Effect of age on virtual reality-assisted subjective visual vertical and subjective visual horizontal at different head-tilt angles

Abstract Objective: Subjective Visual Vertical (SVV) and Subjective Visual Horizontal (SVH) values may reflect bilateral utricle asymmetry. Bilateral utricle static tension balance can be used to evaluate bilateral otolith lesions and otolith-related central neuropathy. Few studies have examined Virtual Reality (VR)-assisted SVV and SVH values at various head-tilt angles across age groups. The present study aimed to determine the effects of age on VR-assisted SVV and SVH values at different head-tilt angles. Methods: We divided 180 healthy subjects into 6 age groups (n = 30 in each group). VR-assisted SVV and SVH measurements were performed at 9 head-tilt angles (head held vertically, 0°; head tilted 30°, 45°, 60°, and 90° to the left/right) in the roll plane. Results: SVV and SVH values significantly differed with head-tilt angle (p < 0.05). No significant difference was detected in the SVH and SVV values between different age groups (p = 0.632 and p = 0.810, respectively), and no interaction between the age group and the head-tilt angle was found for the SVH and SVV values (p = 0.670 and p = 0.084, respectively). Conclusion: These results suggest that age may have little effect on VR-assisted SVV and SVH at different head-tilt angles. Therefore, VR-assisted SVV and SVH can be evaluated as an effective, fast, and simple way to evaluate utricle function. Level of Evidence: Level 4.

Evaluation of subjective vertical perception among stroke patients: a systematic review / Avaliação da percepção vertical subjetiva em pacientes com acidente vascular cerebral: uma revisão sistemática

Abstract Background: Verticality misperception is relatively common among patients after stroke, and it may be evaluated in terms of (a) subjective visual vertical (SVV), (b) subjective haptic vertical (SHV) and (c) subjective postural vertical (SPV). To better understand these assessment methods, we conducted a systematic review of the methodological characteristics of different protocols for evaluating SVV, SHV and SPV among individuals after stroke. Objective: To standardize the methodological characteristics of protocols for evaluating verticality perception after stroke. Methods: We searched the following databases: PUBMED, regional BVS portal (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index and LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Cochrane Library and PEDro. Two review authors independently used the QUADAS method (Quality Assessment of Diagnostic Accuracy Studies) and extracted data. Results: We included 21 studies in the review: most (80.9%) used SVV, eight (38.1%) used SPV and four (19.0%) used SHV. We observed high variability in assessments of verticality perception, due to patient positions, devices used, numbers of repetitions and angle of inclination for starting the tests. Conclusion: This systematic review was one of the first to explore all the methods of assessing verticality perception after stroke, and it provides crucial information on how to perform the tests, in order to guide future researchers/clinicians.

Resumo Antecedentes: A percepção errônea da verticalidade é relativamente comum em pacientes após Acidente Vascular Cerebral (AVC) e pode ser avaliada pelas: (a) vertical visual subjetiva (SVV), (b) vertical háptica subjetiva (SVH) e (c) vertical postural subjetiva (SPV). Para melhor compreender esses métodos de avaliação, realizamos uma revisão sistemática das características metodológicas de diferentes protocolos para avaliações de SVV, SHV e SVP em indivíduos após AVC. Objetivo: Padronizar as características metodológicas de protocolos de avaliação da verticalidade após AVC. Métodos: Foi realizada busca nas bases de dados PUBMED, Portal Regional da BVS (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index, LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Biblioteca Cochrane e PEDro. Dois revisores avaliaram independentemente o QUADAS (Avaliação da Qualidade dos Estudos de Precisão de Diagnóstico) e extraíram os resultados. Resultados: Foram incluídos 21 estudos: a maioria (80,9%) utilizando a SVV, oito (38,1%) a SPV e quatro (19,0%) a SHV. Observou-se grande variabilidade na avaliação da verticalidade, devido às posições dos pacientes, dispositivos utilizados, número de repetições e ângulo de inclinação para iniciar os testes. Conclusão: Esta revisão sistemática é uma das primeiras a explorar todos os métodos de avaliação da verticalidade após o AVC e fornece informações cruciais sobre como realizar os testes para orientar os futuros pesquisadores e clínicos.

