Light cupula: the pathophysiological basis of persistent geotropic positional nystagmus

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.

Pathological Study of Light Cupula Syndrome on a Visual Bionic Semicircular Canal

A type of persistent direction-changing positional nystagmus with a null point during head position deflection is known as light cupula syndrome (LCS) in the clinic. To date, the pathogenesis and biomechanical response of human semicircular canals with light cupula syndrome (LCS) (HSCs-LCS) are still unclear. In this study, based on the anatomical structure and size of the one-dimensional human semicircular canal (HSC) and imitating the pathological changes of the endolymph in HSC with LCS, a visual bionic semicircular canal (BSC) with LCS was fabricated using three-dimensional printing technology, hydrogel modification, and target tracking technology. Through theoretical derivation, mathematical models of the HSC-LCS perception process were established. By conducting in vitro experiments on the bionic model, the biomechanical response process of HSC-LCS was studied, and the mathematical models were validated. The results of pulse acceleration stimulation showed that the pathological changes in the density and viscosity of the endolymph could reduce the deformation of the cupula of the BSC-LCS and increase the time constant. The results of the sinusoidal acceleration stimulation showed that the amplitude-frequency gain of the BSC-LCS decreased and the phase difference increased. The BSC-LCS can be used as a tool for pathological research of the HSC-LCS. The results of this study can provide a theoretical basis for clinical diagnosis.

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.

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.

17O-labeled water distribution in the human inner ear: Insights into lymphatic dynamics and vestibular function

We evaluated the inner ear distribution of 17O-labeled saline administered to the human tympanic cavity. Magnetic resonance imaging was performed after intratympanic administration in five healthy volunteers and one patient with cochlear endolymphatic hydrops. In all volunteers, 17O-labeled water permeated the cochlear basal turn and vestibule at 30 min and disappeared gradually within 2–4 h. All participants experienced positional vertigo lasting a few hours to a few days. Visualization of 17O-labeled water distribution in the endolymphatic space of the posterior ampulla showed indistinct separation of endolymph and perilymph in the cochlea and most of the vestibule in all participants. Intralabyrinthine distribution of 17O-labeled water differed from that in previous reports of intratympanically administered gadolinium-based contrast agent. 17O-labeled water in the endolymphatic space may cause heavier endolymph and positional vertigo. These results of this study may add new insights for investigating the distribution and the effects of molecules in the inner ear after the intratympanic administration in living humans.

[Benign paroxysmal positional vertigo : Typical and unusual clinical findings]

Benign paroxysmal positional vertigo (BPPV) is the most frequent form of vertigo seen in patients attending emergency departments. Leading symptoms are short attacks of vertigo provoked by head or body rotations. BPPV is caused by small calcium crystals, so-called otoconia, which are dislocated from the macula of the utricle mostly into the posterior semicircular canal. Free floating otoconia can move under the influence of gravity inside the semicircular canal (canalolithiasis) or adhere to the cupula (cupulolithiasis) causing displacement of the cupula. This results in positional nystagmus, whose directions and time courses are characteristic for the affected semicircular canal and the underlying cause. In recent years, however, a number of cases were reported, in which direction and times course of nystagmus differed from typical clinical findings. This may cause diagnostic problems.

[Benign paroxysmal positional vertigo : Typical and unusual clinical findings]

Benign paroxysmal positional vertigo (BPPV) is the most frequent form of vertigo seen in patients attending emergency departments. Leading symptoms are short attacks of vertigo provoked by head or body rotations. BPPV is caused by small calcium crystals, so-called otoconia, which are dislocated from the macula of the utricle mostly into the posterior semicircular canal. Free floating otoconia can move under the influence of gravity inside the semicircular canal (canalolithiasis) or adhere to the cupula (cupulolithiasis) causing displacement of the cupula. This results in positional nystagmus, whose directions and time courses are characteristic for the affected semicircular canal and the underlying cause. In recent years, however, a number of cases were reported, in which direction and times course of nystagmus differed from typical clinical findings. This may cause diagnostic problems.

