Minbum Kim

Isolated horizontal positional nystagmus from a posterior fossa lesion

Isolated vertigo with horizontal positional nystagmus as an impending sign of a central lesion has rarely been reported. Here we present neuro‐otologic findings of patients with these clinical signs. Lesion overlays from 6 patients with ageotropic positional nystagmus revealed that the nodulus and vermis are common areas of injury. In contrast, 2 patients with geotropic positional nystagmus had cerebellar peduncle and lateral medullary lesions. These clinical findings suggest that vertigo with horizontal positional nystagmus, even in the absence of other initial neurological signs, may indicate a posterior fossa lesion, including that in the nodulus, vermis, and deep cerebellar structures. Ann Neurol 2014;76:905–910

Canal conversion between anterior and posterior semicircular canal in benign paroxysmal positional vertigo.

Objective To investigate the characteristics of canal conversion between the anterior and posterior semicircular canals in benign paroxysmal positional vertigo (BPPV). Study Design Retrospective chart review. Setting Secondary referral center. Patients A total of 709 patients who were treated with the Epley maneuver for BPPV of the anterior or posterior semicircular canal. Interventions Vestibular examinations with videonystagmography and the canalith repositioning procedure (CRP) to treat BPPV. Results Canal conversion between the anterior and posterior semicircular canals was observed in 18 (2.9%) patients who underwent CRP. In 13 (2.3%) of 564 patients initially diagnosed with posterior canal BPPV (PC-BPPV), switch to anterior canal BPPV (AC-BPPV) was observed at a follow-up visit. In 5 (12.1%) of 41 patients who presented with AC-BPPV, canal switch to PC-BPPV occurred more frequently (p = 0.005). The average number of CRPs before nystagmus resolution was 3.6 in conversion cases versus 1.6 in the nonconversion group (p < 0.001). Conclusion Canal conversion between the anterior and posterior semicircular canals can occur during treatment. The possibility of canal conversions should be considered for appropriate management of BPPV of the vertical semicircular canals.

Intraindividual comparison of psychophysical parameters between perimodiolar and lateral-type electrode arrays in patients with bilateral cochlear implants.

Objective Perimodiolar electrode arrays were developed to improve stimulation of specific neuronal populations and to decrease power consumption; however, they can damage the cochlear structure. We examined and compared psychophysical parameters of perimodiolar and lateral-type electrode arrays in patients who received a different type of bilateral cochlear implant (CI) in each ear. Study Design Retrospective analysis. Setting Tertiary referral center. Patients Eight child patients (three males, five females) received a different CI in each ear (perimodiolar array and lateral array). They received the CIs sequentially (n = 7) or simultaneously (n = 1). Interventions Diagnostic, therapeutic, and rehabilitative. Main Outcome Measures Electrically evoked compound action potential, threshold level, comfort level, and dynamic range (DR) of the basal, mid, and apical electrodes were compared. We also surveyed battery consumption for each device. Results Electrically evoked compound action potential threshold, threshold level, and comfort level were lower for the perimodiolar-type electrode array than for the lateral-type electrode array in most patients. However, the DR for the perimodiolar array was narrower than for the lateral array. For most patients, there was little difference in battery life. Conclusion Although the level of electrical energy required for auditory stimulation seems to be lower for the perimodiolar electrode array than for the laterally placed array, the DR was wider and the amount of battery consumption was similar. The electrode array should be chosen by considering various patient factors, such as residual hearing.

Gene regulation by glucocorticoid in ENaC‐mediated Na+ transport by middle ear epithelial cells

The epithelial sodium channel (ENaC) is a Na+ transport channel located in the apical membrane of the human middle ear epithelium. Although ENaC‐mediated sodium transport has been reported to be upregulated by dexamethasone in human middle ear epithelium, there has been no study of the downstream pathways for increased ENaC expression mediated by glucocorticoids in this tissue. We investigated the effect of dexamethasone on the expression of ENaC and glucocorticoid regulatory genes for ENaC expression in human middle ear epithelial cells (HMEECs).