A pilot study of the unilateral centrifugation subjective visual vertical in healthy young people / 中华耳鼻咽喉头颈外科杂志

Objective@#To evaluate the data of unilateral centrifugation subjective visual vertical (UC-SVV) in healthy young people.To study the function of utricle.@*Methods@#Between Decem ber 2017 and May 2018, thirty-two healthy young volunteers were tested by static subjective visual vertical(SVV) and low velocity UC-SVV with Neuro Kinetics Inc I-portal 6.0 Video nystagmus recording system and NOTC rotating chair system.The static SVV preset angle were -15.00°, 15.00°, -20.00°, 20.00°, -12.00° and 12.00° respectively.UC-SVV test parameters: rotating chair′s peak speed was 60°/s.The shift time from the middle to the lateral position was 30 s and the displacement was 3.85 cm.The chair rotated at 60 s at left, right and middle positions.Subjects underwent SVV during this period.SPSS 17.0 software was used to analyze the data.@*Results@#The mean and standard deviation of static SVV deviation in 32 volunteers was 0.21°±0.17°, 95%CI (-0.14°, 0.55°). The mean and standard deviation of UC-SVV in the left, middle and right positions of the clockwise was 0.24°±0.25°, -0.10°±0.27°, -0.63°±0.26°, 95%CI(-0.26°, 0.74°), (-0.65°, 0.44°), (-1.16°, -0.10°). The mean and standard deviation of UC-SVV in the left, middle and right positions of the counter clockwise was 0.03°±0.27°, -0.11°±0.26°, -0.23°±0.26°, 95%CI(-0.52°, 0.59°), (-0.65°, 0.42°), (-0.76°, 0.30°). There was significant difference in the deviation between the left and the right side of counter clockwise rotation of UC-SVV(t=2.432, P<0.05), however, there was no significant difference in the angle of deviation between the left and right sides and the median position(t value was 0.951, -1.400, both P>0.05). There was no significant difference among each position in clockwise rotation of UC-SVV(F=0.253, P>0.05).@*Conclusion@#UC-SVV test with peak speed of 60°/s can cause vertical line deviation in the left and right lateral position, but the angle is small and the value of clinical application is limited.

Nuevo método para evaluar el Test Subjetivo Vertical / New method for assessing Subjective Visual Vertical Test

Introducción: La prueba Visual Subjetiva Vertical (SVV por sus siglas en inglés) corresponde a una prueba de bajo costo y complejidad que permite el estudio de la función vestibular "estática". En el año 2009 se valida la Prueba del Balde con igual confianza, sensibilidad y especificidad, que la prueba de domo. Sin embargo, diversos factores impresionan disminuir su precisión. Objetivo: Proponer un nuevo método utilizando un programa computacional y una interfaz pantalla-paciente, que permita disminuir la influencia de variables y aumentar la precisión de la evaluación. Material y método: En 43 voluntarios sin historia de patología vestibular y en 32 pacientes con patología vestibular se compararon los resultados de la aplicación de SVV en dos modalidades: prueba del balde tradicionalyuna prueba computarizada propuesta en el presente artículo. Resultados: En nuestro estudio el SVV con balde muestra 57% de sensibilidad y 90% de especificidad, mientras el SVV digital tiene 74% de sensibilidad y 93% de especificidad, el cual también presentó significativamente una menor desviación estándar. Conclusión: En suma, el SVV computarizado arroja un resultado más preciso que SVV con balde, con mejor utilidad clínica al tener mayor de discriminación con mejores perfiles de sensibilidad/especificidad.

Background: Subjective Visual Vertical Test (SVV) is a low-cost and simple evaluation that allows the physician to study the static vestibular function of a patient. In 2009 the Bucket Test was validated as a high confidence, sensitivity and specificity comparable to the hemispheric dome testing device. Although, its result can be affected by multiple variables. Aim: To propose a new method to evaluate SVV using a computer software interface, that allows a reduction ofvariables therefore increasing its precision. Material and method: In a sample of 43 volunteers with no previous history of vestibular pathologies and 32 patients with diagnosed vestibular pathologies we compared the results of 2 different modules of SVV testing: a traditional bucket test and a computerized test proposed in the present article. Results: Bucket test SVV for this research showed a sensitivity of 57% and a specificity of 90%, meanwhile Computerized SVV had a sensitivity of 74% and a specificity of 93%, which also presented a significant smaller standard deviation. Conclusion: In summary, digital SVV testing grants more accurate result in comparison to the Bucket Test, with a better clinical performance due to an improved discriminatory capacity with better Sensitivity/Specificity profiles.

