Subjective Visual Vertical Test Research Articles

Otolith Dysfunction Is Prevalent in Refractory Benign Paroxysmal Positional Vertigo

Objectives: Determine the prevalence of otolith dysfunction in patients who have failed treatment for benign paroxysmal positional vertigo (BPPV). Methods: Case-control study of patients with BPPV who failed standard treatment and subsequently underwent vestibular testing and supervised vestibular rehabilitation. Interventions included videonystagmography, rotary chair, subjective visual vertical test (SVV), and cervical vestibular evoked myogenic potentials (VEMP). We compared the prevalence of abnormalities in tests of otolith dysfunction (SVV and VEMP) in patients who responded or failed vestibular rehabilitation. Results: In 2012, 46 of 251 patients with BPPV failed initial treatment with canalith repositioning maneuvers performed in the office; of these 46 patients, 28 patients had posterior semicircular canal BPPV and 18 cases had atypical presentations (multicanal BPPV, anterior canal BPPV, or signs of uncompensated unilateral peripheral vestibulopathy). Vestibular testing followed by customized vestibular rehabilitation was completed in 40 patients: 21 patients had resolution of their positional vertigo and nystagmus, and 19 patients did not respond to therapy. Abnormal otolith tests (SVV and/or VEMP) were more common in patients who failed therapy (Pearson Chi square, P = 0.002). Conversely, abnormalities of caloric testing did not predict response to therapy. Conclusions: Abnormalities of utricle and saccular function are prevalent in patients with refractory BPPV. This fact is important to take into account when designing rehabilitation strategies for BPPV patients who fail canalith repositioning maneuvers.

The association between impaired perception of verticality and cerebral white matter lesions in the elderly patients with orthostatic hypotension

The morbidity of orthostatic hypotension (OH) increases with aging and the elderly often complain of dizziness associated with OH, which is implicated in white matter lesions (WMLs) on MRI. However little is known how WMLs are contributed to the development of dizziness in elderly patients. We evaluated the involvement of cerebral WMLs in the vertical perception in the elderly with OH. This study consisted of 71 dizzy patients who underwent the examinations including the Schellong orthostatic test and subjective visual vertical (SVV) test. The male patients aged <65 years with OH (1.9 ± 0.9°) showed a significantly higher magnitude of variance of SVV, which reflects an impaired vertical perception, in comparison with the male patients aged <65 years without OH and the male patients aged < 65 years with OH (1.0 ± 0.4°, 0.9 ± 0.4°, p < 0.05). The variance of SVV significantly correlated with the volume of WMLs in both sides on MRI in the male, but not female patients (p < 0.01). Our results suggest that severe WMLs in the elderly with OH are involved in impaired perception of verticality, resulting in inducing subjective dizziness.

New perspectives on vestibular evoked myogenic potentials

Although the vestibular evoked myogenic potential (VEMP) measured from the cervical muscles (cVEMP, cervical VEMP) is well described and has documented clinical utility, its analogue recorded from the extraocular muscles (oVEMP, ocular VEMP) has been described only recently and is currently emerging as an additional test of otolith function. This review will, therefore, summarize recent developments in VEMP research with a focus on the oVEMP. Recent studies suggest that the oVEMP is produced by otolith afferents in the superior vestibular nerve division, whereas the cVEMP evoked by sound is thought to be an inferior vestibular nerve reflex. Correspondingly, the oVEMP correlates better with caloric and subjective visual vertical tests than sound-cVEMPs. cVEMPs are more complicated than often thought, as shown by the presence of crossed responses and conflicting results of recent vibration studies. Altered inner ear mechanics produced by the vestibular diseases superior semicircular canal dehiscence and Ménière's disease lead to changes in the preferred frequency of the oVEMP and cVEMP. The oVEMP provides complementary diagnostic information to the cVEMP and is likely to be a useful addition to the diagnostic test battery in neuro-otology.

Subjective visual vertical perception in patients with vestibular neuritis and sudden sensorineural hearing loss

To determine the subjective visual vertical (SVV) perception in patients with vestibular neuritis (VN) and sudden sensorineural hearing loss (SSHL) using the SVV test and other neuro-otological examinations, namely, the vestibular evoked myogenic potential (VEMP) and caloric tests, and to clarify which vestibular nerve function is associated with an SVV shift. We performed the SVV test in 36 VN patients and 80 SSHL patients. Thereafter, we investigated directional changes in the SVV in the VN and SSHL patients, and compared the results of the SVV test with those of the VEMP and caloric tests. Abnormal SVV (> 2° was found at a rate of 69.4% in the VN patients and 26.3% in the SSHL patients. In all except 1 VN patient, the SVV tilted to the lesion side. The rate of abnormal SVV was significantly higher in patients with complete canal paresis (CP) than in patients with partial CP. There was no significant relationship between the rates of abnormal SVV and VEMP. In the SSHL patients, neither the SVV nor the VEMP affected the hearing outcome and patients with abnormal VEMP tended to show abnormal SVV. VN patients showed a higher rate of abnormal SVV than SSHL patients. From the results, it is speculated that the superior vestibular nerve function mainly affects the SVV tilt, although the inferior vestibular nerve function may also have an effect.

