Unilateral Vestibular Neuritis Research Articles

Trunk Instability in the Pitch, Yaw, and Roll Planes during Clinical Balance Tests: Axis Differences and Correlations to vHIT Asymmetries Following Acute Unilateral Vestibular Loss

BACKGROUND: Clinical dynamic posturography concentrates on the pitch and roll but not on the yaw plane instability measures. This emphasis may not represent the axis instability observed in clinical stance and gait tasks for patients with balance deficits in comparison to healthy control (HC) subjects, nor the expected instability based on correlations with vestibulo-ocular reflex (VOR) deficits. To examine the axis stability changes with vestibular loss, we measured trunk sway in all three directions (pitch, roll, and yaw) during the stance and gait tasks of patients with acute unilateral vestibular neuritis (aUVN) and compared the results with those of HC. Concurrent changes in VORs were also examined and correlated with trunk balance deficits. METHODS: The results of 11 patients (mean age of 61 years) recorded within 6 days of aUVN onset were compared within those of 8 age-matched healthy controls (HCs). All subjects performed a two-legged stance task—standing with eyes closed on foam (s2ecf), a semi-gait task—walking eight tandem steps (tan8), and four gait tasks—walking 3 m with head rotating laterally, pitching, or eyes closed (w3hr, w3hp, w3ec), and walking over four barriers 24 cm high, spaced 1 m apart (barr). The tasks’ peak-to-peak yaw, pitch and roll angles, and angular velocities were measured with a gyroscope system (SwayStarTM) mounted at L1-3 and combined into three, axis-specific, balance control indexes (BCI), using angles (a) for the tandem gait and barriers task, and angular velocities (v) for all other tasks, as follows: axis BCI = (2 × 2ecf)v + 1.5 × (w3hr + w3hp + w3ec)v + (tan8 + 12 × barr)a. RESULTS: Yaw and pitch BCIs were significantly (p ≤ 0.004) greater (88 and 30%, respectively) than roll BCIs for aUVN patients. For HCs, only yaw but not pitch BCIs were greater (p = 0.002) than those of roll (72%). The order of BCI aUVN vs. HC differences was pitch, yaw, and roll at 55, 44, and 31%, respectively (p ≤ 0.002). This difference with respect to roll corresponded to the known greater yaw plane than roll plane asymmetry (40 vs. 22%) following aUVN based on VOR responses. However, the lower pitch plane asymmetry (3.5%) in VOR responses did not correspond with the pitch plane instability observed in the balance control tests. The increases in pitch plane instability in UVL subjects were, however, highly correlated with those of roll and yaw. CONCLUSIONS: These results indicate that greater yaw than pitch and roll trunk motion during clinical balance tasks is common for aUVN patients and HCs. However, aUVN leads to a larger increase in pitch than yaw plane instability and a smaller increase in roll plane instability. This difference with respect to roll corresponds to the known greater yaw plane than roll plane asymmetry (40 vs. 22%) following aUVN observed in VOR responses. However, the lower pitch plane asymmetry (3.5%) in VOR responses does not correspond with the enhanced movements in the pitch plane, observed in balance control tasks. Whether asymmetries in vestibular-evoked myogenic potentials (Vemps) are better correlated with the deficits in pitch plane balance control remains to be investigated. The current results provide a strong rationale for the clinical testing of directional specific balance responses, especially yaw and pitch, and the linking of balance results for yaw and roll to VOR asymmetries.

Development of a Subjective Visual Vertical Test System Using a Smartphone With Virtual Reality Goggles for Screening of Otolithic Dysfunction: Observational Study.

