Healthy ParticipantsCognitiveCPMNCT07234123
Cognitive Conditioned Pain Modulation
A study testing conditioned pain modulation and test stimulus in people with Healthy Participants, run by University of Washington at 1 site in United States.
Trial summary
This "pain reduces pain" study looks at how the brain reduces pain when a person feels two painful sensations at the same time. There is considerable evidence that the brain can "turn down" pain using natural endogenous pain-control systems. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Healthy Participants
- What is being tested?
- conditioned pain modulation and test stimulus
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteUnited States
- Study dates
- 9 Aug 2024to 29 May 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Only University of Washington students in eligible psychological courses are
- eligible. General public is not eligible.
- Enrolled psychology students fluent in English,
- Age ≥18 y, able to follow instructions.
Who cannot join
- Seizure history,
- Migraines,
- Diabetes,
- Extreme pain insensitivity,
- Motion sickness,
- or prior participation in this protocol.
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Washington Seattle
Seattle, Washington, 98195
About this study
Official title: Conditioned Pain Modulation With Ultra-Brief Conditioning Stimulus
This "pain reduces pain" study looks at how the brain reduces pain when a person feels two painful sensations at the same time. There is considerable evidence that the brain can "turn down" pain using natural endogenous pain-control systems. The current CPM study measures whether attentional processes can also make a measurable contribution to pain inhibition alongside neurochemical mechanisms.
Read the detailed description
Conditioned pain modulation (CPM) is a natural process where feeling pain in one part of the body (e.g., a conditioning stimulus to the wrist) can reduce pain felt in another part of the body (a test stimulus to the foot). There is considerable evidence from both animal and human studies that the painful conditioning stimulus can stimulate the brain to activate neurochemical pain-control pathways (e.g., endogenous opioids), which are believed to take 30-120 seconds to fully engage. The current CPM study measures whether attentional processes can also make a measurable contribution to pain inhibition alongside neurochemical mechanisms.
Primary measures: Graphic ratings scale "worst pain" ratings.
The primary measure of the current study graphic ratings scales (worst pain ratings) will measure how much pain participants feel on their foot during foot only (test stimulus), vs. how much pain participants feel on their foot (test stimulus during simultaneous foot (test stimulus) + wrist (conditioning stimulus).
The current investigators predict that pain (e.g., the conditioning stimulus) naturally demands attention and can pull attention away from the original pain source (the test stimulus), resulting in CPM-like reductions in pain of the test stimulus.
Secondary measure #1. Cognitive measures are introduced in the current study, to quantify how much (if at all) the conditioning stimulus reduces pain of the target stimulus via attentional mechanisms. Participants estimate what percentage of their attention was directed to their foot (the test stimulus) during foot only vs. during foot + wrist (test + conditioning stimulus). This will measure whether the conditiioning stimulus to the wrist reduces how much attention participants focus on their foot. Analyses will also measure whether the amount of attention shift away from the foot (via participants; subjective ratings) is correlated with CPM robustness (reduction in pain of foot during duel stimulation).
Secondary measure #2. As another secondary measure of attention during one vs. two simultaneous pain stimuli, this study involves a divided attention auditory listening task that becomes harder when pain demands more attention (Craik et al., odd number divided attention task during single test pain stimuli vs. simultaneous test + conditioning stimuli). The more errors the participant makes on the divided attention task, the more attention diverted away from the auditory task by pain. Analyses will measure whether the number of errors on the divided attention task is correlated with CPM robustness (reduction in pain of foot, during duel thermal stimulation).
Exploratory measures. As exploratory measures, participants will rate how distracted they were and how difficult it was to concentrate (on 0-10 rating scales during test stimulus alone verses test + conditioning noxious thermal heat stimuli).
In summary, embedding these cognitive measures into the CPM protocol may enhance mechanistic interpretation accuracy by quantifying attentional contributions to pain inhibition in specific CPM protocols, thereby complementing existing approaches to pain phenotyping and reducing unexplained variance in CPM outcomes.