Inferior vestibular neuritis

Vestibular neuritis (VN) mostly involves the superior portion of the vestibular nerve and labyrinth. This study aimed to describe the clinical features of VN involving the inferior vestibular labyrinth and its afferents only. Of the 703 patients with a diagnosis of VN or labyrinthitis at Seoul National University Bundang Hospital from 2004 to 2010, we retrospectively recruited 9 patients (6 women, age range 15-75) with a diagnosis of isolated inferior VN. Diagnosis of isolated inferior VN was based on torsional downbeating spontaneous nystagmus, abnormal head-impulse test (HIT) for the posterior semicircular canal (PC), and abnormal cervical vestibular-evoked myogenic potentials (VEMP) in the presence of normally functioning horizontal and anterior semicircular canals, as determined by normal HIT and bithermal caloric tests. All patients presented with acute vertigo with nausea, vomiting, and imbalance. Three patients also had tinnitus and hearing loss in the involved side. The rotation axis of torsional downbeating spontaneous nystagmus was best aligned with that of the involved PC. HIT was also positive only for the involved PC. Cervical VEMP was abnormal in seven patients, and ocular VEMP was normal in all four patients tested. Ocular torsion and subjective visual vertical tests were mostly within the normal range. Since isolated inferior VN lacks the typical findings of much more prevalent superior VN, it may be mistaken for a central vestibular disorder. Recognition of this rare disorder may help avoid unnecessary workups in patients with acute vestibulopathy.

A new method to analyze the subjective visual vertical in patients with bilateral vestibular dysfunction

OBJECTIVE:The aim of this study was to assess the subjective visual vertical in patients with bilateral vestibular dysfunction and to propose a new method to analyze subjective visual vertical data in these patients.METHODS:Static subjective visual vertical tests were performed in 40 subjects split into two groups. Group A consisted of 20 healthy volunteers, and Group B consisted of 20 patients with bilateral vestibular dysfunction. Each patient performed six measurements of the subjective visual vertical test, and the mean values were calculated and analyzed.RESULTS:Analyses of the numerical values of subjective visual vertical deviations (the conventional method of analysis) showed that the mean deviation was 0.326±1.13° in Group A and 0.301±1.87° in Group B. However, by analyzing the absolute values of the subjective visual vertical (the new method of analysis proposed), the mean deviation became 1.35±0.48° in Group A and 2.152±0.93° in Group B. The difference in subjective visual vertical deviations between groups was statistically significant (p<0.05) only when the absolute values and the range of deviations were considered.CONCLUSION:An analysis of the absolute values of the subjective visual vertical more accurately reflected the visual vertical misperception in patients with bilateral vestibular dysfunction.

Vestibular tests for rehabilitation: Applications and interpretation

Vestibular function testing plays a critical role in understanding balance disorders. These tests augment a well-performed history and physical exam in providing quantitative information regarding vestibular reflexes, central oculomotor function and postural control strategies. Video-oculography (VOG) and caloric stimulation play a major role in evaluation of both peripheral vestibular and central oculomotor disorders. Rotational chair testing and, more recently the Dynamic Visual Acuity Test (DVAT) and Gaze Stabilization Test (GST) provide information regarding higher frequency vestibulo-ocular reflex (VOR) function. Computerized Dynamic Posturography (CDP) explores the interaction of the vestibular, visual and proprioceptive systems for posture control. Finally, the cervical Vestibular Evoked Myogenic Potential (cVEMP) test and the Dynamic Subjective Visual Vertical (DSVV) test provide information regarding saccular and utricular function, respectively. New techniques and applications continue to provide knowledge both of disease processes and potential medical, surgical and rehabilitative interventions.

