Subjective Visual Vertical Deviation Research Articles

Effect of drilling on otolithic organ functions in mastoidectomy.

This study aimed to assess the effect of drilling during mastoidectomy on otolithic organ functions and development of benign paroxysmal positional vertigo using objective vestibular tests. The study included 45 adult patients diagnosed with chronic otitis media who underwent mastoidectomy with drilling. Pre-operative and post-operative assessments included tests for subjective visual vertical deviation and videonystagmography. Subjective visual vertical deviation was significantly higher in post-operative periods. On the third day, the subjective visual vertical deviation was at its maximum (1.4 degrees). Post-operatively, benign paroxysmal positional vertigo was detected in 14 patients (31.1 per cent). The most common type was ipsilateral lateral canal benign paroxysmal positional vertigo (57.1 per cent). The effect of drilling on otolithic organ functions in mastoidectomy seems to be temporary and subclinical; however, it potentially could be a risk factor for the development of benign paroxysmal positional vertigo.

Subjective visual vertical and postural control in patients following cochlear implantation.

Cochlear implantation (CI) is associated with changes in the histopathology of the inner ear and impairment of vestibular function. The objectives of our study were to evaluate patients for clinical manifestations of space perception and balance changes before surgery, compare them with asymptomatic subjects (controls), and report changes in posturography and subjective visual vertical (SVV) during the acute post-surgery period in patients. Examination was performed using static posturography and the SVV measurement. We examined 46 control subjects and 39 CI patients. Patients were examined pre-surgery (Pre), 2nd day (D2) and then 14th day (D14) after implantation. Baseline SVV was not different between patients and control group. There was a statistically significant difference (p < 0.001) in SVV between subgroups of right- and left-implanted patients at D2 (-1.36±3.02° and 2.71±2.36°, right and left side implanted respectively) but not Pre (0.76±1.07° and 0.31±1.82°) or D14 (0.72±1.83° and 1.29±1.60°). Baseline posturography parameters between patients and control group were statistically significantly different during stance on foam with eyes closed (p < 0.05). There was no statistically significant difference in posturography among Pre, D2 and D14. CI candidates have impaired postural control before surgery. CI surgery influences perception of subjective visual vertical in acute post-surgery period with SVV deviation contralateral to side of cochlear implantation, but not after two weeks.

Evaluation of subjective visual vertical and horizontal in patients with acoustic neuroma based on virtual reality

ObjectiveTo investigate potential differences in absolute deviation values of subjective visual vertical and horizontal between unilateral acoustic neuroma patients and healthy young adults under varying degrees of static head tilt, as well as the impact of proprioception on these values, with the aim of determining the effect of acoustic neuroma on gravity sensory pathway function in patients.MethodsWe recruited 22 patients diagnosed with unilateral acoustic neuroma and 25 healthy young adults and employed virtual reality technology to assess the absolute deviation values of subjective visual vertical (SVV) and subjective visual horizontal (SVH) under eight different static tilted head positions (Head centered (0° tilt), PdP, Head tilt 15°, 30°, 45° to the left and right), then compare and analyze intergroup differences.ResultsIn the Head-centered position, both SVV and SVH absolute deviated values were significantly higher in the AN group compared to healthy young adults. The AN group exhibited significantly higher absolute deviation values of SVV compared to the healthy group when tilting their head 30° left and right. Additionally, when tilting their heads to the right at 15° and 45° the AN group showed significant increases in SVH absolute deviated values compared to healthy adults. The SVV and SVH absolute deviation values of LAN and SAN groups did not reach statistical significance. The results of the SVV test for PDP position did not show any significant differences among all groups. However, the SVH test revealed that the absolute deviation values of the LAN group was significantly higher than that of healthy individuals.ConclusionOur study shows that the gravity sensing function of patients with unilateral acoustic neuroma is affected to different degrees, however, the degree of gravity sensing function damage of patients has little relationship with tumor size. When acoustic neuroma is larger than 2 cm, the effect of proprioception on patients’ SVH outcome is noteworthy. So, we should pay attention to the postoperative follow-up of patients with acoustic neuroma and the evaluation of vestibular rehabilitation effect. Meanwhile, for patients opting for conservative treatment, it is imperative to monitor the dynamic changes in vestibular function and seize timely opportunities for intervention.

