Assessing the relevance of mental health factors in fibromyalgia severity: A data-driven case study using explainable AI.

BACKGROUND AND OBJECTIVE: Fibromyalgia is a chronic disease that causes pain and affects patients' quality of life. Current treatments focus on pharmacological therapies for pain reduction. However, patients' psychological well-being is also affected, with depression and pain catastrophizing being common. This research addresses the clinicians' need to assess the influence of mental health factors on FM severity compared to pain factors. METHODS: A co-development study between FM clinicians and data scientists analyzed data from 166 FM-diagnosed patients to assess the influence of mental health factors on FM severity in comparison to pain factors. The study used the Polysymptomatic Distress Scale (PDS) and Fibromyalgia Impact Questionnaire (FIQ) as FM severity indicators and collected 15 variables including regarding demographics, pain intensity perceived, and mental health factors. The team used an author's developed framework to identify the optimal FM severity classifier and explainability by selecting a number of features that lead to obtaining the best classification result. Machine learning classifiers employed in the framework were: decision trees, logistic regression, support vector machines, random forests, AdaBoost, extra trees, and RUSBoost. Explainability analyses were conducted using the following explainable AI techniques: SHapley Additive exPlanations (SHAP), Partial Dependence Plot (PDP), and Mean Decrease Impurity (MDI). RESULTS: A balanced random forest with 6 features achieved the best performance with PDS (AUC_ROC, mean = 0.81, std = 0.07). Being FIQ the target variable, due to the imbalance in FM severity levels, a binary and a multiclass classification approaches were considered achieving the optimal performance, respectively, a logistic regression classifier (AUC_ROC, mean = 0.83, std = 0.08) with 6 selected features, and a random forest (AUC_ROC, mean = 0.91, std = 0.04) with 8 selected features. Next, the explainability analysis determined mental health factors were found to be more relevant than pain perceived factors for FM severity. CONCLUSIONS: This study's findings, validated by clinicians, are potentially aligned with FM international guidelines that promote non-pharmacological interventions such as promoting mental well-being of FM patients.

The effect of therapeutic exercise in the prevention of lymphoedema secondary to breast cancer: a systematic review.

Introduction: One of the most frequent complications of breast cancer treatment is lymphoedema (LE), with lymphadenectomy and radiotherapy being the main triggers of this pathology in developed countries. The aim of the study was to determine the efficacy of therapeutic exercise in the prevention of upper limb (UL) lymphoedema evaluated through cirtometry, volumetry, or bioimpedance spectroscopy (BIS) in women after breast cancer removal surgery. Material and methods: The Pubmed, PEDro, and Cochrane databases were consulted up to May 2020, including randomised clinical trials (RCTs) on therapeutic physical exercise as a possible preventive measure against breast cancer-related lymphoedema (BCRL). The studies were requested to have participants with UL lymphoedema and a control group. Results: A total of 304 articles were found, of which 9 were included (stand-alone studies). A therapeutic exercise program (strength and/or aerobic training) in women who had been surgically intervened for breast cancer may prevent lymphedema, compared to a regular care. Conclusions: A therapeutic exercise program (strength and/or aerobic training) in women operated on for breast cancer contributes to reducing the number of cases that could obtain a greater difference in volume in their upper limbs, compared to a regular care program. However, further research is necessary to affirm that therapeutic physical exercise prevents BCRL.

Effectiveness of Transcranial Direct Current Stimulation Combined With Exercising in People With Fibromyalgia: A Randomized Sham-Controlled Clinical Trial.

OBJECTIVE: To evaluate the effectiveness of transcranial direct current stimulation (tDCS) combined with exercising in people with fibromyalgia. DESIGN: Randomized, triple-blind, sham-controlled, clinical trial. SETTING: Primary health care center. PARTICIPANTS: A total of 120 volunteer participants (N=120) between 18 and 65 years old and diagnosed with fibromyalgia. Four participants dropped out of the study for causes unrelated to the intervention. INTERVENTION: Participants were randomized into 3 groups (active tDCS+exercising, sham tDCS+exercising, no-intervention control). The intervention was delivered in 5 sessions over 2 weeks. MAIN OUTCOME MEASURES: Pain intensity and referred pain area after suprathreshold pressure stimulation. RESULTS: Pain intensity further decreased in the active tDCS group vs control (mean, -14.43; 95% confidence interval, -25.27 to -3.58) at post intervention, unlike the sham tDCS group. Both tDCS groups did not achieve greater reductions in referred pain vs control. In the active tDCS group, health status (mean, -14.80; 95% confidence interval, -23.10 to -6.50) and pain catastrophizing (mean, -6.68, 95% confidence interval, -11.62 to -1.73) improved at post intervention, and so did health status (mean, -8.81; 95% confidence interval, -17.11 to -0.51), pain catastrophizing (mean, -7.00; 95% confidence interval, -12.13 to -1.87), and depression (mean, -3.52; 95% confidence interval, -6.86 to -0.19) after 1 month. In the sham tDCS group, improvements were recorded in health status (mean, -13.21; 95% confidence interval, -21.52 to -4.91) and depression (mean, -3.35; 95% confidence interval, -6.35 to -0.35) at post intervention and in health status (mean, -8.77; 95% confidence interval, -17.06 to -0.47), pain catastrophizing (mean, -5.68; 95% confidence interval, -10.80 to -0.55), and depression (mean, -3.98; 95% confidence interval, -7.31 to -0.64) after 1 month. No intergroup differences were observed between active and sham tDCS. CONCLUSIONS: Active and sham tDCS improved health status, pain catastrophizing, and depression vs control, but pain intensity decreased only in the active tDCS group.