- Conditions
- Healthy Participants
- Being tested
- conditioned pain modulation, test stimulus
- Keywords
- Conditioned Pain Modulation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
conditioned pain modulationBehavioural
simultaneous stimuli to foot (test stimulus) and wrist (conditioning stimulus)
test stimulusBehavioural
single brief stimulus to foot only
| Study group | Role | What they receive |
|---|---|---|
| Single pain stimulus | Experimental | test pain stimulus alone Receives: Behavioral: test stimulus |
| dual pain stimuli | Experimental | simultaneous foot (test stimulus + wrist (conditioning stimulus) Receives: Behavioral: conditioned pain modulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
worst pain ratings of foot only
graphic rating scale from 0 (no pain) to 10 (excruciating pain)
Measured: rated immediately after each thermal stimulus
worst pain on graphic rating scale during test+conditioning stimulus
graphic rating scale from 0 (no pain) to 10 (excruciating pain)
Measured: measured immediately after the stimuli
Secondary outcomes (4)
% of attention devoted to foot during test stimulus only (0-100% scale)
verbal ratings where higher numbers = more attention
Measured: rated immediately after the stimuli
% of attention devoted to foot during test+conditioning stimuli (0-100% scale)
verbal ratings where higher numbers = more attention
Measured: rated immediately after the thermal stimuli
Divided attention during test stimulus only (% correct, where 100% is highest accuracy)
Accuracy monitoring a string of auditory numbers, the odd number task during test stimulus
Measured: Day 1, during the thermal stimulus
Divided attention during test stimulus + conditioning stimulus (% correct, 100% is highest )
Accuracy monitoring a string of auditory numbers, the odd number task during dual stimuli
Measured: Day 1, during the thermal stimuli
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Nov 2025
- Study start9 Aug 2024
- Primary completion29 May 2025
- Study completion29 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Healthy ParticipantsStudies of the same condition, open and under way.
- More trials run by University of WashingtonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Model description
- within-subject design
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Washington
- Sponsor type
- University, hospital or other
- Collaborators
- Mayday Fund
- Responsible party
- Principal investigator, Hunter Hoffman, University of Washington
- Investigators
- Hunter Hoffman, Principal investigator, University of Washington
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07234123
- Sponsor's protocol ID
- CPM2025
- Acronym
- CognitiveCPM
- Status last verified
- Jan 2026
- First submitted
- 14 Nov 2025
- Last updated
- 7 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Summary statistics will be made available to researchers upon reasonable request (e.g, for meta-analyses, etc). No individually identifiable information will be made available.
Publications
Yarnitsky D. Conditioned pain modulation (the diffuse noxious inhibitory control-like effect): its relevance for acute and chronic pain states. Curr Opin Anaesthesiol. 2010 Oct;23(5):611-5. doi: 10.1097/ACO.0b013e32833c348b.
PubMed 20543676
Study at a glance
From the registry record, last updated by the sponsor on 7 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Conditioned Pain Modulation With Ultra-Brief Conditioning Stimulus
- ClinicalTrials.gov ID
- NCT07234123
- Acronym / sponsor ID
- CognitiveCPM / CPM2025
- Conditions
- Healthy Participants
- Keywords
- Conditioned Pain Modulation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- University of WashingtonUniversity, hospital or other
- Collaborators
- Mayday Fund
- Study start
- 9 Aug 2024 (actual)
- Primary completion
- 29 May 2025 (actual)
- Study completion
- 29 May 2025 (actual)
- First posted
- 18 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This "pain reduces pain" study looks at how the brain reduces pain when a person feels two painful sensations at the same time. There is considerable evidence that the brain can "turn down" pain using natural endogenous pain-control systems. The current CPM study measures whether attentional processes can also make a measurable contribution to pain inhibition alongside neurochemical mechanisms.
Detailed description
Conditioned pain modulation (CPM) is a natural process where feeling pain in one part of the body (e.g., a conditioning stimulus to the wrist) can reduce pain felt in another part of the body (a test stimulus to the foot). There is considerable evidence from both animal and human studies that the painful conditioning stimulus can stimulate the brain to activate neurochemical pain-control pathways (e.g., endogenous opioids), which are believed to take 30-120 seconds to fully engage. The current CPM study measures whether attentional processes can also make a measurable contribution to pain inhibition alongside neurochemical mechanisms.
Primary measures: Graphic ratings scale "worst pain" ratings.
The primary measure of the current study graphic ratings scales (worst pain ratings) will measure how much pain participants feel on their foot during foot only (test stimulus), vs. how much pain participants feel on their foot (test stimulus during simultaneous foot (test stimulus) + wrist (conditioning stimulus).
