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Trial registered on ANZCTR


Registration number
ACTRN12616000624482
Ethics application status
Approved
Date submitted
9/05/2016
Date registered
13/05/2016
Date last updated
13/05/2016
Type of registration
Prospectively registered

Titles & IDs
Public title
Combined application of brain stimulation and sensorimotor retraining for low back pain
Scientific title
Safety and feasibility of transcranial direct current stimulation (tDCS) combined with sensorimotor retraining in chronic low back pain: a pilot randomised controlled trial
Secondary ID [1] 289057 0
Nil Known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
chronic nonspecific low back pain 298499 0
Condition category
Condition code
Physical Medicine / Rehabilitation 298584 298584 0 0
Physiotherapy
Musculoskeletal 298783 298783 0 0
Other muscular and skeletal disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Active transcranial direct current stimulation (tDCS) plus sensorimotor retraining will be given twice per week for 10 weeks by a qualified physiotherapist trained in the use of tDCS.

Active tDCS: will be delivered to the primary motor cortex while participants are comfortably and quietly seated. Direct current will be delivered for 20 minutes via two 35cm2 surface sponge electrodes. The active electrode (anode) will be positioned over the primary motor cortex contralateral to the side of worst pain and the reference electrode (cathode) over the contralateral supraorbital region. Current intensity will be ramped up (0 mA to 1 mA) and down (1 mA to 0 mA) over 10 s at the beginning and end of the 20-min stimulation period.

Sensorimotor retraining: Immediately following the tDCS intervention, participants will commence 60 minutes of supervised graded sensorimotor retraining. Components of the protocol include localisation and graphesthesia training, laterality recognition, imagined movements and small to full range movements with feedback. Participants will progress through each stage by the physiotherapist based on specific, previously published criteria such as > 80 % accuracy on tactile discrimination or successful dissociation of lumbar from thoracic spine movements (Wand et al 2011). Participants will be provided with a home exercise diary containing visual and written instructions for each exercise (including dosage) and will be asked to practice the training at home for 30 minutes, 3 x per week. The diary will also be used to record adherence to the home program.
Intervention code [1] 294558 0
Rehabilitation
Intervention code [2] 294716 0
Treatment: Other
Comparator / control treatment
Sham transcranial direct current stimulation (tDCS) plus sensorimotor retraining will be given twice per week for 10 weeks by a qualified physiotherapist trained in tDCS.

Sham tDCS: For sham stimulation, electrodes will be placed in an identical position to that used for active stimulation. To provide the initial itching sensation, stimulation will be turned on for 15 seconds and then off. Participants will be informed that they may or may not perceive any sensation during the treatment.

Sensorimotor retraining: identical to that described for the active stimulation group.
Control group
Active

Outcomes
Primary outcome [1] 298080 0
Feasibility - composite primary outcome

The number of participants that (i) meet the inclusion criteria, (ii) agree to be randomised, (iii) complete the intervention and, (iv) attend the post-intervention assessment will be calculated in accordance with CONSORT guidelines. Feasibility will be measured as (i) the number of treatment sessions attended by each participant, (ii) number of drop-outs in each group, (iii) proportion of participants recruited from the total number screened and, (iv) willingness of each participant to undergo therapy on an 11-point numerical rating scale with ‘not at all willing’ at 0 and ‘very willing’ at 10 (measured at baseline) and, (v) the number of home exercise sessions completed.
Timepoint [1] 298080 0
Baseline, Immediately following each intervention session, at the conclusion of the 10 week intervention period
Primary outcome [2] 298082 0
Safety

Safety will be assessed as any adverse effect, defined as “a response to an intervention which is noxious and unintended, and which occurs at doses normally used in man for the prophylaxis, diagnosis, or therapy of disease, or for the modification of physiological function” and that likely has a causal relationship with the intervention (Carlesso, Macdermid, & Santaguida, 2010), reported upon verbal questioning by the treating physiotherapist at each session. A mild tingling or itching sensation under the electrodes, fatigue, headache, nausea, and insomnia have been reported as potential adverse reactions following tDCS (Poreisz, Boros, Antal, & Paulus, 2007). Potential adverse reactions as a result of sensorimotor retraining may include increased pain or muscle soreness in the back. The treating physiotherapist will record a description of any adverse effects along with the severity and duration of symptoms and how the adverse effect was managed.
Timepoint [2] 298082 0
Immediately following each intervention session, at the conclusion of the 10 week intervention period
Secondary outcome [1] 323139 0
Pain severity

The Brief Pain Inventory will be used to measure pain severity. To assess pain, participants will be asked to complete four numerical rating scales anchored with 0 (“no pain”) and 10 (“worst pain imaginable”) for pain at its: i) most intense over the last week, ii) least intense over the last week, iii) average intensity over the last week, and iv) right now. Scores from each scale will be averaged to calculate a final pain severity score out of 10 (Song et al., 2016).
Timepoint [1] 323139 0
Baseline and Immediately following conclusion of the 10 week intervention
Secondary outcome [2] 323140 0
Physical function

The Brief Pain Inventory will be used to measure physical function. Participants will complete seven numerical rating scales to describe how their back pain interfered with daily life (general activity, mood, walking ability, normal work, relationships with other people, sleep, and enjoyment of life) in the past week. Each scale will be anchored with 0 (‘does not interfere with daily life’) and 10 (‘completely interferes’). Scores from the seven scales will be averaged to give a final pain interference score out of 10 (Ger, Ho, Sun, Wang, & Cleeland, 1999).

