Journal of Vestibular Research - Volume 15, issue 3

Authors: Yates, Bill J. | Bronstein, Adolfo M.

Article Type: Research Article

Abstract: The loss of labyrinthine inputs in patients or animal models has been demonstrated to affect autonomic regulation. Considerable evidence suggests that vestibular-autonomic responses serve to adjust blood pressure and respiratory activity during movement and postural alterations. However, following peripheral vestibular lesions, compensation rapidly occurs, such that autonomic disturbances are not readily evident in patients with chronic labyrinthine dysfunction. This manuscript summarizes the evidence suggesting that vestibular inputs influence autonomic regulation, but that cardiovascular and respiratory responses linked to movement recover quickly subsequent to the loss of labyrinthine signals. In addition, the clinical implications of dysfunction of vestibulo-autonomic reflexes are described. …Furthermore, the mechanisms potentially responsible for the return of the ability to produce posturally-related adjustments in blood pressure and respiration following vestibular lesions are discussed. In particular, evidence that somatosensory signals can replace labyrinthine inputs to vestibular nucleus neurons that participate in autonomic regulation is provided. Show more

Keywords: Respiration, blood pressure, labyrinthectomy, inner ear disease, 8th cranial nerve

DOI: 10.3233/VES-2005-15301

Citation: Journal of Vestibular Research, vol. 15, no. 3, pp. 119-129, 2005

Authors: Kaufman, Galen | Weng, Tianxiang | Ruttley, Tara

Article Type: Research Article

Abstract: Vestibulo-ocular reflex (VOR) adaptation and brainstem Fos expression as a result of short radius cross-coupling stimuli were investigated to find neural correlates of the inherent Coriolis force asymmetry from an artificial gravity (AG) environment. Head-fixed gerbils (Meriones unguiculatus, N = 79) were exposed, in the dark, to 60–90 minutes of cross-coupled rotations, combinations of pitch (or roll) and yaw rotation, while binocular horizontal, vertical, and torsional eye position were determined using infrared video-oculography. Centripetal acceleration in combination with angular cross-coupling was also studied. Simultaneous sinusoidal rotations in two planes (yaw with roll or pitch) provided a net symmetrical stimulus …for the right and left labyrinths. In contrast, a constant velocity yaw rotation during sinusoidal roll or pitch provided the asymmetric stimulus model for AG. We found orthogonally oriented half-cycle VOR gain changes. The results depended on the direction of horizontal rotation during asymmetrical cross-coupling, and other aspects of the stimulus, including the phase relationship between the two rotational inputs, the symmetry of the stimulus, and training. Fos expression also revealed laterality differences in the prepositus and inferior olivary C subnucleus. In contrast the inferior olivary beta and ventrolateral outgrowth were labeled bilaterally. Additional cross-coupling dependent labeling was found in the flocculus, hippocampus, and several cortical regions, including the perirhinal and temporal association cortices. Analyses showed significant differences across the brain regions for several factors (symmetry, rotation velocity and direction, the presence of centripetal acceleration or a visual surround, and training). Finally, animals compensating from a unilateral surgical labyrinthectomy who received multiple cross-coupling training sessions had improved half-cycle VOR gain in the ipsilateral eye with head rotation toward the intact side. We hypothesize that cross-coupling vestibular training can benefit aspects of motor recovery or performance. Show more

Keywords: Coriolis, cross-coupling, vestibular, video-oculography, centripetal hypergravity, eye movements, oculomotor, space, asymmetry

DOI: 10.3233/VES-2005-15302

Citation: Journal of Vestibular Research, vol. 15, no. 3, pp. 131-147, 2005

Authors: Bos, Jelte E. | van Erp, Jan | Groen, Eric L. | van Veen, Hendrik-Jan

Article Type: Research Article

Abstract: This paper shows that tactile stimulation can override vestibular information regarding spinning sensations and eye movements. However, we conclude that the current data do not support the hypothesis that tactile stimulation controls eye movements directly. To this end, twenty-four subjects were passively disoriented by an abrupt stop after an increase in yaw velocity, about an Earth vertical axis, up to 120°/s. Immediately thereafter, they had to actively maintain a stationary position despite a disturbance signal. Subjects wore a tactile display vest with 48 miniature vibrators, applied in different combinations with visual and vestibular stimuli. Their performance was quantified by RMS …body velocity during self-control. Fast eye movement phases were analyzed by counting samples exceeding a velocity limit, slow phases by a novel method applying a first order model. Without tactile and visual information, subjects returned to a previous level of angular motion. Tactile stimulation decreased RMS self velocity considerably, though less than vision. No differences were observed between conditions in which the vest was active during the recovery phase only or during the disorienting phase as well. All effects of tactile stimulation found on the eye movement parameters could be explained by the vestibular stimulus. Show more