Normative Data for the Subjective Visual Vertical Test during Centrifugation

The otoliths act as gravito-inertial force sensors and contribute to the perception of spatial orientation. The perception of gravitational vertical can be assessed by asking a subject to adjust a light bar to the vertical. Prior to clinical use of the SVV (subjective visual vertical) test, normative data and test-retest reliability must be established. To obtain normative data and d etermine the test-retest reliability for the SVV test performed in static and dynamic test conditions. A descriptive design was used to obtain normative data. Twenty-four young adults with no history of neurological disease, middle-ear pathology, open or closed head injury, cervical injury, or audiovestibular disorder participated in the study. The SVV angle was measured in the static position and in three dynamic conditions: (1) on-axis clockwise (CW) rotation, (2) off-axis CW rotation of right ear, and (3) off-axis CW rotation of left ear. In young healthy individuals, the SVV was <2° for static and on-axis rotation, and shifted up to 11° during unilateral centrifugation. Test-retest reliability of the SVV was good for all test conditions. The normative data obtained in this study may be useful in identifying patients with chronic utricular dysfunction. We recommend the use of difference angles (on-axis SVV - off-axis SVV) to remove baseline bias and decrease the variability of the SVV angles for the off-axis conditions.

A New Spin on the Vestibular Test Battery: Dynamic Visual Acuity and Subjective Visual Vertical

A New Spin on the Vestibular Test Battery: Dynamic Visual Acuity and Subjective Visual Vertical

A clinical study of the subjective visual vertical during unilateral centrifugation and static tilt

Conclusion: The present study demonstrates that various response patterns of subjective visual vertical (SVV) can be identified during unilateral centrifugation (UC). It is proposed that these response types correspond to different degrees of compensation after disease. This is advantageous for monitoring the effect of rehabilitative measures and is useful in medico-legal issues. It also emerges that diagnosis of unilateral utricle function requires the determination not only of asymmetry ratio but also offset of SVV estimates. Objectives: A retrospective clinical study of SVV test results was performed to establish a classification and model of response types in patients with suspected otolith disorder. Methods: SVV measurements were made in 473 patients recruited from the dizziness clinic. A control group of healthy subjects (n = 43) was tested with the same protocol. Testing with bilateral stimulation (stationary upright, 15°, 30° tilt) and UC was performed. A mathematical model for the UC results was developed. Results: During UC testing 61% of the patients showed an asymmetric response indicating a unilateral utricular hypofunction/dysfunction. These results could be classified into three subgroups, indicating different degrees of compensation. The model parameters can be adapted to reflect this classification.

Subjective visual horizontal in peripheral unilateral vestibular dysfunction

To analyze the characteristics of subjective visual horizontal (SVH) and evaluate its clinical value for vestibular function in peripheral unilateral vestibular hypofunction (UVH). Eighty-five patients with UVH (study group) and 39 normal persons (control group) accepted vestibular function tests, including SVH, subjective visual vertical (SVV) and caloric test by video-nystagmography. The parameters of the angle of SVH and SVV, directional preponderance (DP) and unilateral weakness (UW) of caloric test were observed. The correlation between SVH/SVV, DP, UW and the course of disease were investigated respectively. SPSS 16.0 software was used to analyze the data. Reference range of SVH and SVV was from -2° to 2° in the control group. Among the 85 patients, 46 cases (54.1%) and 43 cases (50.6%) had the abnormal values of SVH and SVV respectively, with no statistical significance (χ(2) = 12.5, P = 0.481) by chi square test. Fifty-five cases (64.7%) with abnormal DP had no statistical significance when compared with SVH and SVV respectively (χ(2) values were 0.19 and 2.86, respectively, P value were 0.164, 0.067, respectively). In UVH, there were positive correlation between SVH, SVV and DP (r value was 0.939, 0.648, 0.658, all P < 0.05) respectively, but no correlation between UW and SVH or SVV (r value was 0.048, 0.085, all P > 0.05). According to the permutation and combination of the four parameters, positive or negative, three main groups could be defined [SVH(+)DP(+)UW(+), SVH(-)DP(+)UW(+), SVH(-)DP(-)UW(+); SVV(+)DP(+)UW(+), SVV(-)DP(+)UW(+), SVV(-)DP(-)UW(+)]. The course of disease in the three main groups was positively skewed distribution, with median of 5.0, 10.0, 15.0 d and 5.0, 9.5, 14.5 d respectively. By Kruskal-Wallis Test, χ(2) value were 8.80 and 6.26, respectively(P value were 0.012, 0.040, respectively), with statistical significance between the above three main groups. The SVH value can evaluate the function of the otolithic. The angle of SVH and SVV are changing in the course of disease, SVH and SVV can be used as a guidance of the vestibular compensation evaluation.

