The Effects of Performing a Motor Imagery Task on Cortical Excitability During Acute Experimental Muscle Pain and Acute Itch

Not Applicable

Recruiting

• Conditions: Itch; Pain
• Interventions: Other: Hypertonic Saline; Other: Histamine; Other: Cowhage; Device: Transcranial magnetic stimulation (TMS)

• Registration Number: NCT06503523
• Lead Sponsor: Aalborg University

Brief Summary

The aim of this project is to determine the effects of performing a motor imagery task on cortical excitability during acute experimental muscle pain (induced by hypertonic saline), acute histaminergic itch (induced by histamine), and non-histaminergic itch stimulation (triggered by Cowhage). We hypothesize that motor imagery will counteract the alterations in cortical excitability observed during experimental muscle pain and both itch models.

Detailed Description

Itch and pain share many similarities and dissimilarities in terms of the mechanisms and molecules involved. Many studies have been conducted to explain all the neurophysiological aspects involved in the pain process, and cortical adaptations have been provoked in healthy individuals using experimental pain models. Unfortunately, all these aspects still need to be clarified regarding itch. Has been previously demonstrated that motor imagery can counteracted the pain-induced decrease in corticospinal excitability observed during acute pain, and it has also been proposed as a potential intervention for individuals with pain to restore maladaptive neuroplasticity. However, whether motor imagery can similarly counteract the itch-induced cortical changes remains unclear. Therefore, the aim of this project is to investigate whether motor imagery would counteract the reduction in cortical excitability during acute itch, similar to the effects observed in the context of acute pain.

Study Timeline

• Study First Submitted: 2024-07-10
• Study First Submitted QC: 2024-07-15
• Study First Posted: 2024-07-16
• Study Start: 2024-10-01
• Status Verified: 2024-11
• Last Update Submitted: 2024-11-20
• Last Update Posted: 2024-11-22
• Primary Completion: 2025-12-31
• Study Completion: 2026-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Healthy men and women
• 18-60 years
• Speak and understand English

Exclusion Criteria

• 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.)
• Presence of implanted hearing aids or metal implants on the face, including permanent makeup or tattoos
• Participation in other trials within one week of study entry (four weeks in the case of pharmaceutical trials)
• Lack of ability to cooperate

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Experimental:Healthy volunteers	Histamine	-
Experimental:Healthy volunteers	Hypertonic Saline	-
Experimental:Healthy volunteers	Transcranial magnetic stimulation (TMS)	-
Experimental:Healthy volunteers	Cowhage	-

Primary Outcome Measures

Name	Time	Method
Numeric rating scales (NRS)	1 minute after every itch/pain induction	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.
Measuring cortical excitability (TEPs)	Post induction of itch or pain	Transcranial magnetic stimulation (TMS) with a figure-eight-shaped cone coil will be used to evoke cortical responses in the motor cortex. The resulting TMS-evoked potentials (TEPs) will be collected using an electroencephalogram (EEG). Similar to the baseline, this assessment will last for 7 minutes after itch or pain.

Secondary Outcome Measures

Name	Time	Method
Pain Catastrophizing Scale (PCS).	Baseline	The PCS assesses negative and exaggerated coping concerning anticipated or experienced painful stimuli. Thirteen items have to be answered on a 5-point Likert-type scale.
Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ).	Baseline	The RST-PQ contains the following subscales: the Fight-Flight-Freeze System (FFFS, 10 items), which represents a defensive factor related to active avoidance of adverse stimuli; the Behavioral Inhibition System (BIS, 23 items), which represents a defensive factor related to anxiety and passive avoidance of adverse stimuli; and the Behavioral Approach System (BAS, 32 items), which reflects reward interest, goal-drive persistence, reward reactivity, and impulsivity. In total, 65 items have to be answered on a 4-point Likert-type scale
The Pittsburg Sleep Quality Index (PSQI)	Baseline	The PSQI consists of 19 items generating seven component scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The seven component scores can be summarized in a global score ranging from zero to 21 with higher scores reflecting a worse overall quality of sleep
Learned Helplessness Scale (LHS)	Baseline	The questionnaire consists of 20 items, and the participant's response to each item is rated on a 4-point Likert scale ranging from strongly agree (1) to strongly disagree (4).
Itch Catastrophizing Scale (ICS).	Baseline	The ICS assesses negative and exaggerated coping concerning anticipated or experienced itchy stimuli. Thirteen items have to be answered on a 5-point Likert-type scale.
Depression, Anxiety, Stress Scale (DASS-21)	Baseline	The questionnaire measures the magnitude of depression, anxiety, and stress. Each of these three subscales consists of 7 questions answered using a 0-3 Likert scale, with 0 meaning "it did not apply to me", and 3 meaning "it applied to me very much".
Positive And Negative Affect Schedule (PANAS)	Baseline	PANAS measures positive and negative affect dimensions. Twenty words are associated with the subject's current feelings and have to be rated on a 5-points Likert-type scale.

Trial Locations

Locations (1)

Aalborg University; 🇩🇰 Gistrup, Denmark