Effectiveness of Pain Science Education (PSE) in Patients With Fibromyalgia Syndrome (FMS) Living in Rural Areas.: a Randomized Clinical Trial.

Pain sensitivity

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

ain sensitivity was measured with the Pain Sensitiv-ity Questionnaire (PSQ), which consists of 17 items in a11-point Likert format. This questionnaire assesses painsensitivity based on pain intensity ratings (range: 0---10)of painful situations that occur in daily life. The PSQ canbe calculated as a total score (PSQ-total), a PSQ mod-erate score (the sum of items 1, 2, 4, 8, 15, 16 and17, which represent situations of moderate pain), or aPSQ minor score (the sum of items 3, 6, 7, 10, 11, 12and 14, which represent situations of mild pain). Items5, 9 and 13 are not taken into consideration becausethey represent non-painful situations. The Spanish vali-dation results showed an excellent internal consistency(Cronbach's ˛ \> 0.9) and a substantial reliability (IntraclassCorrelation Coefficient \> 0.8).

Impact of FMS on daily life

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

To assess the impact of FMS on daily life, the Spanishversion of the revised Fibromyalgia Impact Questionnaire(FIQ) was used. It assesses the function, impact and symp-toms related to FMS and scores from 0 to 100, with100 being the maximum impact of FMS on QoL. TheSpanish FIQR had high internal consistency (Cronbach's ˛0.91---0.95). The test---retest reliability was good for theFIQR total score and its function and symptoms domains(intraclass correlation coefficient (ICC \> 0.70), but modestfor the overall impact domain (ICC = 0.51).

Central sensitization

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

Central sensitization (CS) was measured with the Span-ish version of the Central Sensitization Inventory (CSI).It is a self-report outcome measure designed to identifypatients who have symptoms that may be related to CSor CS syndromes such as FMS. It consists of 25 questionsrelated to common CS symptoms, with total scores rangingfrom 0 to 100. The Spanish version of the CSI demonstratedhigh internal consistency (Cronbach's ˛ = 0.872) and a one-dimensional factor structure.

Pain catastrophizing

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

The Spanish version of the Pain Catastrophizing Scale (PCS) will be used to assess catastrophic thoughts about pain. This scale consists of 3 subscales graded from 0 (no negative thoughts or feelings) to 3 (maximum negative thoughts or feelings). It consists of 13 items with a 5-point Likert-type response scale (0 = Not at all; 4 = All the time), with a theoretical range of 0 to 52 points. Higher scores indicate a greater presence of catastrophic thoughts (43). It showed adequate internal consistency (Cronbach's α = 0.79), test-retest reliability (ICC = 0.84) and sensitivity to change (effect size ≥ 2). It is considered useful for clinical practice and research, having been carried out on a sample of 230 Spanish patients with FM.

Fear of Movement

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

This will be assessed with the short version of the Tampa Kinesiophobia Scale (TSK-11). This is one of the most widely used measures for assessing pain-related fear in patients with pain. It is an 11-item self-report measure of fear of movement and re-injury, rated on a four-point scale from "strongly agree" to "strongly disagree." The total score ranges from 11 to 44. Ratings are summed to obtain a total score, with higher scores indicating greater fear of re-injury. This Spanish version demonstrated good internal consistency (Cronbach's α = 0.79) and moderate test-retest reliability (r = 0.55).

Anxiety and depression

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

Anxiety and depression were assessed using the Span-ish version of the Hospital Anxiety and Depression Scale(HADS). This scale comprises two subscales: the HAD Anx-iety subscale (HADA) and the HAD Depression subscale(HADD). This questionnaire consists of 14 items, ratedfrom 0 (no distress) to 3 (maximum distress). The cut-offscore for the presence of anxiety and depression symp-toms must be equal to or greater than 8. The internalconsistency of the scales of the Spanish version is Cron-bach's ˛ = 0.80 for the HADA and Cronbach's ˛ = 0.85 forthe HADD.

Self-efficacy

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

This will be assessed using the Spanish adaptation of the Chronic Pain Self-Efficacy Scale. The total score, obtained from the summation of the responses to the 19 items comprising the questionnaire, will be used. The subject must answer the degree to which they consider themselves capable of performing certain activities or managing their pain, emotional problems, or other symptoms associated with chronic pain. Responses are made using a Likert-type scale from 0 (I feel totally incapable) to 10 (I see myself as totally capable), with a theoretical range of 0 to 190. High scores indicate a high perception of self-efficacy. It is considered an appropriate instrument for assessing self-efficacy expectations in patients with chronic pain of benign origin. This scale presented good psychometric properties in terms of reliability and construct validity, presenting a high internal consistency (Cronbach's α = 0.91) and a high test-retest reliability (ICC = 0.75) for the total

Knowledge and beliefs about PSE

Time Frame: All outcomes will be measured at the beginning of the study, at the end of all PSE sessions, and at the three-month follow-up.

Knowledge and beliefs about PSE: This will be assessed using the Pain Concept Questionnaire (COPI-Adult). It is unidimensional and consists of 13 items. It has acceptable internal consistency (α=0.78) and good test-retest reliability at one week (Intraclass Correlation Coefficient=0.84 (95% confidence interval: 0.71-0.91).