HongJu Park

Clinical significance of vibration-induced nystagmus and head-shaking nystagmus through follow-up examinations in patients with vestibular neuritis.

Objectives: To verify if vibration-induced nystagmus (VIN) in patients with vestibular neuritis changes over time and to compare the results of VIN test to those of caloric test and head-shaking nystagmus (HSN) test. Study Design: Retrospective study of a series of cases. Methods: We compared VIN and HSN tests using caloric test results in 22 patients (male-to-female ratio, 11:11; age range, 15-67 yr) with acute vestibular neuritis seen at onset and in follow-up after 2 months. The eye movement recordings were made, and the maximum slow-phase eye velocities (SPVs) were calculated during vibration and after head shaking. If spontaneous nystagmus was present, it was subtracted from the SPVs of VIN and HSN. Positive value of the SPVs means slow-phase eye movement to the lesioned side. Results: In acute stage, VIN of which SPV was directed toward the lesioned side was observed in 21 (95%); and HSN, in 22 (100%). In follow-up, VIN of which SPV was directed toward the lesioned side was observed in 19 (86%); and HSN, in 17 (77%). There was a significant decrease of the SPV of VIN and HSN over time. Significant correlations were observed in between canal paresis and SPV of VIN but not in between canal paresis/SPV of VIN and SPV of HSN. Conclusion: Although VIN test can predict the severity of vestibular asymmetry in acute and follow-up stages, HSN test could only probe vestibular asymmetry and could not predict the severity of the vestibular asymmetry. Our results suggest that VIN might represent the peripheral vestibular asymmetry; however, HSN might represent the stored vestibular asymmetry in velocity storage system, which is induced by peripheral asymmetry.

Mechanisms of Vibration-Induced Nystagmus in Normal Subjects and Patients with Vestibular Neuritis

It has been reported that vibration applied either on the mastoid or on the sternocleidomastoid (SCM) muscles induces nystagmus in normal subjects or patients after unilateral vestibular neuritis (VN). The aims of the study were to characterize vibration-induced nystagmus (VIN) in normal and patient groups and to propose the mechanism of VIN. We recorded eye movements during unilateral 100-Hz vibration on the mastoid bone and SCM muscles in 22 normal subjects and 19 patients with unilateral VN. In normal subjects, the direction of slow-phase velocity (SPV) tended to be toward the vibrated side. Vibration on the right/left SCM muscles induced mean SPV of 1.7°/s, –1.9°/s toward the stimulated side in all normal subjects. Vibration on the right/left mastoid bone induced mean SPV of 1.5°/s, –0.4°/s toward the stimulated side in most of the normal subjects. Positive value means SPV to the right side. This directional preponderance to the vibrated side was statistically significant. Among the patients with VN, the slow phase of the VIN was directed towards the lesioned side, irrespective of whether vibration was applied on the lesioned or intact side. Vibration on the right/left mastoid bone induced mean SPV of –10.4°/s, –10.8°/s toward the lesioned side. Vibration on the right/left SCM induced mean SPV of –7.9°/s, –10.5°/s toward the lesioned side. The amplitude of SPV showed a significant correlation with the unilateral weakness of caloric test. Our results suggest that the proprioceptive stimulation plays a major role in producing VIN in normal subjects, while VIN is generated mostly by the vestibular stimulation in patients with unilateral VN, which helps us localize the lesion side. Vibration tests on the SCM muscles as well as on the mastoid are recommended and our hypothetic mechanisms of VIN are presented.

Clinical Significance of Vibration-Induced Nystagmus

The aims of the study were to characterize the vibration-induced nystagmus (VIN) in patients with unilateral vestibular neuritis (VN) and Ménière’s disease (MD), and to clarify the clinical significance of VIN by comparing it with caloric results in patients with VN and MD. We recorded eye movements from 22 VN patients and 24 MD patients using unilateral 100-Hz vibration on the mastoid bone. Eye movements were analyzed and the maximum value of slow-phase eye velocity was obtained during vibration on each mastoid. The average value of slow-phase velocities was calculated. Spontaneous nystagmus was subtracted from the slow-phase velocity, whenever it was present. A canal paresis (CP) greater than 25% was considered pathologic. All but one VN patient showed pathologic CP with the direction of the slow-phase eye movement of VIN toward the lesioned side. Fifteen (63%) out of 24 MD patients showed VIN with the slow-phase eye movement directed to the lesioned side. Pathologic CP was present in 9 (38%) out of 24 MD patients and 8 of them showed slow-phase eye movements of VIN directed to the lesioned side. There were also 8 other MD patients who showed slow-phase eye movement of VIN directed to the intact side. Among them, 3 patients with the slow-phase eye movement more than 5°/s showed CP on the intact side. The amplitude of slow-phase eye velocity showed a significant correlation with CP in patients with either VN or MD. There was no significant difference in the slope of the regression lines between the VN and MD groups. Our results suggest that VIN may probe imbalance of canal responses to low-frequency stimulation similar to the caloric test. It also shows that VIN can help in detecting vestibular imbalance using a stimulation mechanism different from the caloric test. The VIN test can be helpful in determining the lesioned side in patients with VN; however, it has some limitations in localizing the lesioned side in patients with MD.