Otolith Function Tests in Patients with Orthostatic Dizziness / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Orthostatic dizziness (OD) is defined as when dizziness is provoked by standing up from a supine or sitting position. It is usually considered as being associated with orthostatic hypotension (OH). On the other hand, it is recently suggested that otolith organ dysfunction and impaired vestibulosympathetic reflex may account for development of OH and OD. Vestibular evoked myogenic potential (VEMP) and subjective visual vertical and horizontal tests (SVV/SVH) are tools for detecting otolith organ dysfunction. We assessed cervical VEMP (cVEMP) and SVV/SVH test results in the patients with OD to evaluate the relationship between OD and otolith organ function. MATERIALS AND METHODS: Three hundred-eighty-seven patients who visited dizziness clinic were enrolled in this study. Seventy-three patients presented with OD (i.e., group O), while 314 patients did not present OD (i.e., group N). Vestibular function tests including cVEMP and SVV/SVH were performed. RESULTS: cVEMP showed abnormal response in 47.9% of group O and 60.2% of group N. Abnormal SVV was found in 35.6% of group O and 31.5% of group N. Abnormal SVH was highly found in both group O and group N (30.1%, 27.1%). CONCLUSION: The values of SVV/SVH and cVEMP abnormality from both groups were not significantly different between the groups O and N. This finding suggests that otolithic function may not be related with OD.

Como um balde pode contribuir no diagnóstico neurológico? / How a bucket can contribute to neurological diagnosis?

Moedas, chaves e copos são objetos simples que podem ser utilizadosem uma avaliação neurológica de rotina. Recentemente, um balde de plástico tornou-se parte desse arsenal como instrumento para testar a vertical visual subjetiva à beira do leito. O principal empenho deste manuscrito é ressaltar a utilidade do teste do balde no exame à beira do leito visando demonstrar desvios da percepção da verticalidade em doenças comuns na prática neurotológica tais como: acidente vascular cerebral, doença de Parkinson, parkinsonismo, lesão vestibular unilateral e enxaqueca.

Coins, keys or glasses are simple objects that can be used in a routineneurological evaluation. Recently, a plastic bucket became part of the arsenal as a tool for bedside test of the subjective visual vertical. The main effort of this manuscript is to emphasize the usefulness of the bedside bucket test seeking to show verticality perception deviations in common neurologic diseases such as: stroke, Parkinson disease, parkinsonism, unilateral vestibular lesion, and migraine.

Ocular Vestibular Evoked Myogenic Potential in Vestibular Neuritis Patients: Comparative Study with Cervical Vestibular Evoked Myogenic Potential and Subjective Visual Vertical / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Subjective visual vertical (SVV) reflects utricle and superior vestibular neural functions, and cervical vestibular evoked myogenic potentials (cVEMP) reflect saccule and inferior vestibular neural functions. But, origin and characteristics of ocular VEMP (oVEMP) remain controversial, especially in case of evoked by air conducted sound (ACS). Thus, the aim of this study was to identify the origin and characteristics of oVEMP by comparing with various otolith function tests. MATERIALS AND METHODS: Forty vestibular neuritis patients were enrolled from September 2012 to January 2013 in this study. We examined cVEMP, oVEMP using 500 Hz air-counducted sounds. And, we measured static and dynamic SVV. RESULTS: Abnormal cVEMP responses were observed in 6 (15%) patients, and abnormal oVEMP responses were observed in 28 (70%) patients. Abnormal static and dynamic SVV were observed in 18 (45%), 35 (87.5%) patients, respectively. There was strong correlation between oVEMP and dynamic SVV (p=0.009). CONCLUSION: ACS oVEMP responses showed different tendency from cVEMP responses in vestibular neuritis patients, but similar tendency with results of dynamic SVV. The results suggest that origin of oVEMP is different from that of cVEMP and maybe utricle and superior vestibular neuron.