Self-reported disability and function will also be measured using the 24-point RMDQ which has been shown to be valid and reliable in people with low back pain (Chapman et al., 2011).
Timepoint [2] 323140 0
Baseline and Immediately following conclusion of the 10 week intervention
Secondary outcome [3] 323141 0
Global perceived effect of treatment scale, where each participant’s perceived response to therapy is assessed using a 5-point Likert scale ranging from “completely recovered” to “vastly worsened” will be completed (Hassett et al., 2009).
Timepoint [3] 323141 0
Immediately following conclusion of the 10 week intervention
Secondary outcome [4] 323421 0
Pressure pain thresholds

Measured using a hand-held pressure algometer with a probe size of 1cm2. The probe will be applied perpendicular to the skin (rate 40 kPa/s) until the participant first reports that the sensation of pressure has changed to pain. PPTs will be measured three times at i) the site of worst pain and ii) the contralateral thumbnail. The average of the three measurements at each site will be used in the analysis. PPT measures have been shown to be reliable in chronic LBP (Vuilleumier et al., 2015; Walton et al., 2011).
Timepoint [4] 323421 0
Baseline and Immediately following conclusion of the 10 week intervention
Secondary outcome [5] 323422 0
Heat pain thresholds (HPT)

Measured using the conditioned pain modulation system. A 30 x 30 mm Peltier-based thermode will be placed on the skin. The temperature will start at 32 degrees celsius and increase at a rate of 0.5 degrees/second. Participants will push a button when the sensation of heat first turns to a sensation of pain. HPTs will be measured at i) the site of worst pain and ii) the bilateral ventral aspect of the forearm (10 cm distal from the elbow crest). Three measurements will be recorded at each site and the average analysed.
Timepoint [5] 323422 0
Baseline and Immediately following conclusion of the 10 week intervention
Secondary outcome [6] 323423 0
Conditioned pain modulation

We will use pressure pain (PPTs) as the test stimulation and heat pain (1 degree celsius above HPT) as the conditioned stimulation. Three PPTs will be measured before the application of heat pain. Heat pain will then be applied via a 30 x 30 mm thermode. Three PPT measurements will be repeated 30 seconds after applying the conditioned stimulation. Participants will be asked to rate their pain during conditioned stimulation on a numeric rating scale (0-100) at 0 s, 30 s and at the end of the trial. Pain scores will be maintained between 50 and 80/100 during testing. Participants will complete two trials in random order: i) test stimulation applied at the most painful lumbar region (indicated by the participant) and conditioned stimulation at the contralateral forearm; ii) test stimulation at the contralateral forearm and conditioned stimulation at the ipsilateral forearm.
Timepoint [6] 323423 0
Baseline and Immediately following conclusion of the 10 week intervention
Secondary outcome [7] 323594 0
Temporal summation

Temporal summation will be assessed using a 26g nylon monofilament to apply repeated mechanical stimulation according to the Standardized Evaluation of Pain (StEP) protocol (Scholz et al., 2009). The participant will be asked whether a single filament stimulus provokes pain. If the answer is ‘yes’, the participant will then be asked to rate the pain on a numeric rating scale (0-100). If the answer is ‘no’, a ‘zero’ will be recorded on a numeric rating scale. The filament will then be applied to the skin at a rate of 1 Hz for 30 seconds. The participant will be asked to rate the pain on the numeric rating scale again at the end of the 30 stimuli. Temporal summation will be tested on the most painful area and the dorsal aspect of the non-dominant wrist joint.
Timepoint [7] 323594 0
Baseline and Immediately following conclusion of the 10 week intervention

Eligibility
Key inclusion criteria
Participants with chronic non-specific LBP will be recruited. Participants will be required to have an average pain score greater than or equal to 4/10 on a numerical rating scale in the week prior to enrolment and a minimum score of 4 points on the Roland Morris Disability Questionnaire (RMDQ) to limit the potential for floor effects.
Minimum age
18 Years
Maximum age
60 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Participants will be excluded if they: i) present with specific spinal pathology (tumour, spondylolythesis, fracture etc.), nerve root pain or co-existing major muscular, joint, neurological or psychiatric conditions (Airaksinen et al., 2006; Saragiotto et al., 2016), ii) have undergone back surgery, iii) are currently undertaking a structured exercise program for LBP, or (vi) present with contraindications to tDCS (e.g. cuts or blisters under the electrode sites) or conditioned pain modulation techniques (e.g. loss of sensation).

