A new method for evaluating lateral semicircular canal cupulopathy

Clinical characteristics and lateralization of the horizontal semicircular canal light cupula

Introduction

Positional vertigo and nystagmus are the main symptoms and signs of dizziness, respectively. Despite the clinical utility of the supine roll test (SRT) and null point (NP) in diagnosing light cupula, a type of positional vertigo, there exists a notable gap in the literature concerning the comprehensive evaluation of lateralization values based on various nystagmus characteristics and the intensity of direction-changing positional nystagmus (DCPN) in the SRT, particularly in comparison to the NP. Additionally, limited data on abnormal canal paresis (CP) in light cupula patients underscores the need for further research with a larger patient population to elucidate this mechanism. This study aims to investigate the characteristics of positional nystagmus and lateralization of the horizontal semicircular canal (HSCC) light cupula, which is a type of positional vertigo and nystagmus that is poorly understood.

Methods

Eighty-five patients (17 males, 68 females; mean age, 60.9 years) with light cupula were reviewed. We summarized the characteristics of spontaneous nystagmus and positional nystagmus, including supine positioning nystagmus, bow nystagmus, and lean nystagmus. Then, the side of the NP was identified as the affected side, and the values of the fast phase direction of the spontaneous nystagmus, supine positioning nystagmus, bow nystagmus, and lean nystagmus, as well as the intensity of the DCPN in the SRT, were used to diagnose the affected sides. Caloric testing was also performed for some patients.

Results

Light cupula was observed in 5.7% of the patients with positional nystagmus. The frequencies of supine positioning nystagmus (88.2%), bow nystagmus (90.6%), and lean nystagmus (83.5%) were higher than spontaneous nystagmus (61.2%) (p < 0.001). The second NP (NP2) (92.9%) and third NP (NP3) (83.5%) were readily detected, affecting the left and right sides in 38 and 47 patients, respectively. Lateralization through the fast phase directions of bow nystagmus and lean nystagmus did not significantly differ from that of NP (all p > 0.05). However, the accuracy rate of lateralization through the sides with more vigorous DCPN in the SRT was 63.5%, significantly lower than through NP (p < 0.001). Particularly in patients with supine positioning nystagmus (n = 75), the rate was only 58.7% (p < 0.001). However, the rate was 100% in patients without supine positioning nystagmus (n = 10). Among the 70 patients who underwent caloric testing, 37 had abnormal CP, and the sides of the reduced caloric reaction were ipsilateral to the affected sides of the light cupula in 83.8% of the patients.

Conclusion

Besides utilizing the NP to determine the affected side, the fast phase direction of the bow nystagmus or lean nystagmus can also aid in identification. However, a simple comparison of the intensity of DCPN in SRT cannot provide accurate lateralization, especially in patients with supine positioning nystagmus. There is a high incidence of CP on the affected side of the light cupula.

The Light Cupula Phenomenon: A Scoping Review

Direction-changing positional nystagmus (DCPN), which refers to the change in the direction of nystagmus with different head positions, is a well-known characteristic of horizontal semicircular canal BPPV. The supine head roll test is commonly used to diagnose horizontal canal BPPV. However, persistent geotropic DCPN observed during this test cannot be explained by the conventional explanations of canalolithiasis or cupulolithiasis. To account for this unique nystagmus, the concept of a "light cupula" has been recently introduced. In this review, we provide an overview of the historical background, clinical features and diagnostic methods, proposed mechanisms, and treatment strategies associated with the light cupula phenomenon based on the available literature to date.

Efficacy of the Head Rotation Test With Bowing for the Lateral Canal Benign Paroxysmal Positional vertigo

OBJECTIVES

To evaluate the efficacy of the head rotation test with bowing (B-HRT) in the sitting position in diagnosing lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV).

METHODS

The efficacy outcomes of lateralization of 25 patients with LSC-BPPV were prospectively evaluated using B-HRT. Traditional head toration in the supine position (S-HRT) and the bow and lean test were also assessed for comparative effectiveness.

RESULTS

Direction-changing nystagmus was detected in all patients with LSC-BPPV (100%) using B-HRT. The nystagmus direction (geotropic or apogeotropic) determined by B-HRT was consistent with that determined by S-HRT with a perfect level of agreement (Cohen κ = 1.0, p < 0.001**). In 76.0% of the cases, the determination of the affected ear was concordant between B-HRT and S-HRT (Cohen κ = 0.409, p = 0.037*). The concordance rate between B-HRT and bow and lean test showed a fair level of agreement (68.0%; Cohen κ = 0.286, p = 0.126) with no statistical significance. On comparing the peak slow-phase velocity (SPV), SPVs of positional nystagmus on the stronger side and weaker side did not differ statistically significantly between S-HRT and B-HRT. In 12 of the 25 cases, in which the peak SPV asymmetry was determined as less than 30% by S-HRT (average, 11.00 ± 6.87%), the asymmetry determined by B-HRT (average, 47.31 ± 34.78%) was significantly higher, facilitating lesion identification by performing B-HRT together ( p = 0.001*).

CONCLUSION

B-HRT in the sitting position identified direction-changing nystagmus in LSC-BPPV. B-HRT is helpful in facilitating the diagnosis of LSC-BPPV in the sitting position and determination of the affected ears in cases with nonprominent differences in bilateral nystagmus intensity according to S-HRT.

Posterior canal benign paroxysmal positional vertigo with long duration: Heavy or light cupula?

Objective

To investigate the characteristics of positional nystagmus in posterior semicircular canal (PSCC) benign paroxysmal positional vertigo (BPPV) patients with longer durations, and to discuss the possible underlying mechanism of this nystagmus.

Methods

We conducted a retrospective review, and enrolled 118 consecutive patients with unilateral PSCC BPPV. The duration of nystagmus during a Dix-Hallpike test was classified into short (<1 min) and long (≥1 min) durations. For the identification of a neutral point in PSCC BPPV patients with long durations, the patient's head was turned 45° to the lesioned side to set the affected PSCC on the sagittal plane, and the disappearance of positional nystagmus was investigated in a pitch plane.

Results

Among 118 patients with PSCC BPPV, positional nystagmus during a Dix-Hallpike test showed short durations (<1 min) in 112 patients and long durations (≥1 min) in 6 patients. Of 6 PSCC BPPV patients with a long duration, a neutral point was identified in 5 patients whose nystagmus lasted for longer than 2 min; interestingly, a neutral point was observed when the patient's head was slightly tilted backward in all 5 patients.

Conclusion

Considering that a neutral position was identified when the patient's head was slightly tilted backward while keeping the head turned 45° to the right or left, we assume that the light cupula condition of the ipsilateral PSCC or the contralateral anterior semicircular canal, and not PSCC BPPV cupulolithiasis, could be responsible for the occurrence of persistent torsional-upbeating nystagmus in a Dix-Hallpike test.

Level of Evidence

4.

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.

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

OBJECTIVE

Otolithic dysfunction is investigated in cases of direction-changing horizontal positional nystagmus (DCHPN) due to peripheral vestibular disorders.

METHODS

The static-subjective visual vertical (S-SVV) was conducted in DCHPN cases within 48 h after onset.

RESULTS

The absolute values of S-SVV deviations of patients with Light cupula and lateral canal-benign paroxysmal positional vertigo-cupulolithiasis (L-BPPV-Cup) were significantly different from those of healthy subjects (p < 0.001, p < 0.05, respectively), whereas there were no significant differences in those of patients with L-BPPV-Canalolithiasis-geotropic (L-BPPV-Can-g) or L-BPPV-Can-ageotropic (L-BPPV-Can-a) versus healthy subjects. Significant differences were found in S-SVV (+: deviation to the affected side, -: deviation to the unaffected side) between patients with Light cupula and those with L-BPPV-Can-g, L-BPPV-Can-a and L-BPPV-Cup (p < 0.01, p < 0.05, and p < 0.001, respectively), as well as between those with L-BPPV-Can-g and L-BPPV-Cup (p < 0.01). The S-SVV in patients with Light cupula, L-BPPV-Can-g, and L-BPPV-Can-a deviated more to the affected side, whereas that in patients with L-BPPV-Cup deviated more to the unaffected side.

CONCLUSION

Mild otolithic dysfunctions were found in patients with DCHPN due to the presence of peripheral vestibular disorders within 48 h after onset. The extent of otolithic (utricular) disorders in patients with DCHPN is estimated in decreasing order as follows: Light cupula > L-BPPV-Cup > L-BPPV-Can-g and L-BPPV-Can-a. Many patients with L-BPPV-Cup likely suffer from disorders of the pars externa of the utricular macula, whereas many patients with L-BPPV-Can-g likely suffer from disorders of the pars interna of the utricular macula. L-BPPV-Can-a and L-BPPV-Can-g must be induced by a common mild utricular disorder.

Light cupula phenomenon: a systematic review

Geotropic direction-changing positional nystagmus (DCPN) is transient in lateral semicircular canal (LSSK) canalolithiasis; it usually cuts off within a minute and fatigues. However, a “light cupula” mechanism has been described for patients with positional vertigo who exhibit a persistent geotropic DCPN without delay or fatigue. When the cupula becomes lighter than the surrounding endolymph, deflection may occur in the cupula under the influence of gravity. The person experiences dizziness and persistent positional nystagmus can be observed while remaining in that position.

In this review, studies investigating the “light cupula phenomenon,” which is a newly defined phenomenon in the literature, were compiled. A systematic literature search was conducted on the light cupula phenomenon in PubMed and Google Scholar databases to illuminate the clinical side of this new phenomenon and reveal its distinctive features. Turkish and English articles published between 2010 and 2021 were scanned; the thesis, reviews, and books were excluded from the study. Forty-eight articles were included in the study.