Surgical management of acute mastoiditis with epidural abscess

Abstract The prevalence of intracranial complications of acute coalescent mastoiditis in children has decreased significantly; however, this clinical problem persists, with a relatively high mortality. The common practice for management of acute mastoiditis with epidural abscess is mastoidectomy, drainage and placement of a ventilation tube, which means that the main pathology is confined to the mastoid cavity. We suggest that tympanic exploration is mandatory in certain cases, an example of which we present here. We report one case of acute mastoiditis with epidural abscess, in which mastoidectomy with tympanic exploration was needed to ensure drainage throughout the cavities and to prevent pressure rebuilding in the mastoid and tympanic cavities. We stress that if the tympanic membrane is thickened and no fluid is drained when placing a pressure equalization tube, there could be granulation tissue in the tympanum and tympanic exploration is mandatory, especially in a case of acute mastoiditis with intracranial complications accompanied by prolonged symptoms.

Test-retest reliability of vibration-induced nystagmus in peripheral dizzy patients

The purpose of this study was to analyze test-retest reliability of vibration-induced nystagmus (VIN) in dizzy patients. Fifty-two consecutive patients with positive eye movements induced by vibration at all four different stimulation sites were enrolled. Evaluation of VIN was repeated in 2 separate sessions, 30 minutes apart. Maximum slow-phase eye velocities at different sites from the first and second sessions were assessed via the intraclass correlation coefficient (ICC) and the Pearson correlation coefficient. The incidence of directional changing of evoked nystagmus and the abnormal rates were also evaluated. Excellent reliability with ICC values ranging from 0.89-0.98 and substantial-to-excellent correlation was obtained for the maximum slow-phase eye velocities at different sites. The incidence of directional changes of evoked nystagmus was 0%-4% at each stimulation site. Forty-three patients (83%) had abnormal results in the first session and 41 patients (79%) had abnormal results in the second session. Overall, the direction and maximum slow-phase eye velocities of VIN for different stimulation sites had excellent test-retest reliability. The VIN test is a reliable test for detecting vestibular imbalance in evaluating a dizzy patient.

Modified sleeve tympanotomy approach for removal of congenital cholesteatoma.

OBJECTIVE We present a technique which we have found useful for the management of congenital cholesteatoma extensively involving the middle ear. CASE REPORT A five-year-old boy was presented to our department for management of a white mass on the right tympanic membrane. This congenital cholesteatoma extensively occupied the tympanic cavity. It was removed through an extended tympanotomy approach using our modified sleeve technique. The conventional tympanotomy approach was extended by gently separating the tympanic annulus from its sulcus in a circular manner. The firm attachment of the tympanic membrane at the umbo was not severed, in order to avoid lateralisation of the tympanic membrane. CONCLUSION Although various operative techniques can be used, our modified sleeve tympanotomy approach provides a similarly sufficient and direct visualisation of the entire middle ear, with, theoretically, no possibility of lateralisation of the tympanic membrane and subsequent conductive hearing loss.

Short-term changes of hearing and distortion product otoacoustic emissions in sudden sensorineural hearing loss.

Objectives: The function of outer hair cells can be measured objectively and noninvasively by distortion product otoacoustic emission (DPOAE). The aims of the study were to investigate the changes of DPOAE in the recovery course and to pursue the relationship between the changes of DPOAE and hearing improvement in patients with sudden sensorineural hearing loss. Study Design: Retrospective case series review. Methods: Both DPOAE and pure tone audiometry were performed before 7 days after the onset and followed after 2 weeks in 40 patients with sudden sensorineural hearing loss. Patients were grouped on the basis of the initial hearing loss and the results of their recovery. All DPOAE amplitudes were analyzed at 2f1-f2, and DPOAE sum was calculated. Results: The initial DPOAE sum in ears with the initial mild-to-moderate hearing loss (hearing threshold, ≤55 dB) was not different from that in contralateral normal ears, but it was decreased or absent in ears with the initial moderately severe to profound hearing loss (hearing threshold, >55 dB) compared with that in contralateral normal ears. In ears with the initial moderately severe to profound hearing loss, the changes of DPOAE sum values positively correlated with the hearing improvement but not in ears with the initial mild-to-moderate hearing loss. Although the presence of initial DPOAE responses indicated good prognosis, the absence of initial DPOAE responses did not always indicate poor prognosis. Conclusion: Our findings showed that the function of outer hair cells is relatively spared in ears with the initial mild-to-moderate hearing loss, and its recovery is not related to the hearing improvement; however, the function of outer hair cells is impaired in ears with the initial moderately severe to profound hearing loss, and the functional improvement of outer hair cells is important for hearing recovery. Clinical implications of our findings were discussed.