What does the video head impulse test tell us about post-caloric vestibular recruitment?

Abstract Objective: The vestibular recruitment observed in caloric testing is a new tool in the study of the vestibulo-ocular reflex. This study aimed to determine the sensitivity and specificity of the video head impulse test to detect post-caloric vestibular recruitment. Method: In this cross-sectional study, all participants underwent the standard otoneurological assessment of the service, caloric test, and video head impulse test. A non-linear mixed model was used to test for associations. Results: The study group consisted of 250 (89 male and 161 female) patients, with a mean age of 54.84 years. The control group comprised 35 participants, 18 men and 17 women, with a mean age of 40.42 years. Sex and age had no effect on group responses. There was no difference between the study and control groups regarding the interaction between recruitment and gain (p = 0.7487); recruitment and overt (p = 0.7002) and covert saccades (p = 1.0000); and recruitment and anti-compensatory saccades in the contralateral ear (p = 0.3050). The video head impulse test had a sensitivity of 51% and a specificity of 50% as a predictor of post-caloric recruitment. Conclusion: The video head impulse test results showed no relevance in predicting post-caloric vestibular recruitment.

Further exploration of the classification and clinical value of head-shaking nystagmus / 临床耳鼻咽喉头颈外科杂志

Objective:To investigate the classification of head shaking nystagmus（HSN） and its clinical value in vestibular peripheral diseases. Methods:Clinical data of 198 patients with peripheral vestibular disorders presenting with HSN were retrospectively analyzed. Video Nystagmograph（VNG） was applied to detect spontaneous nystagmus（SN）, HSN, and Caloric Test（CT）. The intensity and direction of SN and HSN as well as the unilateral weakness（UW） and direction preponderance（DP） values in caloric test was analyzed in patients. Results:Among the 198 patients with vestibular peripheral disease, there were 105 males and 93 females, with an average age of（49.1±14.4） years （range: 14-87 years）. One hundred and thirty seven patients were diagnosed as Vestibular Neuritis（VN）, 12 as Meniere's Disease（MD）, 41 as sudden deafness（SD） and 8 as Hunt's syndrome accompanied by vertigo. Among them, there were 116 patients in the acute phase, including 68 cases（58.6%） with decreased HSN, 4 cases（3.4%） with increased HSN, 5 cases（4.3%） with biphasic HSN, 38 cases（32.8%） with unchanged HSN, and 1 case（0.9%） with perverted HSN. There were 82 cases in the non-acute phase, 51 cases（62.2%） with decreased HSN, 3 cases（3.6%） with increased HSN, 9 cases（11.0%） with biphasic HSN, and 19 cases（23.2%） with unchanged HSN. In biphasic HSN, the intensity of phase I nystagmus was usually greater than that of phase II, and the difference was statistically significant（P<0.01）. There was no correlation between HSN type and course of disease or DP value. The intensity of HSN was negatively correlated with the course of disease（r=-0.320, P<0.001） and positively correlated with DP value（r=0.364, P<0.001）, respectively. The intensity of unchanged nystagmus and spontaneous nystagmus were（8.0±5.7） °/s and（8.5±6.4）°/s, respectively. There was no statistically significant difference in the intensity of nystagmus before and after shaking the head. Conclusion:HSN can be classified into five types and could be regarded as a potential SN within a specific frequency range （mid-frequency）. Similarly, SN could also be considered as a common sign of unilateral vestibular impairment at different frequencies. HSN intensity can reflect the dynamic process of vestibular compensation, and is valuable for assessing the frequency of damage in peripheral vestibular diseases and monitoring the progress of vestibular rehabilitation.

Achados neurológicos e vestibulares em três casos de Esclerose Múltipla / Neurological and vestibular findings in three cases of Multiple Sclerosis

RESUMO A Esclerose Múltipla (EM) é uma doença autoimune crônica e inflamatória que afeta o sistema nervoso central (SNC). A disfunção do equilíbrio corporal também é um sintoma comum e pode estar relacionada às lesões neurológicas decorrentes desta doença. O objetivo deste estudo foi caracterizar os achados neurológicos e vestibulares de três casos clínicos com diagnóstico de EM. Dados sobre a avaliação neurológica e do exame de ressonância magnética de crânio foram coletados dos prontuários. Os pacientes responderam a uma entrevista inicial e foram submetidos à avaliação clínica do equilíbrio corporal e ao Video Head Impulse Test (vHIT). Observou-se presença de sintomas vestibulares e alterações em pelo menos uma das provas clínicas do equilíbrio corporal e função cerebelar. No vHIT, obteve-se alterações em testes oculomotores, como presença de nistagmo semi-espontâneo e em parâmetros do teste sacádico, e ganho reduzido em um ou mais canais verticais. Foram verificadas lesões, na ressonância magnética de crânio, em áreas centrais que processam as informações vestibulares, como cerebelo e tronco encefálico. A associação destes achados sugere a presença de disfunção vestibular central, compatível com as lesões detectadas nos exames de imagem.

