What this trial measures

• Static QST Measure2 weeks

  Slow Ramp: A slowly ramping thermal stimulus will be delivered to the skin of the participant's dominant forearm using a computer controlled TSAII NeuroSensory Analyzer from Medoc, Inc. Thermal stimuli will increase from a baseline of 35 degrees Celsius to a maximum of 51 degree Celsius in ascending one-degree intervals, each stimulus presented for 1-sec. Participants will be instructed to indicate when the sensation first changes from warmth to pain (pain threshold) and when the sensation becomes "so painful you can no longer tolerate it or So painful that you can't bear it anymore" (pain tolerance). Pressure Pain Threshold: An algometer with a 1 cm diameter rubber tip will be applied at 1 kg/s to the dominant hand at the first dorsal interosseous muscle. Participants will be instructed to indicate when the sensation first changes from pressure to pain (pain threshold). This procedure will be repeated two times, and the average pressure to threshold will be analyzed.

• Dynamic QST Measure2 weeks

  Pressure pain threshold will be measured using a 1 cm² algometer tip applied at 1 kg/s to the dominant foot's web space. Pressure increases until participants report pain at 40/100, then stops. This is repeated twice, and the average is used. For the conditioning stimulus, participants immerse their non-dominant hand in circulating cold water (6°C for males, 8°C for females) for 60 seconds, across four trials. Pain and unpleasantness ratings are collected each trial. Water temperature is adjusted in subsequent trials if ratings are too high or low. Between immersions, the hand is removed for 30 seconds while PPT is reassessed. Conditioned pain modulation is calculated as the difference between post-conditioning and pre-conditioning pain thresholds, with negative values indicating efficient pain inhibition.

• Temporal Summation2 weeks

  Temporal sensory summation (TSS): 6 heat pulses will be applied to the dominant hand of the patient. To ensure temporal summation, an inter-stimulus interval of 2 seconds will be used with temperatures starting at 39°C and increasing to 50°C (the TSA medoc maintains 10°C/sec rate in this range which is sufficient for maintaining the desired inter-stimulus interval). The participants will be asked to rate the magnitude of their delayed (second) pain sensation following each heat pulse using the numeric rating scale. These response ratings are believed to be primarily C-fiber mediated. The magnitude of TSS is calculated by subtracting the rating of intensity at pulse 1 from the peak rating given during the 6 pulses (ie simple slope of summation).

• Aftersenstations2 weeks

  The participants will be asked to rate the magnitude of their pain sensation following the removal of the thermode. The research assistant will cue the participants to rate their pain every 10 seconds. These ratings will be obtained for 60 seconds. These response ratings are also primarily C-fiber mediated.

• Pressure Pain Threshold Upper Extrimity2 weeks

  An algometer with a 1 cm diameter rubber tip will be applied at 1 kg/s to the dominant hand at the first dorsal interosseous muscle. Participants will be instructed to indicate when the sensation first changes from pressure to pain (pain threshold). This procedure will be repeated two times, and the average pressure to threshold will be analyzed.

• Life Orientation Test-Revised (LOT-R)2 weeks

  The LOT-R is a 10-item self-report scale that measures how optimistic or pessimistic a person feels about the future. It measures trait optimism. The LOT-R uses a 5-point Likert scale, with 0 meaning "strongly disagree" and 4 meaning "strongly agree". Items are summed, yielding a range from 0 to 32 and Higher scores indicate greater levels of optimism

• State Optimism Measure (SOM)2 weeks

  The SOM is a 7-item measure that measures a person's state of optimism. It scored from 1 to 7 and higher scores indicate with a higher score indicating greater state optimism. It has been shown to be reliable and valid in both general and clinical populations

• The Perceived Societal Marginalization (PSM)2 weeks

  The PSM scale is a tool that measures how people perceive their social group's lack of recognition and insignificance in the areas of culture, politics, and the economy. The scale's items are scored on a 6-point Likert scale, with 1 representing "strongly disagree" and 6 representing "strongly agree". A higher total score indicates a higher level of perceived societal marginalization

• Anxiety about Pain Testing2 weeks

  A single item visual analogue scale (VAS) for Anxiety about Pain Testing was administered before every session of the protocol. The VAS was 100mm long and participants were instructed that the anchors were "no anxiety about pain testing" on the left and "worst anxiety about pain testing imaginable" on the right.

• Pain Catastrophizing Scale (PCS)2 weeks

  The Pain Catastrophizing Scale is a 13-item questionnaire in which individuals respond to a statement on a five-point ordinal scale from 0 to 4. Individuals respond to the question in terms of a prior painful episode, and higher scores indicate higher pain catastrophizing levels