Abstract Objective: Galvanic vestibular stimulation has been evaluated in the context of vestibular rehabilitation. The objective was to identify evidence in the scientific literature about the clinical applications of galvanic vestibular stimulation. Methods: In this systematic review, the articles describing the applications of galvanic vestibular stimulation were extracted from PubMed, Web of Science, MEDLINE, Scopus, LILACS and SciELO databases. The survey was limited to articles published in English, Portuguese and Spanish. All the articles about the clinical applications of galvanic vestibular stimulation were compiled. Repeated articles in the databases, literature review articles, case reports, letters and editorials were excluded. The descriptors included: galvanic vestibular stimulation, postural balance, central nervous system diseases, vestibular diseases, spinal cord diseases and cognition. Results: The search strategy resulted in the initial selection of 994 articles; the reading of titles and abstracts was accomplished in 470 articles and the complete reading in 23 articles. Clinical applications of galvanic vestibular stimulation included Ménière’s disease, vestibular neuritis, bilateral vestibular disorders, vestibular schwannoma, Parkinson’s disease, ischemic central lesions, motor myelopathies, anxiety disorders, cognition and memory. Conclusion: Galvanic vestibular stimulation has been considered a potentially useful strategy for balance rehabilitation, since it has the effect of stimulating the central connections related to the postural balance, favoring new neuronal synapses that allow the partial or total recovery of postural imbalance.

Introdução: O potencial evocado miogênico vestibular (VEMP) gerado por estimulação galvânica (GVS) reflete uma resposta vestíbulo-espinhal. A resposta obtida no músculo sóleo é bifásica, primeiro com componente de curta latência (CL), em torno de 60 ms, e depois com o de média latência (ML), em torno de 100 ms. O componente de CL associa-se à função otolítica (sáculo e utrículo), e o de ML, aos ductos semicirculares. Objetivo: Descrever os valores de referência do VEMP com estimulação galvânica em indivíduos normais. Casuística e método: Forma de estudo transversal; o VEMP foi gerado por GVS de 2mA/400 ms, aplicada bilateralmente, sob frequência de 5-6 ms. Testou-se resposta no músculo sóleo de 13 sujeitos saudáveis, com idade média de 56 anos. Os sujeitos permaneceram de pé, com cabeça girada contralateral ao GVS aplicado na mastoide. Na configuração catodo direito, anodo esquerda, 30 GVS foi aplicado, seguidos de mais 30 com configuração inversa. Os componentes de CL e de ML da resposta vestibular foram analisados. Resultado: Os componentes de CL e de ML foram semelhantes em ambas as pernas. O valor médio de CL foi 54 ms, e o de ML, 112 ms. Conclusão: Os componentes de CL e de ML do VEMP solear foram replicáveis, sendo medidas úteis de função do trato vestíbulo-espinhal.

Introduction: The vestibular evoked myogenic potential (VEMP) generated by galvanic vestibular stimulation (GVS) is related to the vestibulo-spinal pathway. The response recorded from soleus muscle is biphasic with onset of short latency (SL) component around 60 ms and medium latency (ML) component around 100 ms. The first component reflects otolith function (sacule and utricle) and the last deals with semicircular canals. Aim: To describe VEMP generated by GVS. Methods: In this cross-sectional clinical study, VEMP was generated by 2mA/400 ms binaural GVS, frequency of 5-6 ms that was recorded from soleus muscles of 13 healthy adults, mean age 56 years. The subjects remained standing, head turned contralateral to the GVS applied to the mastoid. Thirty GVS were applied to the mastoid in the position cathode right anode left, followed by 30 in inverted position. SL and ML were measured. Results: SL and ML components were recorded from both legs of all participants and were similar. The average of SL component was 54 ms and of ML was 112 ms. Conclusion: The components SL and ML of the VEMP response in soleus were reproducible and are useful measures of vestibular-spinal function.

TEMA: a estimulação calórica monotermal tem sido considerada como alternativa à prova calórica bitermal para triagem das assimetrias vestibulares. OBJETIVO: avaliar a confiabilidade da estimulação monotermal em relação à bitermal para o diagnóstico das assimetrias labirínticas. MÉTODO: avaliaram-se 389 resultados de vectoelectronistagmografia realizados entre 1998 e 2007. A estimulação monotermal de 30ºC e 44ºC com pontos de corte de predomínio labiríntico (PL) em 20% e em 25% foi comparada à bitermal com ponto de corte em 25% (padrão ouro). Na análise, interessou encontrar qual foi à prova monotemal (30°C ou 44°C) e com qual ponto de corte (20% ou 25%) que apresentou os valores mais elevados de sensibilidade e especificidade quando comparada à prova bitermal. RESULTADOS: a sensibilidade e especificidade da prova monotermal foram respectivamente de: 84% e 80%, a 30°C com PL em 20%; 78% e 90%, a 30°C com PL em 25%; 81% e 78%, a 44°C com PL em 20%; 76% e 85%, a 44°C com PL em 25%. CONCLUSÃO: a prova monotermal com estimulo a 30°C apresentou valores mais elevados de sensibilidade e especificidade quando comparada a bitermal. Contudo, não se observou diferença significativa em relação aos valores observados com estímulo a 44°C. Em todas as análises, a prova monotermal apresentou a limitação da baixa sensibilidade, de modo que testes alterados pela bitermal podem passar como normais pela prova monoternal. Ao se decidir pela realização da prova monotermal como triagem, deve-se realizá-la em indivíduos com menor probabilidade de estar com doença vestibular, a partir da história clínica.

BACKGROUND: the use of monothermal caloric testing as a screening tool for vestibular asymmetry has been considered as an alternative to bithermal caloric testing. AIM: to evaluate the effectiveness of monothermal stimulation when compared to bithermal stimulation in the diagnosis of labyrinth asymmetry. METHOD: the results of 389 vectoelectronystagmography, performed between 1998 and 2007, were analyzed. Monothermal stimulation at 30oC and 44ºC with unilateral weakness (UW) cut-off at 20% and 25% was compared to bithermal stimulation with cut-off at 25% (gold standard). The analysis was aimed at finding which kind of monothermal caloric test (30oC or 44oC) and which kind of cut-off (20% or 25%) presented the highest specificity and sensitivity values in comparison with bithermal caloric testing. RESULTS: sensitivity and specificity of monothermal caloric tests were: 84% and 80%, at 30°C with UW at 20%; 78% and 90%, at 30°C with UW at 25%; 81% and 78%, at 44°C with UW at 20%; 76% and 85%, at 44°C with UW at 25%. CONCLUSION: monothermal caloric testing with 30°C stimulus presented the highest sensibility and specificity values in comparison to the results obtained with bithermal stimulation. However, no significant difference was observed between such values and those obtained with 44°C stimulus. In all of the analyses, monothermal testing presented low sensitivity. Thus, the abnormal result of bithermal caloric testing might be seen as normal in monothermal stimulation. The use of monothermal testing as a screening tool is better recommended for individuals whose medical history suggests a low probability of vestibular disease.