Journal of Vestibular Research - Volume 21, issue 3

Authors: Tsutsumi, Takeshi | Tokumaru, Akiko | Murakami, Miho | Kawaishi, Junko | Chida, Wakako | Watanabe, Kensuke

Article Type: Research Article

Abstract: Rapid head movement was combined with continuous caloric irrigation of the external ear to evaluate the time courses of the on-step (null-to-supine repositioning) and off-step (supine-to-null repositioning) vestibulo-ocular reflexes (VOR) responses in eight healthy subjects. During continuous air-caloric irrigation, each subject's head was positioned with his/her lateral semicircular canal alternately placed in the null (horizontal) and activating (vertical) planes, and the time course of the slow phase eye velocity was evaluated. The resulting responses were characterized by estimates of activation and adaptation components, and their amplitudes and time constants were calculated. Comparisons of the on-step and off-step responses revealed the …activation and adaptation components of the VOR to have similar amplitudes. On the other hand, the time constant for the activation component was prolonged for the off-step response, while that for the adaptation component was shortened. Null-to-supine and reciprocal vestibular stimulation during continuous caloric irrigation of the external ear canal elicited asymmetric VOR responses that exhibited differing time courses. Show more

Keywords: Vestibulo-ocular reflex, caloric, step stimulus

DOI: 10.3233/VES-2011-0392

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 111-115, 2011

Authors: Kingma, Herman | Gauchard, Gérome C. | de Waele, Catherine | van Nechel, Christian | Bisdorff, Alexandre | Yelnik, Alain | Magnusson, Mans | Perrin, Philippe P.

Article Type: Research Article

Abstract: This report identifies fundamental problems to be addressed in order to build relevant clinical tests of human balance while standing. The stated purpose of these tests is identification of lesion site and/or definition of functional balance deficits in a specific patient. During a recent consensus meeting (ESCEBD), 60 researchers and experienced clinical users of posturography (14 European countries, 9 different disciplines) inventoried and critically analyzed the various methodologies of posturography currently used for clinical evaluation. To complement posturography, alternative methods of assessment of balance control were considered. The indications for the clinical use of posturography were defined as well as …recommendations regarding measurement parameters, type of perturbations and signal analysis techniques to improve assessment of balance control. Consensus was reached that a force platform cannot be considered as a technique which is sufficient on its own to perform a clinically relevant test for the assessment of neuro-otological and musculo-skeletal conditions, evaluation of compensation or treatment (rehabilitation) or prediction of falls. It should be supported by complementary methods, such as segment motion analysis, body-fixed 2D or 3D accelerometer-gyroscope or electromyography. At present, no generally applicable posturography test is available with reasonable sensitivity and specificity for the diagnosis of balance disorders. Perturbation techniques are most likely needed to enhance the diagnostic yield of posturography. Show more

Keywords: Balance control, clinical evaluation, posturography

DOI: 10.3233/VES-2011-0397

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 117-125, 2011

Authors: Stratulat, Anca M. | Roussarie, Vincent | Vercher, Jean-Louis | Bourdin, Christophe

Article Type: Research Article

Abstract: Tilt-coordination is a technique which uses the tilt-translation ambiguity of the vestibular system to simulate linear accelerations on dynamic driving simulators, in combination with real linear accelerations. However, the tilt/translation ratio is chosen empirically. We experimentally determine the most realistic tilt/translation ratio to simulate a given value of deceleration. Under specific conditions of driving simulation, five tilt/translation ratios were applied, with an inverse-proportional quantity of tilt and translation, so that the sum of the two (the proportion of the deceleration simulated by translational motion and the proportion simulated by tilt) was always equal to the same overall value (0.8 m/s2 …). We find that different ratios lead to different perceptions, depending on the quantity of tilt and translation. With a higher tilt ratio, the braking is perceived as being stronger than when there is a higher translation ratio and the most realistic tilt/translation ratio found is neither pure tilt, nor pure translation, but 35/65% tilt/translation. The way these different ratios are perceived during braking is discussed from vestibular and non-vestibular points of view. Show more

Keywords: Self-motion perception, vestibular inputs, tilt coordination, braking

DOI: 10.3233/VES-2011-0399

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 127-139, 2011

Authors: Nooij, S.A.E. | Vanspauwen, R. | Bos, J.E. | Wuyts, F.L.