Comparison of verticality perception and postural sway induced by double temple-mastoidal and bipolar binaural 20 Hz sinusoidal galvanic vestibular stimulation.

Galvanic vestibular stimulation (GVS) is believed to be one of the most valuable tools for studying the vestibular system. In our opinion, its combined effect on posture and perception needs to be examined more. The present study was conducted to investigate the effect of a 20 Hz sinusoidal Galvanic Vestibular Stimulation (sGVS) on the body sway and subjective visual vertical (SVV) deviation through two sets of electrode montages (bipolar binaural and double temple-mastoidal stimulation) during a three-stage experiment (baseline, threshold, and supra-threshold levels). While the individuals (32 normal individuals, 10 males, the mean age of 25.37±3.00 years) were standing on a posturography device and SVV goggles were put on, the parameters of the body sway and SVV deviation were measured simultaneously. Following the baseline stage (measuring without stimulation), the parameters were investigated during the threshold and supra-threshold stages (1 mA above the threshold) for 20 seconds. This was done separately for each electrode montage. Then, the results were compared between the three experimental stages and the two electrode montages. In both electrode montages, "the maximum amplitude" of the mediolateral (ML) and anteroposterior (AP) body sway decreased and increased in the threshold and supra-threshold stages, respectively, compared to the baseline stage. Comparison of the amount of "amplitude change" caused by each electrode montages showed that the double temple-mastoidal stimulation induced a significantly greater amplitude change in body sway during both threshold and supra-threshold stages (relative to the baseline stage).The absolute mean values of the SVV deviation were significantly different between the baseline and supra-threshold levels in both electrode montages. The SVV deviation in double temple-mastoidal stimulation was a bit greater than that in the bipolar binaural stimulation. Double temple-mastoidal stimulation has induced greater amount of change in the body sway and SVV deviation. This may be due to the more effective stimulation of the otoliths than semicircular canals.

Subjective visual vertical deviation in patients with early-onset direction-changing horizontal positional nystagmus

ObjectiveOtolithic dysfunction is investigated in cases of direction-changing horizontal positional nystagmus (DCHPN) due to peripheral vestibular disorders. MethodsThe static-subjective visual vertical (S-SVV) was conducted in DCHPN cases within 48 h after onset. ResultsThe absolute values of S-SVV deviations of patients with Light cupula and lateral canal-benign paroxysmal positional vertigo-cupulolithiasis (L-BPPV-Cup) were significantly different from those of healthy subjects (p < 0.001, p < 0.05, respectively), whereas there were no significant differences in those of patients with L-BPPV-Canalolithiasis-geotropic (L-BPPV-Can-g) or L-BPPV-Can-ageotropic (L-BPPV-Can-a) versus healthy subjects. Significant differences were found in S-SVV (+: deviation to the affected side, −: deviation to the unaffected side) between patients with Light cupula and those with L-BPPV-Can-g, L-BPPV-Can-a and L-BPPV-Cup (p < 0.01, p < 0.05, and p < 0.001, respectively), as well as between those with L-BPPV-Can-g and L-BPPV-Cup (p < 0.01). The S-SVV in patients with Light cupula, L-BPPV-Can-g, and L-BPPV-Can-a deviated more to the affected side, whereas that in patients with L-BPPV-Cup deviated more to the unaffected side. ConclusionMild otolithic dysfunctions were found in patients with DCHPN due to the presence of peripheral vestibular disorders within 48 h after onset. The extent of otolithic (utricular) disorders in patients with DCHPN is estimated in decreasing order as follows: Light cupula > L-BPPV-Cup > L-BPPV-Can-g and L-BPPV-Can-a. Many patients with L-BPPV-Cup likely suffer from disorders of the pars externa of the utricular macula, whereas many patients with L-BPPV-Can-g likely suffer from disorders of the pars interna of the utricular macula. L-BPPV-Can-a and L-BPPV-Can-g must be induced by a common mild utricular disorder.

Influence of tonotopic cochlear stimulation on subjective visual vertical - a pilot study.

