Investigation of Corticospinal Excitability Aspects of Itch and Pain

NCT06470737 | Completed DMC

• 1 other identifier: N-20240004 1st subproject
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The experiment consists of three experimental sessions conducted over a period of two weeks. In the first experimental session, we apply in your hand: either an injection of salt water (7% NaCl) or we apply small needles from the plant mucuna pruriens or histamine (1%). For 10 minutes after this, you are to assess the itch and pain you perceive. We will also apply non-invasive magnetic stimulations to your brain. During the experiment, you should fill in questionnaires. The second and third experimental sessions are conducted in the same way as the first session. The purpose of this experiment is to investigate the changes appearing in the brain during artificially applied itch and pain corticomotor adaptations.

Conditions

Itch; Pain

Outcome Measures

Primary Outcomes (6)

• Numeric rating scales (NRS)

  NRS are essentially VAS but have tick marks spaced every centimeter so as to create 11-point scale (from 0 to 10). Subject can use these tick marks as a guide when they mark their severity on the scale.

  1 minute after every itch/pain induction

• Measuring corticospinal excitability

  Transcranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMS-evoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.

  Baseline

• Measuring corticospinal excitability

  Transcranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMS-evoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.

  1 minute after every itch/pain induction for 10 minutes

• Measuring corticospinal excitability

  Transcranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMS-evoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.

  post induction (1 minute)

• Measuring corticospinal excitability

  Transcranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMS-evoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.

  post induction (30 minutes)

• electromyography (EMG) recordings

  For electromyography (EMG) recordings, two electrodes (Disposable Electrode Pack - AMBU Neuroline 720) will be placed on the muscle belly of the FDI muscle. The reference electrode will be placed on the ulnar styloid process of the left arm.

  1 minute after every itch/pain induction

Secondary Outcomes (7)

• Pain Catastrophizing Scale (PCS).

  Baseline

• Itch Catastrophizing Scale (ICS).

  Baseline

• Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ).

  Baseline

• The Pittsburg Sleep Quality Index (PSQI)

  Baseline

• Depression, Anxiety, Stress Scale (DASS-21)

  Baseline

Study Arms (1)

Healthy volunteers

EXPERIMENTAL

Other: Hypertonic Saline; Other: Histamine; Other: Cowhage; Device: Transcranial magnetic stimulation (TMS)

Interventions

Hypertonic Saline OTHER

A bolus injection of hypertonic saline (7% NaCl) will be administered to the FDI muscle using a 1 mL syringe with a disposable needle (27G), and the volume of the bolus will be 0.2 mL

Healthy volunteers

Histamine OTHER

A small drop of histamine dihydrochloride will be applied to a previously determined area on the volar forearm, followed by a prick through the drop

Healthy volunteers

Cowhage OTHER

This insertion is conducted by forceps using a stereo-microscope, and 30-35 spicules are gently rubbed into a 1 cm diameter skin area.

Healthy volunteers

Transcranial magnetic stimulation (TMS) DEVICE

Transcranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMS-evoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.

Healthy volunteers

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy men and women
• years
• Speak and understand English

You may not qualify if:

• Pregnancy or lactation
• Drug addiction defined as any use of cannabis, opioids, or other addictive drugs
• Previous or current history of neurological (e.g. neuropathy), immunological (e.g. asthma, immune deficiencies, arthritis), musculoskeletal (e.g. muscular pain in the upper extremities,), cardiac disorder (e.g., heart stroke), or psychiatric diagnoses (e.g. depression) that may affect the results
• Current use of medications that may affect the trial, such as antihistamines, antipsychotics, and painkillers, as well as systemic or topical steroids
• Skin diseases (e.g., atopic dermatitis, pruritus nodularis, eczema, psoriasis)
• Moles, scars, or tattoos in the area to be treated or tested.
• Consumption of alcohol or painkillers 24 hours before the study days and between these
• Acute or chronic pain
• Unable to pass the "Transcranial Magnetic Stimulation Adult Safety Screen" (subproject 1 and 2)
• Contraindications to transcranial magnetic stimulation (TMS) application (history of epilepsy, metal implants in head or jaw, etc.) (subproject 1 and 2)
• Presence of implanted hearing aids or metal implants on the face, including permanent makeup or tattoos (subproject 1 and 2)
• Participation in other trials within one week of study entry (four weeks in the case of pharmaceutical trials)
• Lack of ability to cooperate

Sponsors & Collaborators

• Aalborg University: lead

Study Sites (1)

Aalborg University

Gistrup, 9260, Denmark

Location

MeSH Terms

Conditions

Pruritus; Pain

Interventions

Saline Solution, Hypertonic; Histamine; Transcranial Magnetic Stimulation

Condition Hierarchy (Ancestors)

Skin Diseases; Skin and Connective Tissue Diseases; Skin Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Neurologic Manifestations

Intervention Hierarchy (Ancestors)

Hypertonic Solutions; Solutions; Pharmaceutical Preparations; Biogenic Monoamines; Biogenic Amines; Amines; Organic Chemicals; Ethylamines; Imidazoles; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Autacoids; Inflammation Mediators; Biological Factors; Magnetic Field Therapy; Therapeutics

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: we apply one of three experimental methods in your hand: either an injection of salt water (7% NaCl) or we apply small needles from the plant mucuna pruriens or histamine (1%) Histamine is an itch-provoking substance formed in the human body. For 10 minutes after this, you are to assess the itch and pain you perceive on a scale from 0 to 10, in which 0 is no itch/pain and 10 is worst itch/pain imaginable. We will also apply non-invasive magnetic stimulations to your brain.

Study Record Dates

• First Submitted: June 14, 2024
• First Posted: June 24, 2024
• Study Start: July 1, 2024
• Primary Completion: September 30, 2024
• Study Completion: October 31, 2024
• Last Updated: November 22, 2024

Record last verified: 2024-11

Data Sharing

• IPD Sharing: Will not share

Locations

DK (1)