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Background: Tinnitus is the perception of sound in the absence of actual external stimuli. Other associated symptoms include frustration, annoyance, anxiety, depression, stress, cognitive dysfunction, insomnia, or emotional exhaustion. Objective: In this study, we aimed to conduct a systematic review and meta-analysis on the effectiveness of the non-invasive neuromodulation of the vagus nerve in patients with tinnitus. Methods: Six databases were searched from their date of inception to 15 June 2022 to identify clinical trials in which at least one group received any form of non-invasive neuromodulation of the vagus nerve for tinnitus management, with outcomes based on annoyance and related disability. Data on participants, interventions, blinding strategies, assessment outcomes, and results were extracted by two reviewers. Results: The search identified 183 articles with five clinical trials eligible for inclusion in the review and four for the meta-analysis. The methodological quality scores ranged from 6 to 8 (mean: 7.3, SD: 0.8) points. The meta-analysis identified a significant positive effect on THI post-treatment for unilateral auricular stimulation (hg = 0.69, 95% CI 0.06, 1.32) or transcutaneous nerve stimulation (hg = 0.51, 95% CI 0.1, 0.9) compared with a comparative group. No effect on loudness intensity was observed. Conclusion: The results of the meta-analysis suggest that the application of the non-invasive neuromodulation of the vagus nerve has a positive effect post-treatment in terms of related disability in patients with tinnitus, although its clinical relevance is low. No firm conclusions about the effect of the non-invasive neuromodulation of the vagus nerve on tinnitus are available based on the current literature.

The aim of this meta-meta-analysis was to assess the current evidence regarding the effect of physical therapy (PT) interventions on pain and functional variables in temporomandibular disorders (TMD). We conducted an umbrella systematic review (SR) and four meta-meta-analyses (MMA) and created an evidence map to determine the effectiveness of PT on pain intensity and maximum mouth opening in patients with TMD. The quality of the included SR was assessed with the AMSTAR 2, and the risk of bias with ROBIS. Of the 31 SR included in the umbrella SR, only 10 were included in the MMA. The MMA showed moderate effects for manual therapy and therapeutic exercise, and large effects for low-level laser therapy on improving pain intensity and maximum mouth opening in patients with TMD, with a limited to moderate quality of evidence. The overlapping analyses showed only a slight overlap for all the MMA according to the corrected covered area (range from 0.07 to 0.2), 23.1% to 41.6%. This umbrella SR showed that manual therapy and exercise interventions, as well as low-level laser therapy interventions, are effective in the reduction in pain intensity and improvement of maximum mouth opening in TMD. This article presents a synthesis of the available evidence related to the various physical therapy interventions used in patients presenting with temporomandibular disorders. These results could help clinicians to select the optimal intervention for their patients and to reject those that are less useful.

To assess neck disability with respect to jaw disability, craniocervical position, cervical alignment, and sensorimotor impairments in patients with temporomandibular disorders (TMD), a systematic review and meta-analysis of observational studies trials were conducted. The meta-analysis showed statistically significant differences in the association between neck disability and jaw disability (standardized mean difference (SMD), 0.72 (0.56–0.82)). However, results showed no significant differences for cervical alignment (SMD, 0.02 (−0.31–0.36)) or for the craniocervical position (SMD, −0.09 (−0.27–0.09)). There was moderate evidence for lower pressure pain thresholds (PPT) and for limited cervical range of motion (ROM). There was limited evidence for equal values for maximal strength between the patients with TMD and controls. There was also limited evidence for reduced cervical endurance and conflicting evidence for abnormal electromyographic (EMG) activity and motor control in TMD patients. Results showed a clinically relevant association between cervical and mandibular disability in patients with TMD. Regarding sensory-motor alterations, the most conclusive findings were observed in the reduction of PPT and cervical ROM, with moderate evidence of their presence in the patients with TMD. Lastly, the evidence on impaired motor control and cervical EMG activity in patients with TMD was conflicting.