ABSTRACT
·Rodents have been used widely in the research of eye diseases to study visual function in animal models. Two methods of visual acuity testing in animals have been internationally recognized:the electrophysiological visual acuity test and the behavioral visual acuity test. Both of these methods have their advantages and limitations. The electrophysiology test (visual evoked potential) is invasive, and animals need recovery time after being implanted with electrodes. Also,the electrophysiological visual acuity test only reflects the electrical activity of a single cell or nuclei, it does not reflect the overall visual function of the animal. The widely used behavioral visual acuity test is able to compensate for these limitations. This paper gives a brief overview of the methods of the behavioral visual acuity test for rodents (rats, mice, guinea pigs,etc.).
ABSTRACT
BACKGROUND: Saccade test, smooth pursuit test, and optokinetic nystagmus test are clinically useful tests to accurately diagnose vertigo. However, there have only been a few studies regarding a correlation between the anatomical site of the lesion and the abnormality of eyeball movement in patients with vertigo.METHODS: The medical records of 97 patients with vertigo between January 2006 and June 2008 were reviewed retrospectively. We classified many kinds of abnormalities regarding the saccade test, smooth pursuit test and optokinetic nystagmus test into several categories and analyzed the localizing lesion of vertigo.RESULTS: According to the saccade test, both total saccade abnormality (S-total) and slow velocity of saccade (S-type 3) were shown to be significantly higher in the central lesion of vertigo. According to the smooth pursuit test, symmetrical unidirectional smooth pursuit abnormality (SP-type 2) was observed to be significantly higher in the peripheral lesion over vertigo. Moreover, according to the optokinetic nystagmus test, total optokinetic nystagmus abnormalities (OKN-total) were shown to be significantly useful findings in the diagnosis of the central lesion of vertigo. The coexisting abnormalities of all three tests (S+SP+OKN abnormalities) were shown to be significantly higher in the central lesion of vertigo.CONCLUSION: These results suggest that all these tests, saccade test, smooth pursuit test, and optokinetic nystagmus test, are very useful to distinguish between the central lesion and the peripheral lesion of vertigo. However, these tests are not beneficial in localizing the central lesion of vertigo.
Subject(s)
Humans , Diagnosis , Medical Records , Nystagmus, Optokinetic , Pursuit, Smooth , Retrospective Studies , Saccades , VertigoABSTRACT
BACKGROUND: Saccade test, smooth pursuit test, and optokinetic nystagmus test are clinically useful tests to accurately diagnose vertigo. However, there have only been a few studies regarding a correlation between the anatomical site of the lesion and the abnormality of eyeball movement in patients with vertigo. METHODS: The medical records of 97 patients with vertigo between January 2006 and June 2008 were reviewed retrospectively. We classified many kinds of abnormalities regarding the saccade test, smooth pursuit test and optokinetic nystagmus test into several categories and analyzed the localizing lesion of vertigo. RESULTS: According to the saccade test, both total saccade abnormality (S-total) and slow velocity of saccade (S-type 3) were shown to be significantly higher in the central lesion of vertigo. According to the smooth pursuit test, symmetrical unidirectional smooth pursuit abnormality (SP-type 2) was observed to be significantly higher in the peripheral lesion over vertigo. Moreover, according to the optokinetic nystagmus test, total optokinetic nystagmus abnormalities (OKN-total) were shown to be significantly useful findings in the diagnosis of the central lesion of vertigo. The coexisting abnormalities of all three tests (S+SP+OKN abnormalities) were shown to be significantly higher in the central lesion of vertigo. CONCLUSION: These results suggest that all these tests, saccade test, smooth pursuit test, and optokinetic nystagmus test, are very useful to distinguish between the central lesion and the peripheral lesion of vertigo. However, these tests are not beneficial in localizing the central lesion of vertigo.
