The purpose of this prospective study is to investigate how close Heat Pain Detection Threshold is associated with the area of secondary hyperalgesia, elicited by the clinical pain model Brief Thermal Sensitization. Furthermore we wish to investigate how close the clinical pain model: Pain during 1 min. heating of the skin (45 degrees celsius), and the psychological tests, Pain Catastrophizing Scale and Hospital Anxiety and Depression Scale are associated with the area of secondary hyperalgesia, elicited by the clinical pain model Brief Thermal Sensitization.
The study participants will be tested with 3 types of clinical pain models on two separate identical study days. A minimum of 7 days will separate the two study days, thus, the minimum length of the study is 7 days, but can be higher. The 3 types of pain conditioning consist of 1) Brief thermal sensitisation (BTS), 2) Heat pain detection threshold (HPDT), and pain during 1 min. thermal stimulation (p-TS. The order of the stimulations (HPDT and BTS) is randomised for each patient and each study day, by a random allocation sequence, computer-generated by Copenhagen Trial Unit and stored in sealed and opaque envelopes to secure adequate allocation concealment. p-TS is conducted subsequent to BTS and HPDT. The participants will complete the psychological tests Pain Catastrophizing Scale (PCS) and Hospital Anxiety and Depression Scale (HADS) in their private home prior to study day 1. The completed tests will be placed in opaque sealed envelopes to secure blinding of the investigator and outcome assessor.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
121
A small area of the skin of the study participants are heated to 45 degree celsius for 3 minutes, followed by evaluation of secondary hyperalgesia.
A small area of the skin of the study participants are heated to 45 degrees celsius for 1 minute. During the 1 minute period, the study participant will continually report pain on an electronic visual analog scale.
The threshold for heat pain are evaluated by heating a small area of the study participants skin. When the study participant feels pain, the temperature (degrees celsius) is registered. 4 threshold measurements per session. Heat pain threshold is defined as the average temperature of the 4 measurements.
Department of anaesthesia and surgery, 4231, Rigshospitalet
Copenhagen, Denmark
Size of the Area of secondary hyperalgesia following Brief thermal sensitization, evaluated by cm2, and heat pain detection threshold registered by degrees celsius.
How close is the Heat Pain Detection Threshold associated with the size of the area of secondary hyperalgesia induced by Brief thermal sensitization? Area of secondary hyperalgesia will be investigated on two separate study days separated with a minimum of 7 days. The association will be expressed in R2 and prediction intervals for the area of BTS given fixed values of HPDT.
Time frame: 7 days
Pain during 1 min. thermal stimulation, evaluated by Area Under the Curve of the visual analog scale, 0-100 mm.
How close is the Visual analog scale (VAS)-AUC (area under the curve) following pain during 1 min. thermal stimulation associated with the size of the area of secondary hyperalgesia induced by Brief thermal sensitization?
Time frame: Study day 1 and 2. A minimum of 7 days
Pain during 1 min. thermal stimulation, evaluated by maximum on the visual analog scale, 0-100mm.
How close is the max. VAS-score following pain during 1 min. thermal stimulation associated with the size of the area of secondary hyperalgesia induced by Brief thermal sensitization?
Time frame: Study day 1 and 2. A minimum of 7 days.
Score of Pain Catastrophizing Scale
How close is the scores of Pain Catastrophizing Scale associated with the size of the area of secondary hyperalgesia induced by Brief thermal sensitization?
Time frame: Study day 1 and 2. A minimum of 7 days.
Score of Hospital Anxiety and Depression Scale
How close is the scores of Hospital Anxiety and Depression Scale associated with the size of the area of secondary hyperalgesia induced by Brief thermal sensitization?
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Time frame: Study day 1 and 2. A minimum of 7 days.
Score of Subscales of Pain Catastrophizing Scale and Hospital Anxiety and Depression Scale.
How close are the subscales in the two psychological tests (PCS-rumination, PCS-magnification, PCS-helplessness, and HADS-Anxiety, HADS-Depression) associated with the size of the area of secondary hyperalgesia?
Time frame: Study day 1 and 2. A minimum of 7 days.