Mechanisms underlying light cupula has been explained as the “heavier endolymph hypothesis” with increased endolymph specific gravity due to an acute attack such as labyrinth hemorrhage, insufficient inner ear perfusion, or inflammation in the inner ear; “lighter cupula hypothesis” based on alcohol acting on the cupula earlier and making it lighter than the endolymph; “light particle hypothesis” due to the buoyancy of light debris, which are degenerative, swollen, and inflammatory cells in the endolymph adhering to the cupula and the “altered endolymph/perilymph density ratio hypothesis” that the difference in density between perilymph and endolymph causes light cupula. The pathophysiology of the light cupula phenomenon is still unclear, but it can be thought that all the different hypotheses may be effective in this phenomenon. Therefore, nystagmus characteristics and clinical course should be considered in patients for a more effective diagnosis and treatment process. In addition, the results of the studies show that light cupula may not be an uncommon disease and that some patients with geotropic DCPN can often be misdiagnosed as canalolithiasis LSCC-BPPV.

Analysis of the nystagmus characteristics of cupula diseases: A case report

INTRODUCTION

Clinically, there is a kind of patients with positional vertigo or dizziness, which occurs when they turn left or right, look down or up, lie down or sit up. With a long duration and varying frequency, it is not consistent with the manifestations of benign paroxysmal positional vertigo (BPPV). In addition, the persistent geotropic direction-changing positional nystagmus (PG-DCPN) was observed in a supine head-roll test.

PATIENT CONCERNS

With no apparent trigger for visual rotation and a sense of self instability, an 81-year-old female patient had suffered from vertigo for 3 days. The vertigo occurred every day, lasting several minutes each time, and associated with head movements and changes in body position. In a supine head-roll test, it appeared persistent geotropic direction-changing positional nystagmus for a long time, without latency, fatigability and in the presence of 3 zero planes.

DIAGNOSIS

Light cupula.

INTERVENTIONS

Difenidol hydrochloride 25 mg orally 3 times/day for 2 weeks and betahistine hydrochloride 12 mg orally 3 times/day for 1 month were administered.

OUTCOMES

After 1 month of treatment, the patient's vertigo symptoms disappeared. And in the supine head-roll test, the persistent geotropic direction-changing positional nystagmus disappeared.

CONCLUSION

We report the characteristics of nystagmus produced in a typical patient with light cupula during the supine head-roll test. After reviewing the relevant literatures, we believe that a simpler method can be used to identify canalolithiasis and cupula disease, to distinguish light and heavy cupula, and to determine the pathological semicircular canal to which the lesion belongs.

Clinical Characteristics of Patients with Persistent Apogeotropic and Persistent Geotropic Direction-Changing Positional Nystagmus

Background and Purpose

This study aimed to determine the clinical features, diagnosis, and treatment of patients with persistent geotropic (pG) and persistent apogeotropic (pAG) direction-changing positional nystagmus (DCPN).

Methods

This retrospective study included 30 patients with pG-DCPN and 44 patients with pAG-DCPN. All patients underwent neurological and neurotological examinations, including an evaluation of gaze-evoked nystagmus, eye-movement tests, and assessments of limb ataxia and balance, as well as magnetic resonance imaging to exclude central causes. The characteristics of positional nystagmus were detected using the supine roll test (SRT) and bow-and-lean test (BLT). The null point (NP) at which the nystagmus disappeared was determined. All patients were treated with the barbecue maneuver, and treatment efficacy was evaluated immediately, 1 week, and 1 month after treatment.

Results

The history of diseases associated with atherosclerosis, peripheral vestibular disorders, otological disease, and migraine differed significantly between patients with pG-DCPN and pAG-DCPN. The affected sides of persistent horizontal DCPN can be determined using the SRT and the BLT, while determining the second NP and vestibular function as well as performing an audiological evaluation can be used to assist in identifying the affected side. The efficacy rates immediately and 1 week after treatment with the barbecue maneuver were higher in patients with pAG-DCPN than in patients with pG-DCPN.

Conclusions

pAG-DCPN was more compatible with the characteristics of cupulolithiasis, and pG-DCPN was more likely to be associated with a light cupula rather than canalolithiasis. pAG-DCPN was more likely to be accompanied by a disease associated with atherosclerosis, while pG-DCPN was often accompanied by autoimmune-related diseases and a history of migraine. The associations between pAG-DCPN, pG-DCPN, and the above-mentioned diseases need to be clarified further. The canalith-repositioning maneuver was effective in patients with pAG-DCPN and ineffective in patients with pG-DCPN, but most cases of pG-DCPN are self-limiting.

Light Cupula: To Be Or Not to Be?

Benign paroxysmal positional vertigo (BPPV) represents the most common form of positional vertigo. It is caused by dislodged otoconia that freely float in the semicircular canals (canalolithiasis) or attach to the cupula (cupulolithiasis). A cupulolithiasis-type (or a heavy cupula-type) of BPPV implicating the lateral semicircular canal (LSCC) exhibits persistent ageotropic direction-changing positional nystagmus (DCPN) in a head-roll test. However, in some cases, unlike any type of BPPV, persistent geotropic DCPN cannot be explained by any mechanisms of BPPV, and don't fit the current classifications. Recently, the notion of light cupula has been introduced to refer to the persistent geotropic DCPN. In this study, we looked at the clinical features of light cuplula and discussed the possible mechanisms and therapeutic strategies of the condition. The notion of light cupula is a helpful addition to the theory of peripheral positional vertigo and nystagmus.