Subject(s)
Humans , Diagnosis , Medical Records , Nystagmus, Optokinetic , Pursuit, Smooth , Retrospective Studies , Saccades , VertigoABSTRACT
ABSTRACT INTRODUCTION: Visual stimuli can induce vestibular adaptation and recovery of body balance. OBJECTIVE: To verify the effect of visual stimuli by digital images on vestibular and body balance rehabilitation of peripheral vestibular disorders. METHODS: Clinical, randomized, prospective study. Forty patients aged between 23 and 63 years with chronic peripheral vestibular disorders underwent 12 sessions of rehabilitation with visual stimuli using digital video disk (DVD) (experimental group) or Cawthorne-Cooksey exercises (control group). The Dizziness Handicap Inventory (DHI), dizziness analog scale, and the sensitized Romberg static balance and one-leg stance tests were applied before and after the intervention. RESULTS: Before and after the intervention, there was no difference between the experimental and control groups (p > 0.005) regarding the findings of DHI, dizziness analog scale, and static balance tests. After the intervention, the experimental and control groups showed lower values (p < 0.05) in the DHI and the dizziness analog scale, and higher values (p < 0.05) in the static balance tests in some of the assessed conditions. CONCLUSION: The inclusion of visual stimuli by digital images on vestibular and body balance rehabilitation is effective in reducing dizziness and improving quality of life and postural control in individuals with peripheral vestibular disorders.
RESUMO INTRODUÇÃO: Estímulos visuais podem induzir a adaptação vestibular e recuperar o equilíbrio corporal. OBJETIVO: Verificar o efeito de estímulos visuais por imagens digitais na reabilitação do equilíbrio corporal de vestibulopatias periféricas. MÉTODO: Estudo clínico, randomizado, prospectivo. Quarenta pacientes com vestibulopatia periférica crônica e idade entre 23 e 63 anos foram submetidos à 12 sessões de reabilitação com estímulos visuais em DVD (grupo experimental) ou aos exercícios de Cawthorne-Cooksey (grupo controle). Dizziness Handicap Inventory (DHI), escala visual analógica de tontura e testes de equilíbrio estático de Romberg sensibilizado e de apoio unipodal foram aplicados antes e após a intervenção. RESULTADOS: Antes e após a intervenção, não houve diferença entre os grupos experimental e controle (p > 0,005) no DHI, escala visual analógica e testes de equilíbrio estático. Após a intervenção, o grupo experimental e o controle apresentaram valores menores (p < 0,05) do DHI e da escala visual analógica de tontura e valores maiores (p < 0,05) nos testes de equilíbrio estático em algumas condições avaliadas. CONCLUSÃO: A inclusão de estímulos visuais por imagens digitais na reabilitação do equilíbrio corporal é eficaz na redução da tontura, na melhora da qualidade de vida e do controle postural de vestibulopatias periféricas.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Young Adult , Dizziness/rehabilitation , Photic Stimulation/methods , Postural Balance/physiology , Vestibular Diseases/rehabilitation , Case-Control Studies , Prospective Studies , Quality of Life , Vestibular Function TestsABSTRACT
RESUMO Objetivo Avaliar os movimentos oculares de sácadas, perseguição e o nistagmo optocinético em adultos, analisando o efeito da idade e das alterações visuais. Métodos Foram avaliados 40 sujeitos de ambos os gêneros, com faixa etária de 20 a 49 anos de idade, sem queixas auditivas ou vestibulares e que apresentaram avaliação audiológica básica dentro dos padrões da normalidade e ausência de nistagmo espontâneo de olhos abertos, nistagmo semi-espontâneo e nistagmo espontâneo de olhos fechados maior que 6º/s. Todos os participantes foram submetidos às provas de nistagmo espontâneo, nistagmo optocinético, movimentos sacádicos fixos, aleatórios e rastreio pendular, por meio da vectoeletronistagmografia computadorizada. Os achados foram analisados segundo as variáveis idade e presença de alteração visual, do tipo ametropias. Os resultados passaram por análise estatística descritiva e inferencial. Resultados Não houve diferença nas provas de nistagmo optocinético, sacádico fixo, aleatório e rastreio pendular, quando analisadas com relação à idade. Quanto à variável alteração visual, a preponderância direcional do nistagmo, observada na prova do nistagmo optocinético, foi maior em indivíduos com alterações visuais. Nos movimentos sacádicos aleatórios, também se observou diferença em relação à velocidade máxima, sendo maior em indivíduos sem alterações visuais. Conclusão As provas oculomotoras não sofreram influência do fator idade na faixa etária pesquisada, porém, a presença de alterações visuais exerceu influência em alguns dos parâmetros das provas oculomotoras.
