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Completed

NCT Number: NCT05415423

Developing an Objective Measure of Experienced Pain

Pain is a public health challenge around the world. However, there is no single standardized measure of pain, to the point that the estimated prevalence of chronic pain in adults ranges between 2% and 64% depending on the methods and definitions used. Existing measures of pain are known to present several problems and results can be hardly compared between people.

The investigators propose and empirically validate a new, simple method to measure experienced pain in clinical trials. The method provides an objective, cardinal measurement of experienced pain which is comparable between people and the investigators test whether it is better able to measure experienced pain than existing procedures. The investigators test the new method in healthy participants using standard protocols (electrical and heat stimuli). The investigators also aim to validate the measure using a causal manipulation which relies on the administration of a topical analgesic product compared to a placebo.

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Key information

Conditions

Pain, Acute Acute Pain Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

SNS Laboratory

Zurich, CH, 8091, Switzerland

About this study

The aim of this study is to establish and validate the proposed method of measuring pain using different pain stimuli. The investigators correlate these measurements with physiological data such as skin-conductance, heart-rate variability, pupil dilation, and with established measures of pain such as Numeric rating scale (NRS), Visual analog scale (VAS), general Labeled Magnitude Scale (gLMS). In addition, the investigators study the test-retest reliability of our measure of pain and its ability to capture a reduction in experienced pain due to a topical analgesic product compared to a placebo treatment.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • age 18-60 years.
  • ability and willingness to participate in the study
  • declaration of consent
  • good English language skills (to ensure understanding of all instructions and the declaration of consent).

Exclusion criteria

  • inability to give the declaration of consent (e.g. due to linguistic difficulties understanding the study information)
  • any neurological disorders
  • reduced general health / chronic diseases (e.g. autoimmune disease, severe cardiovascular diseases, insulin-dependent diabetes, severe depression); chronic pain disorders
  • pregnancy
  • in the week before the experimental session self-reported intake of drugs which could influence pain perception (e.g. cannabis and ADHD medications).

Treatment and study plan

Developing an objective measure of experienced pain

Behavioral

At the beginning of each study, participants are randomly allocated into one of two groups.

Within each group all participants are exposed to the same painful stimulus. One group experiences a painful stimulus of higher intensity compared to that of the other group. The painful stimuli are physically identical for every subject within the same group and within the standard of previous pain research.

Participants are then asked to evaluate the painful stimulus they just received according to a self-reported scale (NRS, VAS, gLMS, NRS-MB). Participants are also asked to decide multiple times whether they prefer a larger amount of money and experience the same or more painful stimulus they received before or a smaller amount of money and no (or a less) painful stimulus. The smaller amount of money is progressively increased across choices until it matches the larger amount, similar to multiple price-list methods (MPL) which are standard in economics.

Primary outcomes

  1. Choices between monetary amounts and painful stimuli

    Time frame: baseline

    Participants' choices between monetary amounts and painful stimuli

  2. self-reported pain ratings according to Numerical Rating Scale (NRS)

    Time frame: baseline

    self-reported pain ratings according to Numerical Rating Scale

  3. self-reported pain ratings according to Visual Analogue Scale (VAS)

    Time frame: baseline

    self-reported pain ratings according to Visual Analogue Scale

  4. self-reported pain ratings according to general Labeled Magnitude Scale (gLMS)

    Time frame: baseline

    self-reported pain ratings according to general Labeled Magnitude Scale

  5. response times

    Time frame: baseline

    Response times relative to participants' choices between monetary amounts and painful stimuli

Secondary outcomes

  1. heart rate variability

    Time frame: baseline

    variation in heat-beat rate in reaction to the painful stimuli.

  2. skin conductance

    Time frame: baseline

    variation in skin conductance in reaction to the painful stimuli.

  3. pupil dilation

    Time frame: baseline

    variation in pupil dilation in reaction to the painful stimuli.

Sponsors and collaborators

Lead sponsor

University of Zurich

Other

Collaborators

  • Balgrist University Hospital

Registry information

Important dates

Study start
2022
Primary completion
2022
Study completion
2022
First posted
Jun 13, 2022
Registry last updated
Oct 12, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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