Semi-automatic measurement of visual verticality perception in humans reveals a new category of visual field dependency

Previous assessment of verticality by means of rod and rod and frame tests indicated that human subjects can be more (field dependent) or less (field independent) influenced by a frame placed around a tilted rod. In the present study we propose a new approach to these tests. The judgment of visual verticality (rod test) was evaluated in 50 young subjects (28 males, ranging in age from 20 to 27 years) by randomly projecting a luminous rod tilted between -18 and +18° (negative values indicating left tilts) onto a tangent screen. In the rod and frame test the rod was displayed within a luminous fixed frame tilted at +18 or -18°. Subjects were instructed to verbally indicate the rod’s inclination direction (forced choice). Visual dependency was estimated by means of a Visual Index calculated from rod and rod and frame test values. Based on this index, volunteers were classified as field dependent, intermediate and field independent. A fourth category was created within the field-independent subjects for whom the amount of correct guesses in the rod and frame test exceeded that of the rod test, thus indicating improved performance when a surrounding frame was present. In conclusion, the combined use of subjective visual vertical and the rod and frame test provides a specific and reliable form of evaluation of verticality in healthy subjects and might be of use to probe changes in brain function after central or peripheral lesions.

Effect of Preset Angle on Subjective Visual Vertical/Horizontal: Comparison between Normal Subjects and Patients with Dizziness / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Subjective visual vertical (SVV) and subjective visual horizontal (SVH) are well known otolith function tests. Patients with acute unilateral vestibular weakness have a tendency to set the bar toward the side of the lesion in SVV and SVH tests. The object of this article is to identify the effect of preset angle on SVV and SVH tests in normal subjects and patients with dizziness. MATERIALS AND METHODS: From October 2008 to March 2009, thirty healthy volunteers, twenty eight vestibular neuritis (VN) patients (14-uncompensated, 14-compensated), Twenty five patients who had migrainous vertigo (MV) were enrolled. All subjects performed the test two times in each of the clockwise and counter-clockwise preset angle. RESULTS: In normal subjects, there was significant influence by preset angle on SVV test, not on SVH test. In VN patients with nystagmus, both SVH and SVV were not influenced by preset angle. In VN patients without nystagmus and in MV patients, there were significant influence by preset angle on both SVV and SVH tests. CONCLUSION: SVV and SVH values depend on the direction of the preset angle in MV and uncompensated VN patients. The preset angle should be considered in the interpretation of SVV and SVH values.

Clinical Implication of Dissociation between Subjective Visual Horizontal and Subjective Visual Vertical / 대한평형의학회지

BACKGROUND AND OBJECTIVES Subject visual vertical (SVV) and subject visual horizontal (SVH) is well known otolith function test. Patients with acute unilateral vestibular weakness fail to set the test bar within normal range in SVH/SVV showing abnormal deviation toward lesion side. In some cases, SVH and SVV are deviated towards different directions, and analysis of these findings is rarely reported. The authors analyzed correlation of SVH/SVV and other vestibular function tests in patients with various vestibular diseases. MATERIALS AND METHODS From April 2005 to July 2007, total 234 patients who had admitted for dizziness were enrolled. All patients were divided in two groups, non-dissociation group (n=215) and dissociation group (n=19). Correlation of SVH, SVV, Videonystagmography (VNG), the rotating chair test was compared. RESULTS 8.1% of patients showed dissociation between SVH and SVV. Clinical features did not showed significant difference between groups. In non-dissociation group, SVH/SVV showed correlation with VNG, rotating chair test. However in dissociation group, VNG and rotating chair test revealed high rate of consistency with deviation of SVH than that of SVV. Also direction of SVH and dizziness had higher consistency (88.9%) than that of SVV (11.1%). CONCLUSION The SVH showed consistency with other vestibular function test and may be more reliable than SVV when the result is dissociated.

Results of Air Caloric and Other Vestibular Tests in Patients with Chronic Otitis Media

OBJECTIVES: Air caloric results are supposed to be influenced by anatomic changes of the middle ear. The aims of our study were to evaluate the incidence and characteristics of abnormal air caloric results in patients with unilateral chronic otitis media and without any history of vertigo, and to compare caloric results with there of other vestibular function tests (VFTs). METHODS: Twenty five patients with unilateral chronic otitis media (COM) who were scheduled for surgery underwent VFTs preoperatively. Hearing was assessed using pure-tone audiometry and vestibular function was assessed using a set of VFTs: air caloric, head-shaking nystagmus (HSN), vibration-induced nystagmus (VIN), and subjective visual vertical (SVV) tests. RESULTS: Six patients (24%) showed pathologic canal paresis (CP) on COM-sided ears. Two patients showed pathologic CP on the contralateral side. However, both of the two showed inverted nystagmus to warm air stimulation on the COM-side and hyperactive nystagmus to cold air stimulation on the COM-side, which means that the COM-sided ear was stimulated too much. There was pathologic HSN in 12 patients (48%), pathologic VIN in 7 (28%), and pathologic SVV in 5 (20%). Overall, 20 (80%) patients showed abnormal findings through a set of VFTs. Patients with an interaural difference of bone-conduction hearing thresholds > or =10 dB tended to show more abnormal VFT results than those for whom the interaural difference of bone-conduction hearing thresholds was <10 dB. CONCLUSION: Our data show that one-fourth of patients with unilateral COM show abnormal caloric results on the COM side. However, subclinical latent vestibular imbalances were found to be common, which might be related to the gradual vestibular involvement in inflammatory processes, regardless of the caloric results. Results of a set of VFTs should be referred to when determining vestibular imbalance in patients with COM.