Binocular and monocular measurements of subjective visual vertical in vestibular loss

The objective of this study was to investigate the possibility to omit the time-consuming monocular vision measurement in the subjective visual vertical (SVV) test by demonstrating that there is no difference in the results between binocular and monocular measurements. Thirty-one patients with unilateral vestibular schwannoma and 20 normal subjects as controls were involved. Both binocular and monocular measurements of SVV were performed. The main outcome of this study was the difference in the results of SVV between binocular and monocular measurements. There were no significant differences in the tilts of the SVV between binocular and monocular measurements in vestibular schwannoma patients as well as in the controls. Abnormal tilts of SVV may be evaluated precisely only by binocular vision instead of monocular vision.

Subjective head vertical test reveals subtle head tilt in unilateral peripheral vestibular loss

Utricular dysfunction has been indirectly measured with subjective visual horizontal or vertical testing. Video-oculography equipment with integrated head position sensor allows direct evaluation of head tilt. The aim was to assess head tilt after peripheral vestibular lesion by recording tilting of the head after excluding visual cues (static test condition), and after three lateral head tilts to both sides [subjective head vertical (SHV)]. Thirty patients with unilateral, peripheral vestibular loss were measured in the acute state, and 3months later. Twenty healthy, age- and sex-matched subjects served as controls. Mean static tilt of 2.6±1.1° in patients with acute vestibular loss differed significantly from that of 1.0±0.4° in healthy subjects (p=0.004), and from that of 1.1±0.5° during the follow-up visit (p=0.008). The mean SHV of 3.4±0.7° in patients with acute vestibular loss was significantly more than that of 1.2±0.5° in controls (p<0.001). The SHV towards the lesion was 4.9±1.0° while returning from the lesion side and 2.0±1.0° while returning from the healthy side. The SHV was definitely abnormal in 60%, moderately abnormal in 20% and normal in 20% of the patients in acute state. Abnormal SHV persisted in only 20% of the patients indicating that recovery of the peripheral utricular function is occurring within months. In summary, head tilts slightly towards acute peripheral lesion, and this tilting is reinforced, when the head is actively moved on the lesion side.

Otolith function in patients with head trauma

This study evaluates the otolith function of patients with head trauma, postulating that otolith dysfunction is a cause of nonspecific dizziness after head trauma. We prospectively enrolled 28 patients referred within 3months after head trauma between March 2007 and December 2009. Pure tone audiometry, caloric testing and otolith function tests, including cervical vestibular evoked myogenic potential (cVEMP) and subjective visual vertical (SVV) tests, were performed on all patients. The relationship between otolith function and otologic symptoms was analyzed. Of the 28 patients with head trauma, 18 complained of dizziness and 12 experienced hearing loss, including 6 patients who complained of both. On defining otolith dysfunction as an abnormal cVEMP or abnormal SVV, a significant difference in otolith dysfunction existed between the groups with and without dizziness [72 (13/18) vs. 20% (2/10)]. In contrast, no significant difference in otolith dysfunction was detected between the abnormal and normal hearing groups. A significant number of the patients who complained of nonspecific dizziness after trauma had abnormal otolith function. After trauma, when patients complain of dizziness, vestibular function tests, including otolith function tests, should be considered.

Head tilt response: A complementary test to the Subjective Visual Vertical

This paper studies the phenomenon of the perceived vertical by means of a novel dynamic experiment. This task is inspired in the Subjective Visual Vertical test and can be regarded as complementary in terms of how the information involved varies (visual, otolithic and neck proprioception). The experiment consists in presenting a white stripe in a pair of virtual reality goggles and adjusting the roll angle of the head until the stripe is aligned with the gravitational vertical. The roll angle of the head is measured and recorded along each trial where the white stripe changes position four times, after a specific amount of time. The task was run on a group of 28 normal subjects and a small sample of 5 patients with vestibular hypofunction. Six parameters derived from Control Theory were extracted from the data to characterize the subject transient response. All parameters for normal subjects were found to be normally distributed. Experimental results show that discrimination is possible between normal subjects and patients using just one or two of the parameters studied.

Subsensory galvanic vestibular stimulation improves arterial pressure control upon head‐up tilt

Previously, we demonstrated that strong galvanic vestibular stimulation (GVS) obscured arterial pressure (AP) control upon posture transition from supine to 60 degree of head‐up tilt (HUT). In the present study, we hypothesized contrary that weak GVS might improve AP control during HUT according to a theory of stochastic resonance that noise enhances signal input and improves response. To verify an effect of the the weak GVS as noise for vestibular input, AP was measured continuously during HUT in 21 human subjects with and without GVS. GVS was applied with biphasic, random interval of square wave. The amplitude was changed from 0.1 mA to 0.6 mA randomly. Vestibular function was also evaluated with caloric test and subjective visual vertical test. Change in AP within 15 seconds upon HUT was correlated with degree of deviation in the vestibular function. 13 subjects decreased mean AP more than 5 mmHg upon HUT, but the decrease was not observed with simultaneous application of the GVS with the amplitude of 0.1 mA below the somatosensory threshold. Thus, orthostatic hypotension might be derived by dysfunction or imbalance of the vestibular system, and it might be able to improve using subsensory amplitude of GVS.

