Trial Outcomes & Findings for Optimized tDCS for Fibromyalgia: Targeting the Endogenous Pain Control System (NCT NCT03371225)
NCT ID: NCT03371225
Last Updated: 2025-12-10
Results Overview
Pain intensity was measured using the Numeric Pain Scale (NPS; 0 = no pain, 10 = worst pain). Higher scores indicate worse pain. A "pain-6 temperature" was first identified (temperature that elicits NPS = 6). Test stimulus: Pain-6 temperature applied for 30s; participants rated pain at 10, 20, and 30s. The test-stimulus score is the average of the three NPS ratings. Conditioned stimulus: After 5 minutes, the left hand was immersed in 10-12°C water for 30s while the same pain-6 temperature was applied again. Pain was rated the same way, and the conditioned-stimulus score is the average of the three NPS ratings. CPM calculation = (test-stimulus average) - (conditioned-stimulus average). Positive values = better endogenous pain inhibition; negative values = worse.
Recruitment status
COMPLETED
Study phase
NA
Target enrollment
116 participants
Primary outcome timeframe
6 weeks
Results posted on
2025-12-10
Participant Flow
116 subjects were enrolled and randomized
Participant milestones
| Measure |
Active tDCS and Active Exercise
Active tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
|
Sham tDCS and Active Exercise
Sham tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
|
Active tDCS and Sham Exercise
Active tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Sham TDCS and Sham Exercise
Sham tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
|---|---|---|---|---|
|
Overall Study
STARTED
|
28
|
28
|
30
|
30
|
|
Overall Study
COMPLETED
|
19
|
20
|
20
|
24
|
|
Overall Study
NOT COMPLETED
|
9
|
8
|
10
|
6
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
Optimized tDCS for Fibromyalgia: Targeting the Endogenous Pain Control System
Baseline characteristics by cohort
| Measure |
Active tDCS and Active Exercise
n=28 Participants
Active tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
|
Sham tDCS and Active Exercise
n=28 Participants
Sham tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
|
Active tDCS and Sham Exercise
n=30 Participants
Active tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Sham TDCS and Sham Exercise
n=30 Participants
Sham tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Total
n=116 Participants
Total of all reporting groups
|
|---|---|---|---|---|---|
|
Age, Continuous
|
46.8 years
STANDARD_DEVIATION 12.5 • n=4 Participants
|
46.3 years
STANDARD_DEVIATION 11.9 • n=50 Participants
|
49.1 years
STANDARD_DEVIATION 10.2 • n=681 Participants
|
46.2 years
STANDARD_DEVIATION 13.3 • n=639 Participants
|
47.1 years
STANDARD_DEVIATION 11.9 • n=277 Participants
|
|
Sex: Female, Male
Female
|
25 Participants
n=4 Participants
|
24 Participants
n=50 Participants
|
28 Participants
n=681 Participants
|
26 Participants
n=639 Participants
|
103 Participants
n=277 Participants
|
|
Sex: Female, Male
Male
|
3 Participants
n=4 Participants
|
4 Participants
n=50 Participants
|
2 Participants
n=681 Participants
|
4 Participants
n=639 Participants
|
13 Participants
n=277 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
22 Participants
n=4 Participants
|
24 Participants
n=50 Participants
|
23 Participants
n=681 Participants
|
20 Participants
n=639 Participants
|
89 Participants
n=277 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
5 Participants
n=4 Participants
|
4 Participants
n=50 Participants
|
6 Participants
n=681 Participants
|
6 Participants
n=639 Participants
|
21 Participants
n=277 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
1 Participants
n=4 Participants
|
0 Participants
n=50 Participants
|
1 Participants
n=681 Participants
|
4 Participants
n=639 Participants
|
6 Participants
n=277 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
1 Participants
n=4 Participants
|
0 Participants
n=50 Participants
|
0 Participants
n=681 Participants
|
0 Participants
n=639 Participants
|
1 Participants
n=277 Participants
|
|
Race (NIH/OMB)
Asian
|
1 Participants
n=4 Participants
|
1 Participants
n=50 Participants
|
1 Participants
n=681 Participants
|
1 Participants
n=639 Participants
|
4 Participants
n=277 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=4 Participants
|
0 Participants
n=50 Participants
|
0 Participants
n=681 Participants
|
0 Participants
n=639 Participants
|
0 Participants
n=277 Participants
|
|
Race (NIH/OMB)
Black or African American
|
2 Participants
n=4 Participants
|
2 Participants
n=50 Participants
|
3 Participants
n=681 Participants
|
3 Participants
n=639 Participants
|
10 Participants
n=277 Participants
|
|
Race (NIH/OMB)
White
|
20 Participants
n=4 Participants
|
21 Participants
n=50 Participants
|
23 Participants
n=681 Participants
|
21 Participants
n=639 Participants
|
85 Participants
n=277 Participants
|
|
Race (NIH/OMB)
More than one race
|
3 Participants
n=4 Participants
|
3 Participants
n=50 Participants
|
2 Participants
n=681 Participants
|
3 Participants
n=639 Participants
|
11 Participants
n=277 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
1 Participants
n=4 Participants
|
1 Participants
n=50 Participants
|
1 Participants
n=681 Participants
|
2 Participants
n=639 Participants
|
5 Participants
n=277 Participants
|
PRIMARY outcome
Timeframe: 6 weeksPain intensity was measured using the Numeric Pain Scale (NPS; 0 = no pain, 10 = worst pain). Higher scores indicate worse pain. A "pain-6 temperature" was first identified (temperature that elicits NPS = 6). Test stimulus: Pain-6 temperature applied for 30s; participants rated pain at 10, 20, and 30s. The test-stimulus score is the average of the three NPS ratings. Conditioned stimulus: After 5 minutes, the left hand was immersed in 10-12°C water for 30s while the same pain-6 temperature was applied again. Pain was rated the same way, and the conditioned-stimulus score is the average of the three NPS ratings. CPM calculation = (test-stimulus average) - (conditioned-stimulus average). Positive values = better endogenous pain inhibition; negative values = worse.
