Trial Outcomes & Findings for Self Transcranial Direct Current Stimulation for Pain in Older Adults With Knee Osteoarthritis (NCT NCT03425019)

NCT ID: NCT03425019

Last Updated: 2021-10-15

Results Overview

Scores on the visual analogue scale (VAS) range from 0 (no pain) to 100 (worst pain imaginable).

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 21 participants
• Primary outcome timeframe: baseline
• Results posted on: 2021-10-15

Participant Flow

1 participant withdrew before the intervention started.

Participant milestones

Measure	Transcranial Direct Current Stimulation Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Overall Study STARTED	20
Overall Study COMPLETED	20
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Self Transcranial Direct Current Stimulation for Pain in Older Adults With Knee Osteoarthritis

Baseline characteristics by cohort

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Age, Continuous	61.2 years STANDARD_DEVIATION 7.23 • n=5 Participants
Sex: Female, Male Female	15 Participants n=5 Participants
Sex: Female, Male Male	5 Participants n=5 Participants
Race/Ethnicity, Customized African American	6 Participants n=5 Participants
Race/Ethnicity, Customized Asian	6 Participants n=5 Participants
Race/Ethnicity, Customized Hispanic	1 Participants n=5 Participants
Race/Ethnicity, Customized White	7 Participants n=5 Participants
Region of Enrollment United States	20 Participants n=5 Participants
Education High School	3 Participants n=5 Participants
Education 2-year college	5 Participants n=5 Participants
Education 4-year college	9 Participants n=5 Participants
Education Master's degree	2 Participants n=5 Participants
Education Doctoral degree	1 Participants n=5 Participants
Body Mass Index (BMI)	28.33 kg/m^2 STANDARD_DEVIATION 8.01 • n=5 Participants
Osteoarthritis duration	29.60 months STANDARD_DEVIATION 26.17 • n=5 Participants

PRIMARY outcome

Timeframe: baseline

Scores on the visual analogue scale (VAS) range from 0 (no pain) to 100 (worst pain imaginable).

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by a Visual Analogue Scale (VAS)

55.23 units on a scale Standard Deviation 25.45

PRIMARY outcome

Timeframe: 2 weeks

Scores on the visual analogue scale (VAS) range from 0 (no pain) to 100 (worst pain imaginable).

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by a Visual Analogue Scale (VAS)

24.85 units on a scale Standard Deviation 22.70

SECONDARY outcome

Timeframe: baseline

The WOMAC is a self-administered questionnaire consisting of 3 subscales related to pain (pain subscale total score range, 0-20), stiffness (stiffness subscale total score range, 0-8), and impairments of physical function (functional impairment subscale range, 0-68), with higher scores indicating worse pain, stiffness, and impairments of physical function, respectively.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Pain Subscale

7.95 score on a scale Standard Deviation 4.39

SECONDARY outcome

Timeframe: 2 weeks

The WOMAC is a self-administered questionnaire consisting of 3 subscales related to pain (pain subscale total score range, 0-20), stiffness (stiffness subscale total score range, 0-8), and impairments of physical function (functional impairment subscale range, 0-68), with higher scores indicating worse pain, stiffness, and impairments of physical function, respectively.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Pain Subscale

5.75 units on a scale Standard Deviation 4.25

SECONDARY outcome

Timeframe: baseline

The WOMAC is a self-administered questionnaire consisting of 3 subscales related to pain (pain subscale total score range, 0-20), stiffness (stiffness subscale total score range, 0-8), and impairments of physical function (functional impairment subscale range, 0-68), with higher scores indicating worse pain, stiffness, and impairments of physical function, respectively.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Stiffness Subscale

4.00 units on a scale Standard Deviation 1.86

SECONDARY outcome

Timeframe: 2 weeks

The WOMAC is a self-administered questionnaire consisting of 3 subscales related to pain (pain subscale total score range, 0-20), stiffness (stiffness subscale total score range, 0-8), and impairments of physical function (functional impairment subscale range, 0-68), with higher scores indicating worse pain, stiffness, and impairments of physical function, respectively.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Stiffness Subscale

