when another painful stimulus (i.e., conditioning stimulus) is applied to a remote area (i.e., pain inhibits pain). Tentatively, we will use the cold water immersion of the non-dominant hand as conditioning stimuli; whereas the test stimuli will be the pressure pain thresholds using a digital handhold algometer, which puts progressively heavier pressure over the lateral area of dominant forearm. Differences in pressure pain threshold between the standard condition and when the CS is applied is assumed as an index of pain inhibitory response. Negative values are indicative of a greater pain inhibitory response.
CPM procedure will be performed at two time-points, this is, one or two days before and after treatment, in order to assess if tES treatment is capable of restoring any dysfunction in this inhibitory pain network.
Endogenous pain facilitation response
Time Frame: TSSP procedure will be performed at two time-points, this is, one or two days before and after treatment, in order to assess if tES treatment is capable of restoring any dysfunction in this facilitatory pain network.
Amplifier pain system will be assessed through the Temporal Summation of Second Pain (TSSP) paradigm, which consists of the augmentation of subjective pain sensations due to the application of repeated noxious stimuli over the same corporal area, even when those stimuli are equal in terms of intensity and duration. Positive values are indicative of a greater pain facilitation score.
TSSP procedure will be performed at two time-points, this is, one or two days before and after treatment, in order to assess if tES treatment is capable of restoring any dysfunction in this facilitatory pain network.
Electrical brain activity over diverse conditions
Time Frame: EEG will be registered at two time-points, this is, one or two days before and one or two days after treatment.
Using the electroencephalography, we will capture the brain default mode network of chronic pain patients. Besides, we will register the evoked potentials elicited by diverse types of noxious heat-stimuli, as they may be reflecting how nociceptive signals are processed by brain. We purport to make a time-frequency and connectivity analysis of the EEG paying special attention to those key frequency bands involved in nociceptive perception, such as theta, alpha and gamma bands.
EEG will be registered at two time-points, this is, one or two days before and one or two days after treatment.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

January 1, 2022

Primary Completion (Anticipated)

May 1, 2023

Study Completion (Anticipated)

May 1, 2023

Study Registration Dates

First Submitted

August 30, 2021

First Submitted That Met QC Criteria

October 18, 2021

First Posted (Actual)

October 29, 2021

Study Record Updates

Last Update Posted (Actual)

October 29, 2021

Last Update Submitted That Met QC Criteria

October 18, 2021

Last Verified

October 1, 2021

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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