Differences in Pain Processing Between Men and Women

Differences in Sensitization Between Men and Women After Cutaneous Thermal Stimuli

Many chronic pain conditions show clear differences between between men and women, such as reported pain intensities or treatment effects, with chronic pain conditions being generally more frequent in women. Yet, the underlying mechanisms causing these differences are poorly understood. Central sensitization (CS) is considered one important mechanism in pain patients which differs between female and male patients. The central hypothesis is that already in the healthy population CS processes are more pronounced in women than in men.

Study Overview

• Status: Completed
• Conditions: Central Sensitisation
• Intervention / Treatment: Other: Cutaneous thermal stimuli

• Study Type: Interventional
• Enrollment (Actual): 66
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Zürich, Switzerland, 8008
    • Balgrist Campus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• good general health
• able to give informed consent

Exclusion Criteria:

• pain complaints for more than two consecutive days over the past three months
• any major medical or psychiatric condition (e.g. heart disease, major depressive disorder)
• any chronic pain condition
• inability to follow study instructions
• consumption of stimulants, drugs, or analgesics within the past 24 hours
• scar tissue or generally reduced sensitivity in the designated testing site areas

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental Arm	Other: Cutaneous thermal stimuli; Application of thermal stimuli of different intensities to the skin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in spatial extent of mechanical hypersensitivity after intervention w.r.t. baseline	Mapping of hypersensitivity in cm2 of sensitized skin area using two quantitative sensory testing tools (256mN von Frey filament and 200-400mN brush) before and after intervention	10-20 minutes before intervention (baseline) and 20-30 minutes after intervention
Changes to the nociceptive withdrawal reflex (NWR) after intervention w.r.t. baseline	Repetitive suprathreshold elicitation of the NWR to monitor its characteristics (such as magnitude and number of responses) before and after intervention	5-10 minutes before intervention (baseline) and 30-35 minutes after intervention

Collaborators and Investigators

• Sponsor: Balgrist University Hospital
• Investigators: Principal Investigator: Petra Schweinhardt, MD, PhD, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2021
• Primary Completion (Actual): December 31, 2022
• Study Completion (Actual): December 31, 2022

Study Registration Dates

• First Submitted: August 11, 2021
• First Submitted That Met QC Criteria: August 30, 2021
• First Posted (Actual): September 1, 2021

Study Record Updates

• Last Update Posted (Actual): April 11, 2023
• Last Update Submitted That Met QC Criteria: April 9, 2023
• Last Verified: April 1, 2023

More Information

Terms related to this study

• Keywords: central sensitization; nociception; heat pain; secondary hyperalgesia; central sensitisation; withdrawal reflex
• Other Study ID Numbers: NWR

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No