ABSTRACT Multiple sclerosis (MS) is a chronic and inflammatory autoimmune disease that affects the central nervous system (CNS). Dysfunction of body balance is also a common symptom and may be related to neurological injuries resulting from this disease. The aim of this study was to characterize the neurological and vestibular findings of three clinical cases diagnosed with MS. Data on the neurological evaluation and the magnetic resonance imaging of the skull were collected from the medical records. The patients responded to an initial interview and underwent clinical assessment of body balance and Video Head Impulse Test (vHIT). Vestibular symptoms and alterations were observed in at least one of the clinical tests of body balance and cerebellar function. In vHIT, changes were obtained in oculomotor tests, such as the presence of semi-spontaneous nystagmus and in parameters of the saccade test, and reduced gain in one or more vertical channels. Lesions were found on MRI of the skull in central areas that process vestibular information, such as the cerebellum and brainstem. The association of these findings suggests the presence of central vestibular dysfunction, compatible with the lesions detected in imaging exams.

Dissociation between video head impulse test and caloric test: a marker of menière's disease? - A systematic review and meta-analysis

Abstract Objective To analyze, by means of a systematic review and meta-analysis, the proportion of patients with Meniere's disease who have altered caloric test and vHIT, as well as to determine the prevalence of altered caloric test and normal vHIT dissociation in the diagnosis of Meniere's disease. Methods The literature search had no restriction regarding the period of publication on the following indexed data platforms: PubMed, PubMed PMC, BVS-Bireme, Web of Science, Embase and Cochrane Library. Articles that evaluated patients with Meniere's disease who underwent caloric test and vHIT were included. Two researchers independently conducted the analysis of the articles, promoting the selection and capture of data, following the recommendations of the PRISMA method, and complying with the criteria for articles inclusion and exclusion defined in the research protocol. In case of disagreement during the selection process, a third researcher was included for analysis. Results From a total of 427 initial studies, the researchers selected 12 articles, published between 2014 and 2021, with a total of 708 patients evaluated, with a mean age of 52.72 years old. The prevalence of patients with Meniere's disease with altered caloric reflex test was 64% (95% CI 57%‒71%), while the prevalence of altered vHIT was only 28% (95% CI 16%-40%). The prevalence of the altered caloric test + normal vHIT dissociation was 47% (95% CI 37%-57%). Conclusion The video head impulse test and the caloric test are valuable tools for vestibular assessment. The dissociation of findings between these two tests in patients with Meniere's disease was more prevalent in this meta-analysis and may be a result of the tonotopy of specialized hair cells in the ampullary crest. The prevalence of altered caloric test was 64% and anormal vHIT was 28%. The dissociation caloric asymmetry and normal vHIT was observed in 47% of the patients. Level of evidence: 1.

Evaluation of the vestibulo-ocular reflex in patients with chronic otitis media / Avaliação do reflexo vestíbulo-ocular em pacientes com otite média crônica

Abstract Introduction In recent years, scientific evidence has shown that chronic otitis media may cause balance and vestibular dysfunction. Objective To compare the results of the video head impulse test (gain and symmetry of the vestibulo-ocular reflex and presence of covert and overt saccades) in patients with chronic otitis media and controls. Methods Cross-sectional study of patients with chronic otitis media (study group), aged between 18 and 60 years. The patients in the study group were further divided according to the chronic otitis media type as (1) non-suppurative, (2) suppurative, and (3) cholesteatomatous. For the comparative analysis, we selected volunteers with no history of ear and vestibular diseases (control group), who met the same inclusion and exclusion criteria as the study group. Patients in both groups underwent a video head impulse test. Results The study group consisted of 96 volunteers, and the control group of 61 individuals. The prevalence of vestibular symptoms was 66% in the study group and 3.2% in the control group (p< 0.001). The results show a higher prevalence of changes in the vestibulo-ocular reflex gain (22.9%) and corrective saccades (12.6%) in the chronic otitis media group compared to the control group (p< 0.001). Despite the higher prevalence of changes in gain, the average vestibulo-ocular reflex gains in the chronic otitis media groups were within the pre-defined values ​​of normality; however, the mean vestibulo-ocular reflex gain in the anterior semicircular canal was statistically worse in the cholesteatomatous chronic otitis media group compared to controls (p< 0.001). Regarding the corrective saccades, the prevalence of saccades was statistically higher in the suppurative and cholesteatomatous chronic otitis media subgroups compared to the non-suppurative and control groups (p= 0.004). Conclusion The present study demonstrated that chronic otitis media is associated with a higher prevalence of vestibular symptoms and also a higher prevalence of changes in gain and corrective saccades when compared to controls.

