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Trial registered on ANZCTR


Registration number
ACTRN12619000667112
Ethics application status
Approved
Date submitted
18/04/2019
Date registered
3/05/2019
Date last updated
3/05/2019
Date data sharing statement initially provided
3/05/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Using transcranial direct current stimulation to boost the hypoalgesic effects of exercise:: A randomised controlled experimental study
Scientific title
Using transcranial direct current stimulation to boost the hypoalgesic effects of exercise in healthy participants:: A randomised controlled experimental study
Secondary ID [1] 298016 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Mechanical hyperalgesia 312465 0
Pain 312466 0
Muscle soreness 312467 0
Condition category
Condition code
Neurological 311016 311016 0 0
Studies of the normal brain and nervous system
Musculoskeletal 311017 311017 0 0
Other muscular and skeletal disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants will attend two sessions in the brain stimulation labs at Western Sydney University (‘Day 0’ and ‘Day 2’), which will take 30 and 90 minutes, respectively. On Day 0, individuals will complete formal screening to determine their eligibility for the study. If included, demographic data will be collected (pre-injection measures: age, height, weight, current levels of physical activity and beliefs about pain) and A 5 µg (0.2 mL) bolus of recombinant human NGF will be administered into the right extensor carpi radialis brevis (ECRB) muscle belly. One experimental will administer all injections. Participants will return on Day 2 and will be randomly allocated using a computer-generated random number table into the intervention group (active tDCS and exercise) or the control group (sham tDCS and exercise). Allocation will be concealed using opaque envelopes (prepared by an independent researcher) and will be opened by the researcher responsible for tDCS settings. The other researcher, responsible for collecting outcome measures, will remain blinded to the group allocation. Participants will receive active or sham tDCS and will complete a subsequent isometric grip exercise. At each timepoint (pre-injection, pre-tDCS, immediately post-exercise and 15-minute post exercise) pressure pain thresholds (PPTs), pain ratings, muscle soreness ratings and conditioned pain modulation (CPM) measures will be taken.

ACTIVE tDCS (INTERVENTION): Participants in the active tDCS group will receive 20 minutes of direct current stimulation (using a DC-Stimulator, Rogue Resolutions Inc., IImenau, Germany) via two 35cm2 surface sponge electrodes soaked with 0.9% saline. The active tDCS electrode (anode) will be positioned on the scalp over the motor cortical representation for the ECRB muscle (the 'hotspot', determined using transcranial magnetic stimulation). Prior to application, the scalp will be lightly abraded using Nuprep skin prep gel (Weaver and Company, Colorado, USA) then cleaned with alcohol to reduce current impedance. The stimulation parameters used for active tDCS will be the same as those used in previous studies that have shown to produce hypoalgesic effects in chronic musculoskeletal pain (Chang et al., 2017). The Active tDCS is delivered at 1 milliAmps and the current will take 10 seconds to build in intensity (fade in) and 10 seconds to decrease in intensity (fade out). Following active tDCS, the grip force task will commence. Participants will remain seated with their right elbow resting on a table in 90 degrees of flexion and forearm in neutral (between pronation and supination). Participants will be asked to squeeze a grip dynamometer as hard as possible (termed ‘maximal voluntary contraction [MVC]’) for 5 seconds and this will be performed 3 times with 1-minute rest between trials. The exercise protocol itself will involve squeezing the grip dynamometer at 25% of the participant's MVC for 3 minutes. Visual feedback will be provided to ensure that the participant maintains this contraction.

Researcher notes will be audited and reviewed by the supervisors of the student conducting the data collection. All participants will be blinded to group allocation. At the conclusion of each session, participants will be asked the group to which they believe they have been allocated. This will be done to assess the fidelity of participant blinding.
Intervention code [1] 314248 0
Treatment: Devices
Comparator / control treatment
CONTROL: Participants in the sham tDCS group will have the electrodes placed in an identical position to the active tDCS group, following the procedure described above. However, stimulation will be turned on for 15 seconds then turned off. This provides participants with the initial itching sensation associated with tDCS but does not induce changes in cortical excitability (Chang et al., 2017). All participants (active and sham tDCS) will be informed that they may or may not experience tingling or itching sensations during stimulation. This procedure has been shown to effectively blind participants to the stimulation condition (Gandiga, Hummel, & Cohen, 2006).

Following sham tDCS, the grip force task will commence. Participants will remain seated with their right elbow resting on a table in 90 degrees of flexion and forearm in neutral (between pronation and supination). Participants will be asked to squeeze a grip dynamometer as hard as possible (termed ‘maximal voluntary contraction [MVC]’) for 5 seconds and this will be performed 3 times with 1-minute rest between trials. The exercise protocol itself will involve squeezing the grip dynamometer at 25% of the participant's MVC for 3 minutes. Visual feedback will be provided to ensure that the participant maintains this contraction.
Control group
Placebo

