Assessments of Subjective Visual Gravity and Spontaneous Nystagmus in Patients With Vestibular Neuritis.

OBJECTIVE: This study aimed to assess the correlation between the spontaneous nystagmus (SN) and the subjective visual vertical/horizontal (SVV/SVH) among patients with vestibular neuritis (VN) at the different head positions. STUDY DESIGN: Case-control study. SETTING: Affiliated Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine. METHODS: This study evaluated the SVV/SVH in both healthy subjects and patients with VN. These evaluations were performed in 5 different head positions: upright, 45° tilt to the left, 90° tilt to the left, 45° tilt to the right, and 90° tilt to the right. Additionally, the intensity of SN, as measured by slow-phase velocity, was recorded. RESULTS: In patients with VN, a significant correlation was observed between SN and SVV/SVH in an upright position. The intensity of SN was higher when the head was tilted 90° toward the affected side compared to other positions. The SVV/SVH displayed an ipsiversive shift, when the head was tilted toward both the lesion and unaffected sides, exhibiting a contraversive direction. Furthermore, the changes in position-induced SN were consistent with the displacements of SVV and SVH caused by head tilt. CONCLUSION: The presence of SN in patients with VN was observed to vary across different head position. These variations could potentially be attributed to the diverse activation patterns of the mechanical properties of otolith organs that are induced by head tilts.

Presence of Spontaneous Nystagmus, Benign Paroxysmal Positional Vertigo, and Tumarkin Fall in Patients With Primary Headache and Their Responses to Caloric and Video Head Impulse Tests.

Background: Migraine, vestibular migraine (VM) and tension-type headache (TTH) are the most common disorders in dizziness and headache clinics, associated with dizziness or vertigo and postural imbalance, causing a substantial burden on the individual and the society. The objective of this research was to examine the presence of spontaneous nystagmus, comorbidity of benign paroxysmal positional vertigo (BPPV), and Tumarkin fall in patients; additionally, the study focused on assessing the patients' responses to bithermal caloric irrigation and video head impulse test (vHIT). Methods: Consecutive patients diagnosed with migraine, VM, and TTH according to the International Classification of Headache Disorders, third edition (beta version (ICHD-3ß)), who were referred to Dizziness and Headache Clinic were enrolled. BPPV and Tumarkin fall were assessed by questionnaires. The presence of BPPV was further evaluated through Dix-Hallpike or head roll maneuver, while spontaneous nystagmus was monitored using video-oculography during interictal period. Lastly, patients' responses to bithermal caloric irrigation and vHIT were analyzed. Results: There was a significantly higher incidence of spontaneous nystagmus in VM compared to both migraine and TTH. The drop attack episodes were slightly more frequent in VM than in TTH and migraine, though not statistically significant. The prevalence of BPPV was significantly higher in VM than in migraine and TTH. Unilateral vestibular paresis was more common in the VM group than in migraine and TTH. There was profound unilateral weakness (UW) in VM patients than in migraine, but no significant difference was found between VM and TTH. In VM, the percentage of saccades along with reduced vHIT gain was significantly higher than in migraine. Lastly, the percentage of abnormal response in vHIT was significantly lower than the percentage of abnormal UW in caloric irrigation across all groups. Conclusions: In VM patients, the prevalences of decompensated peripheral damage and BPPV were higher than in migraine and TTH patients as disclosed by the presence of peripheral spontaneous nystagmus and abnormal vHIT during the interictal period. Our findings suggest that the peripheral vestibular system acts as a significant mechanism in the pathogenesis of VM, and it might also be involved in migraine and TTH cases without vertigo symptoms.

Characteristics of spontaneous nystagmus and its correlation to video head impulse test findings in vestibular neuritis.