The current investigators predict that pain (e.g., the conditioning stimulus) naturally demands attention and can pull attention away from the original pain source (the test stimulus), resulting in CPM-like reductions in pain of the test stimulus.
Secondary measure #1. Cognitive measures are introduced in the current study, to quantify how much (if at all) the conditioning stimulus reduces pain of the target stimulus via attentional mechanisms. Participants estimate what percentage of their attention was directed to their foot (the test stimulus) during foot only vs. during foot + wrist (test + conditioning stimulus). This will measure whether the conditiioning stimulus to the wrist reduces how much attention participants focus on their foot. Analyses will also measure whether the amount of attention shift away from the foot (via participants; subjective ratings) is correlated with CPM robustness (reduction in pain of foot during duel stimulation).
Secondary measure #2. As another secondary measure of attention during one vs. two simultaneous pain stimuli, this study involves a divided attention auditory listening task that becomes harder when pain demands more attention (Craik et al., odd number divided attention task during single test pain stimuli vs. simultaneous test + conditioning stimuli). The more errors the participant makes on the divided attention task, the more attention diverted away from the auditory task by pain. Analyses will measure whether the number of errors on the divided attention task is correlated with CPM robustness (reduction in pain of foot, during duel thermal stimulation).
Exploratory measures. As exploratory measures, participants will rate how distracted they were and how difficult it was to concentrate (on 0-10 rating scales during test stimulus alone verses test + conditioning noxious thermal heat stimuli).
In summary, embedding these cognitive measures into the CPM protocol may enhance mechanistic interpretation accuracy by quantifying attentional contributions to pain inhibition in specific CPM protocols, thereby complementing existing approaches to pain phenotyping and reducing unexplained variance in CPM outcomes.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- within-subject design
| Arm | Type | Receives |
|---|---|---|
| Single pain stimulus | Experimental | Behavioral: test stimulustest pain stimulus alone |
| dual pain stimuli | Experimental | Behavioral: conditioned pain modulationsimultaneous foot (test stimulus + wrist (conditioning stimulus) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Only University of Washington students in eligible psychological courses are
- eligible. General public is not eligible.
- Enrolled psychology students fluent in English,
- Age ≥18 y, able to follow instructions.
Key exclusion criteria (6 listed)
- Seizure history,
- Migraines,
- Diabetes,
- Extreme pain insensitivity,
- Motion sickness,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| conditioned pain modulationsimultaneous stimuli to foot (test stimulus) and wrist (conditioning stimulus) | Behavioural | dual pain stimuli |
| test stimulussingle brief stimulus to foot only | Behavioural | Single pain stimulus |
Primary outcome
worst pain ratings of foot only
Time frame: rated immediately after each thermal stimulus
graphic rating scale from 0 (no pain) to 10 (excruciating pain)
worst pain on graphic rating scale during test+conditioning stimulus
Time frame: measured immediately after the stimuli
graphic rating scale from 0 (no pain) to 10 (excruciating pain)
4 secondary outcomes
% of attention devoted to foot during test stimulus only (0-100% scale)
Time frame: rated immediately after the stimuli
% of attention devoted to foot during test+conditioning stimuli (0-100% scale)
Time frame: rated immediately after the thermal stimuli
Divided attention during test stimulus only (% correct, where 100% is highest accuracy)
Time frame: Day 1, during the thermal stimulus
Divided attention during test stimulus + conditioning stimulus (% correct, 100% is highest )
Time frame: Day 1, during the thermal stimuli
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Jan 2026.
- Background: PubMed 20543676Yarnitsky D. Conditioned pain modulation (the diffuse noxious inhibitory control-like effect): its relevance for acute and chronic pain states. Curr Opin Anaesthesiol. 2010 Oct;23(5):611-5. doi: 10.1097/ACO.0b013e32833c348b.
- Individual participant dataSharing planned: Yes. Summary statistics will be made available to researchers upon reasonable request (e.g, for meta-analyses, etc). No individually identifiable information will be made available.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Hunter Hoffman principal investigator
University of Washington
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing conditioned pain modulation and test stimulus in people with Healthy Participants, run by University of Washington at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
worst pain ratings of foot only (time frame: rated immediately after each thermal stimulus). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07234123, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jan 2026.