The subjective visual vertical (SVV) test can evaluate otolith function and spatial awareness and is performed in dedicated vertigo centers using specialized equipment; however, it is not otherwise widely used because of the specific equipment and space requirements. An SVV test smartphone app was developed to easily perform assessments in outpatient facilities. This study aimed to verify whether the SVV test smartphone app with commercially available virtual reality goggles can be used in a clinical setting. The reference range was calculated for 15 healthy participants. We included 14 adult patients with unilateral vestibular neuritis, sudden sensorineural hearing loss with vertigo, and Meniere disease and investigated the correlation between the SVV test results and vestibular evoked myogenic potential (VEMP) results. The SVV reference range of healthy participants for the sitting front-facing position was small, ranging from -2.6º to 2.3º. Among the 14 patients, 6 (43%) exceeded the reference range for healthy participants. The SVV of patients with vestibular neuritis and sudden sensorineural hearing loss tended to deviate to the affected side. A total of 9 (64%) had abnormal cervical VEMP (cVEMP) values and 6 (43%) had abnormal ocular VEMP (oVEMP) values. No significant difference was found between the presence or absence of abnormal SVV values and the presence or absence of abnormal cVEMP and oVEMP values; however, the odds ratios (ORs) suggested a higher likelihood of abnormal SVV values among those with abnormal cVEMP and oVEMP responses (OR 2.40, 95% CI 0.18-32.88; P>.99; and OR 2, 95% CI 0.90-4.45; P=.46, respectively). The SVV app can be used anywhere and in a short period while reducing directional bias by using virtual reality goggles, thus making it highly versatile and useful as a practical otolith dysfunction screening tool.

A comparative study of detection methods for assessing superior and inferior vestibular nerve damages in patients with vestibular neuritis

Objective:This study aims to compare the examination results of the vestibular evoked myogenic potential（VEMP） and video head impulse testing（vHIT） in patients with vestibular neuritis（VN）, thus exploring the methods to distinguish superior and inferior vestibular nerve damages in VN patients, and their feasibility. Methods:A total of 25 patients with unilateral VN treated in the Otology Department of the First Hospital of Qinhuangdao from May 2018 to July 2021 were recruited. They were respectively tested for ocular VEMP（oVEMP）, cervical VEMP（cVEMP） and vHIT, and the examination results were analyzed. Results:Examination results of oVEMP showed that 96%（24/25） patients had one-ear abnormalities with the amplitude decline or no waveform introduced, and 4%（1/25） patient had no waveform introduced of both ears. The overall abnormal rate examined by oVEMP was 100%（26/26）. Examination results of cVEMP showed that 36%（9/25） patients had one-ear abnormalities with the amplitude decline or no waveform introduced, and 4%（1/25） patients had no waveform introduced of both ears. The overall abnormal rate examined by cVEMP was 40%（10/25）, and 60%（15/25） patients had normal waveforms of both ears. Examination results of vHIT showed that 100%（25/25） patients had semicircular canal gain decline of one side, 92%（23/25） had anterior Semicircular canal decline of one side, and 36%（9/25） had posterior semicircular canal decline of one side. VEMP and vHIT results were compared. Examination results of VEMP showed that 60%（15/25） VN patients had superior vestibular nerve damage, and 40%（10/25） had both superior and inferior vestibular nerve damages. Examination results of vHIT showed that 64%（16/25） VN patients had superior vestibular nerve damage, and 36%（9/25） had both superior and inferior vestibular nerve damages. There was no significant difference in the ratio of VN patients with superior and inferior vestibular nerve damages examined by VEMP or vHIT（χ²=0.085, P>0.05）. The matching ratio of VEMP and vHIT results was 80%（20/25）, and the non-matching ratio was 20%（5/25）. Conclusion:Consistent results obtained from both VEMP and vHIT can preliminarily identify the type of vestibular nerve damage. If their results are not consistent, it is recommended not to identify the scope of the vestibular nerve damage.

Vestibulo-ocular reflex gain improvements at peak head acceleration and velocity following onset of unilateral vestibular neuritis: Insights into neural compensation mechanisms.

