Self Transcranial Direct Current Stimulation and Mindfulness-based Meditation for Pain in Older Adults With Knee Osteoarthritis

The NRS assess average pain over the past 24 hours from 0 (no pain) to 100 (most intense pain imaginable).

The WOMAC ranges from 0 to 96, with higher scores indicating worse osteoarthritis (OA) pain-related symptoms.

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.

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.

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.

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.

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.

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.

The Pain Catastrophizing Scale (PCS) consists of 13 items assessing three components of catastrophizing: rumination, magnification, and helplessness. Each item rated on a 5-point scale: 0 (Not at all) to 4 (all the time).The PCS total score is computed by summing responses to all 13 items, with total scores ranging from 0 - 52. Higher scores indicate a worse outcome.

The Pain Catastrophizing Scale (PCS) consists of 13 items assessing three components of catastrophizing: rumination, magnification, and helplessness. Each item rated on a 5-point scale: 0 (Not at all) to 4 (all the time).The PCS total score is computed by summing responses to all 13 items, with total scores ranging from 0 - 52. Higher scores indicate a worse outcome.

The Freiburg Mindfulness Inventory (FMI) is a 14-item instrument. Respondents indicate their experiences relating to the items on a 4-point Likert scale (rarely, occasionally, fairly often and almost always), and the total score is calculated by adding all the scores on the 14 items of the FMI. Total scores range from 14-56, with higher scores indicating higher levels of mindfulness.

The Freiburg Mindfulness Inventory (FMI) is a 14-item instrument. Respondents indicate their experiences relating to the items on a 4-point Likert scale (rarely, occasionally, fairly often and almost always), and the total score is calculated by adding all the scores on the 14 items of the FMI. Total scores range from 14-56, with higher scores indicating higher levels of mindfulness.

Conditioned Pain Modulation (CPM) was assessed as the change in PPT on the trapezius immediately after the immersion of the contralateral hand up to the wrist in a cold-water bath (Neslab, Portsmouth, NH) at 12 degrees C for 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" to assess pressure pain threshold (PPT).]

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.

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.

Participants immersed their hand in a cold water bath, and at thirty seconds after hand immersion, they rated the cold pain intensity on a scale of 0-100. A higher score indicating higher pain intensity.

To assess pressure pain threshold (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 knee. Participants were asked to notify the experimenter when the pressure sensation ''first becomes painful" to assess pressure pain threshold (PPT).

To assess pressure pain threshold (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 knee. Participants were asked to notify the experimenter when the pressure sensation ''first becomes painful" to assess pressure pain threshold (PPT).