Objective: To explore the direction and SPV (slow phase velocity) of the components of spontaneous nystagmus (SN) in patients with vestibular neuritis (VN) and the correlation between SN components and affected semicircular canals (SCCs). Additionally, we aimed to elucidate the role of directional features of peripheral SN in diagnosing acute vestibular syndrome. Materials and methods: A retrospective analysis was conducted on 38 patients diagnosed with VN in our hospital between 2022 and 2023. The direction and SPV of SN components recorded with three-dimensional videonystagmography (3D-VNG) and the video head impulse test (vHIT) gain of each SCC were analyzed as observational indicators. We examined the correlation between superior and inferior vestibular nerve damage and the direction and SPV of SN components, and vHIT gain values in VN patients. Results: The median illness duration of between symptom onset and moment of testing was 6 days among the 38 VN patients (17 right VN and 21 left VN). In total, 31 patients had superior vestibular neuritis (SVN), and 7 had total vestibular neuritis (TVN). Among the 38 VN patients, all had horizontal component with an SPV of (7.66 ± 5.37) °/s, 25 (65.8%) had vertical upward component with a SPV of (2.64 ± 1.63) °/s, and 26 (68.4%) had torsional component with a SPV of (4.40 ± 3.12) °/s. The vHIT results in the 38 VN patients showed that the angular vestibulo-ocular reflex (aVOR) gain of the anterior (A), lateral (L), and posterior (P) SCCs on the ipsilesional side were 0.60 ± 0.23, 0.44 ± 0.15 and 0.89 ± 0.19, respectively, while the gains on the opposite side were 0.95 ± 0.14, 0.91 ± 0.08, and 0.96 ± 0.11, respectively. There was a statistically significant difference in the aVOR gain between the A-, L-SCC on the ipsilesional side and the other SCCs (p < 0.001). The aVOR gains of A-, L-, and P-SCC on the ipsilesional sides in 31 SVN patients were 0.62 ± 0.24, 0.45 ± 0.16, and 0.96 ± 0.10, while the aVOR gains on the opposite side were 0.96 ± 0.13, 0.91 ± 0.06, and 0.98 ± 0.11, respectively. There was a statistically significant difference in the aVOR gain between the A-, L-SCC on the ipsilesional side and the other SCCs (p < 0.001). In 7 TVN patients, the aVOR gains of A-, L-, and P-SCC on the ipsilesional side were 0.50 ± 0.14, 0.38 ± 0.06, and 0.53 ± 0.07, while the aVOR gains on the opposite side were 0.93 ± 0.17, 0.90 ± 0.16, and 0.89 ± 0.09, respectively. There was a statistically significant difference in the aVOR gain between the A-, L-, and P-SCC on the ipsilesional side and the other SCCs (p < 0.001). The aVOR gain asymmetry of L-SCCs in 38 VN was 36.3%. The aVOR gain asymmetry between bilateral A-SCCs and bilateral P-SCCs for VN patients with and without a vertical upward component was 12.8% and 8.3%, which was statistically significant (p < 0.05). For VN patients with and without a torsional component, the aVOR gain asymmetry of bilateral vertical SCCs was 17.0% and 6.6%, which was statistically significant (p < 0.01). Further analysis revealed a significant positive correlation between the aVOR gain asymmetry of L-SCCs and the SPV of the horizontal component of SN in all VN patients (r = 0.484, p < 0.01), as well as between the asymmetry of bilateral vertical SCCs and the SPV of torsional component in 26 VN patients (r = 0.445, p < 0.05). However, there was no significant correlation between the aVOR gains asymmetry of bilateral A-SCCs and P-SCCs and the SPV of the vertical component in 25 VN patients. Conclusion: There is a correlation between the three-dimensional direction and SPV characteristics of SN and the aVOR gain of vHIT in VN patients. These direction characteristics can help assess different SCCs impairments in patients with unilateral vestibular diseases.

The effects of continuous administration of diazepam on the recovery of lesion-induced nystagmus in unilaterally labyrinthectomised rats.

BACKGROUND: Diazepam, a gamma-aminobutyric acid type A receptor agonist, is classified as a vestibular suppressant and is effective in treating acute vertigo. However, its effects on vestibular compensation (VC) remain unclear. OBJECTIVES: We examined the effects of continuous administration of diazepam on the frequency of spontaneous nystagmus (SN) after unilateral labyrinthectomy (UL) as an index of the initial process of VC in rats. MATERIALS AND METHODS: Diazepam was continuously administered at doses of 3.5 and 7.0 mg/kg/day, intraperitoneally, via an osmotic minipump. The frequency of SN beating against the lesion side after UL was measured. Potassium chloride (KCl) solution (1 M) was injected intratympanically to induce SN beating to the injection side. RESULTS: Continuous administration of diazepam significantly and dose-dependently decreased the frequency of SN after UL, and also reduced the x intercept of the nonlinear regression curve of the decline in UL-induced SN with time in rats. However, the continuous administration of diazepam did not affect the frequency of intratympanic KCl-induced SN in the rats. CONCLUSION: These findings suggested that continuous administration of diazepam accelerates the initial process of VC; however, it does not suppress the nystagmus-driving mechanisms in rats.