Subjective Visual Vertical during Eccentric Rotation in Acute Vestibular Neuritis Patients

BACKGROUND AND OBJECTIVE: By assessing unilateral utricular function at the acute unilateral vestinuloneuritis (Acute UVN), we sought to determine the ability of the subjective visual vertical (SVV) during eccentric rotation (dynamic SVV) in localizing the site of the lesion in unilateral vestibular neuritis (UVN). METHODS: The static SVV and dynamic SVV of fifteen patients diagnosed with acute UVN were enrolled within 10 days of onset (average 7 days). 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 degrees/s. RESULTS: In the acute stage of UVN, the static SVV showed an increase in deviation to the side of the lesion compared to those of normal subjects. Also, we found 73% of abnormal findings in Acute UVN patients by assessing static conventional SVV. The dynamic SVV had a statistically significant increase in deviation to the side of the lesion compared to those of normal subjects and 93% patients showed beyond normal range. CONCLUSIONS: The dynamic SVV would be an effective method in the diagnosis and localization of acute unilateral vestibularneuritis.

Otolith Function Tests in Patient with Meniere's Disease

BACKGROUND AND OBJECTIVES: The aims of this study were to measure otolith function using subjective visual vertical (SVV) test and vestibular evoked myogenic potential (VEMP) test in patients with unilateral Meniere's disease, and to see the relationship of the otolithic impairment with caloric and audiologic results. MATERIALS AND METHODS:Twenty two patients with unilateral Meniere's disease who received treatment and also had been tested for pure tone, caloric, SVV and VEMP tests were enrolled. All the tests were done simultaneously. RESULTS: Five of 22 (23%) patients showed abnormal tilt to the lesion side in SVV test, and 13 of 22 (59%) patients showed abnormal VEMP results on the affected side. There was no correlation between SVV tilts and unilateral weakness (UW) in caloric tests or pure-tone average. There was also no difference of UW in patients with or without VEMP abnormalities. Two patients showed abnormal finding in both SVV & VEMP tests. One patient showed UW (47%) and SVV tilt (3.08degrees) to the lesion side, and the other showed normal UW and SVV tilt (3.22degrees) to the lesion side. CONCLUSION: Our results demonstrate that the otolith system was implicated in 16 out of 22 (73%) patients with Meniere's disease. However, there was no correlation between the abnormal results of the three tests and these findings suggest that impairment of the otolithic function is depending on the extent and/or the localization of Meniere's disease, suggesting vestibular rehabilitation for the specific lesion might be helpful.

Change of Subjective Visual Vertical (SVV) in Patients of Vestibular Neuritis

BACKGROUND AND OBJECTIVES: Measurement of subjective visual vertical (SVV) in darkness with the head upright is one of the static function test of the otolithic system and is simple to perform in the patients. Changes of SVV were measured during the recovery period of vestibular neuritis to investigate the relation between SVV and the subjective improvements reported by the patients. MATERIAL AND METHODS:Sixty-two patients with unilateral vestibular neuritis were investigated. All the patients were diagnosed by physical examination with electronystagmography and the SVV were assessed during the acute period and sequentially followed during the recovery period. At the same time, the subjects were questioned in five scale of symptom improvement which were "Level 5: I am so dizzy to open my eyes", "Level 4: I am dizzy not moving my head", "Level 3: I am not dizzy if I don't move my head", "Level 2: I am not dizzy with head moving", "Level 1: I am not dizzy at all". RESULTS: The calibrated mean values were 5.72+/-4.77 degree in vertical deviated toward the lesion side. There was no relation between the canal paresis and the tilt of SVV. As the SVV reaches the normal value, the symptom scale improved to level 2 (p=0.018). The mean recovery time could be obtained by calculating the regression curve of the well compensated groups. CONCLUSION: These results show that SVV correlated with clinical improvement of dizziness symptoms in vestibular neuritis. Therefore, this method can be used to evaluate vestibular neuritis during the follow up.