Clinical Implications of Horizontal Beating Nystagmus Induced by Dix-Hallpike Test in the Diagnosis of Horizontal Canal Benign Paroxysmal Positional Vertigo

OBJECTIVES

The purpose of this study was to identify the diverse patterns of nystagmus during the Dix-Hallpike test (DHT) and analyze their clinical significance in horizontal canal benign paroxysmal positional vertigo (HC-BPPV).

STUDY DESIGN

Retrospective medical records review.

PATIENTS

Two hundred ninety-five patients diagnosed with HC-BPPV.

METHODS

Various nystagmus patterns identified during the DHT in patients with HC-BPPV were analyzed. The correlation between the affected side of HC-BPPV and the direction of the horizontal beating nystagmus (HBN) during the DHT was also analyzed.

RESULTS

The nystagmus pattern during the DHT in 128 patients with geotropic HC-BPPV demonstrated, direction-changing positional nystagmus on both sides in 48 (37.5%) patients, HBN toward one side in 25 (19.6%) patients, and no nystagmus in 55 (42.9%) patients. In 144 patients with apogeotropic HC-BPPV, 54 (37.5%) patients presented with direction-changing positional nystagmus on both sides, 27 (18.8%) patients presented with HBN toward one side, and 63 (43.7%) patients did not show nystagmus during the DHT. The direction of HBN provoked by the DHT was significantly correlated with the affected side in each subtype of HC-BPPV (geotropic type, p = 0.049; apogeotropic type, p = 0.040; respectively).

CONCLUSION

More than half of the patients with HC-BPPV (56.6%) showed HBN during the DHT. When HBN was present during the DHT, it may provide a clue for determining the subtype and affected side in diagnosis of HC-BPPV before performing the supine roll test.

Update on Nystagmus and Other Ocular Oscillations

This review reports on recent advances in understanding nystagmus and other involuntary eye movements. Advances in quantitative evaluations of eye movements using oculography, computational model simulations, genetics, and imaging technologies have markedly improved our understanding of the pathophysiology of involuntary eye movements, as well as their diagnosis and management. Patient-initiated capture of eye movements, especially when paroxysmal, and the online transfer of these data to clinicians would further enhance the ability to diagnose involuntary eye movements.

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.

Differences in the Head Roll Test, Bow and Lean Test, and Null Plane between Persistent and Transient Geotropic Direction-Changing Positional Nystagmus

Background: Persistent geotropic direction-changing positional nystagmus (DCPN) has the characteristics of cupulopathy, but its underlying pathogenesis is not known. We investigated the relationship of the results of the head roll test, bow and lean test, and side of the null plane between persistent and transient geotropic DCPN to determine the lesion side of persistent geotropic DCPN and understand its mechanism. Methods: We enrolled 25 patients with persistent geotropic DCPN and 41 with transient geotropic DCPN. We compared the results of the head roll test, bow and lean test, and side of the null plane between the two groups. Results: The rates of bowing and leaning nystagmus were significantly higher in the persistent DCPN group. Only 16.0% of the persistent DCPN patients had stronger nystagmus in the head roll test and the null plane on the same side. The rates of the direction of bowing nystagmus in the bow and lean test and stronger nystagmus in the head roll test on the same side were also significantly lower in persistent DCPN than in transient DCPN. Conclusion: It was difficult to determine the lesion side in persistent geotropic DCPN using the direction of stronger nystagmus in the head roll test and null plane when the direction of the stronger nystagmus and null plane were opposite. Further study is needed to understand the position of the cupula according to head rotation and the anatomical position in persistent geotropic DCPN.

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.

Three-dimensional analysis of the vestibulo-ocular reflex and the ability to distinguish the direction of centripetal acceleration in humans during eccentric rotation with the right ear facing downwards

This study was conducted to evaluate the linear vestibulo-ocular reflex (lVOR) mediated by the saccule, and to investigate the relationship between the lVOR and the ability to distinguish the direction of centripetal acceleration during centric and eccentric rotation. Participants sat on a chair in darkness, with the right ear facing downwards, either directly above the center of rotation, or with their nose out, nose in, right shoulder out, or left shoulder out against the center of rotation (eccentric rotation). Participants were given no information about the chair position, and were rotated sinusoidally at 0.1-0.7 Hz. Three-dimensional eye movements during rotation were analyzed. Participants were asked to describe the position of the chair after rotation. Correctly reporting the five possible chair positions requires recognition of the direction of centripetal acceleration. We analyzed the rate of correct answers to assess participants' ability to identify the direction of centripetal acceleration. lVOR mediated by the saccule was observed only at high rotational frequencies. The rate of correct answers was higher at high rotational frequencies than that at low rotational frequencies. These results indicate that high rotational frequency is important for both lVOR mediated by the saccule and distinguishing the direction of centripetal acceleration.

