Aftereffects and Reliability of Two Homeostatic Plasticity Induction Protocols

October 6, 2020 updated by: Priscilla G. Wittkopf, Aalborg University
People suffering from chronic pain exhibit changes in the way the central nervous system processes pain. Some of the changes in the central nervous system are associated with how the brain adapts to the process of different stimuli. There are several physiological mechanisms that regulates how the brain adapts to changes and one of these mechanisms is called homeostatic plasticity (or equilibrium plasticity ). In healthy participants homeostatic plasticity mechanisms have been tested and considered normal, whereas in patients with chronic conditions, such as low back pain, this mechanism was shown to be dysfunctional. However, it is unknown when this difference in the pain system develops. It is possible that homeostatic mechanism becomes impaired over a period of time. Current studies have investigate a cohort of patients and there is a lack of longitudinal designs. In order to investigate the long-term effects of pain on homeostatic plasticity mechanisms it is important to first investigate the reliability of the methods. This study will investigate the reliability of two protocols of homeostatic plasticity induction.

Study Overview

Detailed Description

The aim of this study is to investigate the corticomotor excitability changes provoked by two homeostatic plasticity induction protocols, specifically the duration and the test-retest reliability of such corticomotor excitability changes.

A within-subject repeated-measures design will be used to evaluate the aftereffects and the reliability of two homeostatic plasticity induction protocols using cathodal transcranial direct current stimulation (tDCS) (experiment 1) and anodal tDCS (experiment 2). Each participant will take part in two experimental sessions during which homeostatic plasticity and corticomotor excitability will be induced and measured in the left primary motor cortex.

A sample size calculation was conducted using α of 0.05, β of 0.80 and effect size of 0.48 based on motor evoked potential (MEP) analysis of previous studies (Thapa, Schabrun, 2018, Thapa et al., 2018) resulting in a target of 13 participants. To account for differences in study designs and for the possibility of participant withdrawal/dropout, the investigators set target recruitment at 15 participants for each experiment.

Each participant will attend two identical experimental sessions on the same time in two consecutive days. During the experiment, participants will be seated comfortably with hands and arms at rest. First, the electromyography electrodes will be placed at the right hand muscle to be used for assessing the corticomotor excitability by recordings of motor evoked potentials by transcranial magnetic stimulation (TMS) on the left primary motor cortex. Then, the neoprene cap for tDCS on the left primary motor cortex will be mounted. The optimal scalp position (hot spot) for TMS stimulation will be identified and marked with a pen on the cap for standardisation. The corticomotor excitability in response to the homeostatic plasticity protocol (cathodal tDCS in experiment 1 or anodal tDCS in experiment 2) will be measured before and immediately post paradigm (time point 0-min), and then every 10 minutes for 70 minutes.

Homeostatic plasticity will be induced in the left primary motor cortex using tDCS applied for 7 minutes followed by an interval of 3 minutes and another block of 5 minutes of stimulation (Thapa, Schabrun, 2018, Thapa et al., 2018). A constant current of 1mA will be transmitted through the tDCS system (Starstim, Neuroelectrics, Barcelona, Spain), using two 3.14 cm2 Ag/AgCl gelled electrodes placed into holes of a neoprene cap corresponding to the international 10/10 EEG system, placed on participants head with the central Cz position aligned to the vertex of the head. In experiment 1 the cathode will be placed at C3 and return electrode placed at Fp2. In experiment 2 the anode will be placed at C3 and return electrode placed at Fp2.

Data distribution will be assessed using the Shapiro-Wilk test. A repeated measures analysis of variance (ANOVA) will be conducted on mean MEPs with factors Session (Day1 and Day2) and Time (baseline, 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min). A Greenhouse-Geisser correction will be used if Mauchly's test shows that sphericity cannot be assumed. Adjustments will be made for multiple post-hoc comparisons using the Bonferroni correction. Results will be interpreted according to the level of statistical significance p≤0.05 and effect size reported as partial eta squared.

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Aalborg, Denmark, 9220
        • Aalborg University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 60 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy, aged between 18-60 years, right-handed and can speak and understand English.

Exclusion Criteria:

  • Lack of ability to cooperate
  • History or present chronic pain or current acute pain
  • Pregnancy
  • Drug addiction defined as the use of cannabis, opioids or other drugs
  • Present and previous neurological disorders such as epilepsy, Alzheimer's disease, dementia, stroke, migraine and other headache disorders, multiple sclerosis, Parkinson's disease, neuroinfections, brain tumors and head trauma.
  • Present or previous musculoskeletal disorders such as tendonitis, degenerative disc disease, mechanical back syndrome, and ruptured/herniated disc.
  • Present or previous mental illnesses such as depression, bipolar disorder, and schizophrenia.
  • Current use of medications that may affect the trial (e.g. analgesics, anti-inflammatories, anti-depressives)
  • Contraindications to TMS application (history of epilepsy, metal implants in head or jaw, etc.)
  • Failure to pass the tDCS screening questionnaire
  • Failure to pass the "TASS questionnaire"

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Single arm
This is a within-subject repeated-measures design.
Homeostatic plasticity will be induced in the left primary motor cortex using tDCS applied for 7 minutes followed by an interval of 3 minutes and another block of 5 minutes of stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Motor evoked potentials change from baseline
Time Frame: 0 minutes post homeostatic plasticity induction
0 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 10 minutes post homeostatic plasticity induction
10 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 20 minutes post homeostatic plasticity induction
20 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 30 minutes post homeostatic plasticity induction
30 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 40 minutes post homeostatic plasticity induction
40 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 50 minutes post homeostatic plasticity induction
50 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 60 minutes post homeostatic plasticity induction
60 minutes post homeostatic plasticity induction
Motor evoked potentials change from baseline
Time Frame: 70 minutes post homeostatic plasticity induction
70 minutes post homeostatic plasticity induction

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 15, 2020

Primary Completion (Actual)

June 9, 2020

Study Completion (Actual)

June 9, 2020

Study Registration Dates

First Submitted

March 25, 2020

First Submitted That Met QC Criteria

March 26, 2020

First Posted (Actual)

March 27, 2020

Study Record Updates

Last Update Posted (Actual)

October 8, 2020

Last Update Submitted That Met QC Criteria

October 6, 2020

Last Verified

October 1, 2020

More Information

Terms related to this study

Other Study ID Numbers

  • N-20190069

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Healthy

Clinical Trials on Homeostatic plasticity induction using transcranial direct current stimulation

3
Subscribe