About this trial
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.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Healthy men and women
18-60 years
Speak and understand English
Disqualifiers
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
Trial design
Single group
Treatments tested in this trial
Hypertonic Saline
Other interventionA 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 0.1 mL
Histamine
Other interventionA small drop of histamine dihydrochloride will be applied to a previously determined area on the volar forearm, followed by a prick through the drop
Cowhage
Other interventionThis insertion is conducted by forceps using a stereomicroscope, and 30-35 spicules are gently rubbed into a 1 cm diameter skin area.
Transcranial magnetic stimulation (TMS)
DeviceTranscranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMSevoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.
Treatment groups
Trial outcomes
Primary outcomes
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.
Measuring cortical excitability (TEPs)
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). This assessment will last for 7 minutes before inducing itch or pain.
Measuring cortical excitability (TEPs)
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). This assessment will last for 7 minutes during itch or pain. The pain or itch sensation will last 10 minutes.
Measuring cortical excitability (TEPs)
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). This assessment will last for 7 minutes during motor imagery task.
Secondary outcomes
Pain Catastrophizing Scale (PCS).
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.
Itch Catastrophizing Scale (ICS).
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.
Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ).
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)
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
Sponsors and contacts
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