Two Point Discrimination

Study Purpose

SPECIFIC AIMS Pain in both youth and adults is a complex, subjective and personal experience, and remains poorly understood. One particularly perplexing dimension of some forms of pain is the tendency of pain to spread outside of an affected body site to adjacent location, and then to unaffected body sites. Such widespread pain may reflect an altered spatial tuning of somatosensory processing, such that lateral inhibition is diminished, thereby allowing pain to spread. To date, no therapies exist which are designed specifically to diminish or even reverse the spatial spread of pain. However, training in two-point discrimination holds the potential to retune spatial aspects of somatosensory processing and may represent a novel therapy for widespread pain. Thus, the present investigation will test the following aims: Aim 1. Do youth with chronic pain have disrupted spatial tuning of somatosensory processing? Deficits in two point tactile discrimination have long been noted in adults with chronic pain, but such deficits remain poorly documented in pediatric chronic pain patients. In order to determine if such deficits exist, youth with both chronic pain and healthy youth will undergo assessment of two point discrimination thresholds. Aim 2. Does two-point discrimination training result in diminished pain and disability in youth with somatic pain? After initial characterization of tactile discrimination thresholds, youth with chronic pain will participate in multiple sessions of either two-point discrimination training or a single-point spatially-directed attentional control condition. Training will involve up to 9 additional sessions. Efficacy of training will be assessed by 1) reductions in the spatial extent of pain, 2) reductions in pain intensity and unpleasantness, and 3) reductions in pain-related disability.

Recruitment Criteria

Accepts Healthy Volunteers

Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms

Study Type

An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes.

Searching Both is inclusive of interventional and observational studies.

Eligible Ages 10 Years - 17 Years
Gender All
More Inclusion & Exclusion Criteria

Inclusion Criteria:

Chronic Pain Patients:
  • - Somatically located chronic pain - amplified musculoskeletal pain syndrome - complex regional pain syndrome - low back pain - fibromyalgia - other forms of chronic, widespread pain - Male or female, 10-17 years - High fluency in written and oral English language Control Participants: - Youth in good general health - Male or female, 10-17 years - High fluency in written and oral English language

    Exclusion Criteria:

    - Present significant mental health disorder as defined by DSM V (e.g. psychosis, bipolar disorder, major depression), - alcohol or drug dependence - documented developmental delays or impairments (e.g., autism, cerebral palsy, or mental retardation) of a magnitude that would interfere with adherence to study requirements or safe participation in the study - Primary complaint of migraine or visceral (abdominal) pain, with minimal somatic involvement.

Trial Details

Trial ID:

This trial id was obtained from, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.


Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans.

Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data.

Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.

Early Phase 1
Lead Sponsor

The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.

Children's Hospital Medical Center, Cincinnati
Principal Investigator

The person who is responsible for the scientific and technical direction of the entire clinical study.

Robert C Coghill, Ph.D.
Principal Investigator Affiliation Children's Hospital Medical Center, Cincinnati
Agency Class

Category of organization(s) involved as sponsor (and collaborator) supporting the trial.

Overall Status Recruiting
Countries United States

The disease, disorder, syndrome, illness, or injury that is being studied.

Ehlers-Danlos Syndrome (EDS), Complex Regional Pain Syndrome (CRPS), Amplified Musculoskeletal Pain Syndrome (AMPS), Low Back Pain, Fibromyalgia, Chronic Widespread Pain
Additional Details

STUDY DESIGN Prior to commencing this investigation, investigators will optimize the tactile discrimination threshold testing (i.e. as per baseline visit, below), and the training conditions, in up to ten participants (patients and/or healthy controls). This will serve as a pilot to refine operational aspects of study procedures before investigators commence the main investigation proposed herein. Following this, youth with either chronic pain (ages 10-17, n=40) or healthy youth (ages 10-17, n=20) will undergo assessments of two-point and single-point discrimination thresholds in an initial session (Aim 1). After this initial session, youth with chronic pain will participate in up to 9 additional sessions of attentional training (Aim 2). These chronic pain patients will be randomized to either two-point discrimination training (n=20) or a single-point spatially-directed attentional control condition (n=20). Participants will not be informed of which intervention they will receive (single-blind study). Psychological questionnaires will be completed in the first and last sessions in order to determine how these variables relate to tactile discrimination and response to training. STUDY INTERVENTIONS 5.1 Two Point Discrimination Training: Two-point discrimination threshold (TPD) training may be performed 1) at spatial locations remote from pain, 2) at spatial locations adjacent to the region of pain, and/or 3) at spatial locations in the site of pain, if the participant will tolerate it. TPD is defined as the smallest distance between two points at which someone can recognize two points, and not one, touching their skin. As such this is a test of one's ability to identify separate stimulation of two discrete areas, and relies heavily on lateral inhibition. Highly precise mechanical calipers will be gently placed onto the skin and the distance between the prongs will be increased/decreased. After repeated decreases and increases in the distance between the prongs, the TPD will be deemed as the distance at which participants consistently report two points instead of one. One-point stimuli will be interleaved to serve as a control condition. Participants will be informed immediately of correct and incorrect responses as part of the discrimination training. 5.2 Control Stimulation: Participants will undergo a single-point discrimination training at the same sites as described above. Probes of different sizes will be used for this portion

  • - a small diameter probe (~1-5 mm) and a large diameter probe (~6-50mm).
The probes will be gently placed in contact with the participants' skin, and the participant will be instructed to respond if they were contacted with the small or large probe. Participants will be informed immediately of correct and incorrect responses as part of the discrimination training.

Arms & Interventions


Experimental: Two-point intervention

Two point discrimination training.

Active Comparator: One-point intervention

One point discrimination of size of probe

No Intervention: Healthy Controls

Observational component of differences in discrimination between chronic pain patients and healthy controls.


Behavioral: - Two-point discrimination training

Patients will undergo multiple sessions of two-point discrimination training.

Behavioral: - One-point discrimination training

Patients will undergo multiple sessions of one-point discrimination training.

Contact a Trial Team

If you are interested in learning more about this trial, find the trial site nearest to your location and contact the site coordinator via email or phone. We also strongly recommend that you consult with your healthcare provider about the trials that may interest you and refer to our terms of service below.

Cincinnati, Ohio




Cincinnati Children's Hospital Medical Center

Cincinnati, Ohio, 45229

Site Contact

Geraldine C Schulze, BS

[email protected]