2.90 units on a scale Standard Deviation 1.74

SECONDARY outcome

Timeframe: baseline

The WOMAC is a self-administered questionnaire consisting of 3 subscales related to pain (pain subscale total score range, 0-20), stiffness (stiffness subscale total score range, 0-8), and impairments of physical function (functional impairment subscale range, 0-68), with higher scores indicating worse pain, stiffness, and impairments of physical function, respectively.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Functional Impairment Subscale

29.10 units on a scale Standard Deviation 17.53

SECONDARY outcome

Timeframe: 2 weeks

The WOMAC is a self-administered questionnaire consisting of 3 subscales related to pain (pain subscale total score range, 0-20), stiffness (stiffness subscale total score range, 0-8), and impairments of physical function (functional impairment subscale range, 0-68), with higher scores indicating worse pain, stiffness, and impairments of physical function, respectively.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - Functional Impairment Subscale

20.85 units on a scale Standard Deviation 15.22

SECONDARY outcome

Timeframe: baseline

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The continuous pain subscale assesses throbbing pain, cramping pain, gnawing pain, aching pain, heavy pain, and tender, and total score on the continuous pain subscale ranges from 0-60, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Continuous Pain Summary Scale

22.75 units on a scale Standard Deviation 15.26

SECONDARY outcome

Timeframe: 2 weeks

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The continuous pain subscale assesses throbbing pain, cramping pain, gnawing pain, aching pain, heavy pain, and tender, and total score on the continuous pain subscale ranges from 0-60, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Continuous Pain Subscale

14.05 units on a scale Standard Deviation 13.84

SECONDARY outcome

Timeframe: baseline

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The intermittent pain subscale assesses shooting pain, stabbing pain, sharp pain, splitting pain, electric-shock pain, and piercing, and total score on the intermittent pain subscale ranges from 0-60, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Intermittent Pain Subscale

17.80 units on a scale Standard Deviation 16.18

SECONDARY outcome

Timeframe: 2 weeks

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The intermittent pain subscale assesses shooting pain, stabbing pain, sharp pain, splitting pain, electric-shock pain, and piercing, and total score on the intermittent pain subscale ranges from 0-60, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Intermittent Pain Subscale

12.90 units on a scale Standard Deviation 15.80

SECONDARY outcome

Timeframe: baseline

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The neuropathic pain subscale assesses hot-burning pain, cold-freezing pain, pain caused by light touch, itching, tingling or 'pins and needles', and numbness, and total score on the neuropathic pain subscale ranges from 0-60, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Neuropathic Pain Subscale

11.1 units on a scale Standard Deviation 13.71

SECONDARY outcome

Timeframe: 2 weeks

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The neuropathic pain subscale assesses hot-burning pain, cold-freezing pain, pain caused by light touch, itching, tingling or 'pins and needles', and numbness, and total score on the neuropathic pain subscale ranges from 0-60, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Neuropathic Pain Subscale

8.2 units on a scale Standard Deviation 14.23

SECONDARY outcome

Timeframe: baseline

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The affective description subscale assesses tiring-exhausting, sickening, fearful, and punishing-cruel, and total score on the affective description subscale ranges from 0-40, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Affective Description Subscale

11.7 units on a scale Standard Deviation 11.65

SECONDARY outcome

Timeframe: 2 weeks

The SF-MPQ-2 measures the quality as well as the intensity of pain. Participants complete the SF-MPQ-2 by rating the extent to which they experienced each of 22 pain descriptors in the past week using an 11-point numeric rating scale (0 = "none" to 10 = "worst possible"). The affective description subscale assesses tiring-exhausting, sickening, fearful, and punishing-cruel, and total score on the affective description subscale ranges from 0-40, with a higher score indicating worse pain.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Clinical Pain Intensity as Assessed by Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) - Affective Description Subscale

5.75 units on a scale Standard Deviation 10.40

SECONDARY outcome

Timeframe: baseline

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess HPTH, heat stimuli were delivered to the participant's arm or knee using a computer-controlled TSAII NeuroSensory Analyzer. From a baseline of 32 degrees Celsius, the temperature increased by 0.5 degrees Celsius per second until the participants responded by pressing a button to stop heat stimuli. Participants were instructed to press the button when the sensation ''first becomes painful" to assess the heat pain threshold (HPTH). The temperature at which participants pressed the button to indicate the sensation ''first becomes painful" is reported.