Outcome measures
| Measure |
Active tDCS and Active Exercise
n=28 Participants
Active tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
|
Sham tDCS and Active Exercise
n=28 Participants
Sham tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
|
Active tDCS and Sham Exercise
n=30 Participants
Active tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Sham TDCS and Sham Exercise
n=30 Participants
Sham tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
|---|---|---|---|---|
|
Conditioning Pain Modulation (CPM)
|
0.36 Unit on a scale (NPS 0-10)
Interval -0.23 to 0.95
|
0.05 Unit on a scale (NPS 0-10)
Interval -0.63 to 0.73
|
0.21 Unit on a scale (NPS 0-10)
Interval -0.4 to 0.83
|
-0.55 Unit on a scale (NPS 0-10)
Interval -1.01 to -0.09
|
PRIMARY outcome
Timeframe: 6 weeksParticipants first determined the temperature that elicited Numeric Pain Scale (NPS) = 6 ("pain-6"). Using this temperature, a train of 15 heat pulses (0.4 Hz) was delivered to the right forearm with a TSA-II thermode. Pain was rated using the NPS after the 1st and 15th heat stimulus. TSPS calculation: TSPS = NPS rating after the 15th stimulus - NPS rating after the 1st stimulus. Higher TSPS values represent greater temporal pain summation (worse outcome).
Outcome measures
| Measure |
Active tDCS and Active Exercise
n=28 Participants
Active tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
|
Sham tDCS and Active Exercise
n=28 Participants
Sham tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
|
Active tDCS and Sham Exercise
n=30 Participants
Active tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Sham TDCS and Sham Exercise
n=30 Participants
Sham tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
|---|---|---|---|---|
|
Temporal Slow Pain Summation (TSPS)
|
-0.11 Unit on a scale (NPS 0-10)
Interval -0.6 to 0.38
|
0.48 Unit on a scale (NPS 0-10)
Interval -0.29 to 1.25
|
0.47 Unit on a scale (NPS 0-10)
Interval -0.27 to 1.2
|
0.09 Unit on a scale (NPS 0-10)
Interval -0.44 to 0.61
|
Adverse Events
Active tDCS and Active Exercise
Serious events: 0 serious events
Other events: 23 other events
Deaths: 0 deaths
Sham tDCS and Active Exercise
Serious events: 0 serious events
Other events: 21 other events
Deaths: 0 deaths
Active tDCS and Sham Exercise
Serious events: 0 serious events
Other events: 18 other events
Deaths: 0 deaths
Sham TDCS and Sham Exercise
Serious events: 1 serious events
Other events: 28 other events
Deaths: 0 deaths
Serious adverse events
| Measure |
Active tDCS and Active Exercise
n=28 participants at risk
Active tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
|
Sham tDCS and Active Exercise
n=28 participants at risk
Sham tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
|
Active tDCS and Sham Exercise
n=30 participants at risk
Active tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Sham TDCS and Sham Exercise
n=30 participants at risk
Sham tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
|---|---|---|---|---|
|
Skin and subcutaneous tissue disorders
Allergic reaction
|
0.00%
0/28 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
0.00%
0/28 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
0.00%
0/30 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
3.3%
1/30 • Number of events 1 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
Other adverse events
| Measure |
Active tDCS and Active Exercise
n=28 participants at risk
Active tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
|
Sham tDCS and Active Exercise
n=28 participants at risk
Sham tDCS for 20 min Active exercise (60-70% max HR) for 30 min
Active Exercise: Participants will walk briskly in a treadmill (as to keep at 60-70% maximum heart rate) for 30 minutes
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
|
Active tDCS and Sham Exercise
n=30 participants at risk
Active tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Active tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. 20 minutes of tDCS will be applied.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
Sham TDCS and Sham Exercise
n=30 participants at risk
Sham tDCS for 20 min Sham exercise (within 10% baseline HR) for 30 min
Sham tDCS: Active tDCS: A 1x1 Low-intensity DC Stimulator will be used to deliver direct current through rubber electrodes in saline soaked sponges. The anode will be placed over the left primary motor cortex (M1) while the cathode will be placed over the contralateral supra-orbital area. Only 30 seconds of current will be applied for the sham condition.
Sham Exercise: Participants will walk in a treadmill (as to keep at 10% within their baseline heart rate) for 30 minutes.
|
|---|---|---|---|---|
|
Skin and subcutaneous tissue disorders
Mild Tingling
|
82.1%
23/28 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
75.0%
21/28 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
60.0%
18/30 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
93.3%
28/30 • 4.5 months
Adverse effects were collected with a questionnaire for adverse effects
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place