Vestibular rehabilitation improves spontaneous nystagmus normalization in patients with acute unilateral vestibulopathy.

Introduction: Spontaneous nystagmus (SN) can be observed after acute unilateral vestibulopathy (AUVP). The slow phase eye velocity of the SN progressively decreases in darkness as the result of rebalanced neurophysiological activity between both vestibular nuclei, a process that can take several months. Although this compensatory process can occur spontaneously, there is poor evidence that vestibular rehabilitation (VR) can facilitate the process. Methods: We documented the natural time course of SN reduction in patients with AUVP, as well as the effects of VR by means of a unilateral rotation paradigm. In a retrospective study (Study 1: n = 126 AUVP patients), we compared the time course of the SN reduction in patients with VR (n = 33) and without VR (n = 93). In a prospective study (Study 2: n = 42 AUVP patients), we compared the effects of early VR (n = 22; initiated within the first two weeks of symptoms onset) or late VR (n = 20; initiated after the second week of symptoms onset) on the time course of the SN reduction. Results: Study 1 showed shorter median time of SN normalization in patients with VR compared to patients without VR (14 days and 90 days, respectively). Study 2 showed that AUVP patients with early and late VR had a similar median time of SN normalization. The SN slow phase eye velocity was significantly decreased as early as the end of the first VR session in both groups, and kept decreasing at each subsequent VR session. In the early VR group, 38% of the patients had slow phase eye velocity below 2°/s after the first VR session, 100% after the fifth session. Similar findings were observed in the late VR group. Discussion: Taken together, these results indicate that VR with a unidirectional rotation paradigm speeds up the normalization of SN. This effect seems independent of the time between symptoms onset and commencement of VR, but early intervention is recommended to speed up the SN reduction.

[Further exploration of the classification and clinical value of head-shaking nystagmus].

Objective:To investigate the classification of head shaking nystagmus（HSN） and its clinical value in vestibular peripheral diseases. Methods:Clinical data of 198 patients with peripheral vestibular disorders presenting with HSN were retrospectively analyzed. Video Nystagmograph（VNG） was applied to detect spontaneous nystagmus（SN）, HSN, and Caloric Test（CT）. The intensity and direction of SN and HSN as well as the unilateral weakness（UW） and direction preponderance（DP） values in caloric test was analyzed in patients. Results:Among the 198 patients with vestibular peripheral disease, there were 105 males and 93 females, with an average age of（49.1±14.4） years （range: 14-87 years）. One hundred and thirty seven patients were diagnosed as Vestibular Neuritis（VN）, 12 as Meniere's Disease（MD）, 41 as sudden deafness（SD） and 8 as Hunt's syndrome accompanied by vertigo. Among them, there were 116 patients in the acute phase, including 68 cases（58.6%） with decreased HSN, 4 cases（3.4%） with increased HSN, 5 cases（4.3%） with biphasic HSN, 38 cases（32.8%） with unchanged HSN, and 1 case（0.9%） with perverted HSN. There were 82 cases in the non-acute phase, 51 cases（62.2%） with decreased HSN, 3 cases（3.6%） with increased HSN, 9 cases（11.0%） with biphasic HSN, and 19 cases（23.2%） with unchanged HSN. In biphasic HSN, the intensity of phase I nystagmus was usually greater than that of phase II, and the difference was statistically significant（P<0.01）. There was no correlation between HSN type and course of disease or DP value. The intensity of HSN was negatively correlated with the course of disease（r=-0.320, P<0.001） and positively correlated with DP value（r=0.364, P<0.001）, respectively. The intensity of unchanged nystagmus and spontaneous nystagmus were（8.0±5.7） °/s and（8.5±6.4）°/s, respectively. There was no statistically significant difference in the intensity of nystagmus before and after shaking the head. Conclusion:HSN can be classified into five types and could be regarded as a potential SN within a specific frequency range （mid-frequency）. Similarly, SN could also be considered as a common sign of unilateral vestibular impairment at different frequencies. HSN intensity can reflect the dynamic process of vestibular compensation, and is valuable for assessing the frequency of damage in peripheral vestibular diseases and monitoring the progress of vestibular rehabilitation.

Spontaneous Nystagmus in Patients With Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo.