Comorbid Cupulolithiasis Is Rare in Patients With Horizontal Semicircular Canal Canalolithiasis

OBJECTIVES

Considering that otolith particles pass through the canal until attaching to the cupula in the canal-side horizontal semicircular canal (HSCC) cupulolithiasis, comorbidity of HSCC canalolithiasis and cupulolithiasis may occur. We aimed to investigate the incidence of comorbidity of cupulolithiasis in patients with HSCC canalolithiasis and to improve treatment efficacy.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral academic center.

PATIENTS

Ninety-seven consecutive patients with HSCC canalolithiasis between March 2017 and March 2019 were included.

MAIN OUTCOME MEASURES

Coexistence of HSCC cupulolithiasis was hierarchically investigated. 1) Spontaneous reversal of initial nystagmus is observed bilaterally in a head-roll test (HRT), 2) nystagmus is in the same direction at each of the three times the supine position was tested, and 3) both bowing and leaning nystagmus with opposite direction are observed.

RESULTS

Of 97 patients with HSCC canalolithiasis, 2 patients (2%) had comorbid HSCC cupulolithiasis.

CONCLUSIONS

Although coexistence of HSCC canalolithiasis and cupulolithiasis should be considered when spontaneous reversal of nystagmus direction is observed without position change during a HRT, the incidence of coexistence is very low. However, canalith repositioning maneuvers for both canalolithiasis and cupulolithiasis should be performed in cases with comorbidity.

Direction-fixed and Direction-changing Positional Nystagmus in Ramsay Hunt Syndrome

OBJECTIVES

To investigate the incidence of positional nystagmus (PN) using a head-roll test in patients with Ramsay Hunt syndrome with vertigo (RHS_V) and discuss possible mechanisms.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral academic medical center.

PATIENTS

Twenty-eight patients with RHS_V were enrolled.

MAIN OUTCOME MEASURE

Eye movements were recorded at positions of head roll to the right or left, and PN was classified as direction-fixed or direction-changing. Vestibular function tests including caloric test were performed.

RESULTS

Direction-fixed nystagmus beating away from the affected side was the most common type of PN (61%), followed by direction-changing geotropic type (18%), direction-fixed nystagmus beating toward the affected side (14%), and direction-changing apogeotropic type (7%). The duration of nystagmus was longer than 60 seconds in all patients exhibiting direction-changing PN. Postcontrast T1-weighted internal auditory canal (IAC) magnetic resonance imaging showed enhancement of not only the facial and vestibulocochlear nerves, but also the inner ear structures or dura along the IAC, suggesting inflammatory changes within the labyrinthine membrane or IAC dura.

CONCLUSION

Although direction-fixed PN was more commonly observed (75%), direction-changing PN was also observed in some RHS_V patients (25%). The mechanism of direction-changing PN may be, at least in part, explained by the alteration of specific gravity of the lateral semicircular canal cupula or endolymph due to inflammation in the inner ear membrane.

Clinical Findings in Patients With Persistent Positional Nystagmus: The Designation of "Heavy and Light Cupula"

Objective: Direction-changing positional nystagmus (DCPN) had been observed as persistent horizontal apogeotropic and was considered as “cupulolithiasis or heavy cupula. ” Recently, the concept of “light cupula” exhibiting persistent geotropic DCPN has been introduced. However, the light cupula is not systematically described, while the identification and diagnosis of “light cupula” should be improved. Here we investigated the underlying characteristics and therapeutic options designed to the “light” and “heavy” cupula, respectively; and summarized the clinical characteristics and therapeutic effect in the two groups.

Methods: A total of 359 cases with vertigo and bilateral DCPN were found in the supine roll test. Only 25 patients with persistent DCPN were enrolled and followed up. According to the direction of nystagmus, we further divided the patients into “heavy cupula” (apogeotropic) and “light cupula” (geotropic) groups. We compared the incidence, characteristics of nystagmus and the efficacy of repositioning maneuver in the two groups.

Results: Nine patients with persistent horizontal geotropic DCPN were confirmed as “light cupula,” other 16 patients with persistent horizontal ageotropic DCPN were confirmed as heavy cupula. All 25 patients had null plane; the mean value and standard deviation of the null plane in light cupula and heavy cupula was 25.67 ± 9.31° and 27.06 ± 6.29°, respectively. The mean value and standard deviation of the termination plane in light cupula was 28.78 ± 10.00°, and 30.25 ± 6.53° in heavy cupula. There was no statistical significance between the two groups. We found that the direction of evoked nystagmus in the supine position was toward the intact side in light cupula, while in heavy cupula, it was toward the lesion side. The null plane appeared on the lesion side. For light cupula patients, the effect was not obvious at Day-7 after the treatment, however, treatment for most heavy cupula patients were effective. All patients recovered after 30 days of treatment.

Conclusion: The null plane is crucial in determining the lesion side for light or heavy cupula. Although the short-term therapeutic effect of the light cupula is not as promising as the effect seen in heavy cupula, the long-term prognosis in both groups is comparable; with all patients recovered after 30 days of treatment.

Study design: This is a retrospective cohort study.