Outcomes
Primary outcome [1] 319805 0
Mechanical hyperalgesia (measured using pressure pain thresholds). Pressure is applied perpendicular to the surface of the skin using a handheld algometer (Somedic, 1 cm2 probe) at a rate of 30 kPa/s. The PPT is defined as the point at which the participant reported that a sensation of pressure first changed to a sensation of pain. Three readings are recorded at 1-minute intervals. The average of the three measures is used during statistical analyses.
Timepoint [1] 319805 0
Pre-injection (Day 0), pre-tDCS (Day 2). immediately post-exercise (Day 2, primary time point), 15 minutes post-exercise (Day 2).
Primary outcome [2] 319806 0
Muscle Soreness (in the ECRB muscle) on a 7-point Likert Scale.
Timepoint [2] 319806 0
Pre-injection (Day 0), pre-tDCS (Day 2). immediately post-exercise (Day 2, primary timepoint), 15 minutes post-exercise (Day 2).
Primary outcome [3] 319807 0
Conditioned pain modulation (CPM). In this study, the average of three PPT recordings over the right ECRB represented the test stimulus. Immersion of the left hand in temperature-controlled ice water (4-6oC) was used as the conditioning stimulus. Pressure pain thresholds were recorded prior to cold immersion and following 1 minute of immersion, with the difference in PPT recordings being used to quantify the CPM effect.
Timepoint [3] 319807 0
Pre-injection (Day 0), pre-tDCS (Day 2). immediately post-exercise (Day 2, primary timepoint), 15 minutes post-exercise (Day 2).
Secondary outcome [1] 369581 0
Pain intensity on a 10-point scale (0 = no pain, 10 = worst pain imaginable)
Timepoint [1] 369581 0
Pre-injection (Day 0), pre-tDCS (Day 2). immediately post-exercise (Day 2), 15 minutes post-exercise (Day 2).

Eligibility
Key inclusion criteria
-Healthy
-No previous exposure to transcranial direct current stimulation (tDCS)
- Able to understand and speak English
Minimum age
18 Years
Maximum age
35 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
-Failure to pass the Transcranial Magentic Stimulation Safety Screen questionnaire
-Cardiovascular disorders
-Use of neuroactive drugs
-Pregnancy
-History of neurological illness
-History of musculoskeletal illness
-Previous exposure to TMS
-Contraindications to tDCS or TMS
-Current acute pain or recent musculoskeletal injury
-History of chronic pain

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a computerised random number generator
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
16/05/2019
Actual
Date of last participant enrolment
Anticipated
16/05/2019
Actual
Date of last data collection
Anticipated
31/05/2019
Actual
Sample size
Target
20
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 302538 0
University
Name [1] 302538 0
Western Sydney University
Country [1] 302538 0
Australia
Primary sponsor type
University
Name
Western Sydney University
Address
Western Sydney University, Campbelltown Campus, Narellan Rd & Gilchrist Dr, Campbelltown NSW 2560
Country
Australia
Secondary sponsor category [1] 302450 0
None
Name [1] 302450 0
Address [1] 302450 0
Country [1] 302450 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303188 0
Western Sydney University Human Research Ethics Comittee
Ethics committee address [1] 303188 0
Human Ethics Officer
Research Engagement, Development and Innovation (REDI)
Western Sydney University
Locked Bag 1797
Penrith NSW 2751
Ethics committee country [1] 303188 0
Australia
Date submitted for ethics approval [1] 303188 0
Approval date [1] 303188 0
01/04/2019
Ethics approval number [1] 303188 0

Summary
Brief summary
Exercise is considered a first-line treatment for chronic musculoskeletal pain (Pescatello, 2014). One mechanism contributing to the near-ubiquitous prescription of exercise in chronic pain populations is ‘exercise-induced hypoalgesia’. Exercise-induced hypoalgesia (EIH) is the term used to describe acute reductions in pain sensitivity following exercise (Koltyn, Brellenthin, Cook, Sehgal, & Hillard, 2014). However, in chronic musculoskeletal pain, EIH effects are, at best, small to moderate. Exploration of novel interventions that could bolster EIH effects are therefore warranted. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that provides a promising avenue to boost the EIH response (O'Connell, Marston, Spencer, DeSouza, & Wand, 2018). ’However, the effectiveness of tDCS in enhancing EIH is not known. Therefore, this study will investigate whether tDCS can be used to boost the hypoalgesic effect of isometric exercise .
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 92794 0
Mr Rocco Cavaleri
Address 92794 0
Western Sydney University, Campbelltown Campus, Narellan Rd & Gilchrist Dr, Campbelltown NSW 2560
Country 92794 0
Australia
Phone 92794 0
+61 2 4620 3994
Fax 92794 0
Email 92794 0
[email protected]
Contact person for public queries
Name 92795 0
Mr Rocco Cavaleri
Address 92795 0
Western Sydney University, Campbelltown Campus, Narellan Rd & Gilchrist Dr, Campbelltown NSW 2560
Country 92795 0
Australia
Phone 92795 0
+61 2 4620 3994
Fax 92795 0
Email 92795 0
[email protected]
Contact person for scientific queries
Name 92796 0
Mr Rocco Cavaleri
Address 92796 0
Western Sydney University, Campbelltown Campus, Narellan Rd & Gilchrist Dr, Campbelltown NSW 2560
Country 92796 0
Australia
Phone 92796 0
+61 2 4620 3994
Fax 92796 0
Email 92796 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
All of the individual participant data collected during the trial, after de-identification
When will data be available (start and end dates)?
Immediately following publication until 5 years after publication.
Available to whom?
Case-by-case basis at the discretion of the Principal Investigator
Available for what types of analyses?
Any purpose deemed appropriate by the Principal Investigator
How or where can data be obtained?
Access subject to approvals by Principal Investigator, requirement to sign data access agreement


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseTranscranial Direct Current Stimulation Accelerates The Onset of Exercise-Induced Hypoalgesia: A Randomized Controlled Study.2021https://dx.doi.org/10.1016/j.jpain.2020.08.004
N.B. These documents automatically identified may not have been verified by the study sponsor.