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.

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.

Office-based differential diagnosis of transient and persistent geotropic positional nystagmus in patients with horizontal canal type of benign paroxysmal positional vertigo

CONCLUSION

A 30 s observation of geotropic positional nystagmus is sufficient to distinguish persistent geotropic positional nystagmus (PGPN) from transient geotropic positional nystagmus (TGPN) in patients with horizontal canal type of benign paroxysmal positional vertigo (H-BPPV) in ENT office.

OBJECTIVE

As a canalith repositioning procedure effectively treats H-BPPV with TGPN, but not PGPN, the differentiation between patients with PGPN and with TGPN is essential. The purpose of this study is to determine the observation period enough to distinguish TGPN from PGPN.

METHODS

This study first analyzed positional nystagmus images recorded with an infrared CCD camera three-dimensionally in 47 patients with H-BPPV. PGPN is distinguished from TGPN in patients with H-BPPV precisely by means of time constant calculated form analysis of positional nystagmus. Ten-second and 30-s movies were made of positional nystagmus of the all 47 patients. Ten independent otolaryngologists were then asked to distinguish TGPN from PGPN after a 10 s or 30 s observation of the geotropic positional nystagmus images in 47 patients with H-BPPV.

RESULTS

The sensitivity and specificity to distinguish TGPN from PGPN was 100% and 97% after 30 s observation, but 100% and 40% after 10 s observation, respectively.

Neuro-otology- some recent clinical advances

Vestibular disorders manifesting as vertigo, chronic dizziness and imbalance are common problems in neurological practice. Here, we review some recent interesting and important advances in diagnosis of vestibular disorders using the video head impulse test and in the management of benign positional vertigo and migrainous vertigo.

New scoring system of an interview for the diagnosis of benign paroxysmal positional vertigo

Conclusion This study investigated a novel instrument to diagnose benign paroxysmal positional vertigo (BPPV). Objective To develop a new scoring system of an interview for the diagnosis of BPPV. Methods The answers to questions on dizziness and/or vertigo (D/V) (571 patients) were analyzed and the questions for which the answers differed significantly between the patients with and without BPPV were selected. Results This study established an intensive questionnaire with a scoring system. It consists of the following questions: (1) Is rotary vertigo a characteristic of your D/V? (2) Is your D/V triggered when you roll your head over in a supine position? (3) Does your D/V disappear within 5 min? (4) Have you previously experienced hearing loss in one ear, or have you experienced hearing loss, tinnitus, or ear fullness with this D/V? One point each was given to an answer of 'yes' to questions (1) and (2). Two points were given to an answer of 'yes' to question (3). One point was subtracted upon an answer of 'yes' to question (4). When the total score was greater than two points, the patient was diagnosed with BPPV. The sensitivity of the diagnosis of BPPV by this scoring system was 81% and the specificity was 69%.

Clinical course of persistent geotropic direction-changing positional nystagmus with neutral position-Light cupula

CONCLUSION

A short clinical course and frequent recurrence are common features of persistent geotropic direction-changing positional nystagmus with neutral position (positional nystagmus of light cupula: PNLC) and cupulolithiasis of the lateral semicircular canal. It is suggested that PNLC is caused by light debris attached to the cupula of the lateral semicircular canal.

OBJECTIVES

PNLC is a sub-type of direction-changing positional nystagmus. It is thought to be caused by anti-gravitational deviation of the cupula of the lateral semicircular canal (light cupula); however, the exact mechanism is yet to be elucidated. To this end, the clinical features of PNLC were studied.

METHOD

Clinical charts of 27 patients (13 men and 14 women) with PNLC were reviewed.

RESULTS

The nystagmus had resolved within a week in 70% and within 30 days in 89% of the patients. The recurrence rate was 33%. The subjects did not have a history of alcohol intake, head trauma, or vestibular neuritis.

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.