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)
The randomisation schedule will be concealed in consecutively numbered, sealed opaque envelopes. An investigator not involved in recruitment, treatment or assessment will provide the envelope to the treating clinician who will reveal group allocation.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Random sequence 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)
Safety/efficacy
Statistical methods / analysis
Data for feasibility and safety will be analysed using descriptive statistics. To determine trends for effectiveness, outcomes of pain severity, disability and pain mechanisms will be compared between (active vs. sham tDCS) and within (pre/post the 10-week intervention) groups, according to intention-to-treat and per protocol using two-way analysis of variance (ANOVA). As this is a pilot trial, missing data will not be replaced. Effect sizes will be determined using partial eta-squared from planned contrasts. Bonferroni post-hoc tests will be applied if appropriate. Alpha will be set at 0.05.

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

Funding & Sponsors
Funding source category [1] 293550 0
University
Name [1] 293550 0
Western Sydney University
Address [1] 293550 0
Western Sydney University, Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country [1] 293550 0
Australia
Primary sponsor type
Individual
Name
Siobhan Schabrun
Address
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country
Australia
Secondary sponsor category [1] 292361 0
Individual
Name [1] 292361 0
Matthew Liston
Address [1] 292361 0
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country [1] 292361 0
Australia
Secondary sponsor category [2] 292362 0
Individual
Name [2] 292362 0
Adam Ouellette
Address [2] 292362 0
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country [2] 292362 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294988 0
Western Sydney University Human Research Ethics Committee
Ethics committee address [1] 294988 0
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Ethics committee country [1] 294988 0
Australia
Date submitted for ethics approval [1] 294988 0
Approval date [1] 294988 0
30/05/2013
Ethics approval number [1] 294988 0
H10184

Summary
Brief summary
Low back pain (LBP) is one of the most common reasons for people to seek health care. Of those that report LBP, 44-78% experience a re-occurrence within 12 months, and approximately 25% of individuals develop chronic pain. Despite high prevalence, current treatments for chronic LBP demonstrate at best, small effect sizes. One avenue to improve outcomes in chronic LBP is through the application of combined treatments with synergistic clinical and mechanistic effects.

Sensorimotor retraining is a novel treatment that incorporates motor control exercise and lumbar tactile retraining and has been shown to be effective in early randomized controlled trials and case studies of chronic LBP. The mechanism underpinning improvements in pain and function with sensorimotor retraining is thought to involve normalization of motor and sensory cortical plasticity and improved pain system function. The addition of a second treatment that targets similar mechanisms may boost the effectiveness of sensorimotor retraining in people with chronic LBP.

Transcranial direct current stimulation (tDCS), a form of non-invasive brain stimulation, is thought to promote cortical plasticity and improve pain system function through direct effects on the cortex and thalamus, as well as “downstream” effects on the anterior cingulate cortex and upper brainstem. Studies of healthy individuals and people with some forms of chronic pain suggest that anodal tDCS applied to the primary motor cortex can reduce pain. In addition, the cortical effects of tDCS are hypothesised to increase the brain’s receptiveness to other treatments, a phenomenon known as priming. Thus, tDCS may optimise the responsiveness of the brain to sensorimotor retraining and improve outcomes beyond that which can be achieved with sensorimotor retraining alone. Despite this, no study has examined the effect of a combined tDCS and sensorimotor retraining therapy in chronic pain.

This pilot RCT protocol will outline study methods, and resources required in order to determine the feasibility, acceptability and safety of tDCS combined with sensorimotor retraining for people with chronic LBP. The specific aims are to i) determine the feasibility, safety, perceived patient response to, and acceptability of, a combined tDCS and sensorimotor training intervention in chronic LBP and ii) provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 65326 0
Dr Siobhan Schabrun
Address 65326 0
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country 65326 0
Australia
Phone 65326 0
+61 2 4620 3497
Fax 65326 0
Email 65326 0
s.schabrun@westernsydney.edu.au
Contact person for public queries
Name 65327 0
Dr Matthew Liston
Address 65327 0
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country 65327 0
Australia
Phone 65327 0
+ 61 2 4620 3503
Fax 65327 0
Email 65327 0
m.liston@westernsydney.edu.au
Contact person for scientific queries
Name 65328 0
Dr Matthew Liston
Address 65328 0
Western Sydney University
Campbelltown Campus, Locked Bag 1797, Penrith NSW 2751, Australia
Country 65328 0
Australia
Phone 65328 0
+61 2 4620 3503
Fax 65328 0
Email 65328 0
m.liston@westernsydney.edu.au

No information has been provided regarding IPD availability
Summary results
No Results