Avaliação da vertical visual subjetiva em indivíduos brasileiros normais

Abstract

O sistema vestibular tem a função de estabilização da imagem na retina, manutenção da postura e do equilíbrio, orientação espacial e percepção do movimento, requerendo a integração com os sistemas motor ocular, visual e proprioceptivo 1 . Os órgãos otolíticos, utrículo e sáculo, fornecem informações ao sistema vestibular sobre movimentos de aceleração linear da cabeça e contribuem para a percepção de orientação espacial, que é a capacidade de um indivíduo perceber a vertical e horizontal gravitacionais 2 . As síndromes vestibulares são diagnosticadas por meio da anamnese e do exame físico dirigidos ao sistema vestibular 3 . Os exames complementares de avaliação da função vestibular colaboram com a confirmação diagnóstica, fornecendo dados e/ou registros que muitas vezes são capazes de quantificar o comprometimento deste sistema, tal como o teste da Vertical Visual Subjetiva (VVS).Em situações habituais, o julgamento de verticalidade e horizontalidade é realizado principalmente através das informações visuais, pois há, em qualquer ambiente, linhas verticais e horizontais que auxiliam nesta função. Quando as informações visuais são excluídas, por exemplo, em uma sala completamente escura, uma pessoa normal é capaz de julgar se um bastão iluminado está na posição vertical ou horizontal na ausência de qualquer outra aferência visual. PALAVRAS-CHAVE: sistema vestibular, visual vertical subjetiva, função otolítica. Subjective visual vertical evaluation in normal Brazilian subjectsABSTRACT -Otolith function can be evaluated by subjective visual vertical (SVV) that determine the capacity of a subject to judge if the objects are on vertical position with absence of any visual reference. The aim of this study was to evaluate the SVV in a sample of normal Brazilian subjects using a portable device. Measurements of SVV were performed in 160 normal subjects (aged from 16 to 85). SVV mean value was obtained after ten adjustments. SVV mean values ranged from -2.0º to +2.4º (mean=0.18º, and SD=0.77). Considering all age groups, there was no difference of SVV mean values (Kruskal-Wallis test; p=0.40), but older groups had a greater variance (Levene test; p=0.016). SVV values observed in this study are comparable to those described in previous studies. Although there was no difference in mean SVV-inclination according to age, there was a greater variance in older subjects.

Avaliação da vertical visual subjetiva em adultos jovens

“…In studies conducted with older patients, the results were worse than those of younger individuals (11,13) , that is, there was greater variation in SVV data.…”

“…(6). In Brazil, there are still few studies on SVV (10,13) , and all of them have focused on the same sensory condition, i.e., the individuals were seated with both feet on a flat surface. SVV measurement is extremely important, because 94% of patients with acute unilateral brainstem lesions and 90% of patients with vestibular neuritis will present subjective visual vertical deviation (6) .…”

“…In this way, the evaluation becomes faster and reduces the risk of being influenced by patient fatigue as a variable. Since there was no difference between males and females in previous studies (13) , this variable was not considered in this research.…”

Assessment of gait deviation on the Babinski-Weill test in healthy Brazilians

“…A potential limitation of this study was the high number of younger adults included, although the rationale for this broader sample was to better reflect the demographic age profile of the Brazilian population [21][22][23] .…”

“…The sample distribution for gender and age was similar to that registered in the last 2000 Brazilian Demographic Census, where subjects were stratified into an 18-29 year age band and other bands with increments of 10 years [21][22][23] . Exclusion criteria were as follows: (1) neurological and/or orthopedic deficits affecting gait (such as asymmetry of lower limbs and arthrosis), with motor or sensitivity deficits; (2) history of confirmed or suspected vestibular disorder; (3) auditory deficits or unilateral or bilateral tinnitus complaints; (4) abnormal vision; (5) cognitive disturbance; (6) subjects in use of psychotropic drugs; and (7) history of fall and/or loss of balance secondary to vertigo in the past year.…”