An acute unilateral peripheral vestibular deficit (aUPVD) due to vestibular neuritis causes deficient yaw axis vestibular ocular reflex (VOR) gains. Using video head impulse tests (vHITs), we examined phasic and tonic velocity gains of the VOR over time to determine if these differed at onset and during subsequent improvement. The VOR responses of 61 patients were examined within 5 days of aUPVD onset, and 3 and 7 weeks later using vHIT with mean peak yaw angular velocities of 177°/s (sd 45°/s) and mean peak accelerations of 3660°/s2 (sd 1300°/s2). The phasic velocity or acceleration gain (aG) was computed as the ratio of eye to head velocity around peak head acceleration, and the tonic velocity gain (vG) was calculated as the same ratio around peak head velocity. aG increased ipsi-deficit from 0.45 at onset to 0.67 at 3 weeks and 7 weeks later, and vG increased ipsi-deficit from 0.29 to 0.51 and 0.53, respectively, yielding a significant time effect (p < 0.001). Deficit side aG was significantly greater (p < 0.001) than vG at all time points. Deficit side gain improvements in aG and vG were similar. Contra-deficit aG increased from 0.86 to 0.95 and 0.94 at 3 weeks and 7 weeks, and vG contra-deficit increased from 0.84, to 0.89 and 0.87, respectively, also yielding a significant time effect (p = 0.004). Contra-deficit aG and vG were normal at 3 weeks. Mean canal paresis values improved from 91% to 67% over the 7 weeks. Acceleration and velocity VOR gains on the deficit side are reduced by aUPVD and improve most in the first 3 weeks after aUPVD onset. Deficit side aG is consistently higher than deficit side vG following an aUPVD, suggesting that acceleration rather than velocity sensitive compensatory neural mechanisms are predominant during the compensation process for aUPVD.

Acute unilateral vestibular neuritis contributes to alterations in vestibular function modulating circumvention around obstacles: A pilot study suggesting a role for vestibular signals in the spatial perception of orientation during circumvention.

Walking among crowds avoiding colliding with people is described by patients with vestibular disorders as vertigo-inducing. Accurate body motion while circumventing an impeding obstacle in the gait pathway is dependent on an integration of multimodal sensory cues. However, a direct role of vestibular signals in spatial perception of distance or orientation during obstacle circumvention has not been investigated to date. We examined trunk yaw motion during circumvention in patients with acute unilateral vestibular loss (aUVL) and compared their results with age-matched healthy controls (HCs). Subjects performed five gait tasks with eyes open two times: walk 6 m in total, but after 3 m, circumvent to the left or right, as closely as possible, a cylindrical obstacle representing a person, and then veer back to the original path; walk 6 m, but after left and right circumvention at 3 m, veer, respectively, to the right, and left 45 deg; and walk 6 m without circumvention. Trunk yaw angular velocities (YAVs) were measured using a gyroscope system. Yaw angular velocity peak amplitudes approaching to, and departing from, the circumvented object were always greater for patients with aUVL compared to HCs, regardless of whether passing was to the aUVLs' deficit or normal side. The departing peak YAV was always greater, circa 52 and 87%, than the approaching YAV for HCs when going straight and veering 45 deg (p ≤ 0.0006), respectively. For patients with aUVL, departing velocities were marginally greater (12%) than approaching YAVs when going straight (p < 0.05) and were only 40% greater when veering 45 deg (p = 0.05). The differences in departing YAVs resulted in significantly lower trajectory-end yaw angles for veering trials to the deficit side in patients with aUVL (34 vs. 43 degs in HCs). The results demonstrate the effects of vestibular loss on yaw velocity control during the three phases of circumvention. First, approaching an obstacle, a greater YAV is found in patients with aUVL. Second, the departing YAV is found to be less than in HCs with respect to the approaching velocity, resulting in larger deficit side passing yaw angles. Third, patients with UVLs show yaw errors returning to the desired trajectory. These results could provide a basis for rehabilitation protocols helping to avoid collisions while walking in crowded spaces.

Video Suppression Head Impulses and Head Impulses Paradigms in Patients with Vestibular Neuritis: A Comparative Study.