OBJECTIVE: This study aimed to investigate the incidence of spontaneous nystagmus (SN) in posterior semicircular canal (PSCC) benign paroxysmal positional vertigo (BPPV) and its effect on treatment outcomes. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. METHODS: This study included 50 patients with idiopathic unilateral PSCC BPPV between July 2021 and May 2022. The presence of SN was investigated, and the results of the bithermal caloric test and video head impulse test (vHIT) were compared. RESULTS: SN was observed in 13 (26%) of the 50 patients presenting PSCC BPPV. The direction of SN was mainly unidirectional and horizontal in 12 of the 13 patients with a slow-phase velocity ranging from 2 to 4°/s. One patient presented an upbeating torsional SN at the initial evaluation. The mean vHIT gain of the PSCC on the affected side was significantly lower in patients with SN than those without SN (p = .004, Mann-Whitney U test). The proportion of patients who recovered within 2 sessions of the repositioning maneuver was significantly higher in those without SN than that in those with SN (p < .001, Fisher's exact test). CONCLUSION: This study demonstrated that the treatment outcomes of PSCC BPPV were significantly worse in patients with SN than those without SN. Examining the presence of SN in patients with PSCC BPPV may be helpful in counseling the patients on prognosis, and it is expected that more sessions of canalith repositioning maneuver may be required to treat PSCC BPPV in patients with SN than those without SN.

Vestibular assessment in sudden sensorineural hearing loss: Role in the prediction of hearing outcome and in the early detection of vascular and hydropic pathomechanisms.

Introduction: Predicting hearing outcome in sudden sensorineural hearing loss (SSNHL) is challenging, as well as detecting the underlying pathomechanisms. SSNHL could be associated with vestibular damage since cochleo-vestibular structures share the same vascularization, along with being in close anatomical proximity. Whereas viral inflammations and autoimmune/vascular disorders most likely represent the involved aetiologies, early-stage Menière's disease (MD) can also present with SSNHL. Since an early treatment could beneficially influence hearing outcome, understanding the possible etiology plays a pivotal role in orienting the most appropriate treatment. We aimed to evaluate the extent of vestibular damage in patients presenting with SSNHL with or without vertigo, investigate the prognostic role of vestibular dysfunctions on hearing recovery and detect specific lesion patterns related to the underlying pathomechanisms. Methods: We prospectively evaluated 86 patients with SSNHL. Audio-vestibular investigation included pure-tone/speech/impedance audiometry, cervical/ocular-VEMPs, vHIT and video-Frenzel examination. White matter lesions (WML) were evaluated on brain-MRI. Patients were followed-up and divided into "SSNHL-no-vertigo," "SSNHL+vertigo" and "MD" subgroups. Results: Hearing was more impaired in "SSNHL+vertigo" patients who exhibited either down-sloping or flat-type audiograms, and was less impaired in "MD" where low frequencies were mostly impaired (p < 0.001). Otolith receptors were more frequently involved than semicircular canals (SCs). Although the "SSNHL-no-vertigo" subgroup exhibited the lowest vestibular impairment (p < 0.001), 52% of patients developed otolith dysfunctions and 72% developed nystagmus. Only "MD" subjects showed anterior SC impairment and upbeating spontaneous/positional nystagmus. They more frequently exhibited cervical-VEMPs frequency tuning (p = 0.036) and ipsilesional spontaneous nystagmus (p < 0.001). "SSNHL+vertigo" subjects presented with more frequently impaired cervical-VEMPs and posterior SC and with higher number of impaired receptors (p < 0.001). They mainly exhibited contralesional spontaneous and vibration-induced nystagmus (p < 0.05) and only they showed the highest WML score and "vascular" lesion patterns (p < 0.001). Concerning the outcomes, hearing was better in "MD" and worse in "SSNHL+vertigo" (p < 0.001). Hearing recovery was mostly affected by cervical-VEMPs impairment and the number of involved receptors (p < 0.05). Patients with "vascular" lesion patterns presented with the highest HL degree and WML score (p ≤ 0.001), while none of them exhibited a complete hearing recovery (p = 0.026). Conclusions: Our data suggest that vestibular evaluation in SSNHL can provide useful information on hearing recovery and underlying aetiologies.

The role of vestibular cold caloric tests in the presence of spontaneous nystagmus.

