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Background: A better understanding of how vestibular asymmetry manifests across tests is important due to its potential implications for balance dysfunction, motion sickness susceptibility, and adaptation to new environments. Objective: We report the results of multiple tests for vestibular asymmetry in 32 healthy participants. Methods: Asymmetry was measured using perceptual reports during unilateral centrifugation, oculomotor responses during visual alignment tasks, vestibulo-ocular reflex gain during head impulse tests, and body rotation during stepping tests. Results: A significant correlation was observed between asymmetries of subjective visual vertical and verbal report during unilateral centrifugation. Another significant correlation was observed between the asymmetries of ocular alignment, vestibulo-ocular reflex gain, and body rotation. Conclusions: These data suggest that there are underlying vestibular asymmetries in healthy individuals that are consistent across various vestibular challenges. In addition, these findings have value in guiding test selection during experimental design for assessing vestibular asymmetry in healthy adults. [ABSTRACT FROM AUTHOR]

Background: A better understanding of how vestibular asymmetry manifests across tests is important due to its potential implications for balance dysfunction, motion sickness susceptibility, and adaptation to new environments. Objective: We report the results of multiple tests for vestibular asymmetry in 32 healthy participants. Methods: Asymmetry was measured using perceptual reports during unilateral centrifugation, oculomotor responses during visual alignment tasks, vestibulo-ocular reflex gain during head impulse tests, and body rotation during stepping tests. Results: A significant correlation was observed between asymmetries of subjective visual vertical and verbal report during unilateral centrifugation. Another significant correlation was observed between the asymmetries of ocular alignment, vestibulo-ocular reflex gain, and body rotation. Conclusions: These data suggest that there are underlying vestibular asymmetries in healthy individuals that are consistent across various vestibular challenges. In addition, these findings have value in guiding test selection during experimental design for assessing vestibular asymmetry in healthy adults.

Vestibular disorders are frequent in the general population. The clinical experience suggests that emotional/mood states could have a physiopathologic role on them, however, there is not yet enough scientific evidence. Bipolar disorder is a neuropsychiatric disorder that shows cyclic changes of mood between depression, euphoria (mania) and euthymic (normal mood). To document the vestibular activity in different mood states, we registered rotary chair vestibular tests with electronystagmography during different affective phases in a woman and man with bipolar disorder. [ABSTRACT FROM AUTHOR]

Vestibular asymmetry is a common cause of dizziness in the elderly, for whom it precipitates the risk of falling. Previous studies have shown that those with vestibular asymmetry displayed an altered variability in double support time (DST) compared to controls. However, swing time (SwT) variability findings are conflicting. In this study, we investigated if vestibular asymmetry might be causally connected to increased DST variability. We studied a group of eight elderly fallers with wrist fractures across three months, during which time four of them regained vestibular symmetry while four others developed an asymmetry. We evaluated the variability of DST and SwT, both when the participants suffered from vestibular asymmetry and when they did not. On average, variability in DST was significantly greater by 2.38%CV (coefficient of variation) when participants scored positive for vestibular asymmetry compared to when not, t(5)=4.39, p=0.01, ξ=1.67. In contrast, SwT variability differed non-significantly by 0.44%CV when participants had tested positive versus negative for vestibular asymmetry, t(5)=-0.87, p=0.39, ξ=-0.29. As a possible rationale for our results, we propose that increased DST variability may be the result of a re-stabilization strategy. Further research on DST variability and its correlation to the duration of vestibular asymmetry is recommended. [ABSTRACT FROM AUTHOR]

Migraine is a neurologic disease, which often is associated with a unilateral headache. Vestibular abnormalities are common in migraine. Vestibular evoked myogenic potentials (VEMPs) assess otolith function in particular functional integrity of the saccule and the inferior vestibular nerve. We used VEMP to evaluate if the migraine headache can affect VEMP asymmetry parameters. A total of 25 patients with migraine (22 females and 3 males) who were diagnosed according to the criteria of IHS-1988 were enrolled in this cross-sectional study. Control group consisted of 26 healthy participants (18 female and 8 male), without neurotological symptoms and history of migraine. The short tone burst (95 dB nHL, 500 Hz) was presented to ears. VEMP was recorded with surface electromyography over the contracted ipsilateral sternocleidomastoid (SCM) muscle. Although current results showed that the amplitude ratio is greater in migraine patients than normal group, there was no statistical difference between two groups in mean asymmetry parameters of VEMP. Asymmetry measurements in vestibular evoked myogenic potentials probably are not indicators of unilateral deficient in saccular pathways of migraine patients.