Background: This study aims to explore the clinical relevance of the Suppression Head Impulse Paradigm (SHIMP) to better understand if it represents an additional clinical value compared to the Head Impulse Paradigm (HIMP) in patients with vestibular neuritis (VN) in different stages of the disease. Methods: From January 2020 to June 2022, patients with unilateral VN were found in a database of an ENT vestibular clinic. Clinical presentation, vestibular test outcomes, therapy, and recovery were examined in medical records. Results: A total of 42 patients (16 Females, mean age 51.06 ± 12.96; 26 Male, mean age 62.50 ± 9.82) met the inclusion criteria and were enrolled in the study. The means of the VOR gain for both paradigms were respectively 0.38 ± 0.12 (SHIMP) and 0.46 ± 0.13 (HIMP) at T0 and 0.55 ± 0.20 (SHIMP) and 0.64 ± 0.19 (HIMP) at T1 for the lesional side. For the HIMP, the gain value <0.76 identified the affected side of VN with 100% sensitivity (92–100) and 100% specificity (91–100). For the SHIMP, the gain value <0.66 identified the affected side of VN with 100% sensitivity (92–100) and 100% specificity (91–100) and an AUC of 1.0 (0.96–1.0, p < 0.0001). Conclusion: The SHIMP paradigm has a diagnostic accuracy equal to the classic HIMP paradigm in patients with VN. The assessment of VOR slow phase velocity and vestibulo-saccadic interaction in patients with VN could be easier with the use of the SHIMPs paradigm. SHIMPs paradigm provides helpful information about the evaluation of VOR slow phase velocity and vestibulo-saccadic interaction as new recovery strategies in patients with VN.

Video Head Impulse Test (vHIT): Value of Gain and Refixation Saccades in Unilateral Vestibular Neuritis.

The aim of this study was to evaluate gain and refixation saccades (covert and overt) using a video head impulse test (vHIT) in the horizontal and vertical planes in patients after the onset of unilateral acute vestibular neuritis (AVN). Thirty-five patients were examined in the acute stage of AVN and at follow-up (range, 6–30 months); a control group of 32 healthy subjects also participated. At onset, the mean gain was significantly lower on the affected side in all of the semi-circular canal planes, mainly in the horizontal canal plane, and saccades (covert and overt) were more prevalent in the horizontal compared to the vertical canal planes. Multi-canal affection occurred more frequently (80% for gain, 71% for saccades) than isolated canal affection. At follow-up, which ranged from 6 to 30 months, the gain was recovered in all of the canals (anterior in 50%, horizontal in 42.8%, and posterior canal in 41.1% of cases), while covert and overt saccades were reduced in the horizontal and vertical planes. However, covert saccades were still recorded in a greater proportion (69%) than overt saccades (57%) in the horizontal plane and at a lower rate in the vertical planes. The compensatory mechanisms after AVN mainly involve the horizontal canal, as the refixation saccades—especially covert ones—were more frequently recorded in the horizontal than vertical canals.

Correlation analysis of 3D-FLAIR MRI characteristics of the inner ear and vestibular function in the patients with vestibular neuritis