ABSTRACT Purpose To evaluate saccadic and pursuit ocular movements and optokinetic nystagmus in adults, analyzing the effect of age and visual alterations. Methods We evaluated 40 subjects of both genders, aged 20-49 years, with no auditory or vestibular complaints and who presented a normal basic audiology evaluation, absence of spontaneous nystagmus with open eyes, semi-spontaneous nystagmus, and spontaneous nystagmus with eyes closed greater than 6º/s. All participants underwent the tests of spontaneous nystagmus, optokinetic nystagmus, fixed and random saccadic movements, and pendular tracking using computerized vectoelectronystagmography. The findings were analyzed according to age and visual changes (ametropias). The results underwent a descriptive and inferential analysis. Results There was no difference in the tests of optokinetic nystagmus, fixed and random saccadic movement, and pendular tracking when analyzed with regard to age. As for the variable presence of visual alteration, directional preponderance of nystagmus, observed in the optokinetic nystagmus test, was higher in individuals with visual alterations. In the random saccadic movement, there was also a difference in relation to the maximum velocity, which was higher in individuals with no visual alterations. Conclusion The oculomotor tests were not affected by the age factor in the studied age group, but the presence of visual alterations exerted influence on some of the parameters of the oculomotor tests.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Saccades , Reflex, Vestibulo-Ocular , Nystagmus, Physiologic , Nystagmus, Optokinetic , Vision Disorders , Electronystagmography , Postural Balance , Age FactorsABSTRACT
O objetivo deste estudo foi verificar as alterações vestibulococleares observadas em um caso de ataxia espinocerebelar tipo 6. O caso foi encaminhado do Hospital de Clínicas para o Laboratório de Otoneurologia de uma Instituição de Ensino e foi submetido aos seguintes procedimentos: anamnese, inspeção otológica, avaliações audiológica e vestibular. O caso retrata uma paciente com diagnóstico genético de ataxia espinocerebelar tipo 6, do sexo feminino, com 57 anos de idade, que referiu desequilíbrio à marcha com tendência a queda para a esquerda, disartria e disfonia. Na avaliação audiológica apresentou configuração audiométrica descendente a partir da frequência de 4kHz e curva timpanométrica do tipo "A" com presença dos reflexos estapedianos bilateralmente. No exame vestibular observou-se na pesquisa da vertigem posicional presença de nistagmo vertical inferior e oblíquo, espontâneo e semiespontâneo múltiplo com características centrais (ausência de latência, paroxismo, fatigabilidade e vertigem), nistagmooptocinético abolido e hiporreflexia à prova calórica. Constataram-se alterações labirínticas que indicaram afecção do sistema vestibular central evidenciando-se a importância dessa avaliação. A existência da possível relação entre os achados com os sintomas vestibulares apresentados pela paciente apontou a relevância do exame labiríntico neste tipo de ataxia uma vez que a presença do nistagmo vertical inferior demonstrou ser frequente neste tipo de patologia.
The aim of this study was to investigate the vestibulocochlear alterations observed in a case of spinocerebellar ataxia type 6. The case was referred from the Hospital das Clinicas to the Otoneurology Laboratory of an educational institution and was subjected to the following procedures: anamnesis, otologic examination, as well as audiological and vestibular assessments. The case shows a 57-year-old female patient with a genetic diagnosis of spinocerebellar ataxia type 6 who presented unsteadiness of gait with tendency to fall to the left, dysarthria, and dysphonia. The audiological assessment presented sloping audiometric configuration from 4.0 kHz and tympanogram type “A” with the presence of acoustic reflexes bilaterally. Observed during the survey of positional vertigo in the vestibular assessment were the presence of oblique and vertical downbeat nystagmus, spontaneous and semispontaneous with multiple core features (absence of latency, paroxysm, fatigue and vertigo), abolished optokineticnystagmus and hyporeflexia in the caloric test. We found labyrinthic alterations that indicate central vestibular system disorders and lend credence to the importance of this evaluation. The existence of a possible relationship between the findings and vestibular symptoms displayed by the patient indicated the relevance of the labyrinthine evaluation for this type of ataxia once the presence of vertical downbeat nystagmus proved to be frequent in this type of pathology.