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Threshold (HPTH) arm	37.9 degrees Celsius Standard Deviation 3.3
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Threshold (HPTH) knee	39.1 degrees Celsius Standard Deviation 3.5

SECONDARY outcome

Timeframe: 2 weeks

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess HPTH, heat stimuli were delivered to the participant's arm or knee using a computer-controlled TSAII NeuroSensory Analyzer. From a baseline of 32 degrees Celsius, the temperature increased by 0.5 degrees Celsius per second until the participants responded by pressing a button to stop heat stimuli. Participants were instructed to press the button when the sensation ''first becomes painful" to assess the heat pain threshold (HPTH). The temperature at which participants pressed the button to indicate the sensation ''first becomes painful" is reported.

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Threshold (HPTH) arm	37.3 degrees Celsius Standard Deviation 2.0
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Threshold (HPTH) knee	40.1 degrees Celsius Standard Deviation 3.4

SECONDARY outcome

Timeframe: baseline

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess HPTO, heat stimuli were delivered to the participant's arm or knee using a computer-controlled TSAII NeuroSensory Analyzer. From a baseline of 32 degrees Celsius, the temperature increased by 0.5 degrees Celsius per second until the participants responded by pressing a button to stop heat stimuli. Participants were instructed to press the button when they ''no longer feel able to tolerate the pain." The temperature at which participants pressed the button to indicate they could ''no longer feel able to tolerate the pain" is reported.

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Tolerance (HPTO) arm	43.2 degrees Celsius Standard Deviation 3.1
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Tolerance (HPTO) knee	43.1 degrees Celsius Standard Deviation 3.3

SECONDARY outcome

Timeframe: 2 weeks

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess HPTO, heat stimuli were delivered to the participant's arm or knee using a computer-controlled TSAII NeuroSensory Analyzer. From a baseline of 32 degrees Celsius, the temperature increased by 0.5 degrees Celsius per second until the participants responded by pressing a button to stop heat stimuli. Participants were instructed to press the button when they ''no longer feel able to tolerate the pain." The temperature at which participants pressed the button to indicate they could ''no longer feel able to tolerate the pain" is reported.

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Tolerance (HPTO) arm	43.2 degrees Celsius Standard Deviation 3.2
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Heat Pain Tolerance (HPTO) knee	44.6 degrees Celsius Standard Deviation 3.1

SECONDARY outcome

Timeframe: baseline

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess PPT, a handheld digital pressure algometer (Wagner, Greenwich, CT) was applied at a constant rate of 0.3 kilograms force per centimeter squared (kgf/cm^2) per second to the participant's medial knee, lateral knee, or trapezius. Participants were asked to notify the experimenter when the pressure sensation ''first becomes painful." The pressure at which participants pressed the button to indicate that the pressure sensation ''first becomes painful" is reported.

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Pressure Pain Threshold (PPT) medial knee	3.2 kilograms force (kgf) Standard Deviation 1.4
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Pressure Pain Threshold (PPT) lateral knee	3.5 kilograms force (kgf) Standard Deviation 1.5
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Pressure Pain Threshold (PPT) trapezius	2.9 kilograms force (kgf) Standard Deviation 1.6

SECONDARY outcome

Timeframe: 2 weeks

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess PPT, a handheld digital pressure algometer (Wagner, Greenwich, CT) was applied at a constant rate of 0.3 kilograms force per centimeter squared (kgf/cm^2) per second to the participant's medial knee, lateral knee, or trapezius. Participants were asked to notify the experimenter when the pressure sensation ''first becomes painful." The pressure at which participants pressed the button to indicate that the pressure sensation ''first becomes painful" is reported.

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Pressure Pain Threshold (PPT) medial knee	3.7 kilograms force (kgf) Standard Deviation 1.2
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Pressure Pain Threshold (PPT) lateral knee	4.4 kilograms force (kgf) Standard Deviation 1.3
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Pressure Pain Threshold (PPT) trapezius	3.9 kilograms force (kgf) Standard Deviation 1.3

SECONDARY outcome

Timeframe: baseline

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess PMP, punctate mechanical pain is delivered to the patella or hand by a calibrated nylon monofilament for 10 contacts of the monofilament at one contact per second. Participants rate the pain intensity on a scale from 0 (no pain) to 100 (maximum imaginable pain).