Objective: The bithermal caloric test is commonly used to detect a canal paresis. However, in case of spontaneous nystagmus, this procedure can provide results of non-univocal interpretation. On the other hand, confirming the presence of a unilateral vestibular deficit can help to differentiate between central and a peripheral vestibular involvement. Methods: We studied 78 patients suffering from acute vertigo and showing spontaneous horizontal unidirectional nystagmus. All patients were submitted to bithermal caloric tests, and the results were compared with those obtained using a monothermal (cold) caloric test. Results: We demonstrate the congruence between the bithermal and monothermal (cold) caloric test through mathematical analysis of the results of both tests in patients with acute vertigo and spontaneous nystagmus. Conclusions: We propose to perform the caloric test in the presence of a spontaneous nystagmus using a monothermal cold assuming that the prevalence of the response to the cold irrigation on the side towards which the nystagmus beats is a sign of the presence of pathological unilateral weakness and therefore more likely peripheral in its origin.

Direction-changing spontaneous nystagmus in patients with dizziness.

PURPOSE: The present study aimed to investigate the clinical features of patients with direction-changing spontaneous nystagmus (DCSN) and gain insight into its underlying mechanisms. METHODS: Medical records and vestibular function test results collected in our dizziness clinic between February 2013 and February 2020 were retrospectively reviewed. Spontaneous nystagmus was recorded while sitting upright using videonystagmography for 2 min to confirm the spontaneous changes in nystagmus direction. Causative disease diagnoses were based on the patients' clinical history, audiometry results, vestibular function tests, and imaging studies. RESULTS: Of 4786 patients, DCSN was observed in 41 (0.86%). Causative disease diagnoses included vestibular neuritis (n = 9), lateral semicircular canal cupulopathy (n = 9), cerebellopontine angle tumor (n = 8), vestibular paroxysmia (n = 2), vestibular migraine (n = 2), vestibular nucleus infarction (n = 1), sudden sensorineural hearing loss with vertigo (n = 2), Meniere's disease (n = 2), Ramsay Hunt syndrome (n = 1), labyrinthine fistula due to middle ear cholesteatoma (n = 1), lateral semicircular canal dysplasia (n = 1), post tympanomastoidectomy dizziness (n = 1), and head trauma (n = 2). CONCLUSIONS: Although the periodicity of DCSN could not be determined because of insufficiently long observation times, it was observed in various central and peripheral vestibulopathies. Careful examination of spontaneous nystagmus over a sufficient period may ensure the detection of DCSN when evaluating dizziness.

The frequency and relationship with vestibular function test results of positional preference in acute vestibular neuritis.

Objective: To assess the prevalence and relationship with vestibular function test results of positional preference in acute vestibular neuritis (VN). Methods: We prospectively recruited 33 patients with VN during the acute phase. We assessed the severity of vertigo with a visual analog scale (VAS) and the degree of spontaneous nystagmus (SN) during sitting, the head rolling to the affected, and the healthy side. Patients performed other vestibular function tests, including ocular and cervical vestibular evoked myogenic potential (VEMP), on the same day or the next day of VNG testing. Results: Twelve patients (12/33, 36%) with VN complained of more severe vertigo during lying on the affected side compared to the healthy side under visual fixation. Compared to patients without positional preference (without positional preference group), patients with positional preference (with positional preference group) showed a significantly higher VAS and maximal slow phase velocity (SPV) of SN at all positions except lying on the lesion side. However, there was no difference in the SPV gap between the two groups. 30% (10/33) of patients with VN complained of more severe vertigo while lying on the affected side compared to the healthy side without visual fixation. Maximal SPV of SN was not different between the two groups. There was no other significant difference in both canalith and otolith function test results between the two groups regardless of the visual fixation. Conclusions: One-third of patients with acute VN had more severe vertigo while lying on the affected side than in the supine position. The positional preference was not directly related to the SN intensity or VEMP results. The positional preference might reflect the otolith damage in the setting of activation of the sustained otolith system, not the transient otolithic system.

Factors associated with spontaneous nystagmus changes in acute Ménière's disease.