Article Type: Research Article

Abstract: During the first days of spaceflight, about 50–70% of the astronauts experience symptoms of Space Motion Sickness (SMS). It has been proposed that an asymmetry between the left and right otolith organs contributes to an astronaut's individual susceptibility. A recently developed test to measure unilateral utricular function enabled us to re-investigate this so-called otolith asymmetry hypothesis, while using the paradigm of sustained centrifugation as a ground based model for SMS. This latter paradigm has been shown to elicit symptoms similar to those of SMS and is referred to as Sickness Induced by Centrifugation (SIC). In 15 healthy subjects unilateral utricular …function was assessed by recording ocular counter rolling during a unilateral centrifugation paradigm. In addition, saccular function was assessed by recording Vestibular Evoked Myogenic Potentials (VEMPs), and horizontal semicircular canal function was assessed using bithermal caloric stimulation. SIC-susceptible subjects showed a marginally higher degree of utricular asymmetry, utricular sensitivity and semicircular canal sensitivity (p < 0.1) than the non-susceptible group. Interestingly, a logistic regression model using both utricular and semicircular canal parameters led to a correct classification of 91% of the subjects. As such, these results suggest that otolith asymmetry is at most one factor – and not present in all susceptible subjects – in defining susceptibility to SMS and SIC. Both the utricular and the canal system might be involved as well. Show more

Keywords: Space adaptation syndrome, hypergravity, otoliths, otolith asymmetry, ocular counter roll, unilateral centrifugation

DOI: 10.3233/VES-2011-0400

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 141-151, 2011

Authors: Dannenbaum, Elizabeth | Chilingaryan, Gevorg | Fung, Joyce

Article Type: Research Article

Abstract: A common symptom for people with vestibulopathy is dizziness induced by dynamic visual input, known as visual vertigo (VV). The goal of this study is to present a novel method to assess VV, using a nine-item analog scale. The subjects rated the intensity of their dizziness on each item of the Visual Vertigo Analogue Scale (VVAS), which represented a daily situation typically inducing VV. The questionnaire was completed by participants with vestibulopathy (n = 102) and by subjects receiving out-patient orthopaedic physiotherapy (n = 102). The dizziness handicap inventory (DHI) was also completed by the vestibulopathic group. The …Cronbach's Alpha index indicated the VVAS is internally consistent and reliable (Cronbach's Alpha = 0.94). The study also found that the VVAS severity scores from vestibular and a non-vestibular population were significantly different (Wilcoxon-Mann Whitney test p < 0.0001). Spearman correlation analysis conducted between DHI and VVAS scores for the clients with vestibulopathy showed positive moderate correlations between the VVAS score and the total DHI score (r = 0.67, p < 0.0001). This study showed that the VVAS scale may be useful in providing a quantitative evaluation scale of visual vertigo. Show more

Keywords: Visual vertigo, vestibular assessment, dizziness

DOI: 10.3233/VES-2011-0412

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 153-159, 2011

Authors: Čakrt, Ondřej | Slabý, Kryštof | Viktorinová, Lucie | Kolář, Pavel | Jeřábek, Jaroslav

Article Type: Research Article

Abstract: Idiopathic scoliosis (IS) is characterized by a three-dimensional deviation of the vertebral column and its etiopathogenesis is unknown. Various factors are associated with idiopathic scoliosis, among these a prominent role has been attributed to integration of vestibular information with graviception for perception of space. Subjective visual vertical (SVV) is a sensitive sign of verticality perception. The aim of this study was to determine if SVV in adolescents with IS is different from healthy controls. Examination of SVV was performed using the bucket method. Binocular measurements of SVV were made in 23 adolescents with IS (age 14.5 ± 2.5, mean ± …SD) and 23 healthy subjects (age 14.0 ± 2.9). The groups differed significantly on SVV deviation (p < 0.01): healthy controls (−0.04° ± 0.64°), IS group (0.86° ± 1.39°). There was also significant difference in SVV uncertainty (p < 0.001): healthy controls (1.50° ± 0.94°), IS group (2.46 ± 0.82°). We conclude that the perception of visual vertical is altered in IS which may play role in development of IS. Show more

Keywords: Scoliosis, adolescent, vestibular function, otolith system, bucket method

DOI: 10.3233/VES-2011-0414

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 161-165, 2011

Authors: Roberts, Jess C. | Cohen, Helen S. | Sangi-Haghpeykar, Haleh

Article Type: Research Article

Abstract: Locomotion is impaired in some people with vestibular disorders. Performance on cognitive tasks is also impaired in many people with vestibular disorders. The goal of this study was to determine if patients with vestibular disorders have decreased ability to complete a dual task performance involving a cognitive task, an additional motor task or both tasks, combined along a linear path. Subjects were normal, had benign paroxysmal positional vertigo, or had various vestibular disorders that caused unilateral weakness. They were asked to walk 7.62 m in a straight line with eyes open or closed, without extra tasks, and while nodding the …head, naming things, and both nodding and naming. The patients walked significantly slower than controls, especially when performing the cognitive task. Patients had greater ataxia and began veering sooner than normals. The subjects' veering increased significantly with the addition of cognitive tasks. The patient groups did not differ significantly from each other. The changes in velocity did not affect the veering. These data suggest that patients with vestibular disorders are impaired in their ability to complete a linear path when cognitive tasks are added. Show more

Keywords: Benign paroxysmal positional vertigo, unilateral weakness, cognitive performance, spatial orientation

DOI: 10.3233/VES-2011-0415

Citation: Journal of Vestibular Research, vol. 21, no. 3, pp. 167-174, 2011