Pain, Acute
Conditions
Brief summary
The purpose of the study is to gain a better understanding of pain processing in the brain. Our understanding of how pain is processed in the brain is limited. We are testing for individual differences in pain perception and emotion.
Interventions
BEHAVIORALPlacebo Cream
In the Placebo intervention, participants are given an inert cream with instructions that it is Prodicaine, an effective pain-relieving drug. The cream is applied to two fingers on the left hand.
BEHAVIORALControl Cream
In the Control intervention, participants are given an inert cream with instructions that it is a control cream with no effects . The cream is applied to two fingers on the left hand.
Sponsors
QIMR Berghofer Medical Research Institute
Trustees of Dartmouth College
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
* Participants must be registered in the Colorado Community Twin Sample (CTS).
Exclusion criteria
* Not being registered in the Colorado Community Twin Sample (CTS). * Any MRI contraindications.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pain Rating Scores Made on a Visual Analog Scale (VAS) | Measured during pain tasks at a single 4 hour experimental session (within one month of screening completion). | Self reported pain using a Visual Analogue Scale (VAS) ranging from 0-100 (with 0 representing no pain at all and 100 representing most intense pain imaginable (in the context of the experiment)). Higher scores indicate more pain. 0 is the minimum value and 100 is the maximum value. This scale is used for both thermal and mechanical pain. Reported values reflect averages of VAS ratings for individual stimuli for each of thermal and mechanical pain. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Main All participants completed all conditions, with no groups/arms. | 460 |
| Total | 460 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Physical Constraints | 11 |
| Overall Study | Technical Issues (equipment failure) | 31 |
| Overall Study | Withdrawal by Subject | 7 |
Baseline characteristics
| Characteristic | Main |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 460 Participants |
| Age, Continuous | 36.25 years STANDARD_DEVIATION 2.65 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 26 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 434 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 2 Participants |
| Race (NIH/OMB) Asian | 11 Participants |
| Race (NIH/OMB) Black or African American | 4 Participants |
| Race (NIH/OMB) More than one race | 18 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 2 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 5 Participants |
| Race (NIH/OMB) White | 418 Participants |
| Region of Enrollment United States | 460 participants |
| Sex: Female, Male Female | 272 Participants |
| Sex: Female, Male Male | 188 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 541 |
| other Total, other adverse events | 0 / 541 |
| serious Total, serious adverse events | 0 / 541 |
Outcome results
Primary
Pain Rating Scores Made on a Visual Analog Scale (VAS)
Self reported pain using a Visual Analogue Scale (VAS) ranging from 0-100 (with 0 representing no pain at all and 100 representing most intense pain imaginable (in the context of the experiment)). Higher scores indicate more pain. 0 is the minimum value and 100 is the maximum value. This scale is used for both thermal and mechanical pain. Reported values reflect averages of VAS ratings for individual stimuli for each of thermal and mechanical pain.
Time frame: Measured during pain tasks at a single 4 hour experimental session (within one month of screening completion).
Population: All participants completed both the placebo condition and the control condition. Participants completed both conditions and all analyses were completed within participants. Descriptions of arms and interventions are detailed in the Protocol Section.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Main | Pain Rating Scores Made on a Visual Analog Scale (VAS) | Placebo thermal pain ratings | 0.136 Score on a scale | Standard Deviation 0.123 |
| Main | Pain Rating Scores Made on a Visual Analog Scale (VAS) | Control thermal pain ratings | 0.190 Score on a scale | Standard Deviation 0.141 |
| Main | Pain Rating Scores Made on a Visual Analog Scale (VAS) | Placebo mechanical pain ratings | 0.126 Score on a scale | Standard Deviation 0.174 |
| Main | Pain Rating Scores Made on a Visual Analog Scale (VAS) | Control mechanical pain ratings | 0.160 Score on a scale | Standard Deviation 0.178 |
Comparison: Comparing placebo vs. control for thermal pain ratings with mixed effects models controlling for the stimulus intensity and the familial structure of the data.p-value: <0.00195% CI: [-0.0648, -0.0441]Mixed Models Analysis