Role of subjective visual vertical test during eccentric rotation in the recovery phase of vestibular neuritis

Objectives By assessing unilateral utricular function at the acute and subacute stages, we sought to determine the ability of the subjective visual vertical (SVV) during eccentric rotation (dynamic SVV) in detecting latent abnormality of otolith dysfunction in unilateral vestibular neuritis. In addition, we compared the validity of the dynamic SVV with static SVV during the compensated recovery phase. Methods The static SVV and dynamic SVV of 19 patients diagnosed with acute unilateral vestibular neuritis and 31 patients diagnosed with the subacute stage of vestibular neuritis were determined in this study. First, the static SVV was measured in a dark booth without rotation. The dynamic SVV was measured during rotation with an eccentric displacement of the head to 3.5 cm from the vertical rotation axis during a constant velocity of 300°/s. Results In the acute stage of vestibular neuritis, the static SVV showed an increase in deviation to the side of the lesion compared to findings in normal subjects. In the subacute stage, it did not differ significantly from that of the normal subjects. The dynamic SVV, however, had a statistically significant increase in deviation to the side of the lesion compared to normal subjects in both the acute and subacute stages. Conclusion The dynamic SVV would be an effective method in detecting latent abnormality of otolith dysfunction in unilateral vestibular neuritis, compared to static SVV, especially compensated unilateral vestibular neuritis.

Suppression of the E-effect during the subjective visual and postural vertical test in healthy subjects

In this study the influence of head-on-body and starting roll position of laser bar and chair was investigated on the perception of, respectively, the visual and postural vertical. Sixty-one subjects, between 21 and 82 years, participated in this study. Results show that head-on-body and starting roll position of laser bar or chair have an influence on the outcome for both subjective visual vertical test (SVV) and subjective postural vertical test (SPV). When head-on-body and starting roll positions are combined the E-effect (deviation of the SVV-SPV opposite to the head-on-body tilt, when the roll tilt of the head is <60 degrees -70 degrees ) is observed in the anti-parallel condition, but is suppressed when starting roll position of laser bar or chair are relatively parallel to the length axis of the tilted head. It is suggested that in the assessment of the SVV, when the laser bar is aligned with the length axis of the head (parallel condition), the oblique effect occurs. In the assessment of the SPV, the E-effect is also suppressed in the parallel condition. It is hypothesized that in the parallel conditions, the gravitational reference frames of head and trunk are more aligned with each other providing similar information. In the anti-parallel conditions the reference frames of head and trunk are malaligned, providing contrary input making the estimation of the earth vertical more difficult. It seems that SVV and SPV measurements are influenced by head-on-body and starting roll positions and has to be taken into account in further studies.

Subjective visual vertical in patients with ear surgery

Conclusion: Dysequilibrium is one of the most important side effects of ear surgery. The subjective visual vertical can be used as a good indicator for the evaluation of otolithic function in patients with ear surgery. Objective: To investigate the influence of various types of ear surgery on the otolithic organs. Methods: Seventy-one patients underwent ear surgery. Subjective visual vertical (SVV) test was performed before and after ear surgery. We investigated the directional changes of SVV before and after the ear surgery. Results: The postoperative SVV of two patients who underwent translabyrinthine removal of vestibular schwannoma shifted toward the operated side, but following other surgical procedures the SVV tended to shift toward the healthy side.

Subjective Visual Vertical Test

The otoliths are vestibular organs that act as gravito-inertial force sensors and contribute to the perception of spatial orientation (earth verticality). The subjective visual vertical (SVV) is a psychophysical measure of the angle between perceptual vertical and true (gravitational) vertical. The otoliths contribute to the estimation of the physical vertical orientation, and individuals with normal vestibular function align the SVV within 2 degrees of true vertical (0 degrees). Impaired SVV has been documented in patients with unilateral vestibular disorders. Most research has focused on measuring the static SVV (head upright and stationary); however, more recently, methods have been developed to measure the SVV during stimulation of the otolith organs using on-axis yaw rotation (bilateral centrifugation), off-axis eccentric rotation (unilateral centrifugation), or head tilt for tests of bilateral or unilateral otolith function. The SVV test may be a useful method to assess utricular function in patients complaining of dizziness and/or imbalance and identify stages of recovery for otolith involvement.