Resumo Introdução Nos últimos anos, evidências científicas demonstraram que a otite média crônica se associa a alterações de equilíbrio e disfunção vestibular. Objetivo Comparar os resultados do teste do impulso cefálico por vídeo (ganho e simetria do reflexo vestíbulo-ocular e presença de sacadas cobertas e descobertas) em pacientes com otite média crônica e controles. Método Estudo transversal que envolveu pacientes com otite média crônica (grupo de estudo), entre 18 a 60 anos. Os pacientes no grupo estudo ainda foram divididos de acordo com o tipo de otite média crônica em (1) não supurativa, (2) supurativa e (3) colesteatomatosa. Para análise comparativa, selecionamos voluntários sem história de doenças otológicas e vestibulares (grupo controle), que obedeceram aos mesmos critérios de inclusão e exclusão do grupo de estudo. Os pacientes de ambos grupos foram submetidos ao teste de impulso cefálico por vídeo. Resultados O grupo estudo foi composto por 96 voluntários e o grupo controle por 61 indivíduos. A prevalência de sintomas vestibulares foi de 66% no grupo de estudo e 3,2% no grupo controle (p < 0,001). Os resultados mostram maior prevalência de alterações do ganho do reflexo vestíbulo-ocular (22,9%) e de sacadas corretivas (12,6%) no grupo otite média crônica em comparação ao grupo controle (p < 0,001). Apesar da maior prevalência de alterações de ganho, a média dos ganhos do reflexo vestíbulo-ocular dos grupos de otite média crônica estava dentro dos valores pré-definidos de normalidade; porém, a média do ganho do reflexo vestíbulo-ocular no canal semicircular anterior foi estatisticamente pior no grupo otite média crônica colesteatomatosa em comparação aos controles (p< 0,001). Em relação às sacadas corretivas, a prevalência de sacadas foi estatisticamente maior nos subgrupos otite média crônica supurativa e colesteatomatosa em comparação aos grupos não supurativa e controle (p = 0,004). Conclusão A otite média crônica se associa à maior prevalência de sintomas vestibulares e também maior prevalência de alterações no ganho e de sacadas corretivas em comparação a controles.

Video head impulse test in bilateral vestibulopathy / Teste do impulso efálico com vídeo (vHIT) na vestibulopatia bilateral

Abstract Introduction: Bilateral vestibulopathy is a rare chronic condition with multiple etiologies. Bilateral vestibulopathy is characterized mainly by unsteadiness when walking or standing, which worsens in darkness, as well as oscillopsia. The degree of handicap caused by bilateral vestibulopathy is variable and remains controversial. Objectives: To determine the value of the video Head Impulse Test in quantifying vestibular deficit and to establish its impact on the quality of life. Methods: Twenty patients (mean age, 41.9 years; range 14-80 years) fulfilling the recent Barany criteria of bilateral vestibulopathy, responded to the Situational Vertigo Questionnaire and underwent vestibular examination including fixation, positional tests, oculomotor test battery and video head impulse test. Results: The relation between each of the video head impulse test parameters and the scores from the questionnaire were statistically analyzed. We observed that patients with covert saccades on the video head impulse test were more likely to have a better quality of life than those with both covert and overt saccades, regardless of the vestibulo-ocular reflex gain in each semicircular canal. The presence of covert saccades was found to be associated with an improved quality of life regardless of the severity of vestibule ocular reflex-deficit. Our conclusion was that vestibule ocular reflex gain, measured by video head impulse test, does not quantify the severity of affection of quality of life in patients with bilateral vestibulopathy. Conclusion: Covert saccades are strategies aiming at minimizing the blurring of vision during head movement, that is an adaptive mechanism that improves quality of life. Therefore, we recommend that video head impulse test should be a part of the routine diagnostic workup of bilateral vestibulopathy.

Resumo Introdução: A vestibulopatia bilateral é uma condição crônica rara, com múltiplas etiologias. É caracterizada principalmente por instabilidade ao caminhar ou ficar de pé, que piora na escuridão, e oscilopsia. O grau de deficiência causado pela vestibulopatia bilateral é variável e permanece controverso. Objetivos: Determinar o valor do teste do impulso cefálico na quantificação do déficit vestibular e estabelecer seu impacto na qualidade de vida. Método: Vinte pacientes (média de 41,9 anos; variação de 14 a 80) que atendiam aos critérios recentes da Bárány Society de vestibulopatia bilateral responderam ao Situational Vertigo Questionnaire e foram submetidos a exame vestibular, inclusive fixação, testes posicionais, bateria de testes oculomotores e teste do impulso cefálico com vídeo. Resultados: A relação entre cada um dos parâmetros do teste do impulso cefálico com vídeo e os escores do questionário foram analisados estatisticamente. Observamos que pacientes com sacadas corretivas cobertas do tipo covert no teste de impulso cefálico com vídeo tinham maior probabilidade de ter melhor qualidade de vida do que aqueles com ambas sacadas corretivas cobertas e sacadas corretivas abertas do tipo overt, independentemente do ganho no reflexo vestíbulo-ocular em cada canal semicircular. Verificou-se que a presença de sacadas corretivas do tipo covert está associada a uma melhor qualidade de vida, independentemente da gravidade do déficit no reflexo vestibulo-ocular. Concluímos que o ganho no reflexo vestíbulo-ocular, medido pelo teste do impulso cefálico com vídeo, não quantifica a gravidade do comprometimento da qualidade de vida em pacientes com vestibulopatia bilateral. Conclusão: As sacadas corretivas do tipo covert são estratégias que visam minimizar o embaçamento da visão durante o movimento da cabeça, ou seja, um mecanismo adaptativo que melhora a qualidade de vida. Portanto, recomendamos que o teste do impulso cefálico com vídeo faça parte da rotina de diagnóstico da vestibulopatia bilateral.