Density difference between perilymph and endolymph: A new hypothesis for light cupula phenomenon

Light cupula is an emerging concept accounting for positional nystagmus. It can be diagnosed when persistent geotropic direction-changing positional nystagmus (PG DCPN) is observed in a head-roll test. Although hypotheses explaining light cupula phenomenon such as "light debris", "lighter cupula", and "heavier endolymph" have been proposed, the mechanism underlying light cupula has not been clearly elucidated yet. In the present study, we proposed a new hypothesis accounting for light cupula, i.e., density difference between perilymph and endolymph could elicit characteristic PG DCPN in a head-roll test. We also discussed the mechanism how membranous canal containing endolymph became buoyant within the perilymphatic space under constant influence of gravity when the density of perilymph was higher than that of endolymph.

Is the modified cupulolith repositioning maneuver effective for treatment of persistent geotropic direction-changing positional nystagmus?

OBJECTIVE

Clinicians sometimes see patients with relatively persistent geotropic direction-changing positional nystagmus (DCPN) as a variant of lateral semicircular canal-benign paroxysmal positional vertigo (LSCC-BPPV). Recently, the concept of a "light cupula" in the lateral semicircular canal, exhibiting persistent geotropic DCPN, has been introduced. However, the underlying pathogenesis of light cupula is not known. We investigated the efficacy of a modified cupulopathy repositioning maneuver (mCuRM), designed to reduce light debris attached to the cupula in patients with persistent geotropic DCPN.

STUDY DESIGN

Retrospective cohort study.

METHODS

Participants included 65 patients with a persistent geotropic DCPN: 35 underwent treatment (mCuRM group), and 30 were followed-up but received no treatment (No CuRM group). We compared the therapeutic and survival rate of persistent geotropic DCPN between two groups.

RESULTS

On Day 1, the persistent geotropic DCPN did not resolve in either group. On the first and second follow-up days, persistent geotropic DCPN was observed in 28 (80%) and 21 (60%) of patients, respectively, in the mCuRM group, and in 28 (93.3%) and 24 (80%) patients, respectively, in the no mCuRM group. The differences between groups were not statistically significant. Furthermore, no between-group differences were found in the time from diagnosis to resolution of nystagmus, or the time from symptom onset to resolution of nystagmus. Kaplan-Meier analysis of the time course of persistent geotropic DCPN resolution from the day of diagnosis and day of symptom onset revealed no significant differences between the groups.

CONCLUSION

Our findings indicate that mCuRM had no therapeutic benefit for a persistent geotropic DCPN and suggest that the pathophysiology of persistent geotropic DCPN is less likely to be a light debris attached to the cupula.

Nystagmus intensity and direction in bow and lean test: an aid to diagnosis of lateral semicircular canal benign paroxysmal positional vertigo

The objective was to evaluate nystagmus intensity and direction (NID) during bow and lean test (BLT) in subjects suffering from idiopathic lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV), in order to differentiate between the geotropic and the apogeotropic form and to determine the affected ear before using classic diagnostic procedures. The BLT was performed in 32 subjects affected by LSC-BPPV. "Nystagmus intensity" evaluation allows distinguishing the geotropic variant from the apogeotropic one, while the "nystagmus direction" allows identification of the side. In particular, a more intense nystagmus in the bow position compared to the lean position indicates an ampullipetal flow caused by the presence of free-floating particles in the non-ampullary arm, and is suggestive of geotropic form. In this case, if the nystagmus in the bow position is left beating, the free-floating particles necessarily occupy the left LSC non-ampullary arm, while a right-beating nystagmus indicates the right LSC involvement. In contrast, a more intense nystagmus in the lean position compared to the bow position indicates an ampullifugal flow due to the presence of particles adherent to the cupula (cupulolithiasis) or free-floating in the ampullary arm (canalolithiasis), suggesting an apogeotropic form. In this situation, if the nystagmus in the lean position is left beating, the particles are in the left LSC ampullar arm or are coated on the left LSC cupula; vice versa, a right-beating nystagmus in the lean position is suggestive of the involvement of the right LSC. As a general rule, in both forms the direction of the more intense nystagmus points to the affected side. "NID-BLT" was effective in identifying the form and the side in 22/28 subjects (79% of the study population). The proper execution and interpretation of the "NID-BLT" helps to establish the form (geotropic versus apogeotropic) and side (right versus left) in most cases of LSC-BPPV. Unlike Choung's test, which requires knowing a priori if the form is geotropic or apogeotropic, our test enables fast and accurate diagnosis, or at least provides indispensable elements if the diagnosis of the affected side is doubtful, with the patient remaining in the sitting position.

Utility of the bow and lean test in predicting subtype of benign paroxysmal positional vertigo

OBJECTIVES/HYPOTHESIS

To investigate the role of the bow and lean test (BLT) in the diagnosis of benign paroxysmal positional vertigo (BPPV).

STUDY DESIGN

Retrospective case-control study.

METHODS

Between March 2015 and June 2017, we enrolled 113 patients with posterior semicircular canal (PSCC) BPPV, 74 patients with lateral semicircular canal (LSCC) canalolithiasis, 53 patients with LSCC cupulolithiasis, and 32 patients with light cupula. We retrospectively assessed bowing nystagmus (BN) and leaning nystagmus (LN).