Keywords: Motion perception, spatial orientation, angular yaw motion, VOR, saccades, slow phase eye velocity, velocity storage, human, tactile display, motion sickness

DOI: 10.3233/VES-2005-15303

Citation: Journal of Vestibular Research, vol. 15, no. 3, pp. 149-160, 2005

Authors: Picciotti, Pasqualina M. | Fiorita, Antonella | Di Nardo, Walter | Quaranta, Nicola | Paludetti, Gaetano | Maurizi, Maurizio

Article Type: Research Article

Abstract: In this study, we investigated whether vestibular evoked myogenic potentials (VEMPs) and dynamic posturography (DP) are useful in the evaluation of the vestibular function in patients affected by active monoaural Menière's disease (MD) treated with intratympanic gentamycin. Twelve subjects affected by monoaural MD were treated with weekly intratympanic injections of 0.5 ml of gentamycin at a concentration of 20 mg/ml. VEMPs were used to test saccular function, while postural control was analyzed by DP. The results obtained with these two techniques were compared with those obtained by using bithermal caloric test. The mean follow-up was 15.3 months (6–28 months). …Therapy resulted in complete absence of the caloric response in six subjects (50) and in caloric test-induced asymmetry in the remaining individuals, ranging from 83 to 27. At follow-up, eleven patients (91.6%) were free of vertigo, while one patient had two vertigo spells 9 months after treatment. Before treatment, VEMPs were present in the affected ear of eleven patients. After treatment VEMPs were absent in all the patients. At the end of follow-up, reappearance of VEMPs was observed in two patients, with no changes in latency values and amplitude ratio. DP demonstrated a reduction of the Composite Score (CS) one week after therapy, with a prevalent reduction of the vestibular component. After 6 months, there was an improvement of the CS and, in particular, of the vestibular component. The present study demonstrates that bithermal caloric test and VEMPs allow for the functional evaluation of both the horizontal semicircular canal and the sacculus, suggesting that these techniques might be used together to monitor the efficacy of intratympanic gentamycin therapy. In addition, our data indicate that DP might provide important information on compensation phenomena and show that intratympanic gentamycin can improve postural control in MD patients. Show more

Keywords: VEMPs, dynamic posturography, gentamycin, Menière's disease

DOI: 10.3233/VES-2005-15304

Citation: Journal of Vestibular Research, vol. 15, no. 3, pp. 161-168, 2005

Authors: Magliulo, Giuseppe | Gagliardi, Mario | Cuiuli, Giuseppe | Celebrini, Alessandra | Parrotto, Donato | D'Amico, Raffaello

Article Type: Research Article

Abstract: In our experience some patients subjected to stapedotomy presented vestibular symptoms characterized by brief episodes of vertigo that only lasted 10 to 20 seconds, accompanied by rapid paroxysmal nystagmus similar to that found in benign paroxysmal positional vertigo (BPPV). For this study, 141 otosclerotic patients were enroled and underwent stapedotomy following the Fisch and Dillier's technique. Twelve out (8.5%) of all the patients under study complained of post-operative vertigo and the physical examination of the positional nystagmus confirmed the presence of paroxymal positional vertigo. The percentage seems particularly high and does not agree with the data reported in literature. …The onset of the vestibular symptoms appeared between the 5th and 21st day after surgery. To our knowledge, this is the first prospective study existing in literature on the incidence of BPPV after surgery of the stapes. It must also be stressed that the patient should be informed beforehand during the consultation phase of the possibility of post-stapedotomy BPPV together with the other causes of post-operative vertigo. Show more

Keywords: Stapedotomy, otosclerosis, benign positional paroxysmal vertigo

DOI: 10.3233/VES-2005-15305

Citation: Journal of Vestibular Research, vol. 15, no. 3, pp. 169-172, 2005