This pilot study aimed at evaluating the effect of tonotopic (basal) stimulation on the Subjective Visual Vertical (SVV) in patients unilaterally treated with a Cochlear Implant (CI). Ten adult subjects with severe to profound sensorineural hearing loss, who were implanted with a CI from Advanced Bionics (AB, Stäfa, Switzerland), model HiRes 90KTM or newer, were included in this prospective pilot study between September and December 2020. A specific CI processor (Naída CI Q90) was used to generate five different stimulation modes: simulation of either basal, medial, or apical electrodes, all electrodes on and all electrodes off. The examination of the verticality was carried out by means of SVV goggles both in the upright body position (head position 0 degrees) and with the head tilted sideways (-30°, -15°, +15°, +30°). In each stimulation mode, there was a significant difference (p < 0.05) in SVV between the straight head orientation and the tilted head position. There were, however, no significant differences between the five CI settings in any given head position (p > 0.05). No significant differences could be found regarding the direction of SVV deviation relative to the operated ear (p > 0.05). SVV could not be influenced by tonotopic CI stimulation. Different stimulation settings, patterns and intensity other than the auditory strategy may have to be developed to provide an adequate stimulus to the otolith organs.

Visual and haptic verticality misperception and trunk control within 72 h after stroke

IntroductionStroke patients often exhibit an altered perception of verticality, but there are no studies evaluating verticality perception in the first 72 h after stroke and its relationship with trunk control. Therefore, this study aimed to analyze visual and haptic verticality in the acute phase of stroke. MethodsThis was a cross-sectional study conducted with two groups: (a) 13 individuals with stroke and (b) 12 healthy participants. We assessed verticality via the subjective visual vertical (SVV) and the subjective haptic vertical (SHV); and we measured trunk control with the Trunk Impairment Scale (TIS). We performed t-tests to compare the SVV and SHV between groups. Pearson correlation was performed between verticality tests with National Institutes of Health Stroke Scale (NIHSS) and the TIS. ResultsParticipants with recent stroke presented higher true and absolute SVV deviation values than did the control group. There was significant negative correlation between absolute (r = −0.57; p = 0.02) and true SVV (r = −0.54; p = 0.01) with TIS scores There was also significant positive correlation between absolute (r = 0.63; p = 0.009) and true SVV (r = 0.61; p = 0.003) with NIHSS. A significant negative correlation between NIHSS and TIS scores also was found (r = −0.80; p = 0.005). ConclusionIndividuals with acute stroke presented larger variability in their perceptions of visual verticality than did healthy controls, and verticality perceptions were positively correlated with trunk impairment.

Independent Measures of Utricular Function: Ocular Vestibular Evoked Myogenic Potentials Do Not Correlate With Subjective Visual Vertical or Fundus Photographic Binocular Cyclorotation.

Ocular vestibular evoked myogenic potentials (oVEMPs), subjective visual vertical (SVV), and fundus photographically measured binocular cyclorotation (BCR) are diagnostic tests to assess utricular function in patients with vertigo or dizziness. In 138 patients with chronic vertigo or dizziness, we asked whether the asymmetry ratio of oVEMP (normal, right side pathological, left side pathological) could predict the SVV deviation (normal, rightward deviation, leftward deviation) or BCR (normal, cyclorotation to the right, cyclorotation to the left). There was no correlation between oVEMP and SVV and between oVEMP and BCR, while SVV and BCR correlated highly. Although both oVEMP and SVV measure aspects of utricular function, our findings demonstrate that oVEMP and SVV are not redundant and may reflect different utricular pathologies. The role of fundus photographic BCR may be relegated to only confirm unclear SVV results in vestibular diagnostic workup.

Test-retest reliability of subjective visual vertical measurements with lateral head tilt in virtual reality goggles

Objective:The objective is to investigate the test-retest reliability of subjective visual vertical (SVV) in the upright position and with lateral head tilts through a computerized SVV measuring system using virtual reality (VR) goggles.Materials and Methods:Thirty healthy controls underwent SVV test in upright position, with the head tilted to the right 30°, and with the head tilted to the left 30°. Subjects wore SVV VR goggles, which contained a gyroscope for monitoring the angle of head tilt. Each subject completed 10 adjustments in each head position. The mean value of SVV deviations and SVV imprecision (the intra-individual variability of SVV deviations from the 10 adjustments) were recorded and compared across different head positions. The participants then repeated the same SVV protocol at least 1 week later. The test-retest reliability of SVV deviation and SVV imprecision were analyzed.Results:The SVV deviation (mean ± standard deviation) was 0.22° ± 1.56° in upright position, −9.64° ± 5.91° in right head tilt, and 7.20° ± 6.36° in left head tilt. The test-retest reliability of SVV deviation was excellent in upright position (intra-class correlation coefficient [ICC] = 0.77, P < 0.001), right head tilt (ICC = 0.83, P < 0.001) and left head tilt (ICC = 0.84, P < 0.001). The SVV values from the 10 adjustments made during right and left head tilts were less precise than when measured at upright (P < 0.001). The test-retest reliability of SVV imprecision was poor at upright (ICC = 0.21, P = 0.26) but fair-to-good in right head tilt (ICC = 0.72, P < 0.001) and left head tilt (ICC = 0.44, P = 0.04).Conclusion:The test-retest reliability of SVV deviation during lateral head tilts via VR goggles is excellent, which supports further research into the diagnostic value of head-tilt SVV in various vestibular disorders. In addition, the degree of SVV imprecision during head tilt has fair-to-good test-retest reliability, which suggests SVV imprecision may have clinical applicability.