RESULTS

In PSCC BPPV, 75% of the patients showed at least one of BN and LN, and direction of nystagmus provoked by a Dix-Hallpike test on the affected side was consistent with that of LN and opposite to that of BN. In LSCC canalolithiasis, 65% (48 of 74) of the patients showed both BN and LN, which were in the same direction in 38 patients (of 48) and in the opposite direction in 10 patients (of 48). The affected side can be determined according to the results of THE BLT in 74% (55 of 74) of LSCC canalolithiasis patients, and among them, the side determined according to the results of head-roll test was discordant with that according to the BLT in 20 of 55 patients (36%). In LSCC cupulopathy (n = 85), both BN and LN were persistent and observed in all cases, but we could not distinguish LSCC cupulolithiasis from light cupula according to nystagmus direction in the BLT.

CONCLUSIONS

Although a BLT yields better lateralization in LSCC canalolithiasis, it may be more useful in predicting the diagnosis and lateralization of PSCC BPPV than LSCC canalolithiasis.

LEVEL OF EVIDENCE

4 Laryngoscope, 2600-2604, 2018.

Treatment of benign paroxysmal positional vertigo. A clinical review

Benign paroxysmal positional vertigo (BPPV) is the most frequent episodic vestibular disorder. It is due to otolith rests that are free into the canals or attached to the cupulas. Well over 90% of patients can be successfully treated with manoeuvres that move the particles back to the utriculus. Among the great variety of procedures that have been described, the manoeuvres that are supported by evidenced-based studies or extensive series are commented in this review. Some topics regarding BPPV treatment, such as controlling the accuracy of the procedures or the utility of post-manoeuvre restrictions are also discussed.

The Light Cupula: An Emerging New Concept for Positional Vertigo

Benign paroxysmal positional vertigo (BPPV) is the most common type of positional vertigo. A canalolithiasis-type of BPPV involving the lateral semicircular canal (LSCC) shows a characteristic direction-changing positional nystagmus (DCPN) which beats towards the lower ear (geotropic) on turning the head to either side in a supine position. Because geotropic DCPN in LSCC canalolithiasis is transient with a latency of a few seconds, the diagnosis can be challenging if geotropic DCPN is persistent without latency. The concept of “light cupula” has been introduced to explain persistent geotropic DCPN, although the mechanism behind it requires further elucidation. In this review, we describe the characteristics of the nystagmic pattern in light cupula and discuss the current evidence for possible mechanisms explaining the phenomenon.

Practice Guidelines for the Diagnosis and Management of Benign Paroxysmal Positional Vertigo Otoneurology Committee of Spanish Otorhinolaryngology and Head and Neck Surgery Consensus Document

Benign Paroxysmal Positional Vertigo is the most frequent episodic vestibular disorder. The purpose of this guide, requested by the committee on otoneurology of the Spanish Society of Otolaryngology and Head and Neck Surgery, is to supply a consensus document providing practical guidance for the management of BPPV. It is based on the Barany Society criteria for the diagnosis of BPPV. This guideline provides recommendations on each variant of BPPV, with a description of the different diagnostic tests and the therapeutic manoeuvres. For this purpose, we have selected the tests and manoeuvres supported by evidence-based studies or extensive series. Finally, we have also included a chapter on differential diagnosis and a section relating to general aspects in the management of BPPV.

Direction-reversing Nystagmus in Horizontal and Posterior Semicircular Canal Canalolithiasis

OBJECTIVES

To investigate the incidence and characteristics of direction-reversing nystagmus in patients with horizontal (HSCC) and posterior semicircular canal (PSCC) canalolithiasis, and evaluate the effect of direction-reversing nystagmus on the treatment outcome.

STUDY DESIGN

A retrospective study.

METHODS

Between March 2014 and September 2015, 63 and 92 consecutive patients with HSCC and PSCC canalolithiasis, respectively, were enrolled. Positional nystagmus characteristics were examined using video-nystagmography.

RESULTS

In HSCC canalolithiasis, direction-reversing nystagmus was observed in 73% of patients (46 of 63), of which 19 cases were bilateral and 27 unilateral. In patients with bilateral reversal, maximal slow-phase velocity (mSPV) was significantly greater when the head turned to the lesioned side than to the healthy side in both the first and second phase. In all patients with unilateral reversal, direction-reversing nystagmus always occurred in the side of stronger initial nystagmus in a supine roll test. The mean mSPV of first phase nystagmus was significantly greater on the side with reversal than without (p < 0.001). The duration of second-phase nystagmus exceeded 60 seconds in all patients with reversal. Although not statistically significant (p = 0.059), patients presenting with direction-reversing nystagmus required more repositioning maneuver sessions. In contrast to HSCC canalolithiasis, only 4% of patients (4 of 92) with PSCC canalolithiasis exhibited spontaneous reversal of initial nystagmus.

CONCLUSION

The incidence of direction-reversing nystagmus was higher in HSCC canalolithiasis than in PSCC canalolithiasis, and second-phase (direction-reversing) nystagmus in HSCC canalolithiasis has a prolonged duration. Short-term adaptation of the vestibulo-ocular reflex may be responsible for the development of direction-reversing nystagmus.

