This study looks at the non-invasive brain stimulation technique in people with chronic low back pain to see: * How effective non-invasive brain stimulation is at improving pain intensity in people with chronic low back pain? * How safe non-invasive brain stimulation is and what side effects there may be? * What study participants think of the study procedures and of the non-invasive brain stimulation as a treatment technique for chronic low back pain. Participants will be assigned to receive either active brain stimulation group or sham stimulation group randomly. Participants will be required to attend a total of twelve treatment sessions (approximately 1-hour each, three sessions per week, for four consecutive weeks). Assessments will be done at baseline (in the week 0), immediately post-completion of the intervention (in the week 5), and at the follow-up of one-month (in the week 8), three-months (in the week 16) and six-months (in the week 28) post-completion of intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
164
HD-tIGNS will be administered three times a week (30 minutes/ session) for a total of 4 weeks (i.e., 12 sessions in total) using a 32-channel transcranial current stimulator. The HD-tIGNS will be used to alter the functional connectivity strength between the three cortical networks \[namely the salience network (SN), the default mode network (DMN) and the somatomotor network (SMN)\] in the infraslow frequency spectrum (0.1 Hz). A total of fifteen circular Ag/AgCl electrodes \[eleven stimulation electrodes (C1, C2, C3, C4, F7, F8, FC3, FT7, FPz, Fz, and O2) and four electrodes with zero current (FC1, FC2, FC4, and FCz)\] will be placed on a neoprene head cap following the International 10-10 EEG system. The optimal montages has been created using the Stimweaver optimization software by the Neuroelectrics company, to specifically decrease the functional connectivity i.e., phase synchronization of the brain regions of the SN with the SMN and the DMN.
The Actisham protocol (with FC2 as the itchy electrode) created by the Neuroelectrics will be used for the sham stimulation group. Similar to the active treatment group, the actisham will be administered three times a week (30 minutes/ session) for a total of 4 weeks (i.e., 12 sessions in total) using a 32-channel transcranial current stimulator.Similar to active group, a total of fifteen circular Ag/AgCl electrodes will be placed on a neoprene head cap following the International 10-10 EEG system to appropriately blind the participant. The electrodes would comprise of four stimulation electrodes (FC1, FC2, FC4, and FCz) and eleven electrodes (C1, C2, C3, C4, F7, F8, FC3, FT7, FPz, Fz, and O2) with zero current.
Department of Surgical Sciences, Dunedin School of Medicine, University of Otago
Dunedin, Otago, New Zealand
RECRUITINGPain intensity
Average pain intensity over the past week measured on a numeric pain rating scale (NPRS) of 0 to 10 (0=No pain to 10=Pain as bad as you can imagine) from the Brief Pain Inventory short form
Time frame: The primary endpoint for efficacy assessment of HD-tIGNS will be change in the average pain intensity over the past week from baseline to one-week post completion of treatment.
Pain intensity
Average pain intensity over the past week measured on a NPRS of 0 to 10 (0=No pain to 10=Pain as bad as you can imagine) from the Brief Pain Inventory short form.
Time frame: Change in the average pain intensity over the past week from baseline to one-month, three-months and six-months post completion of treatment.
Pain interference
Brief Pain Inventory (BPI), a standardised, validated questionnaire, will be used to capture pain interference in daily activities
Time frame: Change in the pain interference from baseline to one-week, one-month, three-months and six-months post completion of treatment.
Pain unpleasantness
Pain unpleasantness (affective component) in past one week measured on an 11-point NPRS-unpleasantness scale.
Time frame: Change in the pain unpleasantness from baseline to one-week, one-month, three-months and six-months post completion of treatment.
Pain Bothersomeness
Pain bothersomeness in past one week measured on an 11-point NPRS-bothersomeness scale.
Time frame: Change in the pain bothersomeness from baseline to one-week, one-month, three-months and six-months post completion of treatment.
Patient global impression of change
Patient global impression of change (PGIC) 7-point scale will be used to evaluate participants perception of overall improvement compared to baseline.
Time frame: Recorded at one-week, one-month, three-months, and six-months post completion of treatment.