BACKGROUND: Neuro-otological factors that influence changes in spontaneous nystagmus (SN) during vertigo attacks in Ménière's disease (MD) remain unclear. OBJECTIVE: To identify neuro-otological factors that might influence the initial direction of SN and the directional change of SN. METHODS: A prospective, observational study of 22 patients with definite MD to evaluate the initial direction and directional change of SN during vertigo attacks, endolymphatic hydrops (EH) volume, and the function of horizontal semicircular canal and hearing levels. RESULTS: SN consistently began as irritative in 17 of 22 cases, and 9 of 17 cases showed a definite change in direction after onset. SN consistently began as paralytic in 5 of 22 cases, and 3 of 5 cases showed a definite change in direction after onset. Subjects in the irritative initial SN group had less severe degrees of hearing loss, smaller cochlear and vestibular EH volume than the paralytic initial SN group (P = 0.017, < 0.001, and 0.009, respectively). Subjects in the SN direction change group had significantly smaller maximum slow phase velocity, percentage of caloric weakness and canal paresis than the no SN direction change group (P = 0.001, 0.006, and 0.001, respectively). Simple logistic regression analysis showed that smaller EH volume was significantly associated with initial irritative SN (OR = 0.867, 95% CI 0.762-0.988, P = 0.032) and that the degree of canal paresis was negatively associated with the presence of directional change of SN (OR = 0.022, 95% CI 0.002-0.289, P = 0.004). CONCLUSIONS: The morphology of EH and canal paresis may independently affect the characteristics of SN in patients with MD.

Comparisons of Supine Roll Test and Alternative Positional Tests in HC-BPPV Lateralization.

OBJECTIVE: The purpose of the study was to evaluate the efficiency of the supine roll test (SRT) and alternative positional tests (APTs) including the bow and lean test (BLT), pseudo-spontaneous nystagmus (PSN), and lying down nystagmus (LDN) to identify the affected side in horizontal canal benign paroxysmal positional vertigo (HC-BPPV). METHODS: In our prospective study, we performed a testing profile (PSN, BLT, LDN, SRT) on 59 HC-BPPV patients using videonystagmography. We compared the accuracy and sensitivity of these tests in HC-BPPV lateralization. Data from 30 healthy patients were collected as the control group. RESULTS: When performing positional tests, the elicited nystagmus coinciding with Ewald's second law was defined as a "positive response". In 44 patients with geotropic nystagmus, the rates of positive response in LDN, PSN, and BLT were 22/44 (50%), 19/44 (43%), and 18/44 (41%), respectively, while in 15 patients with apogeotropic nystagmus, the positive response rates of these three tests were 10/15 (66.7%), 9/15 (60%), and 4/15 (27.00%), respectively. The sensitivity of LDN (54.38%) was higher than that of PSN (47.37%) and BLT (38.60%) but lower than that of SRT (89.47%). Notably, the accuracy rate of PSN (71.8%) was higher than that of the other APTs. In 6 patients with symmetrical nysgtamus during the roll test, 5 patients showed a positive response in both LDN and BLT (83.34%), whereas 4 patients showed a positive response in PSN (66.67%). CONCLUSION: All positional tests are helpful for determining the affected side of HC-BPPV, but SRT carries the highest accuracy of lateralization followed by PSN.

Cupulolithiasis as an Alternative Mechanism for Pseudo-spontaneous Nystagmus in Horizontal Canal Benign Paroxysmal Positional Vertigo.

Benign paroxysmal positional vertigo of the horizontal semicircular canal may present a differential diagnostic challenge. In addition to the classical positional nystagmus, a persistent nystagmus in a seated position occasionally occurs, so-called pseudo-spontaneous nystagmus (PSN), which can be mistaken for a central or peripheral spontaneous nystagmus. We report a case with cupulolithiasis of the horizontal semicircular canal presenting with horizontal PSN in a sitting position, with implications for a new pathomechanism of PSN.

Relationship between spontaneous nystagmus and video Head Impulse Test findings among patients with chronic neurotologic conditions.