A New Approach to Assess Blinding for Transcranial Direct Current Stimulation Treatment in Patients with Fibromyalgia. A Randomized Clinical Trial.

Correct blinding is essential for preventing potential biases. The aim of this study was to assess the blinding of participants and a therapist following treatment with transcranial direct current stimulation in subjects with fibromyalgia using James' and Bang's blinding indexes. Eighty subjects were randomly allocated either active or sham stimulation groups in an intervention of five sessions lasting 20 min each. A questionnaire was delivered to both the therapist and patients after the last session to record their guess of which treatment had been applied. No differences between the groups were noted at baseline in terms of demographic or clinical data. James' BI was 0.83 (CI 95%: 0.76-0.90) for the patients and 0.55 (CI 95%: 0.45-0.64) for the therapist. Bang's BI for subjects was -0.08 (CI 95%: -0.24-0.09) and -0.8 (CI 95%: -0.26-0.1) for the active and sham transcranial direct current stimulation groups, respectively. Bang's BI for the therapist was 0.21 (CI 95%: -0.02-0.43) and 0.13 (CI 95%: -0.09-0.35) for the active and sham transcranial direct current stimulation groups, respectively. Protocols of active and sham transcranial direct current stimulation applied in this study have shown satisfactory blinding of the therapist and subjects with fibromyalgia.

Pressure-Induced Referred Pain as a Biomarker of Pain Sensitivity in Fibromyalgia.

BACKGROUND: Fibromyalgia (FM) syndrome is characterized by widespread pain, fatigue, and generalized increased pain sensitivity. Appropriate and simple pain models are methods employed to assess pain mechanisms that can potentially lead to improved treatments. Pressure pain thresholds (PPTs) or mapping the referred pain area produced by pressure stimulation at suprathreshold intensities are used to assess pain mechanisms. The optimal suprathreshold stimulation intensity to elicit referred pain with minimal discomfort for patients with FM has yet to be determined. OBJECTIVES: The aim of this study was to compare the area and intensity of pressure-induced referred pain in patients with FM as elicited by systematic increases in PPTs, compared with controls. STUDY DESIGN: Observational, crossed-section study. SETTING: Research laboratory. METHODS: Twenty-six patients with FM and 26 healthy controls, age- and gender-matched, were included. Suprathreshold stimulation was applied to the infraspinatus muscle of the dominant side at 4 different intensities (PPT +20%, +30%, +40%, and +50%), after which referred pain was evaluated by measuring the area of pain in pixels using a digital body chart and its intensity on a Visual Analog Scale. Factors related to anxiety condition, pain catastrophizing, depression, and quality of life were recorded. RESULTS: The referred pain areas were larger in the FM group compared with healthy individuals at 120% (P = 0.024), 130% (P = 0.001), 140% (P = 0.001), and 150% (P = 0.001) PPT, however, within the FM group no differences were found between the intensity of suprathreshold stimulation and the size of the referred pain areas (P = 0.135) or pain intensity (P > 0.05). There was a positive correlation between the size of referred pain areas and pain catastrophizing in the FM group (r = 0.457, P = 0.032). LIMITATIONS: This study presents some limitations, among which is the variability found in the referred pain areas. CONCLUSIONS: These findings show that referred pain induced by applying a suprathreshold pressure of 120% PPT can be a useful biomarker to assess sensitized pain mechanisms in patients suffering from FM. KEY WORDS: Referred pain, pain sensitivity, fibromyalgia, central sensitization, suprathreshold, pressure pain threshold, biomarker, facilitated pain mechanisms.

[Analgesic effects of transcutaneous electrical nerve stimulation (TENS) in patients with fibromyalgia: A systematic review]. / Efectos analgésicos de la estimulación eléctrica nerviosa transcutánea en pacientes con fibromialgia: una revisión sistemática.

OBJECTIVE: To determine whether transcutaneous electrical nerve stimulation (TENS) has an analgesic effect greater than placebo or other treatments in patients with fibromyalgia. Furthermore, it was intended to analyze the optimal application parameters to achieve a greater reduction of pain. DESIGN: A systematic review. DATA SOURCE: Randomized clinical trials on the effect of TENS on fibromyalgia in the databases Pubmed, Cochrane and PEDro until November 2016. SELECTION OF STUDIES: 8 studies out of a total of 62 were selected. Controlled clinical trials in which TENS was applied in patients with fibromyalgia were included. DATA EXTRACTION: Pain was analyzed as the main variable, although other variables such as fatigue, quality of life and impact, range of motion and depression were also included. RESULTS: 6 out of 8 studies obtained a significant decrease of pain. In 2 studies, TENS was applied as complementary treatment to therapeutic exercise with results evidencing a decrease in pain. The rest of the variables studied presented a great variability and conclusive results could not be established. CONCLUSIONS: Treatment with TENS is effective for reducing pain in people with fibromyalgia. In addition, the inclusion of TENS in therapeutic exercise programs seems to have a greater effect than practicing therapeutic exercise in isolation. However, no efficacy has been demonstrated in other variables different to pain. Further studies are needed to investigate the optimization of the parameters of the TENS and a greater consensus among the variables used.