RESUMEN
Background: Multiple therapeutic strategies have been adopted to reduce pain, odynophagia, and oral mucositis in head and neck cancer patients. Among them, transcranial direct current stimulation (tDCS) represents a unique analgesic modality. However, the details of tDCS mechanisms in pain treatment are still unclear. Aims: (1) to study the analgesic effects of a protocol that encompassed supervised-remote and in-clinic tDCS sessions applied in head and neck patients undergoing chemoradiation therapy; (2) to explore the underlining brain mechanisms of such modulation process, using a novel protocol that combined functional near-infrared spectroscopy (fNIRS), and electroencephalograph (EEG), two distinct neuroimaging methods that bring information regarding changes in the hemodynamic as well as in the electrical activity of the brain, respectively. Methods: This proof-of-concept study was performed on two subjects. The study protocol included a 7-week-long tDCS stimulation procedure, a pre-tDCS baseline session, and two post-tDCS follow-up sessions. Two types of tDCS devices were used. One was used in the clinical setting and the other remotely. Brain imaging was obtained in weeks 1, 2, 5, 7, 8, and after 1 month. Results: The protocol implemented was safe and reliable. Preliminary results of the fNIRS analysis in weeks 2 and 7 showed a decrease in functional connections between the bilateral prefrontal cortex (PFC) and the primary sensory cortex (S1) (p < 0.05, FDR corrected). Changes in EEG power spectra were found in the PFC when comparing the seventh with the first week of tDCS. Conclusion: The protocol combining remote and in-clinic administered tDCS and integrated fNIRS and EEG to evaluate the brain activity is feasible. The preliminary results suggest that the mechanisms of tDCS in reducing the pain of head and neck cancer patients may be related to its effects on the connections between the S1 and the PFC.
RESUMEN
OBJECTIVE: To perform a systematic review of the viscosupplementation effectiveness with hyaluronic acid (HA) in the articular Temporomandibular Dysfunctions (TMDs) clinical management. METHOD: Electronic searches were performed in the following databases: MEDLINE (via PubMed), Scopus, Web of Science, Cochrane Library, EMBASE, LILACS, BBO, SIGLE (System for Information on Grey Literature in Europe), ClinicalTrials.gov, and the Brazilian Clinical Trials Registry (ReBec). Only randomized clinical trials that evaluated the intra-articular administration of HA or its derivatives in osteoarthritis and/or anterior displacement of the temporomandibular joint (TMJ) disc were included. The primary outcomes evaluated were patients' self-report of pain and/or discomfort in the TMJ. Each study was assessed for the risk of bias, using the Cochrane collaboration's risk of bias tool. RESULTS: A total of 640 studies were obtained in the electronic search. After the application of the eligibility criteria, manual search, and duplicate removal, 21 articles were included. Five articles classified their volunteers with internal derangements of the TMJ, in 4 articles the treatment was directed to participants with disc displacement with reduction and the other articles evaluated HA therapy in osteoarthritis. The protocols presented heterogeneity, varying in the form of application, associated or not with arthrocentesis, number of applications, molecular weight, dose and concentration. Nine studies presented high risk of bias. CONCLUSION: Due to the heterogeneity and methodological inconsistencies of the studies evaluated, it was not possible to establish the efficacy of HA in articular TMDs.
