Classification of vestibular signs and examination techniques: Nystagmus and nystagmus-like movements.

This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations.View accompanying videos at http://www.jvr-web.org/ICVD.html.

Preoperative vestibular assessment protocol of cochlear implant surgery: an analytical descriptive study / Protocolo de avaliação vestibular pré-operatória da cirurgia de implante coclear: estudo descritivo analítico

Abstract Introduction: Cochlear implants are undeniably an effective method for the recovery of hearing function in patients with hearing loss. Objective: To describe the preoperative vestibular assessment protocol in subjects who will be submitted to cochlear implants. Methods: Our institutional protocol provides the vestibular diagnosis through six simple tests: Romberg and Fukuda tests, assessment for spontaneous nystagmus, Head Impulse Test, evaluation for Head Shaking Nystagmus and caloric test. Results: 21 patients were evaluated with a mean age of 42.75 ± 14.38 years. Only 28% of the sample had all normal test results. The presence of asymmetric vestibular information was documented through the caloric test in 32% of the sample and spontaneous nystagmus was an important clue for the diagnosis. Bilateral vestibular areflexia was present in four subjects, unilateral arreflexia in three and bilateral hyporeflexia in two. The Head Impulse Test was a significant indicator for the diagnosis of areflexia in the tested ear (p = 0.0001). The sensitized Romberg test using a foam pad was able to diagnose severe vestibular function impairment (p = 0.003). Conclusion: The six clinical tests were able to identify the presence or absence of vestibular function and function asymmetry between the ears of the same individual.

Resumo Introdução: Os implantes cocleares (IC) são indiscutivelmente um método eficaz de recuperação da função auditiva de pacientes surdos. Objetivo: Descrever o protocolo de avaliação vestibular pré-operatória em sujeitos que serão submetidos ao IC. Método: Nosso protocolo institucional prevê o diagnóstico vestibular por meio de seis testes simples: testes de Romberg e Fukuda, nistagmo espontâneo, Head Impulse Test, Head Shaking Nistagmus, prova calórica. Resultados: Foram avaliados 21 pacientes com média de 42,75 ± 14,38 anos. Apenas 28% da amostra apresentaram todos os testes normais. A presença de informação vestibular assimétrica foi documentada pela prova calórica em 32% da amostra e o nistagmo espontâneo mostrou-se pista importante para seu diagnóstico. A arreflexia vestibular bilateral foi diagnosticada em quatro sujeitos; arreflexia unilateral em três e hiporreflexia bilateral em dois. O Head Impulse Test mostrou-se indicador significante (p = 0,0001) para diagnosticar arreflexia da orelha testada. O teste de Romberg sensibilizado em almofada foi capaz de diagnosticar os comprometimentos severos da função vestibular (p = 0,003). Conclusão: Os seis testes clínicos foram capazes de identificar a presença ou não de função vestibular e assimetria da função entre as orelhas de um mesmo indivíduo.

Preoperative vestibular assessment protocol of cochlear implant surgery: an analytical descriptive study.

INTRODUCTION: Cochlear implants are undeniably an effective method for the recovery of hearing function in patients with hearing loss. OBJECTIVE: To describe the preoperative vestibular assessment protocol in subjects who will be submitted to cochlear implants. METHODS: Our institutional protocol provides the vestibular diagnosis through six simple tests: Romberg and Fukuda tests, assessment for spontaneous nystagmus, Head Impulse Test, evaluation for Head Shaking Nystagmus and caloric test. RESULTS: 21 patients were evaluated with a mean age of 42.75±14.38 years. Only 28% of the sample had all normal test results. The presence of asymmetric vestibular information was documented through the caloric test in 32% of the sample and spontaneous nystagmus was an important clue for the diagnosis. Bilateral vestibular areflexia was present in four subjects, unilateral arreflexia in three and bilateral hyporeflexia in two. The Head Impulse Test was a significant indicator for the diagnosis of areflexia in the tested ear (p=0.0001). The sensitized Romberg test using a foam pad was able to diagnose severe vestibular function impairment (p=0.003). CONCLUSION: The six clinical tests were able to identify the presence or absence of vestibular function and function asymmetry between the ears of the same individual.