Background: Fall-related fractures are an increasing problem for society. Dizziness is identified as a risk factor for falls and vestibular asymmetry is often found among patients with fall-related fractures. An option to prevent fall-related fractures may be to identify patients with vestibular asymmetry and to improve their balance and asymmetry by exercise. Objective: To examine whether vestibular rehabilitation improves vestibular function, balance and self-rated health among patients with fall-related wrist fractures. Methods: Sixty-eight persons (65 women) with fall-related wrist fractures, mean age 72 years (54-89) participated in this randomized controlled trial. The following tests and measurements were performed: head shake test to evaluate vestibular asymmetry as primary outcome measure, five clinical balance measures, a force plate to measure postural sway, a tuning fork to measure vibration and the EQ5D questionnaire to measure self-rated health. The intervention comprised group-based vestibular rehabilitation sessions conducted twice a week for 9 weeks. Results: Nystagmus occurred in the head shake test in 65% (44 of 68) of the patients, indicating vestibular asymmetry. More patients in the intervention group (6 of 21) than in the control group (0 of 23) changed from having nystagmus in the head shake test at baseline (indicating vestibular asymmetry) to not having nystagmus at follow-up, and more patients in the control group (3 of 9) than in the intervention group (0 of 3) changed from not having nystagmus at baseline to have nystagmus at follow-up (p < 0.00). No other changes occurred between the two groups between baseline and follow-up. At baseline, patients with vestibular asymmetry had more balance deficits and increased postural sway compared to patients without (p = 0.00-0.05). Conclusion: Group sessions with vestibular rehabilitation twice a week for 9 weeks affected the occurrence of vestibular asymmetry positively among patients having vestibular asymmetry. Patients with vestibular asymmetry had more balance deficits and increased postural sway than patients without vestibular asymmetry. Vestibular assessment is important, and, in patients with diagnosed vestibular asymmetry, vestibular rehabilitation may prove beneficial on balance and possibly reduce the risk of future falls. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

There is a broad consensus on the coupling of deteriorating gait and vestibular asymmetry, which has proved predictive of falls in the elderly. To date, research on this coupling remains inconclusive and has not focused specifically on fallers. In the present study, differences in gait variability were examined in a population of elderly females with fall-related wrist fractures, divided into samples with positive ( N = 28, 73 ± 9 years) and negative head-shaking tests ( N = 6, 67 ± 9 years). Swing, stance, and double support time variability were measured in preferred speed walking using GAITRite ® and statistically evaluated in multivariate analysis of covariance with age as covariate. Results showed overall greater gait variability for the positive nystagmus group ( p = 0.03) despite non-significant adjustment of the covariate ( p = 0.18). In post-hoc analysis, the effect on variability in double support time emerged as a significant and large contributor to this difference ( p = 0.009, η p 2 = 0.20 ). Conversely, the ability of swing and stance time variability to discriminate between groups was both non-significant and small ( p = 0.25, η p 2 = 0.04 and p = 0.34, η p 2 = 0.03 respectively). We believe that the increased variability might stem from a strategic use of double support to re-stabilize from balance perturbations during gait. To some extent, these results diverge from previous findings and need to be reassessed in future studies. [ABSTRACT FROM AUTHOR]

Migraine is a neurologic disease, which often is associated with a unilateral headache. Vestibular abnormalities are common in migraine. Vestibular evoked myogenic potentials (VEMPs) assess otolith function in particular functional integrity of the saccule and the inferior vestibular nerve. We used VEMP to evaluate if the migraine headache can affect VEMP asymmetry parameters. A total of 25 patients with migraine (22 females and 3 males) who were diagnosed according to the criteria of IHS-1988 were enrolled in this cross-sectional study. Control group consisted of 26 healthy participants (18 female and 8 male), without neurotological symptoms and history of migraine. The short tone burst (95 dB nHL, 500 Hz) was presented to ears. VEMP was recorded with surface electromyography over the contracted ipsilateral sternocleidomastoid (SCM) muscle. Although current results showed that the amplitude ratio is greater in migraine patients than normal group, there was no statistical difference between two groups in mean asymmetry parameters of VEMP. Asymmetry measurements in vestibular evoked myogenic potentials probably are not indicators of unilateral deficient in saccular pathways of migraine patients. [ABSTRACT FROM AUTHOR]

