Effects of non-invasive brain stimulation (NIBS) on vestibulopathy disorders: a systematic review

Abstract Objectives New types of treatments have emerged, such as non-invasive brain stimulation (NIBS), to treat chronic vestibular dysfunction (VD). Considering that NIBS is a promising approach to reduce VD symptoms, this review was aimed to analyze the effects of NIBS in patients with VD. Methods We adhered to the methods described in the Cochrane Handbook for Intervention Reviews. The eligibility criteria were as follows: (a) individuals with vestibulopathy having clinical and neuroimaging; (b) Interventions: non-invasive brain stimulation, this intervention comprised transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS); (c) Control: any comparison or sham; and (d) Outcomes: dizziness and balance. We included randomized controlled trials and non-randomized studies from July 2004 to February 2020. We searched the PubMed, CINAHL, Web of Science, Scopus, Cochrane, and Ovid databases. Two pairs of reviewers independently screened all titles and abstracts. Two authors assessed the risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology to rate the certainty of the evidence for each outcome. Results We identified 136 studies, and included two studies. Both studies used tDCS application. One study used anodal cerebellar tDCS or sham at 2 mA for 25 min associated with vestibular rehabilitation therapy (VRT), and the other study used anodal tDCS over the left dorsolateral prefrontal cortex (F3) for 25–30 min associated with VRT at home. Both studies showed clinical improvement in the Dizziness Handicap Inventory (DHI), State-Trait Anxiety Inventory (STAI), Activities-Specific Balance Confidence (ABC), and Self-Rating Depression Scale (SDS) scores. Both studies presented higher-quality evidence on the GRADE scale and a low risk of bias. Conclusions Based on two studies, anodal tDCS over F3 or the cerebellum associated with VRT improved chronic vestibular symptoms.