Chronic Low Back Pain
Conditions
Keywords
tACS, transcranial alternating current stimulation, low back pain, chronic pain, alpha oscillations, heart rate variability
Brief summary
Chronic pain is a severe disabling problem within society, affecting 25-30% of the United States population.. Transcranial alternating current stimulation (tACS) has the potential to provide a treatment option that is safe, scientifically-supported, low-cost, and easy-to-administer method to effectively reduce symptoms in patients suffering from chronic pain. The purpose of this study is to test the feasibility of using tACS to treat patients with chronic pain, and to collect pilot efficacy as well as EEG and EKG biomarker data for optimizing the design of subsequent large-scale studies. The treatment rationale is to renormalize the presumed pathological structure of alpha oscillations in the prefrontal cortex (PFC) of patients with chronic pain.
Interventions
The participant will receive up to one minute of tACS stimulation until the stimulation fades. Sham stimulation mimics the skin sensations a participant would experience during a tACS session
Transcranial alternating current stimulation (tACS) is a method of noninvasive brain stimulation in which weak electrical current are applied to the scalp in a sine wave pattern to induce cortical oscillations at the frequency at which they are applied
Sponsors
National Institute of Mental Health (NIMH)
University of North Carolina, Chapel Hill
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Masking description
This is a double-blind study, meaning that neither the participant nor the experimenter knows what kind of stimulation the participant is receiving. An unblinded monitor (separate from the staff that interacts with the participant) is responsible for creating the stimulation codes that run each session and for ensuring that these codes worked correctly.
Intervention model description
Each participant will receive sham stimulation and 10Hz tACS stimulation at two separate sessions. The order will be randomized (ie, half the participants will receive sham stimulation at the first session and 10Hz tACS stimulation at the second session, and the other half will receive 10Hz tACS stimulation at the first session and sham stimulation at the second session).
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Male or female, aged 18-65 * Diagnosed with nonspecific chronic low back pain by clinician * BMI is less than 30 * Suffered from chronic pain for \> 6 months * Self-report pain measures \>4 * Meets criteria for low depression and suicide risk as defined by the Hamilton-Depression Rating Scale * Capacity to understand all relevant risks and potential benefits of the study (informed consent) * Not currently taking opioids, benzodiazepines, and anticonvulsant medications
Exclusion criteria
* Radicular Pain * Traumatic brain injury, Any brain devices/implants, including cochlear implants and aneurysm clips * History of major neurological or psychiatric illness, including epilepsy * (For females) Pregnancy or breast feeding * Diagnosis of eating disorder (current or within the past 6 months), Obsessive Compulsive Disorder (lifetime), or Attention-Deficit Hyperactivity Disorder (currently under treatment)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Heart Rate Variability Before and After 40-minute Stimulation | before and after 40-minute stimulation at each session | Changes in parasympathetic tone, increase in high frequency band input via spectral analysis on EKG recordings between active and sham stimulation |
| Change in Electroencephalogram Power in Alpha Band Before and After 40-minute Stimulation | 5 minute recordings before and after each 40-minute stimulation at each session. | Changes in the EEG power in the alpha (8-12 Hz) band before and after 40-minute stimulation |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Pain Rating on the Visual Analog Scale Before and After 40-minute Stimulation | before and after 40 minute stimulation session | Self reported pain rating using a Visual Analog Scale (VAS) ranging from 0-10 done before and after stimulation with '0' being no pain and '10' as bad as it could be. Lower values represent a better outcome. (Pain difference was normalized using modulation index to account for ordinal scale) |
Countries
United States
Participant flow
Recruitment details