Background: Dizziness is the most common symptom in elderly patients and has been identified as a risk factor for falls. While BPPV is the most common cause of dizziness among elderly, multisensory deficits is the second, with visual, vestibular and proprioceptive reduced function. Asymmetric vestibular function is overrepresented in elderly persons with hip fractures and wrist fractures and can be accessed for screening. The objective was to study if vestibular asymmetry, vibration sense, balances performance, postural sway in quiet stance and self-perceived handicap because of dizziness could predict falls among elderly, dizzy patients. Methods: In this prospective study with one year observation period, 55 patients (41 women, 14 men), 65 to 90 years old (median 80, interquartile range 11) with multisensory dizziness were included. Vestibular function was screened with the headshake test and vibration sense was assessed using a tuning fork. Balance was assessed with four clinical measures and self-perceived dizziness handicap was assessed by the Dizziness Handicap Inventory. Postural sway was measured using a force plate. Results: Headshake test were pathologic in 24 patients, which substantially increased the risk of falls (OR 3.4). Thirteen of the 21 patients who had fallen (p = 0.03), and all 6 patients who sustained three falls or more (p = 0.04), had vestibular asymmetry. No other measure could predict the risk of falls (OR 0.55-1.71). Conclusion: Signs of vestibular asymmetry among elderly with multisensory dizziness could predict falls. Hence, it seems important to address fall-prevention programs to such a group of patients. Simple bedside tests of vestibular asymmetry might be a possibility to screen for one risk factor for falls among elderly. [ABSTRACT FROM AUTHOR]

Vestibular evoked myogenic potentials (VEMPs) were measured in 22 unilateral Menière patients with monaural and binaural stimulation with 250 and 500 Hz tone bursts. For all measurement situations significantly lower VEMP amplitudes were on average measured at the affected side compared to the unaffected side. Unilateral Menière patients have, in contrast to normal subjects, asymmetric VEMPs, indicating a permanently affected vestibular (most likely otolith) system at the side of hearing loss. The diagnostic value of VEMP amplitude asymmetry measurement in individual patients is low, because of the large overlap of the VEMP amplitude asymmetry range for unilateral Menière patients with that for normal subjects. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the composition of sway in adults and "healthy" elderly people and to evaluate the influence of vibration sensation and asymmetric vestibular function on the sway pattern. Ten adults with a mean age of 37.5 years and 40 healthy senior citizens with a mean age of 74.6 years living independently in the community were studied. Vibration-induced body sway was measured on a force platform. The sway was analyzed and separated into its high and low frequency components above and below 0.1 Hz, respectively. Additionally the elderly subjects were observed for the occurrence of spontaneous gaze and head shake-induced nystagmus using infrared charge-coupled device cameras and the vibration perception in the lower limbs was tested with a tuning fork. Vibration perception was the major determinant for postural control in the elderly subjects. Postural control among the elderly subjects with intact vibration perception in their lower limbs was very similar to that of the adults. The elderly subjects with impaired vibration sensation had increased high frequency sway compared to adults and the elderly subjects with intact sensation. Regardless of the strong influence of vibration sensation on postural control, asymmetric vestibular function might also be a contributing factor to postural instability in the elderly. Age per se had little effect on the outcome of the tests except that the elderly subjects had diminished ability to use visual cues to reduce postural sway. We concluded that sensory status in the lower limbs is of utmost importance for postural control in the elderly. Rehabilitation programs for senior citizens should therefore include exercises to preserve recognition of body motion by the lower limbs. Exercises to facilitate vestibular compensation could be useful for elderly people with vestibular dysfunction. [ABSTRACT FROM AUTHOR]

The static ocular counterrolling (OCR) of the four scientific crew members in the first Spacelab mission was measured during baseline-data-collection before and after the flight of SL-1. It was presumed that the modification of otolithic responses during spaceflight will be reflected in specific changes of the OCR-gain on the first days after recovery. The magnitude of OCR was determined analysing colour-transparencies of subjects right eyes that were produced in different positions of lateral body tilt. In general, one subject did not show any changes at all; three subjects exhibited a significant decrease of OCR-gain after exposure to weightlessness, whereby differences could be found between the responses for small and large angles of lateral body tilt. Moreover, asymmetrical effects of OCR-gain were found between body tilt to the left and tilt to the right side. Two subjects already demonstrated such an asymmetry before the flight with the higher gain on left-tilt (or right eye up), and three subjects exhibited left-right asymmetries after the spaceflight with the higher gain tilting to the right (or right eye down). A possible correlation between these vestibular asymmetries and space-sickness susceptibility is discussed. [ABSTRACT FROM AUTHOR]