Taro Inagaki

Positional and positioning down-beating nystagmus without central nervous system findings

We report the clinical features of 4 cases with positional or positioning down-beating nystagmus in a head-hanging or supine position without any obvious central nervous system disorder. The 4 cases had some findings in common. There were no abnormal findings on neurological tests or brain MRI. They did not have gaze nystagmus. Their nystagmus was observed only in a supine or head-hanging position and it was never observed upon returning to a sitting position and never reversed. The nystagmus had no or little torsional component, had latency and tended to decrease with time. The positional DBN (p-DBN) is known to be indicative of a central nervous system disorder. Recently there were some reports that canalithiasis of the anterior semicircular canal (ASC) causes p-DBN and that patients who have p-DBN without obvious CNS dysfunction are dealt with anterior semicircular canal (ASC) benign paroxysmal positional vertigo (BPPV). There are some doubts as to the validity of making a diagnosis of ASC-BPPV in a case of p-DBN without CNS findings. It is hard to determine the cause of p-DBN in these cases.

Vestibular system changes in sudden deafness with and without vertigo: a human temporal bone study.

Objective To investigate the vestibular system changes in sudden deafness with vertigo (SDwV) and sudden deafness without vertigo (SDwoV) and the cause of persistent canal paresis (CP) in SDwV patients. Study Design Retrospective study. Materials and Methods Four temporal bones from the affected ear in 4 patients with unilateral sudden deafness (SD), 2 SDwV and 2 SDwoV, were selected. Four contralateral temporal bones with normal-hearing ears were defined as the control. Morphologic findings of the labyrinth, the number of Scarpa’s ganglion cells, and the density of vestibular hair cells were investigated in all temporal bones. Clinical data and the results of vestibular tests of 11 patients with unilateral SD, as a separate group, also were investigated. Results Atrophic change of the organ of Corti, tectorial membrane, and stria vascularis in cochlea, and deposits and atrophic otoconial membrane in vestibular sense organs were seen on affected ears more than control ears. The density of Type I hair cells seemed to decrease on the saccular macula and the posterior semicircular canal crista on affected ears, and there was no remarkable difference between SDwV and SDwoV. In 1 patient with SDwoV who died 10 months after the onset of SD, there were large amount of deposits on the cupula, the atrophied otoconial membrane was peeling off from the saccular macula, and the saccular membrane collapsed to the saccular macula in the affected ear. In the clinical data, all SDwV who were examined within 2 years from the onset had CP, and all SDwV had profound hearing loss. Conclusion There is no remarkable difference between SDwV and SDwoV in the number of Scarpa’s ganglion cells and the density of vestibular hair cells. The damage of the extracellular superstructure is seen in SD with or without vertigo. The damage of extracellular superstructure is potentially one of the causes of persistent CP in patients with SD.

Morphological change of the cupula due to an ototoxic agent: A comparison with semicircular canal pathology

Conclusion: The cupula shows various degrees of changes after gentamicin (GM) injection into the inner ear, with or without damage of the sensory cells. This cupula change may be a part of the etiology of peripheral vertigo, and is also potentially one of the mechanisms of reduced caloric response. Objectives: To observe the morphological changes of the cupula after injecting GM in the frog inner ear and to compare the changes of the cupula with those of the ampullary sensory cells. Methods: We injected 300 μg (7.5 μl) of GM into the inner ear of 30 bullfrogs (Rana catesbeiana) using a microsyringe under ether anesthesia. The same amount of saline was injected into the other ear as control. The cupulae were observed at 3, 7, and 14 days after GM injection by stereoscopic microscope. The ampullae were fixed, and the sensory cells were assessed using a scanning electron microscope (SEM). The correlation between the changes in the cupula and sensory cells was evaluated using our own scale. Results: In over half of the cupulae in the 7- and 14-day groups, cupula changes such as shrinkage were observed. In about 50% of the total cases, the degree of cupula and sensory cell change correlated in the two groups. In the 14-day group, these changes were more marked. However, there were cases in which the changes of the cupula and sensory cells did not correlate, indicating that the cupula alone can sustain changes without sensory cell damage.

Subjective visual vertical perception in patients with vestibular neuritis and sudden sensorineural hearing loss

OBJECTIVE To determine the subjective visual vertical (SVV) perception in patients with vestibular neuritis (VN) and sudden sensorineural hearing loss (SSHL) using the SVV test and other neuro-otological examinations, namely, the vestibular evoked myogenic potential (VEMP) and caloric tests, and to clarify which vestibular nerve function is associated with an SVV shift. PATIENTS AND METHODS We performed the SVV test in 36 VN patients and 80 SSHL patients. Thereafter, we investigated directional changes in the SVV in the VN and SSHL patients, and compared the results of the SVV test with those of the VEMP and caloric tests. RESULTS Abnormal SVV (> 2° was found at a rate of 69.4% in the VN patients and 26.3% in the SSHL patients. In all except 1 VN patient, the SVV tilted to the lesion side. The rate of abnormal SVV was significantly higher in patients with complete canal paresis (CP) than in patients with partial CP. There was no significant relationship between the rates of abnormal SVV and VEMP. In the SSHL patients, neither the SVV nor the VEMP affected the hearing outcome and patients with abnormal VEMP tended to show abnormal SVV. CONCLUSION VN patients showed a higher rate of abnormal SVV than SSHL patients. From the results, it is speculated that the superior vestibular nerve function mainly affects the SVV tilt, although the inferior vestibular nerve function may also have an effect.