Emerging and distinct video head impulse test responses in elderly with vestibular symptoms / Respostas emergentes e distintas do teste do impulso cefálico por vídeo em idosos com sintomas vestibulares

Abstract Introduction Dizziness has been reported to be the most common symptom in elderly population. Video head impulse test, VHIT, allows clinicians to assess the vestibular function in elderly individuals, during their initial stages of vestibular symptoms. Inferences from VHIT responses were traditionally low vestibulo-ocular reflex gain or a normal vestibulo-ocular reflex gain. However, the possibility of a third and new variant of the vestibulo-ocular reflex gain has not been clinically explored yet. Objectives To determine and report distinct patterns of vestibulo-ocular reflex gain using VHIT in elderly individuals with vestibular symptoms. Methods Retrospective cross-sectional study was done on a group of elderly patients who were above 70 years of age. These individuals were subjected to VHIT during their symptomatic phase. A vestibulo-ocular reflex gain value between 0.80-01.20 (Horizontal plane) was considered normal. The gain above and below this cutoff range was considered abnormal. Results 39 elderly patients (15 males and 24 females) whose mean age range was 74.71 years were evaluated for the VHIT response. Vestibulo-ocular reflex gain obtained was categorized into three distinct patterns: (i) normal vestibulo-ocular reflex gain, (ii) reduced vestibulo- ocular reflex gain and (iii) increased vestibulo-ocular reflex gain. The mean vestibulo- ocular reflex gain for both left and right horizontal canals varied significantly between the three groups (p< 0.05). No significant effect of age and vestibulo-ocular reflex gain was noted, though vestibulo-ocular reflex gain was higher in 80 years and above age (p> 0.05). Conclusion Elderly individuals with dizziness may show varying responses with vestibulo-ocular reflex gain during the symptomatic period. The third type of hyperactive vestibule-ocular reflex responses that emerged from the current study were potential indicators of fluid dynamic changes in the inner ear. These responses need to be explored further as it relates to new clinical markers for both peripheral and central vestibular disorders.

Resumo Introdução Estima‐se que a tontura seja o sintoma mais comum na população idosa. O teste do impulso cefálico por vídeo, VHIT (do inglês Video Head Impulse Test), permite que os médicos avaliem a função vestibular em idosos, durante os estágios iniciais dos sintomas vestibulares. As inferências das respostas do VHIT tradicionalmente tem sido baixo ganho de reflexo vestíbulo‐ocular ou ganho normal do reflexo vestíbulo‐ocular. Entretanto, a possibilidade de uma terceira e nova variante de ganho do reflexo vestíbulo‐ocular ainda não foi explorada clinicamente. Objetivos Determinar e relatar padrões distintos de ganho do reflexo vestíbulo‐ocular com VHIT em idosos sintomáticos com sintomas vestibulares. Método Estudo transversal retrospectivo feito em um grupo de idosos com mais de 70 anos. Esses indivíduos foram submetidos ao VHIT durante a fase sintomática. Um valor de ganho do reflexo vestíbulo‐ocular entre 0,80 a 01,20 (plano horizontal) foi considerado normal. O ganho acima e abaixo dessa faixa de corte foi considerado anormal. Resultados Foram avaliados para a resposta do VHIT 39 idosos (15 homens e 24 mulheres) com média de 74,71 anos. O ganho do reflexo vestíbulo‐ocular obtido foi categorizado em três padrões: (i) ganho de reflexo vestíbulo‐ocular normal, (ii) ganho de reflexo vestíbulo‐ocular reduzido e (iii) ganho de reflexo vestíbulo‐ocular aumentado. O ganho médio do reflexo vestíbulo‐ocular para ambos os canais horizontais esquerdo e direito variou significativamente entre os três grupos (p < 0,05). Nenhum efeito significante da idade e ganho do reflexo vestíbulo‐ocular foi observado, embora o ganho do reflexo vestíbulo‐ocular fosse maior na idade de 80 anos e acima (p > 0,05). Conclusão Indivíduos idosos com tontura podem apresentar respostas variáveis com o ganho do reflexo vestíbulo‐ocular durante o período sintomático. O terceiro tipo de respostas hiperativas do reflexo vestíbulo‐ocular que emergiram do estudo atual foi indicador potencial de mudanças na dinâmica dos fluidos na orelha interna. Essas respostas precisam ser mais exploradas, pois podem estar relacionadas a novos marcadores clínicos para distúrbios vestibulares periféricos e centrais.

Video Head Impulse Test e doenças do sistema nervoso central: uma revisão integrativa / Video Head Impulse Test and central nervous system diseases: a integrative review

RESUMO Objetivos verificar a aplicabilidade do Video Head Impulse Test (vHIT) em doenças do sistema nervoso central (SNC), bem como os resultados encontrados e as doenças descritas. Estratégia de pesquisa revisão integrativa da literatura, em que foi realizada a busca em nove bases eletrônicas de dados, a partir da palavra-chave "video head impulse test". Critérios de seleção foram incluídos estudos que utilizaram o vHIT no diagnóstico de doenças do SNC e excluídos os estudos publicados antes de 2009 e estudos que realizaram outros procedimentos de investigação clínica, ou que aplicaram o teste no diagnóstico de doenças vestibulares periféricas. Resultados a amostra final foi composta por 18 estudos. Os resultados verificados mostraram que o reflexo vestíbulo-ocular (RVO) tem apresentado alterações na população investigada. Foram observados achados sugestivos de acometimento central, tais como ganho ou média de ganho do RVO nos canais semicirculares verticais, inferior aos laterais, ganho aumentado, correlação negativa do ganho com a gravidade da doença na ataxia espinocerebelar tipo 3, ponto de corte de 0,70 e assimetria de ganho menor de 20% para diferenciar neurite vestibular de derrame no ramo medial da artéria cerebelar posteroinferior, ganho normal com provas oculomotoras alteradas, presença de nistagmo espontâneo vertical, além de alterações no RVO com e sem otimização visual, na perseguição sacádica e no teste de desvio de inclinação. Conclusão verificou-se que o vHIT é aplicável quanto a avaliação do RVO de alta frequência em indivíduos com doenças do SNC, uma vez que trouxe evidências clínicas sobre alterações da função vestibular periférica e central nos diferentes quadros neurológicos.