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Punctate Mechanical Pain (PMP) patella	84.7 score on a scale Standard Deviation 23.4
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Punctate Mechanical Pain (PMP) hand	66.0 score on a scale Standard Deviation 27.0

SECONDARY outcome

Timeframe: 2 weeks

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

To assess PMP, punctate mechanical pain is delivered to the patella or hand by a calibrated nylon monofilament for 10 contacts of the monofilament at one contact per second. Participants rate the pain intensity on a scale from 0 (no pain) to 100 (maximum imaginable pain).

Outcome measures

Measure	Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Punctate Mechanical Pain (PMP) patella	67.4 score on a scale Standard Deviation 26.9
Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Punctate Mechanical Pain (PMP) hand	54.6 score on a scale Standard Deviation 23.9

SECONDARY outcome

Timeframe: baseline

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

CPM is reported as the change in PPT before and immediately following immersion of the contralateral hand up to the wrist in a cold water bath (12 degrees Celsius) for up to one minute. To assess PPT, a handheld digital pressure algometer (Wagner, Greenwich, CT) was applied at a constant rate of 0.3 kilograms force per centimeter squared (kgf/cm^2) per second to the participant's trapezius. Participants were asked to notify the experimenter when the pressure sensation ''first becomes painful." The pressure at which participants pressed the button to indicate that the pressure sensation ''first becomes painful" is reported.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Conditioned Pain Modulation (CPM)

0.9 kilograms force (kgf) Standard Deviation 0.7

SECONDARY outcome

Timeframe: 2 weeks

In order to measure experimental pain sensitivity, a multimodal Quantitative Sensory Testing (QST) battery will be completed: heat pain threshold (HPTH); heat pain tolerance (HPTO), pressure pain threshold (PPT), punctate mechanical pain (PMP), and Conditioned Pain Modulation (CPM).

CPM is reported as the change in PPT before and immediately following immersion of the contralateral hand up to the wrist in a cold water bath (12 degrees Celsius) for up to one minute. To assess PPT, a handheld digital pressure algometer (Wagner, Greenwich, CT) was applied at a constant rate of 0.3 kilograms force per centimeter squared (kgf/cm^2) per second to the participant's trapezius. Participants were asked to notify the experimenter when the pressure sensation ''first becomes painful." The pressure at which participants pressed the button to indicate that the pressure sensation ''first becomes painful" is reported.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Experimental Pain Sensitivity as Assessed by a Multimodal Quantitative Sensory Testing (QST) Battery - Conditioned Pain Modulation (CPM)

1.3 kilograms force (kgf) Standard Deviation 0.6

SECONDARY outcome

Timeframe: 2 weeks

Pain-related cortical response will be measured using a continuous-wave, multichannel fNIRS imaging system (LIGHTNIRS, Shimadzu, Kyoto, Japan) with three semiconductor lasers at 780, 805, and 830 nm. Optical recordings will be collected during thermal pain stimulation.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Number of Participants Who Were Assessed by Functional Near-infrared Spectroscopy (fNIRS)

20 Participants

SECONDARY outcome

Timeframe: 2 weeks

Data will be collected on participants' tDCS experience at the conclusion of tDCS treatment on a scale of 0 (strongly disagree) to 10 (strongly agree): Q1) "Overall the device was easy to use"

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Feasibility as Assessed by a Survey of Participants' tDCS Experience - Ease of Using Device

9.75 score on a scale Standard Deviation 0.44

SECONDARY outcome

Timeframe: 2 weeks

Data will be collected on participants' tDCS experience at the conclusion of tDCS treatment on a scale of 0 (strongly disagree) to 10 (strongly agree): Q2) "It was easy to prepare the device and accessories"

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Feasibility as Assessed by a Survey of Participants' tDCS Experience - Ease of Preparation of Device

9.75 score on a scale Standard Deviation 0.44

SECONDARY outcome

Timeframe: 2 weeks

Data will be collected on participants' tDCS experience at the conclusion of tDCS treatment on a scale of 0 (strongly disagree) to 10 (strongly agree): Q3) "The effectiveness of the treatment increased over the course of treatment."