Comparison of Air Caloric Test and Vibration-Induced Nystagmus Test in Patients with Unilateral Chronic Otitis Media without Vertigo

BACKGROUND AND OBJECTIVES: The aims of the study were to characterize the vibration-induced nystagmus (VIN) and air caloric test in patients with unilateral chronic otitis media, and to clarify the clinical availability of VIN by comparing the results of VIN test with those of air caloric test. MATERIALS AND METHODS: Nineteen patients with unilateral chronic otitis media who had had no vestibular symptoms in past history were investigated. Pure tone audiometry (PTA), air caloric, VIN and subjective visual vertical (SVV) tests were done and the results were analyzed to estimate the utility for investigating vestibular imbalance. RESULTS: If we consider a patient with abnormal results from two or more tests as a patient with latent vestibular imbalance, because they had no previous vestibular symptoms, 3 patients was considered to have latent asymmetric vestibular function. False positive rate were 32% in air caloric test, 5% in VIN test and 0% in SVV test. CONCLUSION: Our findings show that vestibular imbalance in patients with chronic otitis media should be determined through various tests and vibration-induced nystagmus test can be more useful than air caloric test in estimating the vestibular imbalance.

Otolith Function Tests in Patient with Vestibular Neuritis

BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potentials (VEMP) test provides a useful method for assessment of saccule function and the functional integrity of the inferior vestibular nerve, and subjective visual vertical (SVV) abnormalities are presumably related to a lesion of the utricle. The aim(s) of this study were to measure otolith function using SVV and VEMP tests, and to define the influence of the otolithic organs in patients suffering from vestibular neuritis. MATERIALS AND METHOD: From September 2005 to January 2006, twelve patients who received treatment in hospital and also had been tested for caloric test, subjective visual vertical (SVV) and vestibular evoked myogenic potential (VEMP) tests with unilateral vestibular neuritis were enrolled. All the tests were done within 8 days after the onset of their symptoms, simultaneously. The SVV was measured in 34 normal subjects as well as in patients. RESULTS: Eight of 12 patients showed abnormal tilt to the lesion side in SVV test, and five of 8 patients showed no VEMP on the affected side. There was no correlation between SVV tilts and unilateral weakness (UW) in caloric tests. Two patients with abnormal UW (54, 82%) showed normal finding in SVV & VEMP tests. One patient with abnormal UW (83%) and SVV tilts (18.04Degree) to the lesion side was normal in VEMP test. Two patients with abnormal UW (28, 37%) and no response in VEMP test were normal in SVV test. CONCLUSION: Our results demonstrate that the incidence of abnormal results were 62.5, 66.7% in VEMP and SVV tests in acute stage of vestibular neuritis, respectively. There was no correlation between the abnormal results of the tests and these findings suggest that impairment of the otolithic function is depending on the extent and/or the localization of vestibular neuritis.

Otolith Function Tests in Patient with Vestibular Neuritis

BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potentials (VEMP) test provides a useful method for assessment of saccule function and the functional integrity of the inferior vestibular nerve, and subjective visual vertical (SVV) abnormalities are presumably related to a lesion of the utricle. The aim(s) of this study were to measure otolith function using SVV and VEMP tests, and to define the influence of the otolithic organs in patients suffering from vestibular neuritis. MATERIALS AND METHOD: From September 2005 to January 2006, twelve patients who received treatment in hospital and also had been tested for caloric test, subjective visual vertical (SVV) and vestibular evoked myogenic potential (VEMP) tests with unilateral vestibular neuritis were enrolled. All the tests were done within 8 days after the onset of their symptoms, simultaneously. The SVV was measured in 34 normal subjects as well as in patients. RESULTS: Eight of 12 patients showed abnormal tilt to the lesion side in SVV test, and five of 8 patients showed no VEMP on the affected side. There was no correlation between SVV tilts and unilateral weakness (UW) in caloric tests. Two patients with abnormal UW (54, 82%) showed normal finding in SVV & VEMP tests. One patient with abnormal UW (83%) and SVV tilts (18.04Degree) to the lesion side was normal in VEMP test. Two patients with abnormal UW (28, 37%) and no response in VEMP test were normal in SVV test. CONCLUSION: Our results demonstrate that the incidence of abnormal results were 62.5, 66.7% in VEMP and SVV tests in acute stage of vestibular neuritis, respectively. There was no correlation between the abnormal results of the tests and these findings suggest that impairment of the otolithic function is depending on the extent and/or the localization of vestibular neuritis.