Objective: The characteristics of 3D-FLAIR MRI images of the inner ear of patients with vestibular neuritis were preliminarily studied to explore the possible pathogenesis of vestibular neuritis, and the correlation analysis was conducted in combination with vestibular function to provide a basis for accurate diagnosis of vestibular neuritis. Methods: A total of 36 patients with vestibular neuritis (VN) from December 2019 to October 2020 were collected from the Vertigo Department of Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University. There were 36 cases (18 females, 18 males) with unilateral acute vestibular neuritis, 17 cases of left ear and 19 cases of right ear. According to the results of 3D-FLAIR MRI in the inner ears, the patients were divided into the enhanced group and the non-enhanced group (the health side served as the normal control group). The results of vestibular function examination in the two groups were compared. SPSS19.0 software was used for statistical processing to analyze the relationship between the vestibular function and the characteristics of 3D-FLAIR imaging in the inner ears. Results: Abnormal enhancement of 3D-FLAIR was found in 31 cases (86.1%) of the 36 cases, including 14 cases of both vestibular nerve and vestibular terminal organ enhancement, eight cases of superior vestibular nerve enhancement alone, seven cases of vestibular terminal organ enhancement alone, and two cases of cochlear enhancement alone. Observation of abnormal reinforcement of vestibular nerve showed: twenty-one cases of superior vestibular nerve reinforcement, one case of superior and inferior vestibular nerve reinforcement. No abnormalities were found in 3D-FLAIR of inner ear in 5 cases. According to the analysis of vestibular function results, there were 19 cases (52.8%) with total vestibular involvement, sixteen cases (44.4%) with superior vestibular involvement alone, and one case (2.8%) with inferior vestibular involvement alone. Comparison of vestibular function between the five cases (non-enhancement group) and the 31 cases (enhanced group) in the 3D-FLAIR group of the inner ears showed that the CP values of caloric tests in the enhanced group were higher (60.81±3.49 vs 34.12±7.37), with statistically significant difference (t=-2.898, P<0.01). Conclusion: In patients with vestibular neuritis, 3D-FLAIR MRI scan of the inner ear provides visual imaging evidence for clinical practice, considering that the lesion site of vestibular neuritis is not only in the vestibular nerve, but also in the vestibular end organ. Patients with 3D-FLAIR enhanced in the inner ear may have more significant vestibular function damage.

The clinical course of vestibular neuritis from the point of view of the ocular vestibular evoked myogenic potential

Studying otolith functions after unilateral vestibular neuritis using ocular vestibular-evoked myogenic potentials and subjective visual vertical tests could give different results. A total of 39 patients underwent a vestibular assessment that included the Dizziness Handicap Inventory and horizontal and vertical semicircular canal function testing with video head impulse testing, ocular vestibular-evoked myogenic potential testing, cervical vestibular-evoked myogenic potentials and subjective visual vertical testing. All patients showed a significant alteration (asymmetry ratio more than 40 per cent) for ocular vestibular-evoked myogenic potentials as well as for subjective visual vertical testing (more than -2° to more than +2°) during the acute phase, whereas after 72 hours from the acute vertigo attack normal values (asymmetry ratio less than 40 per cent) were found in 6 out of 39 patients for ocular vestibular-evoked myogenic potentials and 36 out of 39 for the subjective visual vertical (less than -2° to less than +2°). Ocular vestibular-evoked myogenic potentials are the most suitable test to evaluate otolith functions in patients with unilateral vestibular neuritis in the acute and sub-acute phase.

Change of gait after unilateral vestibular neuritis: a prospective longitudinal observation study

Although symptoms of unilateral vestibular neuritis (uVN) resolve spontaneously within several weeks, recovery of gait function has unclearness in gait parameter changes and mediolateral stability improvements. In addition, prospective longitudinal studies on gait parameters after uVN are lacking. This study was conducted to reveal longitudinal change of gait function after acute uVN and to help the precise rehabilitation planning. Twenty three participants with uVN and 20 controls were included. 3D gait analyses were conducted three times after uVN onset at monthly intervals. From the gait analysis data, spatio-temporal parameters, inclination angle (IA) representing the relationship between center of mass (CoM) and center of pressure (CoP) in the frontal plane, and IA variability were obtained. Time effects on gait metrics were tested. Walking speed of participants with uVN improved significantly between the 1st and 3rd tests, but they were not significantly different to that of control, even in the 1st test. The step width of participants with uVN was significantly larger than that of control in the 1st test and improved significantly in the 2nd test. Variability of IA in affected side was significantly larger than that in controls in the 1st test and improved significantly in the 3rd test compared to the 1st test. Improvement of overall gait function and mediolateral stability during gait continued after acute stage of uVN (two months from onset in this study). Rehabilitation intervention should be continued after the acute stage of uVN to enhance appropriate adaptation in gait.