Pseudo-spontaneous nystagmus in horizontal semicircular canal canalolithiasis

Benign paroxysmal positional vertigo (BPPV) involving horizontal semicircular canal (HSCC) is characterized by direction-changing positional nystagmus (DCPN) in a supine roll test, and the occurrence of spontaneous nystagmus in HSCC BPPV has been reported recently. The aim of this study is to investigate the characteristics of pseudo-spontaneous nystagmus (PSN) in patients with HSCC canalolithiasis, and evaluate the effect of the presence of PSN on treatment outcome.Between April 2014 and January 2016, 75 and 59 patients with HSCC canalolithiasis and cupulolithiasis, respectively, were enrolled. Spontaneous and positional nystagmus were examined.PSN was observed in 31 of 75 patients (41%) with HSCC canalolithiasis, and 55 of 59 patients (93%) with HSCC cupulolithiasis. PSN persisted during the period of observation, which was at least 1 minute in all patients with PSN. In HSCC canalolithiasis, direction-reversing nystagmus was observed in 58 patients (25 bilateral and 33 unilateral). Nine of 25 patients with bilateral direction-reversing nystagmus, and 22 of 33 patients with unilateral direction-reversing nystagmus showed PSN. None of 17 patients without direction-reversing nystagmus showed PSN. The direction of PSN corresponded to that of direction-reversing nystagmus in all 22 patients with unilateral direction-reversing nystagmus. The proportion of patients who recovered after 1 session of repositioning maneuver was not significantly different between patients with and without PSN (P = .867).PSN was observed more commonly in HSCC cupulolithiasis than canalolithiasis. The pathophysiologic mechanism underlying PSN can be explained by natural inclination of HSCC and medial to lateral orientation of the HSCC cupular axis in cupulolithiasis, and by spontaneous reversal of initial positional nystagmus (direction-reversing nystagmus) generated by short-term adaptation of vestibulo-ocular reflex in canalolithiasis. The presence of PSN in HSCC canalolithiasis may not affect the treatment outcome.

Sudden sensorineural hearing loss with positional vertigo: Initial findings of positional nystagmus and hearing outcomes

OBJECTIVES

To investigate the initial findings of positional nystagmus in patients with sudden sensorineural hearing loss (SSNHL) and positional vertigo, and to compare hearing improvement among patients with different types of positional nystagmus.

DESIGN

The characteristics of positional nystagmus upon initial examination were analysed, and the initial mean pure-tone audiometry (PTA) threshold was compared with that at three months after treatment.

STUDY SAMPLE

Forty-four SSNHL patients with concomitant positional vertigo were included.

RESULTS

Positional nystagmus was classified into five subgroups; persistent geotropic direction-changing positional nystagmus (DCPN) in head-roll test (HRT) and negative Dix-Hallpike test (DHT), persistent apogeotropic DCPN in HRT and negative DHT, positive DHT and negative HRT, persistent geotropic DCPN in HRT and positive DHT, and persistent apogeotropic DCPN in HRT and positive DHT. PTA threshold improvement was significantly greater in SSNHL patients with negative DHT than with positive DHT (p = 0.027).

CONCLUSIONS

When geotropic DCPN was elicited by HRT, the nystagmus was persistent, which suggests that alteration of specific gravity of the endolymph, rather than the lateral canal canalolithiasis, may be a cause of this characteristic positional nystagmus. Positive DTH may be a prognostic factor for worse hearing recovery among patients with SSNHL and positional vertigo.

Nystagmus in patients with unilateral acute otitis media complicated by serous labyrinthitis

Conclusion The patients with serous labyrinthitis caused by acute otitis media (AOM) exhibited various patterns of nystagmus in which direction-fixed irritative-type nystagmus was the most common pattern. Differential effects on inner ear function by toxic or inflammatory mediators may be responsible for the various manifestation of nystagmus. Objective This study aimed to investigate nystagmus patterns in patients with serous labyrinthitis, and discuss possible mechanisms. Methods From October 2011 to March 2014, 13 consecutive patients with serous labyrinthitis were included. Eye movements of the patients were serially examined using video-nystagmography, and patterns of nystagmus were investigated. Results The most commonly observed pattern was direction-fixed nystagmus (nine of 13 patients). Of these, eight showed irritative-type, and one showed paretic-type. Direction of nystagmus, although the intensity gradually decreased, was not changed during the course of treatment. One patient showed direction-changing spontaneous nystagmus, which changed into paretic-type direction-fixed nystagmus 1 day after myringotomy. Three patients exhibited persistent direction-changing positional nystagmus in a supine head-roll test. Of them, two showed apogeotropic and one showed geotropic type. In all 13 patients, vertigo and hearing loss were improved after the treatment.

Change of nystagmus direction during a head-roll test in lateral semicircular canal cupulolithiasis

OBJECTIVE

To demonstrate positional nystagmus during a head-roll test in two patients with lateral semicircular canal (LSCC) cupulolithiasis who presented with spontaneous detachment of otoliths from the LSCC cupula, and to confirm that otoliths may adhere to both the utricle and canal sides of the cupula.