Movement Evoked Pain: Repeated spinal bending
Participants will be asked to perform 20 repetitions each of 2 repeated spinal bending tasks (forward and backward bending) independently, with at least a 10-15 minute rest in between. Participants will rate their pain intensity on a NPRS (0=no pain to 100=worst pain imaginable) before commencing the movements, then following every 5 repetitions.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Movement Evoked Pain: Back Performance scale
Back Performance scale (BPS) will be used to assess movement evoked pain (MEP) intensity during five functional tasks. Participants will be asked to rate their "pain rating at worst" during each task on a 0 to 100 NPRS. An MEP intensity composite score will be calculated by averaging pain ratings for the 5 tasks, with higher scores indicating greater MEP intensity.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Mechanical temporal summation
Mechanical temporal summation (MTS): will be assessed using a nylon monofilament (Semmes monofilament 6.65, 300 g) at the most painful low back region (nominated by the participant) and the non-dominant wrist (distant region). Brief 10 repetitive contacts will be delivered at a rate of 1 Hz, externally cued by auditory stimuli. Participants will be asked to rate the level of pain experienced on NRS (0=no pain to 100=extreme pain) immediately after the first contact and to rate their greatest pain intensity after the 10th contact; with the difference representing the maximum amount of MTS across 10 contact points. Average of three trials will be calculated, with a positive score indicating an increase in MTS. The MTS index will be defined as the ratio of 'follow-up' pain rating divided by 'baseline' pain rating.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Pressure Pain Threshold
Pressure pain threshold (PPT) will be assessed over the most painful low back region (nominated by the participant) and the non-dominant wrist (distant region) using a computerized, handheld digital algometer (AlgoMed; Medoc, Ramat Yishai, Israel) probe pressed over marked test site at a rate of 30 kPa/s. Participants will press the algometer trigger button in the patient control unit when pressure sensation changes to first pain. Average of three trials will be calculated and used for analysis
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Function
Roland-Morris Disability Questionnaire (RMDQ) will be used to assess self-reported functional abilities; within-group MCID is 30% decrease from baseline.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Health Related Quality of Life
European Quality of Life-5 Dimensions scale will be used to assess the health-related quality of life; within-group MCID is 0.03 and 10.5 from baseline for the health index and the thermometer respectively.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Well-Being
World Health Organization- Five Well-Being Index (WHO-5) will be used to measure the participant's current mental wellbeing.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Depression
Depression and Somatic Symptoms Scale (DSSS) will be used to evaluate the severity of depression (cutoff score of ≥15).
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Catastrophizing
Pain Catastrophizing Scale (PCS) will be used to measure the extent of catastrophic thoughts and feelings about their pain.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Attention to pain
Pain Vigilance and Awareness Questionnaire (PVAQ) will be used to measure the frequency of habitual 'attention to pain' over the past two weeks.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Positive and Negative Affect
Positive and Negative Affect Schedule (PANAS-short form) will be used to measure the two-dominant dimensions of affect style, positive and negative affect.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Self-efficacy
Pain self-efficacy (PSE), a 2-item questionnaire, will be used to assess pain self-efficacy beliefs.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Intolerance to Uncertainity scale short form
Intolerance of uncertainty (IUS) scale- short form (12 item), will be used to assess how individuals perceive and respond to uncertainty in their daily lives. Total score ranges between 5 to 60 with higher scores indicating higher levels of intolerance to uncertainity.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Tampa scale of Kinesiophobia
Tampa Scale of Kinesiophobia (TSK-11), will be used to quantify fear of movement. The scores ranges from 11 to 44, where higher scores indicate greater fear of pain, movement, and injury.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment.
Rescue analgesics / Concomitant treatment
The Quantitative analgesic questionnaire (QAQ) will be used to capture daily medication usage and a score will be generated to calculate weekly average pain medication use throughout the study. Other concomitant treatments including exercises, healthcare visits, etc. with the type and dosage will also be recorded throughout the study period using a diary.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment. QAQ will also be collected during intervention period, either at start of sessions (S1, S4, S7, S10) or after completion of the session (S12).
Electroencephalography
Resting-state eyes closed electroencephalogram (EEG) (\~10 minutes) will be obtained using SynAmps RT Amplifier (Compudemics Neuroscan) with 64 electrodes placed in the standard 10-10 International placement. During the intervention phase, resting state EEG will be collected using the Neuroelectrics Starstim32 system. Exact low-resolution brain electromagnetic tomography (eLORETA), will be used through the LORETA-key software package to estimate the intracerebral electrical sources that generate scalp-recorded electrical activity. Lagged phase synchronization will be used as a measure of functional connectivity and will be calculated between the targeted brain regions (i.e., dorsal anterior cingulate cortex, Somatosemsory cortex, motor cortex, Insula, pregenual anterior cingulate cortex) in the infraslow frequency band (0.1Hz).
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment. EEG will also be collected during intervention phase either at start of the sessions (S1,S4,S7,S10) or after completion of sessions (S1 and S12).
Emotional Stroop Task
Participants will be presented with words from 3 interference categories (Sensory pain-related, Affective pain-related, and Positive-emotional) and 3 control categories (comprising of matched neutral words) in four different colours (blue, red, yellow, green) and will be asked to press one of four response keys to indicate the colour of the words regardless of their meaning. The participant's response, the correctness of the response, and the response latency (in ms) of each of the 6 different categories will be recorded. Each word will be displayed for 1.5s and there will be 16 words in a 24s block. A single trial will be conducted, and it will include 16 blocks, i.e., 2 blocks for each word-type, 2 blocks for each corresponding control word set, and four fixation-cross (rest) blocks (24s duration) presented on the screen at the beginning and twice within a trial. The average of two test blocks will be calculated and used for analysis.
Time frame: Recorded at baseline, and at one-week, one-month, three-months, and six-months post completion of treatment. Stroop testing will be also be done during the intervention phase either at start of sessions (S4, S7, S10) or after completion of session (S12).
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