The Modulatory Effect of Female Sex Hormones on Spinal Neuroplasticity (TMSpine)

TMSpine: The Modulatory Effect of Female Sex Hormones on Spinal Neuroplasticity

The goal of this project is to test our central hypothesis that the spinal cord neuroplasticity in females will be modulated by the level of estradiol concentration. under aim 1 we will determine the influence of estradiol fluctuations on spinal circuit excitability post afferent (sensory) mediated subthreshold motor priming in young healthy females and males. We will use an established repetitive peripheral nerve electrical stimulation with a stimulation intensity below the motor threshold to prime the spinal motor circuits. under aim 2 we seek to characterize the input output property of spinal circuit excitability after descending drive (motor) mediated priming in young healthy male participants. in aim 3 we will examine the influence of estradiol fluctuations on descending drive mediated motor priming in young healthy females.

Study Overview

• Status: Recruiting
• Conditions: Healthy
• Intervention / Treatment: Device: Magstim Rapid2

• Study Type: Observational
• Enrollment (Estimated): 50

Contacts and Locations

• Study Contact: Name: Yu-Chen Chung, PT, Ph.D.; Phone Number: 214-648-8838; Email: yu-chen.chung@utsouthwestern.edu
• Study Contact Backup: Name: Subaryani Soedirdjo, Ph.D.; Email: subaryani.soedirdjo@utsouthwestern.edu

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75390
      • Recruiting
      • University of Texas Southwestern Medical Center
      • Contact: Yu-Chen Chung, PT, Ph.D.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

(1) Healthy females (2) Healthy males (control)

Description

FEMALES

Inclusion Criteria:

• Ages 18-39 years
• Eumenorrheic (regular monthly cycles of 24-35 days)
• Moderately active (less than 7 hours of vigorous physical activity per week)
• History of pregnancy is allowed if patient is in post-lactation phase

Exclusion Criteria:

• History of musculoskeletal or orthopedic injury of the spine, hip, knee, ankle or foot
• History of neurological injury of the peripheral or central nervous system
• Current smoker
• History of disordered eating
• History of stress fracture in the lower limb
• History of a connective tissue disorder (Marfan's syndrome, Ehlers-Danlos disease)
• Pacemaker, metal implants in the head and spine region
• Pregnancy
• On a hormonal contraceptive regimen (oral, transdermal or vaginal)
• History of menstrual dysfunction (primary or secondary amenorrhea, oligomenorrhea, anovulatory cycles, polycystic ovarian disease)
• Started or stopped taking oral contraceptives within the previous 6 months
• Exercise vigorously more than 7 hours per week or currently participating in competitive level sports.

MALES

Inclusion Criteria:

• Ages 18-39
• Moderately active (less than 7 hours of vigorous physical activity per week)

Exclusion Criteria:

• History of musculoskeletal or orthopedic injury of the spine, hip, knee, ankle or foot
• History of neurological injury of the peripheral or central nervous system
• Current smoker
• History of disordered eating
• History of stress fracture in the lower limb
• History of a connective tissue disorder (Marfan's syndrome, Ehlers-Danlos disease)
• Pacemaker, metal implants in the head and spine region

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Healthy Females	Device: Magstim Rapid2; AIM 1: Investigate the estradiol effect on spinal circuit excitability post afferent (sensory) mediated subthreshold motor priming in young healthy women and men. AIM 2: Characterize the Input output property of spinal circuit excitability following descending drive (motor) mediate priming in young healthy participants AIM 3: Examine the estradiol effect on spinal circuit excitability following descending drive (motor) mediated priming in young healthy females
Healthy Males (control)	Device: Magstim Rapid2; AIM 1: Investigate the estradiol effect on spinal circuit excitability post afferent (sensory) mediated subthreshold motor priming in young healthy women and men. AIM 2: Characterize the Input output property of spinal circuit excitability following descending drive (motor) mediate priming in young healthy participants AIM 3: Examine the estradiol effect on spinal circuit excitability following descending drive (motor) mediated priming in young healthy females

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Spinal circuit excitability	Change in Spinal circuit excitability will be assessed by measuring Hoffmann reflex/ M wave ratio of the soleus muscle. Higher scores indicate poorer outcome.	Baseline 1, Post-60mins after peripheral nerve stimulation
Change in Motor neuron excitability	Changes in motor neuron excitability, as quantified by Delta-F values.	Baseline 2, Post-60mins after priming
Change in spinal reflex expression		Baseline 2, Post-60mins after priming
Change in descending drive mediated motor priming		Baseline 2, Post-60mins after priming

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Investigators: Principal Investigator: Yasin Dhaher, Ph.D., University of Texas Southwestern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2020
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: August 21, 2024
• First Submitted That Met QC Criteria: October 21, 2024
• First Posted (Actual): October 24, 2024

Study Record Updates

• Last Update Posted (Actual): March 30, 2026
• Last Update Submitted That Met QC Criteria: March 25, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: STU-2020-0738

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No