Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
The goal of this clinical trial is to investigate the effects and mechanisms of high-definition transcranial direct current stimulation over left dorsolateral prefrontal cortex on chronic low back pain and balance in older adults. The main questions it aims to answer are:
Primary hypothesis 1: Active stimulation would have greater improvement in pain and balance, reduced left dorsolateral prefrontal cortex activation than sham stimulation.
Primary hypothesis 2: Active stimulation would have enhanced functional connectivity than sham stimulation.
Primary hypothesis 3: The balance improvement would be related to reduced pain, decreased left dorsolateral prefrontal cortex activation, enhanced functional connectivity, attention, and/or executive function.
Participants will be randomly received a single-session of high-definition transcranial direct current stimulation (active or sham stimulation). Before and immediately after the intervention, balance (semi-tandem stance and timed up-and-go test (TUG)) and cognitive (attention and executive function) tests will be assessed.
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Active stimulation | Experimental | For the active stimulation, the current will be ramped up from 0 to 2 mA over the initial 30-s period and then maintain the current of 2 mA for 20 minutes, following by a 30-s ramp-down period. |
|
| Sham stimulation | Experimental | The participants will receive the same intervention procedures, but the intervention will have no therapeutic effect. Specifically, for the sham stimulation, participants will only experience 30-s ramp-up and 30-s ramp-down periods at both the commencement and end of the stimulation. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| high-definition transcranial direct current stimulation | Device | High-definition transcranial direct current stimulation is a novel non-invasive brain stimulation technique based on the principle that when weak intensity electric currents are targeted on specific areas of the scalp, they cause underlying cortical stimulation. The anode increases cortical excitability, while cathode decreases cortical excitability. |
| Measure | Description | Time Frame |
|---|---|---|
| Current back-pain intensity | The current back-pain intensity will be assessed with the 11-point numerical rating scale anchored with "no pain" at zero and "worst pain imaginable" at 10. | Before and immediately after the intervention. |
| Measure | Description | Time Frame |
|---|---|---|
| Resting-state blood oxygen concentration | Resting-state blood oxygen concentration (indicated by Oxyhemoglobin concentration (μmol)) will be measured using the portable fNIRS imaging system (NIRSport 2, NIRx Medical Technologies LLC, Glen Head, NY, USA). We will instruct participants to sit still and comfortably with their eyes open, lean against the back rest, and look at a fixation cross one meter in front of them for 5 minutes. |
Not provided
Inclusion Criteria:
Exclusion Criteria:
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| The Hong Kong Polytechnic University | Hong Kong | Hong Kong | 999077 | China |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
The allocation of the participants will be sealed in an envelope, blinding the subjects and assessors, and a third person (intervention implementer) will perform the blinding.
|
| Before and immediately after the intervention. |
| Arithmetic performance | Participants will be required to perform the cognitive task in the seated postition (3 x 30s). The cognitive task is serial subtraction from a random three-digit number (200-999) by 7s audibly. The number of correct and incorrect answers will be recorded. | Before and immediately after the intervention. |
| Postural sway | Postural sway will be assessed by APDM® Mobility Lab (APDM, Inc., Portland, OR, USA) in the following tests in a random order: (1) semi-tandem stance on firm surfaces without cognitive task (3 x 30s), (2) semi-tandem stance on firm surfaces with cognitive task (3 x 30s), (3) semi-tandem stance on foam surfaces without cognitive task (3 x 30s), (4) semi-tandem stance on foam surfaces with cognitive task (3 x 30s). The cognitive task is serial subtraction from a random three-digit number (200-999) by 7s audibly. No instructions are given regarding task prioritization. During the standing tests, cortical activation will be measured using the NIRSport 2 system with its control box placed in a backpack worn by participants. | Before and immediately after the intervention. |
| Timed up-and-go test (TUG) | TUG will be performed in random order in the following tests: (1) TUG without a cognitive task (3 trials) and (2) TUG with a cognitive task (3 trials). The cognitive task involves serial subtraction from a random three-digit number (ranging from 200 to 999) by subtracting 7s audibly. No specific instructions are provided regarding task prioritization. The time (in seconds) taken to complete the TUG, along with the number of correct and incorrect answers, will be recorded for statistical analysis. | Before and immediately after the intervention. |
| Attention | Attention will be assessed using the Trail Making Test - A (TMT-A). TMT-A involves connecting a series of 25 square and circle encircled numbers in ascending order, without lifting the pen from the paper. Errors will be corrected immediately and re-establish the sequence. The time (in seconds) to complete the TMT-A will be recorded for statistical analysis. | Before and immediately after the intervention. |
| Executive function | Executive function will be assessed using TMT-A and the Trail Making Test - B (TMT-B). TMT-A involves connecting a series of 25 square and circle encircled numbers in ascending order, without lifting the pen from the paper. In TMT-B, the numbers from 1 to 25 are twice presented in square and circle shapes ("1" is only presented once). Participants are instructed to connect the numbers in ascending order, alternating between the squares and circles. Errors will be corrected immediately and re-establish the sequence. The time to complete the TMT-A and TMT-B will be recorded. Executive function will be indicated by the difference in TMT-A and TMT-B (TMT-B minus TMT-A in seconds). | Before and immediately after the intervention. |
| Side or adverse effects | Any side or adverse effects (e.g., itching, tingling and burning sensations under electrodes) related to the interventions will be monitored in all participants. | During and 1 hour after the intervention. |
| Blinding efficacy | A blinding efficacy questionnaire will be completed after intervention. If the participant believes that they receive active or sham stimulation, they will be asked to state their confidence in this belief on a scale of 1 (not confident) to 3 (very confident). | Immediately after the intervention. |