ABSTRACT Purpose To verify the applicability of the Video Head Impulse Test (vHIT) in central nervous system (CNS) diseases, as well as the results found and the diseases described. Research strategy Integrative literature review, in which nine electronic databases were searched using the keyword "video head impulse test". Selection criteria Studies that used the vHIT in the diagnosis of CNS diseases were included, and studies published before 2009, studies that performed other clinical investigation procedures or that concerned the diagnosis of peripheral vestibular diseases were excluded. Results The final sample consisted of 18 studies. The verified results show that the vestibulo-ocular reflex (VOR) has shown alteration in this population. Suggestive findings of central involvement were observed, such as lower gain or average VOR in the vertical semicircular canals than in the lateral ones, increased gain, the negative correlation of gain with disease severity in Spinocerebellar Ataxia Type 3, cutoff point of 0.70, and gain asymmetry of less than 20% to differentiate vestibular neuritis from a stroke in the medial branch of the posteroinferior cerebellar artery, normal gain with altered oculomotor tests, presence of spontaneous vertical nystagmus, as well as alterations in the VOR with and without visual enhancement, in saccadic pursuit, and the tilt deviation test. Conclusion We found that the vHIT applies to the assessment of high-frequency VOR in individuals with CNS diseases since it provided clinical evidence of changes in peripheral and central vestibular function in different neurological conditions

Does the video head impulse test replace caloric testing in the assessment of patients with chronic dizziness? A systematic review and meta-analysis / O video head impulse test substitui a prova calórica na avaliação de pacientes com tontura crônica? Uma revisão sistemática e metanálise

Abstract Introduction: Caloric testing is the most frequently used test to assess peripheral vestibular function since the beginning of the 20th century. However, the video head impulse test, vHIT, has gained prominence in the field of neurotology, as it is a faster examination, easier to perform and less uncomfortable for the patient. Objective: To compare, through systematic review and meta-analysis, the proportion of altered cases between vHIT tests and caloric testing in patients with chronic dizziness, in addition to assessing the sensitivity and specificity of vHIT, with caloric testing as the gold standard. Methods: The literature search was carried out in the PubMed, Scopus, BVS-Bireme, Web of Science, Embase, Cochrane and ProQuest indexed databases, with no restrictions regarding the publication period. All articles that contained the results of the two tests were included in the evaluation of patients with dizziness. Two researchers independently conducted data selection and extraction from the studies, strictly following the inclusion and exclusion criteria defined in the research protocol. In case of disagreement during the selection, a discussion was carried out with a third evaluator. Results: Eleven of the 1293 initial articles met the eligibility criteria and were analyzed. 2670 patients were evaluated, of which 1112 (41.6%) were males and 1558 (58.4%) females, with a mean age of 51.6 years. The proportion of altered results in the vHIT was 21% (95%CI 9% --33%), and 55% in the caloric testing (95%CI 43% --67%). Conclusion: The vHIT does not substitute for caloric testing. The tests are complementary in assessing the patient with dizziness, as they describe the tonotopy of the ampullary crest at different frequency ranges of stimulation. In chronic cases, the vHIT has a low sensitivity and high diagnostic specificity in comparison to caloric testing.

Resumo Introdução: A prova calórica é o exame mais usado para avaliação da função vestibular periférica desde os primórdios do século XX. Porém, o vídeo teste de impulso cefálico, vHIT, tem ganhado destaque no campo da otoneurologia por ser um exame mais rápido, de fácil execução e menos desconfortável para o paciente. Objetivo: Comparar, através de revisão sistemática e metanálise, a proporção de casos alterados entre os exames vHIT e prova calórica nos pacientes com tontura crônica, além de avaliar a sensibilidade e especificidade do vHIT, tendo a prova calórica como padrão-ouro. Método: A busca na literatura foi feita nas bases de dados indexadas PubMed, Scopus, BVS-Bireme, Web of Science, Embase, Cochrane e ProQuest, sem restrições quanto ao período da publicação. Foram incluídos todos os artigos que tivessem os resultados dos dois exames na avaliação de pacientes com tontura. Dois pesquisadores conduziram de forma independente a seleção e extração de dados dos estudos, obedeceram rigorosamente os critérios de inclusão e exclusão definidos no protocolo de pesquisa. Em caso de discordância na seleção, fez-se discussão com um terceiro avaliador. Resultados: Onze dos 1.293 artigos iniciais preencheram os critérios de elegibilidade e foram analisados. Foram avaliados 2.670 pacientes, 1.112 (41,6%) do sexo masculino e 1.558 (58,4%) do feminino, com média de 51,6 anos. A proporção de exames alterados no vHIT foi de 21% (95% IC 9%-33%) e na prova calórica foi de 55% (95% IC 43%-67%). Conclusão: O vHIT não substitui a prova calórica. Ambos os testes são complementares na avaliação do paciente com tontura, pois descrevem a tonotopia da crista ampular em diferentes faixas de frequência de estimulação. Nos quadros crônicos, o vHIT tem baixa sensibilidade e alta especificidade diagnóstica em relação à prova calórica.