PATIENTS AND METHODS

Using video nystagmography, positional nystagmus was evaluated in two patients with LSCC cupulolithiasis who showed the change of nystagmus direction during a head-roll test.

RESULTS

Both patients presented with persistent left-beating and right-beating nystagmus when the head was bent forward and backward, respectively. This suggests the presence of either cupulolithiasis on the right side or light cupula on the left side of the LSCC. In Case 1, transformation from cupulolithiasis to canalolithiasis occurred, implicating the detachment of otoliths from the canal side of the right LSCC cupula. In Case 2, vigorous right-beating nystagmus was followed by persistent left-beating nystagmus when the head was rolled to the left. Following this, direction-fixed left-beating nystagmus was observed at all positions, which may indicate that otoliths attached on utricle side of the right LSCC cupula were detached and fell into the utricle under the influence of gravity. A conversion of nystagmus direction may be explained by an expression of short-term adaptation of vestibular tone.

CONCLUSIONS

Otoliths can be attached to either side of the cupula in LSCC cupulolithiasis. Because it is difficult to determine the attached side at the time of diagnostic maneuver, the therapeutic approach should include maneuvers designed to detach otolith particles from both the utricle and canal side.

Lateralization of horizontal semicircular canal canalolithiasis and cupulopathy using bow and lean test and head-roll test

Accurate lateralization is important to improve treatment outcomes in horizontal semicircular canal (HSCC) benign paroxysmal positional vertigo (BPPV). To determine the involved side in HSCC-BPPV, the intensity of nystagmus has been compared in a head-roll test (HRT) and the direction of nystagmus was evaluated in a bow and lean test (BLT). The aim of this study is to compare the results of a BLT with those of a HRT for lateralization of HSCC-canalolithiasis and cupulopathy (heavy cupula and light cupula), and evaluate treatment outcomes in patients with HSCC-canalolithiasis. We conducted retrospective case reviews in 66 patients with HSCC-canalolithiasis and 63 patients with HSCC-cupulopathy. The affected side was identified as the direction of bowing nystagmus on BLT in 55 % (36 of 66) of patients with canalolithiasis, which was concordant with the HRT result in 67 % (24 of 36) of cases (concordant group). Lateralization was determined by comparison of nystagmus intensity during HRT in 30 patients who did not show bowing or leaning nystagmus. The remission rate after the first treatment was 71 % (17 of 24) in the concordant group and 45 % (5 of 11) in the discordant group. Both bowing and leaning nystagmus were observed in all patients with cupulopathy, and the side of the null plane was identified as the affected side. In conclusion, bowing and/or leaning nystagmus were observed in only 55 % of patients with HSCC-canalolithiasis, and the first treatment based on the result of BLT alone was effective in only 45 % of the patients in whom the BLT and HRT were discordant, which may suggest that the usefulness of BLT in lateralizing the HSCC-canalolithiasis may be limited.

Persistent Positional Vertigo in a Patient with Sudden Sensorineural Hearing Loss: A Case Report

Because inner ear organs are interconnected through the endolymph and surrounding endolymphatic membrane, the patients with sudden sensorineural hearing loss (SSNHL) often complain of vertigo. In this study, we report a patient with SSNHL accompanied by persistent positional vertigo, and serial findings of head-roll tests are described. At acute stage, head-roll test showed persistent geotropic direction-changing positional nystagmus (DCPN), which led to a diagnosis of SSNHL and ipsilateral light cupula. Although vertigo symptom gradually improved, positional vertigo lasted for more than 3 weeks. At this chronic stage, persistent apogeotropic DCPN was observed in a head roll test, which led to a diagnosis of the heavy cupula. Although the mechanism for the conversion of nystagmus direction from geotropic to apogeotropic persistent DCPN is unclear, the change of specific gravity of the endolymph might be one of the plausible hypothetical explanations.

Conversion between geotropic and apogeotropic persistent direction-changing positional nystagmus

CONCLUSION

Clinical features in the course of conversion differed between patients with SSNHL and cupulopathy, which indicates that the pathophysiology of persistent geotropic or apogeotropic DCPN and the mechanism of the change in nystagmus direction may differ between the two groups.

OBJECTIVE

The aim of this study is to investigate clinical characteristics of 10 patients with persistent DCPN who exhibited a conversion of nystagmus direction between geotropic and apogeotropic, and discuss possible mechanisms.

METHODS

Using video-oculography, serial examinations of nystagmus in a head-roll test were performed.

RESULTS

Of these 10 patients, five had sudden sensorineural hearing loss (SSNHL) and the remaining five had cupulopathy. In SSNHL, direction of nystagmus changed from geotropic to apogeotropic in three patients and from apogeotropic to geotropic in two patients. In cupulopathy, persistent apogeotropic DCPN always preceded persistent geotropic DCPN. The change in nystagmus direction occurred earlier in patients with cupulopathy (1 or 2 days after vertigo onset) than in patients with SSNHL (4-23 days after vertigo onset). While the null plane was consistently identified on one side, regardless of the nystagmus direction in cupulopathy, it was not always identified on the side of hearing loss in SSNHL.