Differential Diagnosis of the Acute Vestibular Syndrome

Acute vestibular syndrome refers to the rapid onset of vertigo, nausea, vomiting, and unsteady gait. Acute unilateral vestibular neuritis is the most common cause of acute vestibular syndrome. However, vascular lesions involving the brainstem and cerebellum also produce acute vestibular syndrome even without other neuro-logic deficits. The vestibular nucleus or nucleus prepositus hypoglossi in the dorsal portion of the brainstem, cerebellar structures including flocculus, tonsil, and nodulus, and cerebellar peduncle can produce isolated vertigo and imbalance when damaged. Early recognition of the pseudo-vestibular neuritis of the vascular etiology is warranted for clinicians. Keywords: Vertigo; Vestibular neuritis; Brainstem vertigo

Unilateral Vestibular Neuritis after Snakebite: Is There a Causal Relationship?

Unilateral Vestibular Neuritis after Snakebite: Is There a Causal Relationship?

Improvement of Asymmetric Vestibulo-Ocular Reflex Responses Following Onset of Vestibular Neuritis Is Similar Across Canal Planes.

Background: We examined whether, after onset of acute unilateral vestibular neuritis (aUVN), initial disease effects, subsequent peripheral recovery and central compensation cause similar changes in vestibular ocular reflex (VOR) gains in all 3 semi-circular canal planes.Methods: 20 patients, mean age 56.5 years, with pathological lateral canal video head impulse test (vHIT) VOR gains due to aUVN, were subsequently examined with vHIT in all 3 canal planes on average 4.3 and 36.7 days (“5 weeks”) after aUVN onset.Results: Lateral and anterior deficit side (DS) average gains equaled 0.41 at aUVN onset. Non-deficit, normal, side (NS) gains were 0.88 and 0.81, respectively. Mean posterior DS gain was similar at onset, 0.43, provided only gains lower than 0.6 (lower limit of healthy controls) were considered. NS posterior mean gain at onset (0.68) was less (p ≤ 0.0006) than lateral and anterior NS gains. After 5 weeks, DS lateral, anterior and posterior canal gains increased (p ≤ 0.05), on average, to 0.65, 0.59, and 0.58, respectively. NS gains increased to 0.91, 0.87, and 0.76 (p = 0.007), respectively. At 5 weeks deficit-lateral/normal-lateral canal plane gain asymmetries were significantly (p < 0.0008) reduced from 36.9 to 19.4%, deficit-anterior/normal-posterior asymmetry decreased from 28.6 to 18.1%, while deficit-posterior/normal-anterior asymmetry changed from 29.7 to 21.4%, all to circa 20%. Roll plane asymmetries decreased slightly over 5 weeks (28.6–18.1%) but pitch plane asymmetries remained significantly less (p = 0.001), not different from 0% regardless of initial DS posterior canal vHIT gain. Yaw plane asymmetry changes are identical to those of the lateral canals (36.7–19.4%).Conclusions: These results indicate that, at onset, aUVN of the superior vestibular nerve has a similar effect on lateral and anterior deficit DS VOR gains, and on posterior DS canal VOR gains if the inferior nerve was also affected at onset. The significant improvements to equal 5 week levels of DS gains and slightly greater posterior NS gain improvements, compared to lateral and anterior NS gains, yielding a common canal plane gain asymmetry of 20% at 5 weeks, suggest similar neural compensation mechanisms were active along VOR pathways. Unexpectantly, canal plane improvement was not replicated in pitch plane asymmetries.

Is there any relationship between unilateral vestibular neuritis and internal acoustic canal measurements?

Is there any relationship between unilateral vestibular neuritis and internal acoustic canal measurements?

Suppression Head Impulse Paradigm (SHIMP) in evaluating the vestibulo-saccadic interaction in patients with vestibular neuritis.

Evaluate the potential clinical application of the Suppression Head Impulse Paradigm (SHIMP) in evaluating the vestibulo-saccadic interaction in patients with vestibular neuritis (VN). A retrospective study was performed. Fifteen patients diagnosed with unilateral VN were identified from a database of ENT vestibular clinic from January 2011 to February 2020. Medical records were reviewed to determine clinical presentation, vestibular testing results, treatment, and recovery. Fifteen patients (7 left ear, 8 right ear, mean age 58.73 ± 10.73, six female) met the inclusion criteria and were enrolled in the study. Significant differences were found in the within-subjects analysis at T1 in DHI score (p = 0.001), VOR gain (p < 0.005), and in the percentages of impulses containing a SHIMPs saccade when the head is passively turned toward the affected side (p = 0.001). SHIMPs paradigm provides useful information about the value of vestibulo-saccadic interaction as new recovery strategies in patients with VN.