A supressão do (La supresión del) reflexo vestíbulo-ocular humano / The human supression vestibulo-ocular reflex

O objetivo do presente estudo foi revisar os conceitos relativos ao funcionamento e alterações da supressão do reflexo vestíbulo-ocular (SRVO) e as principais formas de avaliação atualmente. Trata-se de uma pesquisa descritivo-exploratória, baseada em uma revisão da (El trabajo es una investigación descriptiva-exploratoria, basada en una revisión de la) literatura, realizada no (en el) Portal de Periódicos da Capes, no período de abril de 2020. Os (Los) operadores booleanos utilizados foram vestibulo-ocular reflex (OR), semicircular canal (OR), vestibular (AND) suppression. Como estratégia de pesquisa, na (en la) etapa de triagem (selección) foram utilizados os filtros: descritores no (en) título, publicações dos (de los) últimos dez anos, tipo de material, idioma e artigos revisados por pares. Dos 30 artigos triados (seleccionados), 20 apresentaram resumo de acordo com o tema e 13 estudos atenderam aos critérios de incluso (presentaron resúmenes relacionados al tema y 13 estudios cumplieron los criterios de inclusión). Scopus, Medline/PubMed e Science Citation Index Expanded foram as bases mais abrangentes (fueron las bases más abarcativas). A maioria dos (La mayoría de los) estudos, sobretudo os mais recentes, utilizaram os testes de impulso cefálico com o paradigma ´suppression head impulse test´ (SHIMP) comparando-o ao ´head impulse test´ (HIMP). A cadeira rotatória (La silla rotatoria) com eletronistagmografia foi o segundo teste mais utilizado. Apenas um estudo utilizou a Scleral Search Coil. A partir dessa revisão constata-se que a SRVO é influenciada pela idade, pode ser alterada por disfunções vestibulares periféricas unilaterais ou bilaterais, mas também por alterações neurológicas, como as cerebelares (las cerebelosas). Além da via visual, a SRVO pode ser desencadeada por fontes auditivas, somestésicas e até mesmo imagéticas (e incluso imaginativas, fantasiosas)

The present study aimed to review the concepts related to the functioning and changes in vestibular-ocular reflex suppression (VORS) and the most used assessments today. This is descriptive-exploratory research, based on a literature review, carried out on the Capes Journals Portal, in April 2020. The Boolean operators used were Vestibulo-ocular reflex (OR) Semicircular canal (OR) Vestibular (AND) Suppression. As a research strategy, in the screening stage, with the filters: descriptors in the title, last ten years, type of material, language, and peer-reviewed articles. Thirty articles were screened, 20 presented a summary according to the theme and 13 studies met the inclusion criteria. Scopus, Medline/PubMed, and Science Citation Index Expanded were the most comprehensive databases. Most studies, especially the most recent ones, used cephalic impulse tests with the SHIMP paradigm (suppression head impulse test) comparing it to the HIMP (head impulse test, HIMP). The rotary chair with electronystagmography was the second most used test. Only one study used the Scleral Search Coil. From this review, it appears that the SRVO is influenced by age; it can be altered by unilateral or bilateral peripheral vestibular disorders, but also by neurological changes, such as the cerebellar ones. In addition to the visual pathway, other sources can trigger SVOR, such as auditory, somesthetic and even imagery sources

Normal Vestibulo Ocular Reflex (VOR) gain Measured Using the Video Head Impulse Test (vHIT) in Healthy Young Adults

@#Introduction: Many new objective tests to assess the function of specific structures of the vestibular organ are currently adopted in vestibular clinics. One of the objective assessments include the video head impulse test (vHIT) where gain & velocity responses of eye relative to the head movements are recorded using an infrared camera. Methods: Thirty normal hearing subjects age between 18 to 25 years old participated in this study. At least ten Lateral, Left Anterior Right Posterior (LARP), and Right Anterior Left Posterior (RALP) responses were recorded for each participant by making small and rapid unpredictable head movements. Results: The average velocity gain for Lateral responses at 40 ms, 60 ms and 80 ms were 1.05 ± 0.003, 1.03 ± 0.002 and 1.01 ± 0.003 respectively. The LARP average velocity regression were 1.01 ± 0.24 for Left Anterior and 1.05 ± 0.25 for Right Posterior, with an average gain asymmetry of 5.13%. The RALP average velocity regression were 1.08 ± 0.31 for Right Anterior and 1.12 ± 0.30 for Left Posterior, with an average gain asymmetry of 5.87%. One sample T-test were conducted to compare Lateral responses to a previous study by Mossman et al. (2015) where significant differences in velocity gain at 60 ms and 80 ms between studies were found where, t (59) = 5.56, p <0.01 and t (59) = 2.86, p < 0.01 respectively. Conclusion: This indicates the importance of establishing on-site norms for every clinical settings as techniques used and equipment differences could affect the results.