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Feasibility as Assessed by a Survey of Participants' tDCS Experience - Effectiveness of Treatment Over Time

6.75 score on a scale Standard Deviation 3.17

SECONDARY outcome

Timeframe: 2 weeks

The participants will be asked in an open-ended manner whether they have experienced any side effects, and they will then be asked specifically about tingling, itching sensation, burning sensation, pain at the stimulation site, fatigue, nervousness, headache, difficulty concentrating, mood change, and changes in vision or visual perception.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Tolerability as Assessed by Number of Participants With Side Effects

0 Participants

SECONDARY outcome

Timeframe: baseline

The 7-item PROMIS anxiety-short form assesses the pure domain of anxiety in individuals age 18 and older, and each item on the measure is rated on a 5-point scale (1=never; 2=rarely; 3=sometimes; 4=often; and 5=always) with a range in score from 7 to 35 with higher scores indicating greater severity of anxiety.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Anxiety as Assessed by the PROMIS Anxiety-short Form

13.6 score on a scale Standard Deviation 6.73

SECONDARY outcome

Timeframe: 2 weeks

The 7-item PROMIS anxiety-short form assesses the pure domain of anxiety in individuals age 18 and older, and each item on the measure is rated on a 5-point scale (1=never; 2=rarely; 3=sometimes; 4=often; and 5=always) with a range in score from 7 to 35 with higher scores indicating greater severity of anxiety.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Anxiety as Assessed by the PROMIS Anxiety-short Form

12.05 score on a scale Standard Deviation 6.86

SECONDARY outcome

Timeframe: baseline

The 8-item PROMIS depression-short form assesses the pure domain of depression in individuals age 18 and older, and each item on the measure is rated on a 5-point scale (1=never; 2=rarely; 3=sometimes; 4=often; and 5=always) with a range in score from 8 to 40 with higher scores indicating greater severity of depression.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Depression as Assessed by the PROMIS Depression-short Form

12.3 units on a scale Standard Deviation 7.69

SECONDARY outcome

Timeframe: 2 weeks

The 8-item PROMIS depression-short form assesses the pure domain of depression in individuals age 18 and older, and each item on the measure is rated on a 5-point scale (1=never; 2=rarely; 3=sometimes; 4=often; and 5=always) with a range in score from 8 to 40 with higher scores indicating greater severity of depression.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Depression as Assessed by the PROMIS Depression-short Form

11.85 units on a scale Standard Deviation 6.98

SECONDARY outcome

Timeframe: baseline

The 8-item PROMIS sleep disturbance-short form assesses the pure domain of sleep disturbance in individuals age 18 and older, and each item on the measure is rated on a 5-point scale (1=never; 2=rarely; 3=sometimes; 4=often; and 5=always) with a range in score from 8 to 40 with higher scores indicating greater severity of sleep disturbance.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Sleep Disturbance as Assessed by the PROMIS Sleep Disturbance-short Form

24.3 units on a scale Standard Deviation 7.87

SECONDARY outcome

Timeframe: 2 weeks

The 8-item PROMIS sleep disturbance-short form assesses the pure domain of sleep disturbance in individuals age 18 and older, and each item on the measure is rated on a 5-point scale (1=never; 2=rarely; 3=sometimes; 4=often; and 5=always) with a range in score from 8 to 40 with higher scores indicating greater severity of sleep disturbance.

Outcome measures

Measure

Transcranial Direct Current Stimulation n=20 Participants Transcranial Direct Current Stimulation (tDCS) involves the application of weak direct electric current to the head in a noninvasive and painless manner. tDCS with a constant current intensity of 2 mA will be applied for 20 minutes per session daily for 2 weeks (Monday to Friday) via the Soterix 1x1 tDCS mini-CT Stimulator device. Participants will self-administer tDCS at their home or a private room for two weeks (Mondays-Fridays) under real-time supervision by the research staff.

Sleep Disturbance as Assessed by the PROMIS Sleep Disturbance-short Form

19.85 units on a scale Standard Deviation 8.10

Adverse Events

Transcranial Direct Current Stimulation

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Hyochol Ahn

The University of Texas Health Science Center at Houston

Phone: (713) 500-2179

Email: hahn@fsu.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place