Recruitment ran from August 2017 - December 2017. This clinical trial utilized multiple recruitment strategies including UNC University Physical Therapy and Pain clinic locations, informational notify.unc.edu system, and jointheconquest.org along with the listing on clinicaltrials.gov
Participants by arm
| Arm | Count |
|---|---|
| Sham Then Active 10 Hz tACS At session 1 this group received sham tACS and at session 2 they received active 10Hz tACS | 11 |
| Active 10 Hz Then Sham tACS At session 1 this group received active 10Hz tACS and at session 2 they received sham 10Hz tACS | 10 |
| Total | 21 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Washout (1-3 Weeks) | Lost to Follow-up | 1 | 0 |
Baseline characteristics
| Characteristic | Sham Then Active 10 Hz tACS | Active 10 Hz Then Sham tACS | Total |
|---|---|---|---|
| Age, Continuous | 42.6 years STANDARD_DEVIATION 13.8 | 43.4 years STANDARD_DEVIATION 13.6 | 43 years STANDARD_DEVIATION 13.4 |
| BMI | 25.98 kg/m^2 STANDARD_DEVIATION 4.1 | 25.92 kg/m^2 STANDARD_DEVIATION 5.1 | 25.94 kg/m^2 STANDARD_DEVIATION 4.5 |
| Duration of Pain | 4.8 years STANDARD_DEVIATION 3 | 9.3 years STANDARD_DEVIATION 7.4 | 7.1 years STANDARD_DEVIATION 6 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 1 Participants | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 11 Participants | 8 Participants | 19 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 2 Participants | 2 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 11 Participants | 8 Participants | 19 Participants |
| Region of Enrollment United States | 11 Participants | 10 Participants | 21 Participants |
| Sex: Female, Male Female | 3 Participants | 9 Participants | 12 Participants |
| Sex: Female, Male Male | 8 Participants | 1 Participants | 9 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 21 | 0 / 20 |
| other Total, other adverse events | 0 / 21 | 0 / 20 |
| serious Total, serious adverse events | 0 / 21 | 0 / 20 |
Outcome results
Primary
Change in Electroencephalogram Power in Alpha Band Before and After 40-minute Stimulation
Changes in the EEG power in the alpha (8-12 Hz) band before and after 40-minute stimulation
Time frame: 5 minute recordings before and after each 40-minute stimulation at each session.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Sham tACS | Change in Electroencephalogram Power in Alpha Band Before and After 40-minute Stimulation | 0.03 square microvolts | Standard Deviation 0.16 |
| Active10 Hz tACS | Change in Electroencephalogram Power in Alpha Band Before and After 40-minute Stimulation | 0.4 square microvolts | Standard Deviation 0.15 |
Primary
Change in Heart Rate Variability Before and After 40-minute Stimulation
Changes in parasympathetic tone, increase in high frequency band input via spectral analysis on EKG recordings between active and sham stimulation
Time frame: before and after 40-minute stimulation at each session
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Sham tACS | Change in Heart Rate Variability Before and After 40-minute Stimulation | 0.206 ms^2 | Standard Deviation 0.76 |
| Active10 Hz tACS | Change in Heart Rate Variability Before and After 40-minute Stimulation | -0.01 ms^2 | Standard Deviation 0.56 |
Comparison: A 2x2 ANOVA was used to measure change in HF-HRV by condition (10 Hz vs sham) and session (first vs second) as within subjects variablesp-value: 0.319ANOVA
Secondary
Change in Pain Rating on the Visual Analog Scale Before and After 40-minute Stimulation
Self reported pain rating using a Visual Analog Scale (VAS) ranging from 0-10 done before and after stimulation with '0' being no pain and '10' as bad as it could be. Lower values represent a better outcome. (Pain difference was normalized using modulation index to account for ordinal scale)
Time frame: before and after 40 minute stimulation session
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Sham tACS | Change in Pain Rating on the Visual Analog Scale Before and After 40-minute Stimulation | -0.178 units on a scale | Standard Deviation 0.97 |
| Active10 Hz tACS | Change in Pain Rating on the Visual Analog Scale Before and After 40-minute Stimulation | 0.18 units on a scale | Standard Deviation 0.31 |
Comparison: Investigators hypothesized that active stimulation would have a greater normalized pain change using a modulation index \[(Pre-Post)/(Pre+Post)\]p-value: 0.0488Wilcoxon (Mann-Whitney)