Non-invasive Modulation of Spinal Cord Nociceptive Reflexes

Sponsor

Max Planck Research Group Pain Perception (Other)

Overall Status

Not yet recruiting

CT.gov ID

NCT05711498

Collaborator

(none)

Enrollment

Arms

Anticipated Duration (Months)

Study Details

Study Description

Brief Summary

The aims of this study are threefold. First, to investigate whether spinal nociceptive processing - represented here by the nociceptive flexion reflex (NFR) - is influenced by thoracic transcutaneous spinal direct current stimulation (tsDCS) in a spatially selective manner, i.e., whether effects are only observed for lower limb NFRs, but not for upper limb NFRs. Second, to investigate - in a double-blind, sham-controlled, within-participant design

whether anodal and cathodal tsDCS do affect the NFR in a polarity-dependent manner. Third, to investigate whether tsDCS effects observed on a spinal measure (NFR) are also observed in responses that are mediated supra-spinally, namely autonomic parameters and pain intensity ratings.

Condition or Disease	Intervention/Treatment	Phase
Pain	Other: Transcutaneous spinal direct current stimulation (tsDCS)	N/A

Study Design

Study Type:

Interventional

Anticipated Enrollment :

40 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Masking:

Double (Participant, Investigator)

Primary Purpose:

Basic Science

Official Title:

Non-invasive Investigation of Excitability Changes in the Human Spinal Cord: the Effect of Transcutaneous Spinal Direct Current Stimulation (tsDCS) on Nociceptive Flexion Reflexes

Anticipated Study Start Date :

Jan 31, 2023

Anticipated Primary Completion Date :

Dec 31, 2023

Anticipated Study Completion Date :

Dec 31, 2023

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Anodal thoracic tsDCS Anodal tsDCS will be applied over the T12 vertebra	Other: Transcutaneous spinal direct current stimulation (tsDCS) tsDCS will be carried out using a direct current stimulator (DC-Stimulator Plus, neuroConn, Ilmenau, Germany), with one electrode placed above the thoracic spinal cord and the other electrode placed on the right shoulder. We will employ rectangular electrodes of 7 x 5 cm size (neuroConn, Ilmenau, Germany) covered by electrode paste (Ten20 Conductive Paste, Weaver and Company, Aurora, USA). Stimulation will consist of the following phases: a fade-in period of 15 seconds, a plateau period of 20 minutes (with stimulation at 2.5mA either anodally or cathodally) and a fade-out period of 15 seconds. Sham stimulation will follow the anodal montage with 15-second fade-in and fade-out periods, but only 45 seconds of plateau stimulation at 2.5 mA. Such a combination of stimulation and electrodes results in a current density of 0.071mA/cm2, well below thermal and histological limits for current density.
Experimental: Cathodal thoracic tsDCS Cathodal tsDCS will be applied over the T12 vertebra	Other: Transcutaneous spinal direct current stimulation (tsDCS) tsDCS will be carried out using a direct current stimulator (DC-Stimulator Plus, neuroConn, Ilmenau, Germany), with one electrode placed above the thoracic spinal cord and the other electrode placed on the right shoulder. We will employ rectangular electrodes of 7 x 5 cm size (neuroConn, Ilmenau, Germany) covered by electrode paste (Ten20 Conductive Paste, Weaver and Company, Aurora, USA). Stimulation will consist of the following phases: a fade-in period of 15 seconds, a plateau period of 20 minutes (with stimulation at 2.5mA either anodally or cathodally) and a fade-out period of 15 seconds. Sham stimulation will follow the anodal montage with 15-second fade-in and fade-out periods, but only 45 seconds of plateau stimulation at 2.5 mA. Such a combination of stimulation and electrodes results in a current density of 0.071mA/cm2, well below thermal and histological limits for current density.
Sham Comparator: Sham thoracic tsDCS Sham tsDCS will be applied over the T12 vertebra	Other: Transcutaneous spinal direct current stimulation (tsDCS) tsDCS will be carried out using a direct current stimulator (DC-Stimulator Plus, neuroConn, Ilmenau, Germany), with one electrode placed above the thoracic spinal cord and the other electrode placed on the right shoulder. We will employ rectangular electrodes of 7 x 5 cm size (neuroConn, Ilmenau, Germany) covered by electrode paste (Ten20 Conductive Paste, Weaver and Company, Aurora, USA). Stimulation will consist of the following phases: a fade-in period of 15 seconds, a plateau period of 20 minutes (with stimulation at 2.5mA either anodally or cathodally) and a fade-out period of 15 seconds. Sham stimulation will follow the anodal montage with 15-second fade-in and fade-out periods, but only 45 seconds of plateau stimulation at 2.5 mA. Such a combination of stimulation and electrodes results in a current density of 0.071mA/cm2, well below thermal and histological limits for current density.