Analysis of Age-Dependent Normative Values of Suppression Video-Head-Impulse Test in Healthy Korean Subjects / 대한평형의학회지

OBJECTIVES: Suppression head impulse paradigm (SHIMP) in video head impulse test is now newly used to test vestibular function. The aim of this study was to analyze normative values of SHIMP for healthy Korean subjects in each decade of life. METHODS: SHIMP and HIMP responses were measured with the video head impulse test in 70 healthy subjects. Vestibulo-ocular reflex gain and anticompensatory saccade were analyzed and compared at each decade of life. RESULTS: All subjects produced anticompensatory saccades in SHIMP. Gain values did not vary significantly with age. Gain values in SHIMP were lower than gain values in HIMP. The gain values of rightward impulse were higher than the gain values of leftward impulse. CONCLUSIONS: Gain values and anticompensatory saccades in SHIMP were consistently equal in each decade of life. Normative values of SHIMP seems largely unaffected by aging.

Exploración de los conductos semicirculares verticales con estimulación rotatoria inducida / Exploration of vertical semicircular ducts with induced rotatory stimulation

Las pruebas rotatorias han sido utilizadas durante más de un siglo para el estudio de la función vestibular por ser un estímulo fisiológico controlado muy efectivo sobre el laberinto posterior, habitualmente son los conductos semicirculares horizontales los que se exploran, pues se afectan con más frecuencia y son más fáciles de estudiar, sin embargo en ocasiones son los verticales los lesionados y por tanto deben emplearse otras alternativas para llegar a un diagnóstico certero. Se presenta un caso donde se evalúa la función fisiológica de los conductos semicirculares verticales a través de la electronistagmografía con estimulación rotatoria, empleando la técnica de estimulación tiempo-velocidad, con fases sucesivas de aceleración, velocidad constante, desaceleración y parada brusca, con una silla rotatoria computarizada, acoplada a un electronistagmógrafo. Se obtuvo arreflexia del canal vertical anterior derecho. A velocidades inferiores a 1 Hz es posible evaluar el reflejo vestíbulo ocular en los conductos semicirculares verticales, a pesar de que la frecuencia del estímulo está por debajo del nivel en que este reflejo funciona en las actividades diarias(AU)

Rotatory tests have been used for over a century for the study of vestibular function because it is a very effective physiological controlled stimulus on the posterior labyrinth, usually the horizontal semicircular ducts that are explored, since they are affected more frequently and are more easy to study, however sometimes the injured are vertical and therefore other alternatives must be used to arrive at a correct diagnosis. The aim of this study is to evaluate the range of physiological function of vertical semicircular ducts using electronystagmography and rotary stimulation. The method used was the technique of time - speed stimulation, with successive phases of acceleration, constant speed, deceleration and abrupt stop, with a computerized rotating chair. Vestibulo-ocular arreflexia of the right anterior vertical channel. It was shown that at speeds lower than 1 Hz it is possible to evaluate the Ocular Lobe Reflex in the vertical semicircular ducts, although the frequency of the stimulus is below the level at which this reflex works in daily activities(AU)

Clinical Feasibility of Suppression Head Impulse Test in Vestibulopathy Patients / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The suppression head impulse (SHIMP) test has emerged as one of the new vestibular function tests. The SHIMP test is an analysis of anti-compensatory saccadic movements in gazing moving targets as the head moves. In this study, we investigated the accuracy and sensitivity of the test. SUBJECTS AND METHOD: We analyzed the results of SHIMP test (gain, amplitude, and latency) in 24 cases, which included normal, vestibular neuritis, benign paroxysmal positional vertigo (BPPV), Meniere's disease, bilateral vestibular function loss, temporal bone fracture, tuberculosis meningitis and acoustic schwannoma patients. We also carried out a physical exam, audiologic study, video electronystagmography (vENG) and a conventional video head impulse test to evaluate the feasibility of SHIMP test in cases of vesitibulopathy. RESULTS: In patients with vestibulopathy, the analysis of SHIMP test indicated high sensitivity and accuracy, which were supported by accompanying audio-vestibular studies. Patients suspected with BPPV, vestibular neuronitis and Meniere's disease showed low vestibulo ocular reflex (VOR) gain and delayed anticompensatory saccade with smaller and more scattered amplitudes than the control. Patients with bilateral vestibular function loss, temporal bone fracture, tuberculosis meningitis, and acoustic schwannoma showed delayed latency, and small amplitude or few anticompensatory saccades. Finally, changes in the SHIMP test values might be a hint that patients had recovered from vestibular neuronitis and tuberculosis meningitis. CONCLUSION: We found the feasibility of SHIMP test in detecting the pathologic condition of VOR in vestibulopathy patients. We argue that the usefulness of SHIMP test might be extended to evaluating the effectiveness of rehabilitation.

Clinical Application and Update of Video Head Impulse Test / 대한평형의학회지

Recently with the introduction of video head impulse test (vHIT), it can be easily performed quantitative and objective measurement of vestibulo-ocular reflex (VOR). vHIT has been used as a clinical vestibular function test that can individually evaluate the function of each semicircular canal. Loss of VOR gain and corrective catch-up saccades that occur during the vHIT usually indicate peripheral vestibular hypofunction, whereas in acute vestibular syndrome, normal vHIT should prompt a search for a central lesion. In this study, we will examine the principle of vHIT and its interpretation, and explain its clinical application in peripheral and central vestibulopathy. In addition, we will compare the caloric test and the differences, and review the most recently introduced suppression head impulse paradigm test.