Acute binocular diplopia: peripheral or central?

ObjectivesAcute diplopia is a diagnostic challenge for clinicians, in particular in the emergency department. The most common cause of acute diplopia are ocular motor nerve palsies (OMP). In this prospective study, we focused on identifying the most crucial signs and symptoms for differentiating between peripheral and central OMP.MethodsWe prospectively evaluated 56 non-consecutive patients who presented at our emergency department with acute binocular diplopia (≤ 10 days). The patient history was taken using a standardized questionnaire and patients underwent a neurological, neuro-ophthalmological and neuro-otological examination, including measurement of the subjective visual vertical (SVV), Harms tangent screen test, and cranial MRI.ResultsForty-six out of 56 patients were diagnosed with an ocular motor cranial nerve palsy (OMP), 21 of peripheral and 23 of central origin; in two patients, the etiology remained unknown. The following features were different in peripheral and central OMP: (1) the presence of vertigo/dizziness was more frequent in central (43.5%) than in peripheral (9.5%) OMP. (2) Central ocular motor signs, such as saccadic smooth pursuit, additional internuclear ophthalmoplegia, skew deviation, and saccade palsies, were also found more frequently in the central than in the peripheral group (86.7% vs. 33.3%). (3) Further, a pathological SVV deviation by monocular testing of the non-affected eye was also more common in central (77.3%) than in peripheral OMP (38.9%). The presence of all three factors has a positive predictive value of 100% (CI 50–100%) for the presence of a central lesion.ConclusionsIn acute diplopia due to central OMP, the most important accompanying symptom is vertigo/dizziness, and the most important clinical signs are central ocular motor disorders (which require examination of the non-paretic eye) and an SVV deviation in the non-paretic eye.

Relations between gait characteristics and subjective visual vertical results in young adults.

Subjective visual vertical (SVV) deviation can indicate impairments of motion perception and spatial orientation in individuals with vestibular disorders. This study investigated the influence of SVV on tandem gait ability by assessing differences between temporal, spatial, and kinematic characteristics in young adults. We recruited sixteen young adults with increased SVV and 17 age-matched control subjects. All subjects recruited for this study were with no history of neurological or musculoskeletal diseases. Knee and hip-joint kinematic data, spatio-temporal parameters, and gait variability were measured during tandem gait. Stride time variability and stride velocity variability were significantly greater in the experimental group than the control group (p < 0.05). In addition, a significant correlation was observed between stride time variability and SVV results (r = 0.345, p < 0.05). However, hip and knee joint angles were non-significantly different in the experimental and control groups (p > 0.05) and spatio-temporal parameters were similar between the two groups (p > 0.05). Stride time variability and stride velocity variability during tandem gait were significantly different in the experimental and control groups. We presume that increased SVV deviation is related to greater gait variability during tandem gait.

Isolated Dizziness with Subjective Visual Vertical Tilt in Acute Infarction of Temporo-Parieto-Occipital Junction

Pathological tilts of the subjective visual vertical (SVV) in the roll plane are most sensitive and frequent clinical vestibular signs of unilateral lesions extending from the labyrinths via the brainstem and thalamus to the cortex. SVV deviations in cortical lesion are usually related with the parietoinsular vestibular cortex or superior temporal gyrus. We report isolated dizziness with contralesional SVV tilt with a focal infarction restricted to the right temporo-parieto-occipital junction. Key Words: Visual perception, Stroke, Dizziness

Relationship between subjective visual vertical and balance in individuals with multiple sclerosis.

