Electroacupuncture analgesia is associated with increased serum brain-derived neurotrophic factor in chronic tension-type headache: a randomized, sham controlled, crossover trial.

BACKGROUND: Chronic tension-type headache (CTTH) is characterized by almost daily headaches and central sensitization, for which electroacupuncture (EA) might be effective. The central nervous system (CNS) plasticity can be tracked in serum using the brain-derived neurotrophic factor (BDNF), a neuroplasticity mediator. Thus, we tested the hypothesis that EA analgesia in CTTH is related to neuroplasticity indexed by serum BDNF. METHODS: We enrolled females aged 18-60 years with CTTH in a randomized, blinded, placebo-controlled crossover trial, comparing ten EA sessions applied for 30 minutes (2-10 Hz, intensity by tolerance) in cervical areas twice per week vs. a sham intervention. Treatment periods were separated by two washout weeks. Pain on the 10-cm visual analog scale (VAS) and serum BDNF were assessed as primary outcomes. RESULTS: Thirty-four subjects underwent randomization, and twenty-nine completed the protocol. EA was superior to sham to alleviate pain (VAS scores 2.38 ± 1.77 and 3.02 ± 2.49, respectively, P = 0.005). The VAS scores differed according to the intervention sequence, demonstrating a carryover effect (P < 0.05). Using multiple regression, serum BDNF was adjusted for the Hamilton depression rating scale (HDRS) and the VAS scores (r-squared = 0.07, standard ß coefficients = -0.2 and -0.14, respectively, P < 0.001). At the end of the first intervention period, the adjusted BDNF was higher in the EA phase (29.31 ± 3.24, 27.53 ± 2.94 ng/mL, Cohen's d = 0.55). CONCLUSION: EA analgesia is related to neuroplasticity indexed by the adjusted BDNF. EA modulation of pain and BDNF occurs according to the CNS situation at the moment of its administration, as it was related to depression and the timing of its administration.

Cross-cultural adaptation and validation of the profile of chronic pain: screen for a Brazilian population.

OBJECTIVE: To translate the original English version of the Profile of Chronic Pain: Screen (PCP:S) into Brazilian Portuguese and examine basic psychometric properties of the translated version. We investigated ceiling and floor effects, internal consistency, factor structure, convergent validity, and the ability of the Brazilian PCP:S (B-PCP:S) to discriminate persons with pain who were either employed or not working, or in treatment or not in treatment. METHODS: The Brazilian Portuguese version of the Profile of Chronic Pain: Screen (B-PCP:S) was administered to a sample of 414 adults (men = 67). Pain catastrophizing was also assessed. Subsamples with special conditions (working despite pain [N = 116] vs not working due to pain [N = 122], and not receiving treatment for pain [N = 119] vs receiving treatment [N = 119]) were identified to investigate the discriminative properties of B-PCP:S. RESULTS: For the B-PCP:S, Cronbach's α values were 0.76 (severity), 0.88 (interference), and 0.87 (emotional burden). Confirmatory factor analysis supported the original, English language three-factor structure, with the comparative fit index = 0.93, root mean square error of approximation = 0.075, and normed fit index = 0.93. Significant correlations were found between pain intensity, pain interference, and emotional burden, and a criterion measure of catastrophizing (correlation coefficients ranged from 0.48 to 0.66, P < 0.01). B-PCP:S scores (severity, interference, and emotional burden) were higher in subjects under a doctor's care for pain and in those not working due to pain. CONCLUSION: This B-PCP:S version was found to be a reliable instrument, with basic evidence of validity for the evaluation of pain severity, interference, and emotional burden in Brazilian Portuguese adults. The profile of B-PCP:S scores was similar to that observed in the original version.

Cross-cultural adaptation and validation of the Brazilian Portuguese version of the pain catastrophizing scale.

