Transcranial Direct Current Stimulation Treatment for Warriors Experiencing Chronic Pain

The DVPRS assesses chronic pain using a visual analogue scale of 0 to 10, including general level of pain, and assessment of interference with daily activities, mood, sleep, and stress in 5 subscales. It is widely used in clinical care and research and has demonstrated reliability and validity within the military and Veteran population. This is a clinical measure collected per standard of care at intake. However, this measure was collected for research purposes at additional timepoints, including each tDCS session, 1-10, and all follow-up visits.

For each subscale, this is a visual analogue scale of 0 to 10, with higher scores meaning more intensity or interference

The DVPRS assesses chronic pain using a visual analogue scale of 0 to 10, including general level of pain, and assessment of interference with daily activities, mood, sleep, and stress in 5 subscales. It is widely used in clinical care and research and has demonstrated reliability and validity within the military and Veteran population. This is a clinical measure collected per standard of care at intake. However, this measure was collected for research purposes at additional timepoints, including each tDCS session, 1-10, and all follow-up visits.

For each subscale, this is a visual analogue scale of 0 to 10, with higher scores meaning more intensity or interference

The DVPRS assesses chronic pain using a visual analogue scale of 0 to 10, including general level of pain, and assessment of interference with daily activities, mood, sleep, and stress in 5 subscales. It is widely used in clinical care and research and has demonstrated reliability and validity within the military and Veteran population. This is a clinical measure collected per standard of care at intake. However, this measure was collected for research purposes at additional timepoints, including each tDCS session, 1-10, and all follow-up visits.

For each subscale, this is a visual analogue scale of 0 to 10, with higher scores meaning more intensity or interference

The DVPRS assesses chronic pain using a visual analogue scale of 0 to 10, including general level of pain, and assessment of interference with daily activities, mood, sleep, and stress in 5 subscales. It is widely used in clinical care and research and has demonstrated reliability and validity within the military and Veteran population. This is a clinical measure collected per standard of care at intake. However, this measure was collected for research purposes at additional timepoints, including each tDCS session, 1-10, and all follow-up visits.

For each subscale, this is a visual analogue scale of 0 to 10, with higher scores meaning more intensity or interference

The DVPRS assesses chronic pain using a visual analogue scale of 0 to 10, including general level of pain, and assessment of interference with daily activities, mood, sleep, and stress in 5 subscales. It is widely used in clinical care and research and has demonstrated reliability and validity within the military and Veteran population. This is a clinical measure collected per standard of care at intake. However, this measure was collected for research purposes at additional timepoints, including each tDCS session, 1-10, and all follow-up visits.

For each subscale, this is a visual analogue scale of 0 to 10, with higher scores meaning more intensity or interference

Patient-reported outcome (PRO) measures use answers provided directly by patients to assess their symptoms, functioning, and overall well-being. The PROMIS Pain Intensity Short Form 3a assesses pain intensity using three patient-reported items: (1) pain intensity at its worst during the past 7 days, (2) average pain intensity during the past 7 days, and (3) pain intensity right now. Each item is rated on a 5-point scale ranging from 1 (no pain) to 5 (very severe pain).

Responses to the three items are summed to obtain a raw score ranging from 3 to 15, with higher scores indicating greater pain intensity.

The PROMIS Pain Interference Short Form 8a assesses the self-reported impact of pain on daily functioning and quality of life. The instrument consists of 8 items evaluating the extent to which pain interferes with social, cognitive, emotional, physical, and recreational activities, as well as enjoyment of life and sleep, over the past 7 days. Example items include: "In the past 7 days, how much did pain interfere with your day-to-day activities?" and "In the past 7 days, how much did pain interfere with the things you usually do for fun?"

Each item is rated on a 5-point scale ranging from 1 (Not at all) to 5 (Very much). Item scores are summed to obtain a total raw score ranging from 8 to 40, where higher scores indicate greater pain interference and a worse outcome.

Patient-reported outcome (PRO) measures use responses provided directly by patients to assess symptoms, functioning, and overall well-being.

The PCL-5 is a 20-item self-report measure of PTSD severity in the past week, during treatment, and a month for follow-up. Each item ranges from 0 (not at all) to 4 (extremely). Total scores range from 0 to 80. Cut points and psychometrics are pulled from the most recent studies on the new PCL-5. This is a clinical measure collected per standard of care.

The PHQ-9 is a 9-item, well-validated measure of depression and a secondary outcome. The PHQ-9 assesses symptoms of major depression in the past two weeks from 0 (not at all) to 3 (nearly every day) and has excellent internal and test-retest reliability as well as construct and criterion validity (80). The PHQ-9 is effective in detecting treatment changes in depression in PC settings.

Score on a scale sum of all 9 items rated on a 0 (not at all) to 3 (nearly every day) scale, with higher meaning more depressed. Total scores range from 0 to 27.

On each study day (Days 2, 5, 7, 11), three samples were obtained: before the transcranial direct current stimulation (tDCS) session, immediately before the therapy session, and after the therapy session. BDNF concentrations were measured in pg/mL.

To quantify within-day changes in BDNF, measurements from the three time points were combined using the Area Under the Curve with Respect to Increase (AUCI) method described by Pruessner et al. (2003). The resulting AUCI values were log-transformed to improve the normality of the distribution. AUCI values may be positive or negative and have no predefined minimum or maximum value. Positive values indicate an overall increase in BDNF concentrations across the session, whereas negative values indicate that later BDNF measurements were lower than the initial measurement. Higher values reflect a greater increase in BDNF during the study

CAPS is an interview measure of PTSD severity that is collected for the purposes of the clinical treatment program (standard of care). Current PTSD will be assessed by assessors in relation to the trauma that is currently most upsetting. The CAPS-5 has excellent psychometrics and requires about 45 minutes to complete. 20% of CAPS will be rated by a second rater to ensure reliability.

Collection of saliva will be done pre tDCS, prior to the Therapy Session, and post-Therapy Session. Saliva will be assayed to examine Brain-derived neurotrophic factor (BDNF) and change in BDNF over the intervention session.

The study team will collect these samples from all participants to test feasibility and reliability of saliva as a clinically useful BDNF source.