Subjective visual vertical (SVV) deviations have been correlated to abnormal cerebellar function in individuals diagnosed with multiple sclerosis (MS). It has been shown that individuals with MS have increased incidence of SVV abnormalities, yet this is not routinely tested in this population during physical therapy evaluation. This study aims to determine if there is a relationship between SVV and balance performance in people with MS who have cerebellar involvement. We hypothesize that individuals with greater SVV deviations will have worse balance performance. Fifteen females and five males (mean age 54.5years [±7.03 SD]) with the diagnosis of MS and cerebellar involvement participated. Computerized SVV testing included rod and rod-and-frame conditions. None of the balance outcomes were correlated with the rod-only condition. Because there was a difference in magnitude of results within the rod-and-frame condition, based on whether the frame was rotated clockwise (CW) or counterclockwise (CCW), they were analysed independently. For all six of the balance outcomes, there was a statistically significant moderate correlation with SVV deviations when the frame was tilted CCW: Barthel Index (r=-0.47, p=0.018), Berg Balance Score (r=-0.59, p=0.003), gait velocity (r=-0.52, p=0.010), International Cooperative Ataxia Rating Scale (r=0.56, p=0.006), Scale for the Assessment and Rating of Ataxia (r=0.62, p=0.002), and Timed Up and Go (r=0.58, p=0.003). Interestingly, the Barthel Index was the only outcome that had statistical significance with a moderate correlation (r=-0.66, p=0.001) when the frame was rotated CW. In this cohort, greater deviations during the rod-and-frame condition of SVV testing correlated with worse functional outcomes, especially when the frame was tilted CCW. Individuals with MS who demonstrate decreased balance performance may rely more heavily on visual backgrounds. Implementation of SVV assessment for individuals with MS may provide clinicians with valuable information to identify clinical interventions.

Manipulation of Human Verticality Using High-Definition Transcranial Direct Current Stimulation.

Background: Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it is possible to manipulate subjective visual vertical (SVV) and postural control. We also demonstrated that high-definition tDCS (HD-tDCS) can achieve substantially greater cortical stimulation focality than conventional tDCS. However, it is critical to establish dose-response effects using well-defined protocols with relevance to clinically meaningful applications.Objective: To conduct three pilot studies investigating polarity and intensity-dependent effects of HD-tDCS over the right TPJ on behavioral and physiological outcome measures in healthy subjects. We additionally aimed to establish the feasibility, safety, and tolerability of this stimulation protocol.Methods: We designed three separate randomized, double-blind, crossover phase I clinical trials in different cohorts of healthy adults using the same stimulation protocol. The primary outcome measure for trial 1 was SVV; trial 2, weight-bearing asymmetry (WBA); and trial 3, electroencephalography power spectral density (EEG-PSD). The HD-tDCS montage comprised a single central, and 3 surround electrodes (HD-tDCS3x1) over the right TPJ. For each study, we tested 3x2 min HD-tDCS3x1 at 1, 2 and 3 mA; with anode center, cathode center, or sham stimulation, in random order across days.Results: We found significant SVV deviation relative to baseline, specific to the cathode center condition, with consistent direction and increasing with stimulation intensity. We further showed significant WBA with direction governed by stimulation polarity (cathode center, left asymmetry; anode center, right asymmetry). EEG-PSD in the gamma band was significantly increased at 3 mA under the cathode.Conclusions: The present series of studies provide converging evidence for focal neuromodulation that can modify physiology and have behavioral consequences with clinical potential.

Plantar cutaneous afferents influence the perception of Subjective Visual Vertical in quiet stance

The estimation of Subjective Visual Vertical (SVV) involves the allocentric, gravitational and egocentric references, which are built by visual, vestibular and somatosensory afferents. Our goals were to assess the influence of plantar cutaneous afferents on the perception of SVV, and to see if there is a difference according to the efficiency of plantar cutaneous afferents. We recruited 48 young and healthy subjects and assessed their SVV and postural performances in quiet stance with a force platform, at 40 or 200 cm, in four ground conditions: on firm ground, on foam, with a bilateral, or with a unilateral 3 mm arch support. We also assessed the efficiency of our subjects’ plantar afferents with the plantar quotient method and divided them in two groups: subjects with a normal use of plantar afferents and subjects with Plantar Exteroceptive Inefficiency (PEI). The results showed significant decreases in the counter clockwise SVV deviation only with the unilateral arch support, at near distance, and among the typically behaving subjects. We conclude that asymmetric foot cutaneous afferents are able to bias the egocentric vertical reference and hence influence the perception of SVV. This influence disappears among subjects with PEI, probably because of a distortion of the plantar signal.

