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.

Clinical Characteristics of Horizontal Canal Benign Paroxysmal Positional Vertigo with Persistent Geotropic Direction Changing Positional Nystagmus / 대한평형의학회지

OBJECTIVE: The purpose of this study was to identify the clinical characteristics of horizontal canal benign paroxysmal positional vertigo (h-BPPV) with persistent geotropic direction changing positional nystagmus (DCPN). METHODS: One hundred thirty two patients diagnosed as the geotropic subtype of h-BPPV were analyzed retrospectively. Patients were classified into two groups: persistent h-BPPV (ph-BPPV) group which means h-BPPV showing persistent (>1 minute) geotropic DCPN and short duration h-BPPV (sh-BPPV) group that means h-BPPV with short duration (< or =1 minute) geotropic DCPN. We compared the clinical characteristics and treatment outcomes between the two groups. RESULTS: The study included 34 patients with ph-BPPV and 98 patients with sh-BPPV. There were no differences between the two groups in age, distribution of sex and the affected side. The ph-BPPV group had higher secondary BPPV preponderance and dizziness handicap index (DHI) score compared to the sh-BPPV group. The ph-BPPV group required higher number of canalith repositioning procedures (CRPs) until resolution and higher multiple/single CRP ratio than the sh-BPPV group. In addition, the ph-BPPV group showed longer duration until the remission of subjective symptoms (vertigo, dizziness) compared to the sh-BPPV group. CONCLUSION: ph-BPPV was more frequently associated with secondary causes of BPPV and demonstrated higher DHI score, total number of CRP, and longer remission duration of subjective symptoms compared to sh-BPPV. This information may be helpful for clinicians in counseling and managing the patients with persistent geotropic DCPN h-BPPV.

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.

A Case of Congenital Vestibular Anomaly with Direction Changing Positional Nystagmus / 대한이비인후과학회지

Direction changing positional nystagmus (DCPN) is defined as a nystagmus that changes its direction with different head and body positions. In the past, it was usually thought that DCPN was the sign of central vestibular system lesion. But recently, there have been some reports that DCPN definitely does not localize the site of lesion in the central vestibular pathway, and that it more often indicates a peripheral vestibular site. However, congenital vestibular dys- or hypoplasia was not reported as a cause of DCPN. Recently, we experienced a 17-year-old patient who had a vestibular dys- or hypoplasia and showed a transient geotrophic DCPN with a normal cochlea. We report that congenital vestibular dys- or hypoplasia can be one of the causes of DCPN and present its possible mechanism.

Direction Changing Positional Nystagmus from Canalolithiasis and Cupulolithiasis of Lateral Semicircular Canal / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Clinical features of positional nystagmus may be different according to the etiology. Thus, efforts have been made to find out etiologies of various positional nystagmus. Until recently, positional vertigo was thought to arise from lesions of central nervous system. However, more recent investigations suggest that the peripheral lesion may be the main cause. Moreover, there have been some reports suggesting that directional changing positional nystagmus occurs due to canalolithiasis and cupulolithiasis of the lateral semicircular canal. The objectives of the study were to investigate the etiologies and clinical aspects of DCPN (direction changing positional nystagmus) from canalolithiasis and cupulolithiasis of the lateral semicircular canal, and to assess the effectiveness of the treatment. MATERIALS AND METHODS: Among 15 patients with DCPN, 9 patients showed nystagmus compatible with canalolithiasis of lateral semicircular canal and 6 patients with cupulolithiasis of lateral semicircular canal. Patients with cupulolithiasis and canalithiasis of the lateral semicircular canal did not respond to physical therapy for posterior semicircular canal. However, they were completely recovered by reposition maneuver for the lateral semicircular canal with or without using vibrator although 3 of them had recurred symptom. Four patients had BPPV of the posterior semicircular canal prior to the development of DCPN and 3 patients underwent the treatment of previous Meniere's disease. CONCLUSION: The patients with DCPN were due to canalithiasis and cupulolithiasis of the lateral semicircular canal, and physical therapy for lateral semicircular canal was rewarding.