Vestibular tests for rehabilitation: applications and interpretation.

Vestibular function testing plays a critical role in understanding balance disorders. These tests augment a well-performed history and physical exam in providing quantitative information regarding vestibular reflexes, central oculomotor function and postural control strategies. Video-oculography (VOG) and caloric stimulation play a major role in evaluation of both peripheral vestibular and central oculomotor disorders. Rotational chair testing and, more recently the Dynamic Visual Acuity Test (DVAT) and Gaze Stabilization Test (GST) provide information regarding higher frequency vestibulo-ocular reflex (VOR) function. Computerized Dynamic Posturography (CDP) explores the interaction of the vestibular, visual and proprioceptive systems for posture control. Finally, the cervical Vestibular Evoked Myogenic Potential (cVEMP) test and the Dynamic Subjective Visual Vertical (DSVV) test provide information regarding saccular and utricular function, respectively. New techniques and applications continue to provide knowledge both of disease processes and potential medical, surgical and rehabilitative interventions.

Vertigo and balance in children--diagnostic approach and insights from imaging.

Common causes of vertigo and dizziness in childhood are vestibular migraine and associated syndromes (benign paroxysmal vertigo), unilateral vestibular failure due to labyrinthitis, positioning vertigo, and somatoform syndromes. Although the same spectrum of diseases as in adults can be found, the frequency differs widely. Further, balance disorders not related to vestibular function, like cerebral palsy, can present with dizziness. Vestibular function can reliably be addressed at the bedside by head impulses to test vestibulo-ocular reflex function, ocular motor testing of the central vestibular system, and balance tests for vestibulo-spinal function. Vestibulo-ocular reflex function can now be quantified by recording eye and head movements with high resolution video-oculography (256 Hz) and inertial sensors. Posturographic measures using artificial neuronal networks are used to classify dysbalance. Quantitative gait analysis further helps to distinguish balance disorders caused by e.g. sensory dysfunction or supraspinal disturbances. Recently, functional neuroimaging opened a view to the brain network for the control of posture and locomotion. From frontal cortex the locomotor signal is conveyed via the basal ganglia to the centers for locomotion and postural control in the brainstem tegmentum. The cerebellum is involved in sensory integration and rhythm generation during postural demands. To summarize, most syndromes causing dizziness, vertigo and imbalance can be diagnosed based on history and clinical tests. However, new data from neurophysiology and imaging help to understand the pathophysiology and the therapeutic principles in these disorders.

Classification of human rotation test results using parametric modeling and multivariate statistics.

The usefulness of vestibular testing is directly related to the accuracy of the test interpretations. Two factors, subjective analysis of large test data sets and failure to make appropriate age corrections, tend to reduce test accuracy. Correction of these problems can be accomplished by application of physiologically based models of vestibular function and multivariate classification techniques to the test data, thereby creating a more objective test interpretation procedure. Herein we report our results on the use of this strategy for analysis of sinusoidal harmonic acceleration (SHA) test interpretation. For each patient, models reduce the large set of SHA test variables to three key parameters: asymptotic gain, vestibulo-ocular reflex time constant, and bias. In addition, the new technique objectively adjusts these parameters for the patient's age. Finally, each patient's set of parameters are statistically classified as either normal or as unilateral peripheral deficit. Based on learning sets of 57 normals and 30 patients with a full unilateral peripheral deficit, this new technique resulted in a misclassification rate between the categories of normal and full unilateral loss of 3.4%, comparing favorably to the present method's misclassification rate between normal and abnormal of 13.8%. We also analyzed and classified a test group consisting of patients with possible partial unilateral deficits using the same classification function as the normal and full unilateral learning sets. Even though the classifier was not optimized for the partial group, results seemed favorable relative to the human interpreter. These results validate the accuracy and utility of physiological parametric models and multivariate statistical classification in SHA test interpretation.