Can pre-screening vestibulocerebellar involvement followed by targeted training improve the outcomes of balance in cerebellar ataxia?

Balance problems and frequent falls are common among clients with Cerebellar Ataxia (CA). CA is not a disease by itself but a collection of symptoms due to the involvement of cerebellum or its pathways. Presently the treatment for balance problems for CA is not standardized. Interventions available to improve balance are not specific to symptoms presentation. Functionally the cerebellum is divided into the spinocerebellum, vestibulocerebellum and corticocerebellum. Each functional zone has a distinct role in maintaining balance. Therefore, the presentation of symptoms will vary according to the functional zone involved. Pre-screening clients with CA for identifying the part of cerebellum involved will facilitate clinicians to provide tailor-made interventions for targeting specific symptoms for better outcomes. Pre-screening clients with CA according to the part of cerebellum involved is not in practice and our study will introduce this concept. We hypothesize pre-screening participants with spinocerebellar ataxia (SCA) for the involvement vestibulocerebellum followed by prescribing vestibulocerebellum targeted exercises will have better outcomes when compared to conventional balance training. We plan to conduct two related studies. In study 1 we will screen participants with CA for the involvement of vestibulocerebellum. In study 2, the effects of vestibulocerebellum targeted balance exercises on balance will be studied. We will assess the Subjective Visual Vertical (SVV) deviation and postural sway pattern to screen participants into people with and without vestibulocerebellar involvement. SVV deviation will be estimated using a computerized Subjective Visual Vertical (cSVV) device and postural sway pattern will be assessed using the limits of stability program of the Bertec© Balance system. The obtained SVV deviation scores will be used to derive at cut-off scores to discriminate clients with and without vestibulocerebellar involvement. The second study will test the treatment effects of conventional exercises plus vestibulocerebellum targeted exercises to improve balance by correcting SVV deviation in SCA with vestibulocerebellar involvement. The intervention is planned as 12 one-to-one sessions over three months period. Participants will be reassessed after the intervention and 3 months post-intervention. The findings of this cutting-edge research are extremely important to the clinicians, researchers and clients with SCA.

Pisa Syndrome in Parkinson\u2019s Disease: Pathogenic Roles of Verticality Perception Deficits

We elucidated whether verticality misperception is associated with the generation of Pisa syndrome (PS) in patients with Parkinson’s disease (PD). To examine the heterogenous influence of verticality perception, we also identified the characteristics distinguishing between PD patients with PS who tilted toward the deviation of perceived verticality and those who did not. Subjective visual vertical (SVV) testing was performed in 54 PD patients with PS and 36 without PS to measure verticality perception. Other potential risk factors for PS were evaluated by assessing the asymmetry of motor symptoms, EMG activities of paraspinal muscles, bithermal caloric tests, back pain history, and Berg Balance Scale. Abnormal SVV (odds ratio (OR) 18.40, p = 0.006), postural imbalance (OR 0.71, p = 0.046), and unilateral EMG hyperactivity of paraspinal muscles (OR 39.62, p = 0.027) were independent contributors to PS. In subgroup analysis, EMG hyperactivity of paraspinal muscles contralateral to the leaning side and postural imbalance were associated with PD patients with PS who tilted toward the SVV deviation, whereas back pain was more frequent in those who did not. Verticality misperception is a potent risk factor for PS in PD and contributes differentially to PS depending on the congruence between its direction and PS direction, indicating distinct pathogenic roles.