Results of Vestibular Function Tests in Patients with Cerebello-Pontine Aangle Tumors

BACKGROUND AND OBJECTIVES: Acoustic neuroma (AN) is commonly encountered in the cerebello-pontine angle (CPA) and AN arises principally from the vestibular division of the nerve, which can show not only hearing disturbance but also various vestibular symptoms and laboratory findings by affecting central and peripheral vestibular system. Vestibular testing is reported not to be a useful screening test for AN, but can be helpful in defining whether the tumor arises from the superior or inferior division and identifying the cause of dizziness or vertigo. MATERIALS AND METHOD: We are presenting four patients with CPA tumors accompanied by various abnormal findings of vestibular function tests including head-shaking nystagmus, vibration-induced nystagmus, hyperventilation- induced nystagmus and vestibular evoked myogenic potential and subjective visual vertical, which can enable us to understand the pathomechanism of the abnormal results. RESULTS: All patients presented hearing loss and mild dizziness. Caloric test, head thrust test and vibration-induced nystagmus was helpful in localizing the disease, but head-shaking nystagmus and hyperventilation-induced nystagmus was less helpful. Otolith tests did not always show abnormal results. CONCLUSION: We should consider abnormal results of the vestibular function tests in a whole to estimate the status of vestibular compensation in patients with CPA tumors.

The Effect of Somatosensory Input on Subjective Visual Vertical in Normal Subjects

BACKGROUND AND OBJECTIVES: Aims of the study were to determine if the somatosensory input influences on vertical perception by comparing the results with the head or body tilted (15Degree to the right and to the left, and to examine the influence of tactile sensation in the perception of verticality in head lateral positions. MATERIALS AND METHOD: We tested 34 normal subjects in their ability to set a straight line to the perceived gravitational vertical. Measurements were taken in static conditions, sitting upright, head tilted (15Degree, body tilted (15Degree, and head lateral positions (90Degree on the right/left sides with or without physical support under the head. RESULTS: The normal range of the subjective visual vertical (SVV) was 0.65Degree/-.23Degreein upright position. The normal ranges of SVV in head-tilts 15Degreeto the left/right sides were -0.47Degree/-.76Degreeand 1.88Degree/-.94Degree which were significantly different from those in upright position (E-effect). But the normal ranges of SVV in body-tilts 15Degreeto the left/right were not different from those in upright position. And the normal ranges of SVV in head lateral positions maintained actively and passively were not different each other, but significantly larger than that in upright position (A-effect). CONCLUSION: Our results support that neck somatosensory input plays a part in the perception of verticality. In contrast, tactile sensation of the head had no effect on the settings of a visual line to visual vertical in head lateral positions.

Effects of Galvanic Vestibular Stimulation on the Subjective Visual Vertical / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The aim of this study was to determine the otolithic effects of galvanic vestibular stimulation on the perception of subjective visual vertical in normal subjects. SUBJECTS AND METHOD: Fifteen normal subjects were selected on the basis of medical history and neurological examination. We measured subjective tilt of a central vertical line during galvanic vestibular stimulation (0, 1.0, 2.5, 4.0 mA). Binaural and monaural electric current was applied to each subject's mastoid and forehead for vestibular stimulation. RESULTS: Anodal stimulation of the right mastoid led to clock-wise subjective visual vertical. Anodal stimualtion of the left mastoid led to counter clock-wise subjective visual vertical. There was a correlation between the amount of the measured parameter and the strength of the applied current. More consistent parameters were obtained from the binaural stimulation than the monaural stimualtion. CONCLUSION: Galvanic vestibular stimulation had effects on the vestibular functions, making changes in the subjective visual vertical. Since the galvanic stimulation had consistency with the direction of the stimulation and was proportionate to the intensity, it is thought to be a useful method for assessing otolith functions.