Pain Modulation - Experimental Assessments Using Different Modalities
Overview
- Phase
- N/A
- Intervention
- Not specified
- Conditions
- Low Back Pain
- Sponsor
- Schweinhardt Petra
- Enrollment
- 705
- Locations
- 1
- Primary Endpoint
- Temporal Summation of Pain (TSP)
- Status
- Recruiting
- Last Updated
- 3 years ago
Overview
Brief Summary
The goal of this study is to investigate how different painful stimuli are processed and modulated in the nervous system. In various pain conditions, including low back pain, often no specific source can be identified as the cause of the pain. Scientific findings point towards a possible involvement of sensitization processes in the central nervous system (spinal cord and brain) that can contribute to the development and persistence of chronic pain. There is a need for reliable and well established experimental methods to better investigate and understand these processes. Frequently used methods comprise the application of thermal, mechanical or electrical stimulations. These modalities are processed in different parts of the nervous system, each allowing its own conclusions. This can be an advantage, but it also poses a challenge regarding comparability and generalizability of obtained results.
This study aims to apply and compare various experimental methods in people without and people with low back pain and shed light on the methodological differences. In the future, this could enable better identification and characterization of sensitization processes in the nervous system and build the basis for individually adapted, mechanism-targeted treatments with better patient outcomes.
Investigators
Schweinhardt Petra
Head of Research Department of Chiropractic Medicine
Balgrist University Hospital
Eligibility Criteria
Inclusion Criteria
- •German or English proficiency
- •Informed consent
- •primary pain complaint localized between the 12th rib and the gluteal fold
- •low back pain for more than one week
- •low back pain clinically not attributable to "red flags" (including infection, trauma, fractures, inflammatory)
Exclusion Criteria
- •unable to give informed consent (e.g. due to language problems)
- •any neurological condition
- •any major medical or psychiatric condition (e.g. severe heart disease, diabetes, autoimmune disorders, major depressive disorder), any chronic pain condition other than low back pain
- •pregnancy
- •Radiating pain below knee level (radicular pain)
Outcomes
Primary Outcomes
Temporal Summation of Pain (TSP)
Time Frame: 1-4 weeks
TSP is measured as the change in perceived pain over time in response to repetitive noxious stimulation. In this study, a series of stimulations will be applied using different modalities (pressure, superficial mechanical, heat or electrical stimuli). Participants will be asked to report the perceived pain in response to the stimulations on an 11-point numerical rating scale (0: no pain, 10: most intense pain) or a visual analogue scale (VAS). VAS will be anchored with 0 ("no sensation"), 40 ("just painful," defined as the pain threshold), and 100 ("most intense pain tolerable"). Reflex parameters (thresholds in milliampere (mA); amplitude in μV) will be recorded at start and end of the series. Differences in read-outs (pain ratings, reflex thresholds or reflex amplitudes) at the start of the series compared to the end of the series or the slope of the pain ratings over the series will serve as TSP measures. Greater differences (end-start) or steeper slopes represent a greater TSP.
Conditioned Pain Modulation (CPM)
Time Frame: 1-4 weeks
CPM measures the modulation of a noxious test stimulus by another noxious conditioning stimulus applied at a remote body region. In this study, test stimuli of different modalities (pressure, superficial mechanical, heat or electrical stimuli) will be applied at different body regions before and after or before, during and after a cold water bath or neutral water bath (hand immersion) as conditioning stimulus. Changes in test stimuli read-outs (during-before or after-before) will serve as CPM measure. Negative changes represent inhibitory, positive changes facilitatory CPM effects. For all test stimuli read-outs, CPM effects will be expressed as percentage changes. Test stimuli read-outs include: pain ratings (numerical rating scale or VAS, anchors see TSP outcome); perception thresholds (in kg for pressure, millinewton for superficial mechanical, °C for heat and mA for electrical stimuli); pain thresholds; reflex parameters (thresholds in mA and/or amplitudes).
CPM effect on TSP
Time Frame: 1-4 weeks
Changes in TSP in response to the intervention (conditioning stimulus: cold water bath or SHAM).
Secondary Outcomes
- Pressure sensory and pain sensitivity(1-4 weeks)
- Mechanical sensory and pain sensitivity(1-4 weeks)
- Anxiety(1-4 weeks)
- Pain duration(1-4 weeks)
- Spatial pain extent(1-4 weeks)
- Heat sensory and pain sensitivity(1-4 weeks)
- Electrical sensory and pain sensitivity(1-4 weeks)
- Pain Catastrophizing(1-4 weeks)
- Fear of pain(1-4 weeks)
- Depression(1-4 weeks)
- Somatic symptoms(1-4 weeks)