Subjective visual vertical in different peripheral vestibular disorders

Context: The subjective visual vertical (SVV) is considered to be a functional measure of otolith-mediated verticality perception. Aims: This study aims to detect the normative data of SVV and to analyze SVV changes in peripheral vestibular disorders. Settings and Design: This was a observational, cross-sectional study. Subjects and Methods: Forty-five adult patients with chronic peripheral vestibular disorders endolymphatic hydrops, vestibular neuritis, and benign paroxysmal positional vertigo and 20 normal individuals were included in this study. After full history taken, SVV deviations and caloric tests were completed. Statistical Analysis Used: Independent Student's t-test for independent sample when comparing 2 groups. ANOVAs test compared three or more means for statistical significance. Tukey's test compared the means of every treatment to the means of every other treatment. Chi-square test was performed. Normal cutoff value was calculated by mean +2 standard deviation (SD) as high limit and mean −2 SD as low limit. Results: The normative data of SVV ranged from −0.2° to 1.26° in clockwise direction and from −0.04° to 0.95° in the counterclockwise direction. SVV in counterclockwise direction were significantly deviated among the three groups of Peripheral vestibular disorder (PVD) patients when compared with controls. It revealed a significant deviation in counterclockwise tilt between left diseased ears in relation to controls. Conclusions: Normal adults displayed a narrow range of one-degree SVV deviation (1.06° and 0.91°) in clockwise and counterclockwise direction, respectively. The three vestibular disorders significantly deviate the SVV in counterclockwise direction compared to control with no gender difference. SVV test alone cannot differentiate between different PVD.

Disturbance of verticality perception and postural dysfunction in Parkinson's disease.

Verticality perception is known to be abnormal in Parkinson's disease (PD), but in which stage respective dysfunctions arise and how they relate to postural disorders remains to be settled. These issues were studied with respect to different dimensions of the subjective visual vertical (SVV) in relation to clinical parameters of postural control. All participants had to orientate a luminous line at random planar orientations to a strictly vertical position using an automated operator system. The SVV was analyzed in 58 PD patients and 28 control subjects with respect to (i) the angle between true and subjective vertical (deviation) and (ii) the variability of this across five measurements (variability). Results were referred to the subjective upright head position (SUH), the disease stage, and clinical gait/balance features assessed by the MDS-UPDRS and the Tinetti test. Parkinson's disease patients had significantly higher SVV deviation and variability than controls. With respect to disease stage, deviation developed before abnormal variability. SVV variability was associated with poor balance and gait performance, as well as postural instability. Deficits in SUH and SVV deviation were correlated and mostly unidirectional, but did not correspond to the side of motor symptom dominance. Visual verticality perception in PD is deviated already in early stages, conceivably as a relatively static internal misrepresentation of object orientation. Variability about verticality perception emerges in more advanced stages and is associated with postural and balance abnormalities.

EPV 20. Vascular encephalopathy is a major risk factor for poor vestibular compensation

Background and aim Acute unilateral vestibular loss leads to vertigo sensation, nystagmus and postural imbalance. As a rule, a behavioral recovery of the signs and symptoms follows over days to months due to central vestibular compensation (VC). The present study aimed to investigate the influence of cerebral vascular lesions on VC by following a large cohort of patients after vestibular neuritis. Methods 235 patients (mean age: 54.2 ± 15.2, 53.4% men) with the clinical picture or history of an acute unilateral vestibulopathy, who were seen at the Department of Neurology and the German Center for Vertigo and Balance Disorders over the last 10 years, were included in the study. All patients underwent a detailed neuro-ophthalmological and neurological examination, including measures of the subjective visual vertical (SVV), ocular torsion (OT), head impulse test (HIT), provocation nystagmus (PN), visual acuity and postural control and were followed along their course of VC (mean number of visits 3.5 ± 1.2, mean time of follow-up 217 ± 625 days). In all patients a cranial MRI was available at onset of vestibular failure. The MRI was assessed by a two senior neuro-radiologist. Extent of supra- and infratentorial vascular white matter lesions was classified by the ARWMC scale (0–3 points). Strategic lesions in the vestibular network (medulla, vestibulocerebellum, thalamus) were registered separately. Patients were indicated as poorly compensated, if deviation of SVV (>2.5°), PN and postural asymmetry persisted for longer than 3 months after vestibular failure. Results 13.3% of patients were classified as poorly compensated at 3 months (PN: 55%, SVV deviation: 36%, postural asymmetry: 22%), 12.8% at 6 months and 10.6% at 12 months after acute unilateral vestibulopathy. These patients had significantly higher ARWMC scales as compared to patients with regular VC ( p Conclusions About 10% of patients have an impeded course of VC after acute unilateral vestibulopathy. Supratentorial vascular encephalopathy is a major risk factor for poor VC and should be considered to guide the intensity of physical treatment following acute unilateral vestibulopathy.