Four Cases of Wernicke's Encephalopathy with Impaired Horizontal Vestibular Ocular Reflexes / 대한평형의학회지

Wernicke's encephalopathy (WE) is a neurological disorder induced by a dietary vitamin B1 (thiamine) deficiency which is characterized by encephalopathy, gait ataxia, and variant ocular motor dysfunction. In addition to these classical signs of WE, a loss of the horizontal vestibulo-ocular reflex (VOR) is being reported as the major underdiagnosed symptoms in WE. In this retrospective single center study, we report four cases of WE initially presented with impaired horizontal VOR in addition to the classical clinical presentations, and imaging and neurotological laboratory findings were described.

Vestibulo-Ocular Reflex Recordings of Small Rodents using a Novel Marker Array / 대한평형의학회지

OBJECTIVE: Recording the nystagmus of small experimental rodents is an integral technique in vestibular research. Theoretically, the size and the shape of markers strongly affect the analysis of 3 dimensional nystagmus. METHODS: The nystagmus of 6 healthy ICR mice were recorded and their gain values were compared using 200 µm, 300 µm, 400 µm, and 600 µm isosceles triangle markers at the peak velocity of 60°/sec and 100°/sec with the rotational stimulations of 0.1 Hz, 0.2 Hz, and 0.5 Hz. RESULTS: The gain values of 3 different sizes of the markers showed no significant differences in horizontal- vertical-torsional component. However, it was unable to record the nystagmus with 200 µm markers since the markers were too small to be placed and stayed on the center of the pupils. CONCLUSION: Technicians can decide the size of the markers from 200 to 600 µm to record the nystagmus of mice, depending on the technicians' skills.

Normal Caloric Responses during Acute Phase of Vestibular Neuritis

BACKGROUND AND PURPOSE: We report a novel finding of caloric conversion from normal responses into unilateral paresis during the acute phase of vestibular neuritis (VN). METHODS: We recruited 893 patients with a diagnosis of VN at Dizziness Clinic of Seoul National University Bundang Hospital from 2003 to 2014 after excluding 28 patients with isolated inferior divisional VN (n=14) and those without follow-up tests despite normal caloric responses initially (n=14). We retrospectively analyzed the neurotological findings in four (0.5%) of the patients who showed a conversion from initially normal caloric responses into unilateral paresis during the acute phase. RESULTS: In those four patients, the initial caloric tests were performed within 2 days of symptom onset, and conversion into unilateral caloric paresis was documented 1-4 days later. The clinical and laboratory findings during the initial evaluation were consistent with VN in all four patients except for normal findings in bedside head impulse tests in one of them. CONCLUSIONS: Normal findings in caloric tests should be interpreted with caution during the acute phase of suspected VN. Follow-up evaluation should be considered when the findings of the initial caloric test are normal, but VN remains the most plausible diagnosis.

Normal Caloric Responses during Acute Phase of Vestibular Neuritis

BACKGROUND AND PURPOSE: We report a novel finding of caloric conversion from normal responses into unilateral paresis during the acute phase of vestibular neuritis (VN). METHODS: We recruited 893 patients with a diagnosis of VN at Dizziness Clinic of Seoul National University Bundang Hospital from 2003 to 2014 after excluding 28 patients with isolated inferior divisional VN (n=14) and those without follow-up tests despite normal caloric responses initially (n=14). We retrospectively analyzed the neurotological findings in four (0.5%) of the patients who showed a conversion from initially normal caloric responses into unilateral paresis during the acute phase. RESULTS: In those four patients, the initial caloric tests were performed within 2 days of symptom onset, and conversion into unilateral caloric paresis was documented 1-4 days later. The clinical and laboratory findings during the initial evaluation were consistent with VN in all four patients except for normal findings in bedside head impulse tests in one of them. CONCLUSIONS: Normal findings in caloric tests should be interpreted with caution during the acute phase of suspected VN. Follow-up evaluation should be considered when the findings of the initial caloric test are normal, but VN remains the most plausible diagnosis.

Bilaterally Abnormal Head Impulse Tests Indicate a Large Cerebellopontine Angle Tumor

BACKGROUND AND PURPOSE: Tumors involving the cerebellopontine angle (CPA) pose a diagnostic challenge due to their diverse manifestations. Head impulse tests (HITs) have been used to evaluate vestibular function, but few studies have explored the head impulse gain of the vestibulo-ocular reflex (VOR) in patients with a vestibular schwannoma. This study tested whether the head impulse gain of the VOR is an indicator of the size of a unilateral CPA tumor. METHODS: Twenty-eight patients (21 women; age=64+/-12 years, mean+/-SD) with a unilateral CPA tumor underwent a recording of the HITs using a magnetic search coil technique. Patients were classified into non-compressing (T1-T3) and compressing (T4) groups according to the Hannover classification. RESULTS: Most (23/28, 82%) of the patients showed abnormal HITs for the semicircular canals on the lesion side. The bilateral abnormality in HITs was more common in the compressing group than the non-compressing group (80% vs. 8%, Pearson's chi-square test: p<0.001). The tumor size was inversely correlated with the head impulse gain of the VOR in either direction. CONCLUSIONS: Bilaterally abnormal HITs indicate that a patient has a large unilateral CPA tumor. The abnormal HITs in the contralesional direction may be explained either by adaptation or by compression and resultant dysfunction of the cerebellar and brainstem structures. The serial evaluation of HITs may provide information on tumor growth, and thereby reduce the number of costly brain scans required when following up patients with CPA tumors.