Cardiac-Gated Neuromodulation Increased Baroreflex Sensitivity and Reduced Pain Sensitivity in Female Fibromyalgia Patients.

The study presents a novel approach of programing pain inhibition in chronic pain patients based on the hypothesis that pain perception is modulated by dysfunctional dorsal medial nucleus tractus solitarii (dmNTS) reflex arcs that produce diminished baroreflex sensitivity (BRS) resulting from a conditioned response. This study tested whether administration of noxious and non-noxious electrical stimuli synchronized with the cardiac cycle resets BRS, reestablishing pain inhibition. A total of 30 pain-free normotensives controls (NC) and 32 normotensives fibromyalgia (FM) patients received two, ≈8 min-epochs of cardiac-gated, peripheral electrical stimuli. Non-painful and painful electrical stimuli were synchronized to the cardiac cycle as the neuromodulation experimental protocol (EP) with two control conditions (CC1, CC2). BRS, heart-rate-variability (HRV), pain threshold and tolerance, and clinical pain intensity were assessed. Reduced BRS in FM at baseline increased by 41% during two, ≈8 min-epochs of stimulation. Thresholds in FM increased significantly during the experimental protocol (all Ps < 0.001) as did HRV. FM levels of clinical pain significantly decreased by 35.52% during the experimental protocol but not during control stimulations (p < 0.001). Baroreceptor training may reduce FM pain by BRS-mediated effects on intrinsic pain regulatory systems and autonomic responses.

Efficacy of Systolic Extinction Training in Fibromyalgia Patients With Elevated Blood Pressure Response to Stress: A Tailored Randomized Controlled Trial.

OBJECTIVE: An intrinsic pain regulatory system is modulated by both cardiovascular dynamics that influence baroreflex sensitivity (BRS) and is diminished in fibromyalgia (FM). Baroreceptors relay cardiovascular output to the dorsal medial nucleus tractus solitarius reflex arcs that regulate pain, sleep, anxiety, and blood pressure. The aim of this study was to evaluate the effects of systolic extinction training (SET), which combines operant treatment (OT) with baroreflex training (BRT). BRT delivers peripheral electrical stimulation within a few milliseconds of the systolic or diastolic peak in the cardiac cycle. In addition, we compared SET to OT-transcutaneous electrical stimulation (TENS) independent of the cardiac cycle and aerobic exercise (AE)-BRT in FM patients with elevated blood pressure responses to stress. METHODS: Sixty-two female patients with FM were randomized to receive either SET (n = 21), OT-TENS (n = 20), or AE-BRT (n = 21). Outcome assessments were performed before treatment (T1), after 5 weeks of treatment (T2), and after the 12-month follow-up (T3). RESULTS: In contrast to patients receiving OT-TENS or AE-BRT, those receiving SET reported a significantly greater reduction in pain and pain interference (all P < 0.01) that was maintained at the 12-month follow-up. Clinically meaningful pain reduction at T3 was achieved in 82% of patients in the SET group, 39% of those in the OT-TENS group, and only 14% of those in the AE-BRT group. Patients in the SET group showed a significant increase (57%) in BRS following treatment, while neither the AE-BRT group or the OT-TENS group showed significant changes over time. CONCLUSION: SET resulted in statistically significant, clinically meaningful, and long-lasting pain remission and interference compared to OT-TENS and AE-BRT. These results suggest that BRS modification is the primary mechanism of improvement. Replication of our results using larger samples and extension to other chronic pain conditions appear to be warranted.

Evidenced-Based Guidelines on the Treatment of Fibromyalgia Patients: Are They Consistent and If Not, Why Not? Have Effective Psychological Treatments Been Overlooked?

We compared the recommendations and methodology of several recent evidence-based guidelines for the management of patients with fibromyalgia published by professional organizations: 1) American Pain Society (APS; 2005), 2) Association of the Scientific Medical Societies in Germany (AWMF; 2012), 3) Canadian Pain Society (CPS; 2013; also used in the United Kingdom), and 4) European League Against Rheumatism (EULAR; 2016). Each guideline used systematic reviews and meta-analyses as highest level of evidence; APS, CPS, and AWMF also included individual randomized clinical trials. The APS, CPS, and AWMF assigned the highest ranking of recommendation to aerobic exercise, cognitive-behavioral therapy, amitriptyline, and multicomponent treatment. In contrast, the most recent EULAR guidelines assign the highest level of recommendation to exercise, contrary to the 2008 EULAR guidelines, which recommended pharmacotherapy. Although there was some consistency for pharmacological treatment recommendations among the 4 guidelines, APS, CPS, and AWMF guidelines gave the higher ranking to cognitive-behavioral therapy and multicomponent treatments. The inconsistencies across guidelines can be attributed to the criteria used for study inclusion, outcome measures used, weighting systems, and composition of the review panels. A guideline consensus is needed to harmonize the discrepancies. PERSPECTIVE: This article presents an overview and highlights the inconsistencies of 4 recent clinical practice guidelines for treatment of fibromyalgia patients related to study inclusion criteria, outcome measures used, ranking system used, and composition of the review panels. The discrepancies suggest a need to create a guideline consensus to synthesize guidelines.