The vestibulo-ocular reflex (VOR) in neurotologic patients can be evaluated most quickly by spontaneous nystagmus examinations, and the video Head Impulse Test (vHIT) quantitatively evaluates the VOR of the semicircular canals. We aimed to clarify the concordance and discrepancies between spontaneous nystagmus and vHIT findings, to provide guidance on screening vestibular functions by initial spontaneous nystagmus examination then vHIT. We evaluated 169 outpatients by spontaneous nystagmus examination in the dark using a charge-coupled device camera, then by horizontal vHIT the same day. Vestibular loss on vHIT was defined if both reduced VOR gain (<0.8) and corrective saccade were observed. Adjusted logistic regression modelling revealed that differences in right and left VOR gain positively impacted the presence of nystagmus, which suggests lateralised vestibular dysfunction (P<0.05; odds ratio 1.39 [95% confidence interval, 1.1-1.8] per 0.1 increment). When vHIT is regarded as the standard clinical test, the positive predictive value of nystagmus for vestibular loss on vHIT was 44.4%, and the negative predictive value was 93.5%. The adjusted odds ratio of adults ≥65 years old compared to younger patients associated with a discrepancy of nystagmus and vHIT was significant (2.4 [1.1-5.3]). In conclusion, if spontaneous nystagmus is initially observed in patients, further assessment by vHIT could confirm vestibular dysfunction in 40-50% of cases. If no nystagmus is observed, vHIT might also result in a negative finding in >90% of cases. Older adults appear more likely to show discrepancies between nystagmus and vHIT.

Direction-changing spontaneous nystagmus in cerebellopontine angle tumour.

The most common symptoms of tumours involving the cerebellopontine angle (CPA) are unilateral sensorineural hearing loss, dizziness, and asymmetric tinnitus. While the clinical manifestations have been well documented in previous studies, the nystagmus findings in these patients have not been thoroughly investigated yet. This study aimed to investigate the incidence of direction-changing spontaneous nystagmus in patients with CPA tumours, evaluate their radiologic characteristics, and gain insight into the mechanisms underlying nystagmus. Direction-changing spontaneous nystagmus was observed in 6 out of 83 patients (7%) with CPA tumours during the 7-year period. Temporal bone magnetic resonance imaging findings revealed the presence of an intrameatal mass in CPA tumours in all six patients with direction-changing spontaneous nystagmus. Vestibular schwannomas were confined within the internal auditory meatus in four patients, and petroclival meningiomas extended into the internal auditory meatus in two patients. The mechanism of direction-changing spontaneous nystagmus may be explained as paroxysmal secondary central hyperactivity in the vestibular nucleus due to the long-standing pressure effect in the vestibular nerve by tumours, or by ephaptic discharges in the vestibular nerve.

Pseudo-spontaneous nystagmus in patients with lateral canal benign paroxysmal positional vertigo.

BACKGROUND: Pseudo-spontaneous nystagmus (PSN) can be detected in patients with lateral canal benign paroxysmal positional vertigo (LC-BPPV). Its frequency, and correlation with the therapeutic outcome have been less described and conflicting results have been reported. OBJECTIVE: This study aims to investigate its clinical and prognostic significance. MATERIAL AND METHOD: One hundred and eighty-four patients with LC BPPV (98 apogeotropic, 86 geotropic type) were enrolled for the study. Clinical parameters were reviewed in patients with or without PSN. The Chi-square and one way ANOVA tests were used to compare the difference between study groups. Statistical significance was set at p < .05. RESULTS: Twenty-two patients with apogeotropic (22.4%; 98/22) and 17 patients with geotropic nystagmus (19.7%; 86/17) had PSN. The incidence, age, male-female ratio, mean slow phase velocity (SPV), duration of BPPV and the rate of recurrence were not significant in patients with LC-BPPV whether they have PSN or not. CONCLUSION: Prognostic role of PSN in patients with LC BPPV seems to be questionable. SIGNIFICANCE: Appearance and disappearance of PSN with regard to head position helps to differentiate BPPV from other acute vestibular disorders. Additionally, direction of nystagmus assists to determine the site of the affected canal. However, prognostic significance is obscure.

Pseudo-spontaneous nystagmus increases Bow and Lean Test accuracy.

OBJECT: The aim of this study was to evaluate the effectiveness of the Bow and Lean Test (BLT) based on nystagmus intensity and direction evaluation (NID-BLT) in the diagnosis of benign paroxysmal positional vertigo of the lateral semicircular canal (LSC-BPPV). We hypothesised that the presence of a pseudo-spontaneous nystagmus increases the diagnostic accuracy of the test. METHODS: The BLT was performed in 32 subjects affected by LSC-BPPV. RESULTS: BLT was positive in 27 cases with a sensitivity of 84.3% and an accuracy of 70.4%. In other words, it was possible to carry out a BPPV root canal diagnosis (LSC) with BLT in 27 patients, of whom 19 also received a diagnosis of side and form. Pseudo-spontaneous nystagmus was detected in 15 patients, all of whom were BLT positive. In these patients, a clear diagnosis of form and side was also obtained in 14 cases (accuracy 93.3%). In the 12 patients without pseudo-spontaneous nystagmus and BLT positive, a diagnosis of side and form was reached in 5 cases (accuracy 41.6%). The comparison between percentages (Chi square test) showed a significant difference (p = 0.038). CONCLUSIONS: The presence of a pseudo-spontaneous nystagmus, as an expression of more mobile debris within the canal or a more deflectable cupula, increases the accuracy of the BLT.