Arm

Intervention/Treatment

Experimental: Anodal thoracic tsDCS

Anodal tsDCS will be applied over the T12 vertebra

Other: Transcutaneous spinal direct current stimulation (tsDCS)

tsDCS will be carried out using a direct current stimulator (DC-Stimulator Plus, neuroConn, Ilmenau, Germany), with one electrode placed above the thoracic spinal cord and the other electrode placed on the right shoulder. We will employ rectangular electrodes of 7 x 5 cm size (neuroConn, Ilmenau, Germany) covered by electrode paste (Ten20 Conductive Paste, Weaver and Company, Aurora, USA). Stimulation will consist of the following phases: a fade-in period of 15 seconds, a plateau period of 20 minutes (with stimulation at 2.5mA either anodally or cathodally) and a fade-out period of 15 seconds. Sham stimulation will follow the anodal montage with 15-second fade-in and fade-out periods, but only 45 seconds of plateau stimulation at 2.5 mA. Such a combination of stimulation and electrodes results in a current density of 0.071mA/cm2, well below thermal and histological limits for current density.

Experimental: Cathodal thoracic tsDCS

Cathodal tsDCS will be applied over the T12 vertebra

Other: Transcutaneous spinal direct current stimulation (tsDCS)

Sham Comparator: Sham thoracic tsDCS

Sham tsDCS will be applied over the T12 vertebra

Other: Transcutaneous spinal direct current stimulation (tsDCS)

Outcome Measures

Primary Outcome Measures

Change in NFR amplitude [Baseline and immediately after the intervention]
90-150ms for lower limb, 60-200ms for upper limb
Change in pain intensity rating [Baseline and immediately after the intervention]
One rating per trial on a standard visual analogue scale (VAS); internally numbered from 0 (no sensation) to 100 (unbearable pain)
Change in skin conductance response [Baseline and immediately after the intervention]
Amplitude maximum before onset of pain rating
Change in heart period acceleration [Baseline and immediately after the intervention]
Amplitude maximum before onset of pain rating

Secondary Outcome Measures

Change in NFR area [Baseline and immediately after the intervention]
90-150ms for lower limb, 60-200ms for upper limb

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 40 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Healthy volunteers between the ages of 18 and 40 years
Having participated in the MRI medical assessment session and consented to taking part in 3T MRI measurements in written form
Having participated in the magnetic/electric neurostimulation medical assessment session and consented to taking part in magnetic/electric neurostimulation experiments in written form
Voluntary participation and signing of the study-specific consent form

Exclusion Criteria:

Existence of any contraindications for MRI measurements and magnetic/electric neurostimulation experiments
Pregnancy or breastfeeding
Very dry or sensitive skin (e.g., intolerance to creams/shampoos)
Chronic skin diseases - such as eczema or neurodermatitis - in the area of somatosensory / nociceptive stimulation (arm or hand, leg or foot) or electrophysiological data recording (upper body, arm, leg)
Scar tissue in the area of somatosensory / nociceptive stimulation (arm or hand, leg or foot) or electrophysiological data recording (upper body, arm, leg)
Acute sunburn in the area of somatosensory / nociceptive stimulation (arm or hand, leg or foot) or electrophysiological data recording (upper body, arm, leg)
Current or recurring pain
Injuries to the nervous system
History of or current neurological or psychiatric disorders
Chronic diseases that require permanent medication (e.g., asthma, diabetes mellitus, etc.)
Persons not capable of giving consent (e.g., in case of dementia)
Lack of consent with regards to report of incidental findings

Contacts and Locations

Locations

No locations specified.

Sponsors and Collaborators

Max Planck Research Group Pain Perception

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

Responsible Party:

Max Planck Research Group Pain Perception

ClinicalTrials.gov Identifier:

NCT05711498

Other Study ID Numbers:

PP016

First Posted:

Feb 3, 2023

Last Update Posted:

Feb 6, 2023

Last Verified:

Feb 1, 2023

Individual Participant Data (IPD) Sharing Statement:

Plan to Share IPD:

Studies a U.S. FDA-regulated Drug Product:

Studies a U.S. FDA-regulated Device Product:

Study Results

No Results Posted as of Feb 6, 2023