Pain Management
Conditions
Brief summary
This study looks at the effect of combined breathing-controlled electrical stimulation (BreEStim) and transcranial direct current stimulation (tDCS) on neuropathic pain after spinal cord injury, amputation, or brain injury. The hypothesis is that a single session of combined BreEStim and tDCS will produce an additive analgesic effect. This record covers the study in a population of spinal cord injury patients. Note that this study will also enroll healthy volunteers, brain injury patients, and amputation patients and that this study as applied to these other populations will be covered in separate ClinicalTrials.gov records.
Interventions
Sponsors
The University of Texas Health Science Center, Houston
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* between 18 and 75 years * male and female subjects * has neuropathic pain after traumatic spinal cord injury * has chronic pain, \>3 months * is stable on oral pain medications at least two weeks. (patients are allowed to continue their pain medications, i.e., no change in pain medications.)
Exclusion criteria
* currently adjusting oral pain medications for their neuropathic pain * have pain, but not neuropathic (e.g., from inflammation at the incision wound of the residual limb or neuroma) * have a pacemaker, or other metal and/or implanted devices * have amputation in their arm(s) * have spinal cord injury (SCI) involving impairment of arms * have cognitive impairment from brain injury or are not able to follow commands, or to give consent * have asthma or other pulmonary disease * are not medically stable * have preexisting psychiatric disorders * alcohol or drug abuse * have a history of seizures/Epilepsy, or taking benzodiazepines, anticonvulsants, and antidepressants. * Mini-mental state examination (MMSE), a brief 30-point questionnaire test that is commonly used in the literature, will be used to screen for cognitive impairment. A brain injury patient with a score of 24 or lower on MMSE will be excluded.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pain as Assessed by Visual Analogue Scale (VAS) | baseline, 10 minutes after tDCS, 10 minutes after BreEstim | A Visual Analogue Scale (VAS) is a measurement instrument that tries to measure a characteristic or attitude that is believed to range across a continuum of values and cannot easily be directly measured. It is often used in epidemiologic and clinical research to measure the intensity or frequency of various symptoms. To allow a continuous assessment of pain, VAS uses a 10 cm line labelled at '0' with 'no pain' and '10' with 'worst pain'. The line is marked at a point corresponding to the assessment of the pain. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Electrical Pain Threshold | baseline, 10 minutes after tDCS, 10 minutes after BreEstim | Trimmed surface electrodes (1 inch by 1 inch) were used to examine electrical pain thresholds upon application of electrical stimulation (electrical stimulator 7SA, Digitimer). To measure electrical pain threshold, a pair of electrodes was placed next to each other centered on the thenar eminence (which is a group of muscles on the palm of the human hand at the base of the thumb); the intensity of electrical stimulation was started from the sensation threshold level (determined in outcome measure 3) and increased in steps of 1 mA; and subjects were instructed to close their eyes and to say ''yes'' when they first felt electrical stimulation painful. The electrical pain threshold is the mA level at which a participant first felt electrical stimulation painful. To improve consistency among subjects, they were advised that the pain threshold level was equivalent to 1 on the 0-10 VAS scale. Three repetitions were made and the average was used as the electrical pain threshold. |
| Electrical Sensation Threshold | baseline, 10 minutes after tDCS, 10 minutes after BreEstim | Trimmed surface electrodes (1 inch by 1 inch) were used to examine electrical sensation threshold upon application of electrical stimulation (electrical stimulator 7SA, Digitimer). To measure electrical sensation threshold, a pair of electrodes was placed next to each other centered on the thenar eminence (which is a group of muscles on the palm of the human hand at the base of the thumb); the intensity of electrical stimulation was started from zero and gradually increased in steps of 0.1 mA; and subjects were instructed to close their eyes and to say ''yes'' when they explicitly felt electrical stimulation. The electrical sensation threshold is the mA level at which a participant explicitly felt electrical stimulation. Three repetitions were made and the average was used as the electrical sensation threshold. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| All Participants This study has a single-blinded, single-center, sham-controlled, crossover design. It included 2 separate visits, each with either a 20-min sham tDCS or M1 tDCS to the current dominant primary motor cortex(M1), both followed by a 20-min BreEStim to the median nerve(160 times) transcutaneously on the current dominant side. | 12 |
| Total | 12 |
Baseline characteristics
| Characteristic | All Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 12 Participants |
| Race/Ethnicity, Customized Black | 2 Participants |
| Race/Ethnicity, Customized Hispanic | 3 Participants |
| Race/Ethnicity, Customized White | 7 Participants |
| Region of Enrollment United States | 12 Participants |
| Sex: Female, Male Female | 5 Participants |
| Sex: Female, Male Male | 7 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 10 | 0 / 12 |
| other Total, other adverse events | 0 / 10 | 0 / 12 |
| serious Total, serious adverse events | 0 / 10 | 0 / 12 |
Outcome results
Primary
Pain as Assessed by Visual Analogue Scale (VAS)
A Visual Analogue Scale (VAS) is a measurement instrument that tries to measure a characteristic or attitude that is believed to range across a continuum of values and cannot easily be directly measured. It is often used in epidemiologic and clinical research to measure the intensity or frequency of various symptoms. To allow a continuous assessment of pain, VAS uses a 10 cm line labelled at '0' with 'no pain' and '10' with 'worst pain'. The line is marked at a point corresponding to the assessment of the pain.