Measurement of horizontal ocular deviation on magnetic resonance imaging in various disease with acute vertigo.

In our previous study, we found that horizontal ocular deviation (OD) was significantly increased in patients with unilateral vestibular neuritis (VN). This study is aimed to compare the measurements of horizontal OD in various diseases which can present as acute vertigo in the emergency department. We retrospectively reviewed patients who visited the emergency department and underwent brain MRI due to acute vertigo. We compared them to healthy controls who underwent brain MRI for a regular health examination. Among the study participants, 149 patients who were diagnosed with benign paroxysmal positional vertigo (BPPV), unilateral Ménière's disease (MD), vestibular migraine (VM), unilateral vestibular neuritis (VN), or posterior inferior cerebellar artery (PICA) infarction were enrolled. Absolute angles of horizontal OD were larger in the definite MD (19.1 ± 12.7°), possible and probable MD (15.5 ± 11.7°), and VN (22.2 ± 11.7°) groups compared to the control group (4.3 ± 3.7°). Most VN patients (83.3%) had horizontal OD toward the direction of the lesion. About half of the MD patients (46.2%) and half of the patients with PICA infarction (50.0%) had horizontal OD toward the opposite direction of the lesion. Regarding PICA infarction, horizontal OD was observed only in patients who immediately underwent an MRI after developing the PICA territory vestibulocerebellar infarction. Although the exact mechanism of horizontal OD is unclear, this study suggests that horizontal OD reflects a static vestibular imbalance, and that the eyeball is deviated to the weaker of the two vestibular nuclei during neural resting activity. Therefore, horizontal OD could be helpful in assessing for a prior vestibular imbalance.

Superior vestibular neuritis: improved detection using FLAIR sequence with delayed enhancement (1 h)

Vestibular neuritis is the second cause of vertigo and new imaging protocols using delayed FLAIR with double-dose of gadolinium are proposed for its diagnosis. Our aim is to demonstrate that a single dose of gadolinium is sufficient. Thirty-three patients with a unilateral vestibular neuritis are compared to a control group. All patients underwent a FLAIR sequence, 1hour after intravenous injection of a single dose of gadolinium, on a 1.5 Tesla MRI. Two radiologists analyzed the enhancement intensity of the superior (sup VN) and inferior vestibular nerve (inf VN) and ratios to the signal of the cerebellum were calculated (supVN/C). The statistics were performed using Bayesian analysis. A strong enhancement of the sup VN was observed on the pathological side in 85% of patients with vestibular neuritis. The average signal intensity of the pathological sup VN (139 units ± 44) was more than two times the average intensity in the control group (58.5 units ± 5). The average ratios supVN/C were significantly different between the pathological side in vestibular neuritis (2.43 units ± 0.63) and the control group [1.16 ± 0.14 (Pr(diff > 0) = 1)]. A delayed enhancement > 71.5 units had a sensitivity of 96% and a specificity of 100% for the diagnosis of superior vestibular neuritis. A delayed FLAIR sequence, acquired 1hour after a single dose of gadolinium injection, is a useful method for the diagnosis of vestibular neuritis. An enhancement of the sup VN > 71.5 units was in favor of the diagnosis.