OBJECTIVE: Catastrophizing is a maladaptive response to pain and is one of the factors that contribute to the chronicity of some pain syndromes. The Pain Catastrophizing Scale (PCS) assists both treatment planning and outcome assessment. Its use is limited in Portuguese-speaking countries because of the lack of a validated translated version. We conducted the validation of the Brazilian Portuguese (BP)-PCS and explored its psychometric properties. This study reports the internal consistency, factor structure, and its capability to discriminate pain reported by patients with specific chronic pain conditions. METHODS: Three hundred eighty-four patients, 317 women (82.55%), aged 18-79 years with chronic nonmalignant pain attending an outpatient multidisciplinary pain center participated in this cross-sectional study. The instruments were the BP-PCS, pain intensity, pain interference in functional capacity, and a sociodemographic questionnaire. One subsample with chronic tensional headache (CTH) according to the criteria of the International Headache Society (N = 19), and another with a diagnosis of fibromyalgia according to the American College of Rheumatology criteria (N = 50) were selected to assess the discriminative properties of BP-PCS. RESULTS: We observed good internal consistency (Cronbach's α values of 0.91 for the total BP-PCS, and 0.93 [helplessness], 0.88 [magnification], and 0.86 [rumination] for the respective subdomains). The item-total correlation coefficients ranged from 0.91 to 0.94. Confirmatory factor analysis (CFA) supported the three factors structure, with the comparative fit index = 0.98, root mean square error of approximation = 0.09, and normed fit index = 0.98. Significant correlations were found for pain intensity, pain interference, and patient's mood (correlation coefficients ranged from 0.48 to 0.66, P < 0.01). No significant gender difference was observed for BP-PCS scores. When comparing scores of BP-PCS scale and subscales between the selected control group (patients with pain scores on visual analog scale equal or lower than 40 mm in the most part of the day in the last 6 months) and patients with fibromyalgia or CTH, we observed lower scores for the former group. CONCLUSION: Our findings support the validity and reliability of the BP-PCS. The scale showed satisfactory psychometric properties. CFA provides support for the three-factor structure reported in previous studies. This factor structure presented good discriminative properties to identify catastrophizers who present with mild chronic pain, fibromyalgia, and CTH. The BP-PCS is a valuable tool for use in scientific studies and in the clinical setting in patients with chronic pain in Brazilian Portuguese-speaking countries.

Clinical Value of Serum Neuroplasticity Mediators in Identifying the Central Sensitivity Syndrome in Patients With Chronic Pain With and Without Structural Pathology.

BACKGROUND AND OBJECTIVES: Central sensitivity syndrome (CSS) encompasses disorders with overlapping symptoms in a spectrum of structural pathology from persistent somatic nociception (eg, osteoarthritis) to absence of tissue injury such as in fibromyalgia, chronic tension-type headache, and myofascial pain syndrome. Likewise, the spectrum of the neuroplasticity mediators associated with CSS might present a pattern of clinical utility. METHODS: We studied the brain-derived neurotrophic factor (BDNF), tumor necrosis factor-α (TNF-α), and interleukins 6 (IL-6) and IL-10 in female patients with CSS absent of structural pathology (chronic tension-type headache [n=30], myofascial pain syndrome [n=29], fibromyalgia [n=22]); with CSS due to persistent somatic/visceral nociception (osteoarthritis [n=27] and endometriosis [n=32]); and in pain-free controls (n=37). RESULTS: Patients with CSS absent of structural pathology presented higher serum TNF-α (28.61±12.74 pg/mL) and BDNF (49.87±31.86 ng/mL) than those with persistent somatic/visceral nociception (TNF-α=17.35±7.38 pg/mL; BDNF=20.44±8.30 ng/mL) and controls (TNF-α=21.41±5.74 pg/mL, BDNF=14.09±11.80 ng/mL). Moreover, CSS patients absent of structural pathology presented lower IL levels. Receiver operator characteristics analysis showed the ability of BDNF to screen CSS (irrespective of the presence of structural pathology) from controls (cutoff=13.31 ng/mL, area under the curve [AUC]=0.86, sensitivity=95.06%, specificity=56.76%); and its ability to identify persistent nociception in CSS patients when experiencing moderate-severe depressive symptoms (AUC=0.81; cutoff=42.83 ng/mL, sensitivity=56.80%, specificity=100%). When the level of pain measured on the visual analog scale was <5 and moderate-severe depressive symptoms were observed TNF-α discriminated structural pathology in the chronic pain conditions (AUC=0.97; cutoff=22.11 pg/mL, sensitivity=90%, specificity=91.3%). CONCLUSION: Neuroplasticity mediators could play a role as screening tools for pain clinicians, and as validation of the complex and diffuse symptoms of these patients.