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PURPOSE: The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects, and subjects who need legal assistance. We designed an objective system for visual acuity test (SOVAT) consisting of three components: stimuli applied via a suppression method, display and evaluation and made a suppression method as stimuli component for SOVAT. Usefulness of the SOVAT was evaluated. METHODS: The visual stimuli were presented on a high-resolution head-mounted display (HMD). An eye movement tracking program and gaze monitoring device allowed us to monitor the patient's fixation status during the test. The suppression method, in addition to a conventional induction method, was developed to use with the SOVAT and its accuracy and confidence level were evaluated. RESULTS: On the basis of clinical data, we present the reference values for the SOVAT as below. For the induction method, objective visual acuity (smallest pixel size), the presumed subjective visual acuity was 3: 0.35-0.6, 7: 0.05-0.25, 12: below 0.05 and for the suppression method it was 1: 0.6-1.0, 1.5: 0.4-0.7, 3: 0.15-0.4, 5: 0.1-0.2. CONCLUSIONS: SOVAT using this suppression method to assess objective visual acuity proved to be more useful than that with a conventional induction method, especially in the range of high visual acuity.
Subject(s)
Humans , Infant , Eye Movements , Nystagmus, Optokinetic , Organothiophosphorus Compounds , Reference Values , Track and Field , Visual AcuityABSTRACT
Normally, the fast phase of optokinetic nystagmus (OKN) beats on the opposite direction to the movement of an optokinetic stimulus. The fast component of OKN beating in the same direction are called "reversed OKN". Eventhough the mechanism of reversed OKN is still disputed, it is well known that reversed OKN occurs exclusively in patients with congenital nystagmus, or in some cases, with acquired neurologic disease. It is easy to diagnose the congenital nystagmus when the spontaneous nystagmus can be seen at birth. But when the congenital nystagmus can be seen only on eccentric gaze or when the patient has a wide neutral region around the primary position, the abnormal eye movement can not be detected until a medical examination is performed. It is thought that causes of reversed OKN may be the abnormal neural decussation of the visual system or spontaneous nystagmus. Recently, we experienced two cases of bidirectional reversed OKN as a congenital nystagmus. One patient had bilateral reversed optokinetic nystagmus and gaze evoked nystagmus, whereas the other patient had periodic alternative nystagmus and bilateral reversed OKN. Bilateral reversed OKN may be one of the pathognomic signs of congenital nystagmus.
Subject(s)
Humans , Eye Movements , Nystagmus, Congenital , Nystagmus, Optokinetic , ParturitionABSTRACT
Optokinetic nystagmus(OKN) is commonly employed in the assessment of central vestibular lesion. Asymmetry in the OKN has been found in lesions ipsilateral to the direction of the slow phase in parietal lobe, in brain stem, and in the cerebellum. Asymmetry of the OKN may also occur in peripheral vestibular lesions due to spontaneous nystagmus, and this may explain why even enhanced velocities of OKN are sometimes met in these patients. The ocular abnormality as congenital strabismus, extraocular paresis, and congenital nystagmus can cause abnormalities of optokinetic nystagmus. We investigated the clinical significance of OKN test and spontaneous nystagmus for differentiation of peripheral and central vestibular disorder. In this study, we recorded the optokinetic nystagmus by the electronystagmography. We divided the optokinetic response from normal to type III according to direction of the nystagmus and difference of(Rt-Lt) Vmean. At the result, all of the vestibuloneuronitis who had the optokinetic abnormality showed type I OKN abnormality with spontaneous nystagmus. Type II and type III OKN abnormality always appeared in central vertigo patients. Type I OKN abnormality could be seen in peripheral and central vertigo patient. But half of the central vertigo patients who had type I OKN abnormality did not have spontaneous nystagmus. We could not correlated OKN abnormality with specific location of central nervous system.
Subject(s)
Humans , Brain Stem , Central Nervous System , Cerebellum , Electronystagmography , Nystagmus, Congenital , Nystagmus, Optokinetic , Paresis , Parietal Lobe , Strabismus , VertigoABSTRACT
This paper reports oculomotor central tests on 25 normal subjects, 41 cases of peripharal'diseases.and 25 cases of centra) diseasses.All tets were normal in normal subjects.The tests were normal in peripheral diseases except that three cases of eye tracking test were type Ⅲ.Ocular saccade was abnormal in 10 cases (40%) , eye tracking test was typeⅢ-IV in 15 cases (60%) , and abnormality of optokinetic nystagmus was 80% in central diseases.A marked difference was found in ocular saccade, eye tracking and optokinetic nystagmus tests among three groups(P