NCT06470737

Investigation of Corticospinal Excitability Aspects of Itch and Pain

Investigation of the Neurophysiological and Psychological Aspects of Itch

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 30 (actual)
• Sponsor: Aalborg University · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

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.

Conditions

• Itch
• Pain

Interventions

Type	Name	Description
OTHER	Hypertonic Saline	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
OTHER	Histamine	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
OTHER	Cowhage	This insertion is conducted by forceps using a stereo-microscope, and 30-35 spicules are gently rubbed into a 1 cm diameter skin area.
DEVICE	Transcranial magnetic stimulation (TMS)	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.

Timeline

• Start date: 2024-07-01
• Primary completion: 2024-09-30
• Completion: 2024-10-31
• First posted: 2024-06-24
• Last updated: 2024-11-22

Locations

1 site across 1 country: Denmark