Time frame: baseline, 10 minutes after tDCS, 10 minutes after BreEstim
Population: In the Sham tDCS and then BreEStim arm, only 10 participants were analyzed because 2 patients did not return for the second visit.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham tDCS and Then BreEStim | Pain as Assessed by Visual Analogue Scale (VAS) | baseline | 6.0 units on a scale | Standard Deviation 2.03 |
| Sham tDCS and Then BreEStim | Pain as Assessed by Visual Analogue Scale (VAS) | After tDCS | 5.4 units on a scale | Standard Deviation 2.26 |
| Sham tDCS and Then BreEStim | Pain as Assessed by Visual Analogue Scale (VAS) | After BreEstim | 3.5 units on a scale | Standard Deviation 1.91 |
| Active tDCS (M1) and Then BreEStim | Pain as Assessed by Visual Analogue Scale (VAS) | baseline | 5.9 units on a scale | Standard Deviation 1.65 |
| Active tDCS (M1) and Then BreEStim | Pain as Assessed by Visual Analogue Scale (VAS) | After tDCS | 5.3 units on a scale | Standard Deviation 1.66 |
| Active tDCS (M1) and Then BreEStim | Pain as Assessed by Visual Analogue Scale (VAS) | After BreEstim | 3.1 units on a scale | Standard Deviation 2.08 |
Secondary
Electrical Pain Threshold
Trimmed surface electrodes (1 inch by 1 inch) were used to examine electrical pain thresholds upon application of electrical stimulation (electrical stimulator 7SA, Digitimer). To measure electrical pain threshold, a pair of electrodes was placed next to each other centered on the thenar eminence (which is a group of muscles on the palm of the human hand at the base of the thumb); the intensity of electrical stimulation was started from the sensation threshold level (determined in outcome measure 3) and increased in steps of 1 mA; and subjects were instructed to close their eyes and to say ''yes'' when they first felt electrical stimulation painful. The electrical pain threshold is the mA level at which a participant first felt electrical stimulation painful. To improve consistency among subjects, they were advised that the pain threshold level was equivalent to 1 on the 0-10 VAS scale. Three repetitions were made and the average was used as the electrical pain threshold.
Time frame: baseline, 10 minutes after tDCS, 10 minutes after BreEstim
Population: In the Sham tDCS and then BreEStim arm, only 10 participants were analyzed because 2 patients did not return for the second visit.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham tDCS and Then BreEStim | Electrical Pain Threshold | After tDCS | 31.1 mA | Standard Deviation 27.05 |
| Sham tDCS and Then BreEStim | Electrical Pain Threshold | Baseline | 30.4 mA | Standard Deviation 25.53 |
| Sham tDCS and Then BreEStim | Electrical Pain Threshold | After BreEstim | 34.5 mA | Standard Deviation 24.14 |
| Active tDCS (M1) and Then BreEStim | Electrical Pain Threshold | Baseline | 35.0 mA | Standard Deviation 26.04 |
| Active tDCS (M1) and Then BreEStim | Electrical Pain Threshold | After tDCS | 33.9 mA | Standard Deviation 26.37 |
| Active tDCS (M1) and Then BreEStim | Electrical Pain Threshold | After BreEstim | 35.2 mA | Standard Deviation 21.58 |
Secondary
Electrical Sensation Threshold
Trimmed surface electrodes (1 inch by 1 inch) were used to examine electrical sensation threshold upon application of electrical stimulation (electrical stimulator 7SA, Digitimer). To measure electrical sensation threshold, a pair of electrodes was placed next to each other centered on the thenar eminence (which is a group of muscles on the palm of the human hand at the base of the thumb); the intensity of electrical stimulation was started from zero and gradually increased in steps of 0.1 mA; and subjects were instructed to close their eyes and to say ''yes'' when they explicitly felt electrical stimulation. The electrical sensation threshold is the mA level at which a participant explicitly felt electrical stimulation. Three repetitions were made and the average was used as the electrical sensation threshold.
Time frame: baseline, 10 minutes after tDCS, 10 minutes after BreEstim
Population: In the Sham tDCS and then BreEStim arm, only 10 participants were analyzed because 2 patients did not return for the second visit.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham tDCS and Then BreEStim | Electrical Sensation Threshold | Baseline | 7.3 mA | Standard Deviation 2.41 |
| Sham tDCS and Then BreEStim | Electrical Sensation Threshold | After tDCS | 7.4 mA | Standard Deviation 2.84 |
| Sham tDCS and Then BreEStim | Electrical Sensation Threshold | After BreEstim | 7.3 mA | Standard Deviation 2.66 |
| Active tDCS (M1) and Then BreEStim | Electrical Sensation Threshold | Baseline | 8.4 mA | Standard Deviation 2.59 |
| Active tDCS (M1) and Then BreEStim | Electrical Sensation Threshold | After tDCS | 8.1 mA | Standard Deviation 2.51 |
| Active tDCS (M1) and Then BreEStim | Electrical Sensation Threshold | After BreEstim | 8.3 mA | Standard Deviation 2.47 |