Isosorbide Concentration in Perilymph of the Guinea Pig After Oral Administration Versus That After Round Window Perfusion

Objectives The aims of this study were to investigate the feasibility of isosorbide delivery into perilymph through the round window membrane (RWM), and to compare the intracochlear isosorbide concentration in perilymph after oral administration (PO) versus that after round window perfusion (RWP). Methods Sixteen male guinea pigs (32 ears) were used. Isosorbide, an osmotic diuretic, was administered via RWP or PO. First, to investigate the optimal perfusion time, perilymph sampling of scala tympani from the RWM was performed after RWP for 15, 30, or 60 minutes. Second, to compare the drug concentration after RWP versus that after PO, perilymph was aspirated at 3 and 6 hours after administration. Intracochlear concentration of isosorbide was analyzed by high-performance liquid chromatography coupled to refractive index detection. Results Isosorbide passed through the RWM into perilymph after RWP. After RWP for 15, 30, and 60 minutes, mean isosorbide concentrations in perilymph were 116.27±44.65, 245.48±112.84, and 279.78±186.32 mM, respectively. The intracochlear concentration after RWP for 30 minutes was higher than that after RWP for 15 minutes (P=0.043). At 3 and 6 hours after PO, isosorbide concentrations in perilymph were 28.88±4.69 and 12.67±2.28 mM, respectively. In contrast, the corresponding concentrations after RWP were 117.91±17.70 and 75.03±14.82 mM at 3 and 6 hours, respectively. Isosorbide concentrations in perilymph following RWP were significantly higher than those following PO at both 3 and 6 hours (P=0.025 and P=0.034, respectively). Conclusion Isosorbide can rapidly pass through the RWM after RWP in guinea pigs, and 30 minutes of perfusion is considered to be appropriate. In addition, over a 6-hour period, RWP can deliver higher concentrations of isosorbide into perilymph than those achieved with PO.

Bonebridge Implantation for Conductive Hearing Loss in a Patient with Oval Window Atresia

The occurrence of oval window atresia is a rare anomaly with conductive hearing loss. Traditional atresia surgeries involve challenging surgical techniques with risks of irreversible inner ear damage. Recent reports on Bonebridge (Medel, Innsbruck, Austria), a novel implantable bone conduction hearing aid system, assert that the device is safe and effective for conductive hearing loss. We present a case of Bonebridge implantation in an eight-year-old girl with bilateral oval window atresia.

Response to Letter to the Editor: Prevalence of vestibular and balance disorders in children and adolescents according to age category: A multi-center study in Korea ☆

First, we thank you for your interesting comments on our study. This study was designed to identify the etiologies and prevalence of vestibular and balance disorders according to age categories, in children and adolescents, in a multi-center study. In our study, vestibular migraine (VM) was the most common cause of vertigo and balance disorders in children and adolescents (29.2%). The next most common cause was BPVC (22.9%); these results differed from those in your study. There was a difference in the patient age distribution between our and your study populations. In your study, 7-year-olds were the youngest, and only two (1.6%) were younger than 10 years. However, in our study, 31 (7.5%) patients were under 6 years of age and 96 (23.4%) patients were under 10 years old. As we reported that the prevalence of disease by age showed differing distributions in children and adolescents with vertigo, the difference in age distribution is considered to be an important factor in the difference between the causes of dizziness of your and our studies. As a cause of dizziness, you classified hyperventilation/anxiety and psychogenic dizziness separately, and we included hyperventilation/anxiety in the psychogenic vertigo category. Psychogenic vertigo is a vertigo-inducing disorder associated with different psychiatric comorbidities (anxiety disorders, depressive, dissociative, and somatoform disorders) [1]. Although your study had a higher percentage of the older age group, which is known to have a higher prevalence of psychogenic vertigo, the proportion of hyperventilation seems to be high in your study compared not only with our study but also with other previous reports [2e4]. Although in young adults, “phobic postural vertigo” is the most common diagnosis [5], there has been no systematic study on psychogenic vertigo in children and adolescents and further studies are needed. In our paper, we mentioned that ‘Others’ was used to indicate diseases that were seldom diagnosed and ‘Others’ accounted for 9.2% of all patients. Compared with adults, it is difficult to consider the medical history of children as definite. However, if pediatric patients with dizziness are 5 years old or older, we can get important information related to their symptoms, and necessary for a diagnosis, from them. To do so, we have spent more time taking a detailed history and reaching a definite diagnosis. Also, our studywas designed as amulti-center study to include a wide range of population groups at different locations and to increase the generalizability of the study. As mentioned in the Methods, we collected pediatric dizziness patients in 11 hospitals in Korea, including primary, secondary, and tertiary hospitals. Thus, we consider that the patient group in our study was