Subjective Evaluation of Balance by the Dizziness Handicap Inventory Does Not Predict Fall Risk in Older Adults Visiting Otolaryngology Clinics.

OBJECTIVES: Subjective symptoms of dizziness in older adults are affected not only by objective data such as postural balance, but also by complex psychological factors. Published data analyzing how simultaneous evaluations of both objective and subjective assessments of balance can predict fall risk remain lacking. This study examined how fall risk can be predicted based on both objective data for balance and hearing and subjective symptoms of dizziness among older adults visiting otolaryngology clinics. METHODS: Medical charts of 76 patients ≥65 years old with dizziness/vertigo who visited the otolaryngology clinic were reviewed. Objective data were evaluated by postural balance (posturographic data with eyes open and closed, and one-leg standing test), spontaneous nystagmus, and mean hearing levels. Subjective handicap associated with dizziness/vertigo was assessed using the Dizziness Handicap Inventory (DHI). Subjective mental status of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS). Information on history (cardiovascular diseases) and fall accidents within the preceding year was collected using an in-house interview sheet. RESULTS: Objective data on postural balance did not correlate with subjective symptoms on DHI or HADS (P > .05, Pearson's correlation coefficient). Adjusted logistic regression modeling with the outcome of incident falls revealed that poor postural balance significantly predicted fall risk (P < .05; 4.9 [1.4-16.8] per 10-cm2 increment). Nystagmus tended to be associated with fall risk. In contrast, DHI score did not predict fall risk (P = .43; 1.0 [0.9-1.03]). Receiver operating characteristic analysis proposed a cut-off for postural sway with eyes closed >6.1 cm2 as optimal to predict falls in patients with nystagmus (AUC, 0.74; 95% confidence interval, 0.48-0.997). CONCLUSION: Poor postural balance is associated with increased fall risk after adjusting for subjective symptoms in older adults at otolaryngology clinics. Conversely, the self-perceived dizziness handicap of DHI score is an insufficient tool to evaluate their fall risk.

Rat Model of Ménière's Attack: Intratympanic Injection of Potassium Chloride Produces Direction-Changing Spontaneous Nystagmus and Hearing Fluctuations.

The major symptoms of Ménière's disease are episodic vertigo, fluctuating hearing loss, and tinnitus. Direction-changing spontaneous nystagmus is a characteristic vestibular finding in Ménière's disease. In the acute stage, spontaneous nystagmus beating to the affected side (irritative nystagmus) is often observed, while paralytic nystagmus beating to the healthy side is found in the chronic stage. This direction-changing nystagmus can be reproduced in guinea pigs by increasing the potassium ion concentration in the perilymph. The objectives of the present study were to examine the effects of increasing the potassium ion concentration of the rat perilymph on hearing and nystagmus. Under isoflurane anesthesia, 22 rats received intratympanic injection of different concentrations of potassium chloride (KCl) solution or distilled water: groups 1, 2, 3, and 4 received saturated (3.4 M) KCl solution, 2 M KCl, 1 M KCl, and distilled water, respectively. The nystagmus direction and number per 15 s were monitored for 150 min. In the other 8 rats, hearing was monitored 30 min and 20 h after intratympanic injection of 2 M KCl (group 5) or distilled water (group 6) using the auditory brainstem responses. Rats in groups 1 and 2 showed spontaneous irritative nystagmus beating to the affected ear followed by paralytic nystagmus beating to the contralateral side. In group 3, irritative nystagmus occurred but paralytic nystagmus was rarely observed. Rats in group 4 showed no nystagmus. Rats in group 5 showed significant hearing impairment 30 min after KCl injection that recovered 20 h later. Control animals in group 6 showed no significant changes in hearing. The reversible hearing impairment with direction-changing spontaneous nystagmus induced by potassium injection into the tympanic cavity in rats was quite similar to that observed in acute Ménière's attacks. This rat model could be used for basic research investigating the pathophysiological mechanisms underlying Ménière's attacks.