Effect of peripheral vestibular pathologies on reading ability and auditory-verbal memory

Background and Aim: Auditory-verbal mem­ory and reading problems are frequently obser­ved in patients with vestibular disorders, but rarely considered as a cognitive consequence of vestibular disease. Many clinicians do not rec­ognize or ignore the psychological symptoms of vestibular disease. This approach could under­estimate the cognitive problems of the patients, or even led to misdiagnosis of a combined ves­tibular-cognitive condition. The current study aimed to assess the cognitive impact of acute vestibular disorders.&#x0D; Methods: A total of 71 patients with unilateral vestibular neuritis, Meniere’s disease, and ben­ign paroxysmal positional vertigo underwent a through audiologic evaluation, including otos­copy, pure tone audiometry, tympanometry, vestibular evoked myogenic potentials, video­nystagmography plus caloric testing, and video head impulse testing in the plane of horizontal semicircular canals. After determination of the disease, the Persian version of the dizziness handicap inventory, the Persian reading test, and Rey auditory-verbal learning test were admi­nistered.&#x0D; Results: There were no significant difference between the patient groups with regard to their inabilities like reading and learning problems according to their auditory verbal memory score induced by acute vertigo. However, acute ver­tigo can reduce the reading ability and capacity of auditory-verbal memory of the patients com­pared with normal subjects.&#x0D; Conclusion: Unilateral vestibular disorders in which patients suffer from acute rotatory vertigo could lead to reading difficulties and learning because of auditory-verbal memory impairment. The exact mechanism of vestibular impairment is not a determinant factor for these cognitive problems.

Recovery Pattern of High-Frequency Acceleration Vestibulo-Ocular Reflex in Unilateral Vestibular Neuritis: A Preliminary Study.

Objective: To explore the recovery pattern of the high-frequency acceleration vestibulo-ocular reflex (VOR) function in unilateral vestibular neuritis (UVN).Methods: Forty-seven consecutive patients with UVN were recruited within 10 days of symptom onset for this study. The high-frequency acceleration horizontal VOR function was assessed using the video head impulse test (vHIT). Patients returned for follow-up evaluation at ~6 months after the onset of symptoms. According to the dizziness handicap inventory questionnaire (DHI), the patients were classified into the normal to mild dizziness group (DHI score ≤30) and moderate to severe dizziness group (DHI score >30) at the follow-up. All the obtained horizontal vHIT gains and corrective saccades parameters were analyzed.Results: vHIT results showed a significantly horizontal VOR gain recovery in UVN patients at the follow-up on the lesion side (p < 0.01). A significantly reduction in the occurrence of corrective saccades (overt and covert) and velocity of corrective saccades (overt and covert) were observed at the follow-up (p < 0.05). At the follow-up, the normal to mild dizziness group (DHI score ≤30) had a significantly higher normal rate of VOR gain, the mean vHIT gains and occurrence of isolated covert saccades (P < 0.05). Furthermore, the occurrence of mixed saccades and the mean velocity of covert saccades were significantly lower in normal to mild dizziness group (P < 0.05).Conclusion: Apart from the recovery of the VOR gain, recovery pattern of corrective saccades can play a key role in vestibular compensate.

Diagnostic value of eye movement and vestibular function tests in patients with posterior circulation infarction

Objective: To evaluate the diagnostic value of eye movements and vestibular function tests in PCI patients.Methods: Thirty-eight PCI patients and 31 patients with unilateral vestibular neuritis (UVN) were enrolled and underwent eye movement tests and vestibular function tests (spontaneous nystagmus [SN], head-shaking nystagmus [HSN]).Results: The rates of eye movement abnormality were 78.9% and 41.9% in PCI and UVN patients, respectively. The positive rate of SN and HSN were, respectively, 41.2% and 43.8% in cerebellar infarction patients, 33.3% and 66.7% in medullary infarction patients, and 100.0% and 86.2% in UVN patients. The horizontal direction of SN and HSN coincided with the affected side in cerebellar infarction patients, and the healthy side in UVN patients, which coincided with the healthy side and the affected side, respectively in medullary infarction patients. The horizontal direction of HSN was bidirectional nystagmus in 16.0% (4/25) of UVN patients.Conclusions and significance: Eye movement and vestibular function tests contribute to the early diagnosis of PCI. The horizontal direction of SN and HSN are consistently toward the affected side in cerebellar infarction patients and the healthy side in UVN patients, in contrast to medullary infarction patients, and deserve further investigations.