Clinical trial NCT06470737: Investigation of Corticospinal Excitability Aspects of Itch and Pain
Official title: Investigation of the Neurophysiological and Psychological Aspects of Itch
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Itch
Pain
Lead sponsor: Aalborg University
Sponsor class: OTHER
First posted: 2024-06-24
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: 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.
Primary purpose: BASIC_SCIENCE

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.

Detailed description: The experiment consists of three experimental sessions conducted over a period of two weeks. The duration of each session is approx. two hours. In the first experimental session, 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. This is done using a magnetic coil which is held over your head. During the experiment, you should fill in questionnaires about how you experience itch/pain and about your personality. The second and third experimental sessions are conducted in the same way as the first session. However, we will apply one of the other two experimental methods than the one used in the first session (i.e., first session: histamine, second session: plant needles, third session: injection with salt water). The experimental methods will be applied in random order.

Eligibility criteria: 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.) (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

Primary outcomes:
measure: Numeric rating scales (NRS)
timeFrame: 1 minute after every itch/pain induction
measure: Measuring corticospinal excitability
timeFrame: Baseline
measure: Measuring corticospinal excitability
timeFrame: 1 minute after every itch/pain induction for 10 minutes
measure: Measuring corticospinal excitability
timeFrame: post induction (1 minute)
measure: Measuring corticospinal excitability
timeFrame: post induction (30 minutes)
measure: electromyography (EMG) recordings
timeFrame: 1 minute after every itch/pain induction
Secondary outcomes:
measure: Pain Catastrophizing Scale (PCS).
timeFrame: Baseline
measure: Itch Catastrophizing Scale (ICS).
timeFrame: Baseline
measure: Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ).
timeFrame: Baseline
measure: The Pittsburg Sleep Quality Index (PSQI)
timeFrame: Baseline
measure: Depression, Anxiety, Stress Scale (DASS-21)
timeFrame: Baseline
measure: Learned Helplessness Scale (LHS)
timeFrame: Baseline
measure: Positive And Negative Affect Schedule (PANAS)
timeFrame: Baseline
Other outcomes:
Locations:
city: Gistrup
country: Denmark
facility: Aalborg University
Study officials:
References: