Mecanismos neurofisiológicos de la rehabilitación vestibular / Neurophysiological mechanisms of vestibular rehabilitation

RESUMEN La rehabilitación vestibular es un concepto terapéutico utilizado en pacientes que presentan síntomas como vértigos y/o mareos, asociados a una afectación vestibular, además de otras manifestaciones clínicas. Este artículo busca entregar un análisis amplio de los elementos que interactúan para definir una patología, como a su vez intervenir en su compensación. Serán presentados elementos neuroanatómicos, fisiológicos y conceptuales de la rehabilitación para este tipo de pacientes con un enfoque clínico basados en la evidencia.

ABSTRACT Vestibular rehabilitation is a therapeutic concept used in patients suffering from dizziness and/or dizziness, in addition to other clinical manifestations. This article gives a broad analysis of the elements that interact to define a pathology, as well as to intervene in their compensation. Neuro anatomical, physiological and conceptual elements of rehabilitation for this type of patients will be presented with a clinical approach based on evidence.

Caloric test and video head impulse test sensitivity as vestibular impairment predictors before cochlear implant surgery

OBJECTIVES: Currently, cochlear implant procedures are becoming increasingly broad and have greatly expanded. Bilateral cochlear implants and cochlear implants are more frequently applied in children. Our hypothesis is that the video head impulse test may be more sensitive than the caloric test in detecting abnormal vestibular function before cochlear implant surgery. The objective of this study was to compare the video head impulse test and caloric test results of patients selected for cochlear implant procedures before surgery. METHODS: The patients selected for cochlear implant surgery were submitted to a bithermal caloric test and video head impulse test. RESULTS: By comparing angular slow phase velocity values below 5° in the bithermal caloric test (hypofunction) and video head impulse test with a gain lower than 0.8, we identified 37 (64.9%) patients with vestibular hypofunction or canal paresis and 21 (36.8%) patients with abnormal video head impulse test gain before the cochlear implant procedure. Of the 37 patients with caloric test vestibular hypofunction, 20 (54%) patients exhibited an abnormal gain in the video head impulse test. CONCLUSION: The caloric test is more sensitive than the video head impulse test (Fisher's exact test, p=0.0002) in detecting the impaired ear before cochlear implant delivery. The proportion of caloric test/video head impulse test positive identification of abnormal vestibular function or caloric test/video head impulse test sensitivity was 1.8:1.

Intratympanic Gentamicin Versus Labyrinthectomy: Inner Ear Sensitivity to Gentamicin and Impact on the Contralateral Labyrinth

OBJECTIVES: To investigate the impact of labyrinthectomy and intratympanic (IT) gentamicin injections on the contralateral labyrinth, we also assessed the response of each individual semicircular canal to each IT gentamicin application. METHODS: We performed a pilot observational study on tertiary, referral, academic settings. Thirteen patients with unilateral vestibular pathology were organized into two groups, group I (seven patients) receiving IT gentamicin and group II undergoing labyrinthectomy (six patients). All patients underwent six-canal video-head-impulse test in predetermined time intervals. Patients receiving gentamicin were additionally tested 3 to 5 days after every sequential injection, until all ipsilateral canals were ablated, to determine the order of response to gentamicin. We recorded the vestibular-ocular reflex gains and the presence of covert/overt saccades for each canal. RESULTS: The posttreatment ipsilateral gains were abnormal. No patient from the gentamicin group developed abnormal contralateral responses, while patients undergoing labyrinthectomy had abnormal contralateral responses from at least one canal, even several months posttreatment. Finally, the lateral semicircular canal was the first one to be affected by IT gentamicin followed by the posterior canal: the superior canal was ablated last. CONCLUSION: In our study, labyrinthectomy had an impact on the responses recorded from the contralateral ear, while IT gentamicin ablated the ipsilateral labyrinthine function without affecting the contralateral responses, possibly because of a milder, more gradual impact. We also show for the first time the order that IT gentamicin application affects the semicircular canals, with the lateral being the first to be affected.

Confiabilidad interevaluador de la prueba video head impulse test en estudiantes de primer año de la generación 2016 de la Escuela de Fonoaudiología de la Universidad de Valparaíso Casa Central / Inter-rater reliability of the video head impulse test in students from the School of Speech and Language therapist of the University of Valparaiso main campus class 2016

RESUMEN Introducción: El video head impulse test es un método rápido, no invasivo y cómodo para evaluar el reflejo vestíbulo ocular, el cual está siendo utilizado con mayor frecuencia en la evaluación de pacientes con alteraciones del equilibrio. Sin embargo, en Chile se evidencia una falta de estudios relacionados a la confiabilidad interevaluador de dicha prueba. Objetivo: Determinar el nivel de concordancia de los resultados de la eficiencia del reflejo vestíbulo ocular de los canales semicirculares horizontales, obtenidos mediante la aplicación de la prueba video head impulse test, por parte de 3 evaluadores. Material y método: Estudio cuantitativo, correlacional, no experimental transversal descriptivo, con muestreo no probabilístico, de participación voluntaria. La prueba video head impulse test fue aplicada por 3 examinadores a 30 estudiantes que cumplieron con los criterios de inclusión. Resultados: El método de Bland y Altman mostró gran concordancia en las mediciones realizadas entre los 3 examinadores. La correlación intraclase para la ganancia del canal semicircular horizontal derecho e izquierdo fue de 0,85 y 0,91 respectivamente y de 0,75 para el valor de asimetría. Conclusión: El estudio mostró una confiabilidad interevaluador adecuada de la prueba video head impulse test para la evaluación de los canales semicirculares horizontales.

ABSTRACT Introduction: The video head impulse test is a rapid, non-invasive and comfortable method for the evaluation of the vestibulo-ocular reflex that is being used more often in the evaluation of patients with balance disorders. In Chile there is a lack of studies related to the inter-rater reliability for this test. Aim: To determine the level of agreement on the results for the vestibulo-ocular reflex of the horizontal semicircular canals obtained by the execution of the video head impulse test by 3 raters. Material and method: Quantitative, correlational, non-experimental, cross-sectional descriptive study with a type of non-probability sampling with voluntary participation. The video head impulse test was applied by 3 raters to 30 students who fulfilled the inclusion criteria. Results: The Bland-Altman method demonstrated good agreement in the measurements made between the 3 raters. The inter-rater reliability for the gain of the left and right horizontal semicircular canals was 0.85 and 0.91 respectively and 0.75 for the asymmetry value. Conclusion: The study showed an adequate inter-rater reliability for the video head impulse test in the evaluation of the horizontal semicircular canals.

Sensitivity of caloric test and video head impulse as screening test for chronic vestibular complaints

OBJECTIVE: This study compared the results of the caloric test with those of the video head impulse test obtained during the same session and evaluated whether the former can be used to screen for non-acute vestibular dysfunction. METHODS: A total of 157 participants complaining of dizziness with vestibular characteristics of varying durations and clinical courses completed the caloric test and video head impulse test. RESULTS: Significantly more caloric test results than video head impulse test results were abnormal. CONCLUSIONS: The results of the caloric test and video head impulse test are distinct but complement each other. Within our sample, the caloric test was more sensitive for vestibular dysfunction. Therefore, the video head impulse test is not a suitable screening tool of the vestibular system in patients with chronic complaints.

Research on dynamic visual function difference / 军事医学

Objective To detect the dynamic visual acuity ( DVA) before and after vestibular habituation of subjects in order to optimize the DVA assessment criteria .Methods The vestibular function examination system was applied to the detection of static and dynamic visual function in 16 healthy subjects .Results When the speed of left or right swinging was fast enough , DVA before and after vestibular habituation was different .Conclusion Subjects with vestibular habituation can reduce their sensitivity to the vestibular system , the changes in DVA are better than before habituation , and the vestib-ular function adaptability training may have effect on DVA .