Measuring and Modulating Changes in EEG Resting State Functional Connectivity During Short-term and Long-term Pain

resting state functional connectivity is assessed using Granger causality. It can take on any value starting with "0" representing no connectivity. Higher granger causality scores indicate higher connectivity.

Intensity rated by the participants on a numerical rating scale anchoring from 0 "no pain" to 10 "the worst imaginable pain" . Higher numerical rating scores indicate higher pain intensity.

Warmth detection threshold is assessed using a thermal stimulator probe (3 × 3 cm, Pathway Medoc Ltd, Israel). Higher threshold scores indicate less sensitivity.

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Cold detection threshold is assessed using a thermal stimulator probe (3 × 3 cm, Pathway Medoc Ltd, Israel). Higher threshold scores indicate less sensitivity.

Heat detection threshold is assessed using a thermal stimulator probe (3 × 3 cm, Pathway Medoc Ltd, Israel). Higher threshold scores indicate less sensitivity.

Cold pain threshold is assessed using a thermal stimulator probe (3 × 3 cm, Pathway Medoc Ltd, Israel). Higher threshold scores indicate less sensitivity.

Mechanical pain thresholds was assessed using a set of seven weighted pinprick stimulators consisting of steel tubes ending with a tip contact area of 0.25 mm diameter and excreting forces of 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, and 51.2 g. Higher threshold scores indicate less sensitivity.

Pain Vigilance and Awareness Questionnaire (PVAQ). This questionnaire consists of 16 items evaluating preoccupation and attention to one's pain over the past two weeks, rated between 0 = "never" and 5 = "always", with a maximum score of 80. The higher the scores, the higher the preoccupation with pain.

Scale (PCS). This questionnaire comprises 13 items assessed on a 5-point scale ranging from 0 = "not at all" to 4 = "all the time", with a maximum score of 52. It evaluates three scales of catastrophizing: rumination, magnification, and helplessness. Ratings reflect the degree to which specific thoughts and feelings are present when experiencing pain over the last three months. Higher scores indicate a higher degree of pain catastrophizing.

Pittsburgh Sleep Quality Index (PSQI). This questionnaire determines sleep quality and sleep patterns across seven areas: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction over the last month. These areas are evaluated on a scale ranging from 0 = "no difficulty" to 3 = "severe difficulty," with a maximum score of 21. Higher scores reflect poor sleep quality.

Modified Fatigue Impact Scale (MFIS). The MFIS evaluates the degree to which fatigue influences overall perceived function over the last 4 weeks. It assesses three subscales: cognitive (9 items), physical (10 items), and psychosocial (2 items) functioning. Items are measured on a scale from 0 = "no problem" to 4 = "extreme problem", with a maximum score of 120. Higher scores indicate higher levels of fatigue.

Positive and Negative Affect Scale (PANAS). This scale consists of 20 items assessing two groups of emotions: negative and positive (10 items each). Subjects rate the intensity of a specific emotion they are experiencing at the moment on a scale (1 = "very slightly or not at all" to 5 = "Extremely"). for each emotion group with a maximum of 50. Higher scores indicate more intense emotions. The positive affect items were "interested," "excited," "strong," "enthusiastic," "proud," "alert," "inspired," "determined," "attentive," and "active." The negative affect items were "distressed," "upset," "guilty," "scared," "hostile," "irritable," "ashamed," "nervous," "jittery," and "afraid."

Beck Depression Inventory (BDI-II). The BDI determines the severity of depressive mood states and consists of 21 questions assessing hopelessness, guilt, fatigue, and other physical symptoms, rated between 0 = "no symptom impact" and 3 = "maximum symptom impact" with a maximum score of 63. Higher scores indicate severe depressive symptoms. To obtain measures of trait depression, subjects in this study are instructed to rate the items in relation to how they generally feel.