Research has shown that chronic pain is related to variety of perceptual distortions. Little is known on how acute pain experience influences perception, especially precision of touch. This project is aiming to test the hypothesis of pain as a process of biological value leading to improvement in tactile acuity.
This project has following goals: 1. To test the hypothesis of pain as a process of biological value leading to improvement in tactile acuity 2. To investigate intra-rater reliability of tests measuring perceptual distortions in pain 3. To investigate validity of novel tests measuring perceptual distortions in pain 4. To explore the influence of acute neck pain on left/right recognition task 5. To explore the effect of acute neck pain on body perception
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
30
In the saline injection condition, acute neck pain will be induced via 0.5 ml hypertonic (5% NaCl) saline bolus injection which is a commonly used model of acute pain. Saline will be injected into the right (or left) trapezius muscle at the level of C7 cervical level. Injections will be performed by a physician under ultrasound imaging guidance to ensure that each single injection will be equally placed at the same depth. The side for the pain induction will be randomised across subjects. The place of needle insertion and corresponding point on the opposite side of the body will be covered by placing a small piece of adhesive plaster to ensure blinding.
In the sham-injection condition (nocebo comparator), a real needle will be shown to the participants to imitate and produce the anticipation of a pain experience. A pinprick sensation will be produced by a weighted stimulus applied perpendicularly to the skin without piercing the skin. A stimulus of 512 millinewtons (mN) will be used to produce a pinprick sensation and activation of cutaneous nociceptors. Adhesive tapes covering stimulation points will also be provided. The stimuli will be applied in exactly the same spot as the real injection in previous experimental condition.
The Jerzy Kukuczka Academy of Physical Education
Katowice, Poland
Tactile acuity measured by two-point discrimination test (TPD).
Mechanical callipers will be delicately applied to the spot just below the location where real or sham injection will be administered. Tactile stimuli will be applied until the very first blanching of the skin. Testing will be commenced with 0 mm between the two calliper's tips, and then the distance between them will be gradually increased until participants will able to verbally report that two points had been touched instead of one. Subsequently, the descending sequence will be applied until the perception of the two points disappeared.
Time frame: TPD change from baseline at 30 seconds post-manipulation period (e.g. saline injection).
Laterality judgements measured by left/right recognition application.
A set of images displaying human neck in different orientation in space will be show to participants. The goal of the task is to decide whether given picture depicts neck rotated to the left or right or flexed into left o right side. The accuracy and response time is measured.
Time frame: Measured at baseline and ~30 seconds after manipulation (e.g. saline injection).
Sensory dissociation measured by two-point estimation task (TPE).
One tactile stimulus will be applied until the very first blanching of the skin, with a 120 mm horizontal separation between the calipers' tips. Participants will be then asked to indicate with their calipers the distance they have perceived.
Time frame: Measured at baseline and ~30 seconds after manipulation (e.g. saline injection).
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