Pathologic correlations of otologic symptoms in acute lymphocytic leukemia

OBJECTIVES To assess the clinicopathologic correlations of otologic complaints in patients with acute lymphocytic leukemia. DESIGN Otologic complaints and histologic findings were evaluated in 25 temporal bones of 13 acute lymphocytic leukemia patients. RESULTS Nine patients had a history of otologic complaints, including hearing loss, otalgia, otorrhea, and vertigo in 5, 3, 3, and 2 patients, respectively. Hemorrhage was most commonly observed in the middle ear (6 patients, 9 temporal bones) and was also observed in cochlea (4 patients, 4 temporal bones), and vestibule (6 patients, 6 temporal bones). Leukemic infiltration was observed in the petrous apex (13 patients, 24 temporal bones), middle ear (7 patients, 14 temporal bones), cochlea (3 patients, 4 temporal bones), vestibule (3 patients, 4 temporal bones), and internal auditory canal (5 patients, 8 temporal bones). Inflammatory changes were observed in the cochlea (5 patients, 8 temporal bones) and vestibule (5 patients, 8 temporal bones). Middle ear effusion containing floating tumor cells was observed in 4 temporal bones of 3 patients. Irreversible histopathologic changes of the middle ear, such as the destruction of the ossicles, perforation of the tympanic membrane, and granulation tissues were observed in 5 temporal bones of 4 patients. CONCLUSIONS Ear involvement is common in acute lymphocytic leukemia patients. With prolonged survival due to the progress of treatment, the diagnosis and treatment of nonhematopoietic system symptoms, such as ear problems due to acute lymphocytic leukemia, have become more important.

Ocular vestibular evoked myogenic potentials induced by bone-conducted vibration in patients with unilateral inner ear disease

Abstract Conclusion: Patients with vestibular neuritis (VN) with complete canal paresis (CP) showed a higher rate of abnormal ocular vestibular evoked myogenic potential (oVEMP) than those with partial CP. From these results, it is speculated that the superior vestibular nerve function mainly affects oVEMP. Significant correlation was found between the grades of the hearing outcome and oVEMP in sudden sensorineural hearing loss (SSHL). Objective: We attempted to correlate the results of oVEMP with the results of cervical VEMP (cVEMP), results of subjective visual vertical (SVV), and clinical course in patients with various vestibular disorders. Methods: Twenty-two patients with VN, 65 with SSHL, and 22 with Menieres disease (MD), were enrolled in this study. We compared the results of oVEMP with those of cVEMP, SVV, and the caloric test. Furthermore, the oVEMP results were compared with the initial hearing threshold, presence of vertigo, and hearing recovery in the patients with SSHL. Results: The patients with VN with complete CP showed a higher rate of abnormal oVEMP than those with partial CP. In the patients with SSHL, the hearing recovery rate was lower in the patients with abnormal oVEMP than in those with normal oVEMP.

Effect of cupula shrinkage on the semicircular canal activity.

Abstract Conclusion: With half-sized cupula, the semicircular canal nerve potentials decreased under slow stimulus, thus potentially leading to reduced caloric response. This also suggests that shrunken cupula may cause dizziness because of its hypermobility. Objectives: To examine the physiological effect of half-sized cupula on the semicircular canal nerve potential. Methods: The isolated cupula of the bullfrog was sectioned in half with fine scissors and was replaced on the crista. Mechanical endolymphatic flow and slow and fast stimuli were delivered and the evoked action potentials were recorded. Results: The cupula was successfully sectioned in half and was replaced on the crista. With the half-sized cupula, the action potentials became smaller under slow stimulus than under fast stimulus.

Efficacy of physical therapy for intractable cupulolithiasis in an experimental model.

OBJECTIVE To investigate what kinds of stimuli are effective in detaching otoconia from the cupula in three experimental models of cupulolithiasis. METHODS Three experimental models of cupulolithiasis were prepared using bullfrog labyrinths. Three kinds of stimuli were applied to the experimental models. In experiment one (gravity), the labyrinth preparation was placed so that the cupula-to-crista axis was in the horizontal plane with the canal side in the downward position. In experiment two (sinusoidal oscillation), the labyrinth preparation was placed 3 cm from the rotational centre of a turntable, which was sinusoidally rotated with a rotational cycle of 1 Hz and a rotational angle of 30°. In experiment three (vibration), mechanical vibration was applied to the surface of the bony capsule around the labyrinth using a surgical drill. RESULTS In experiments one, two and three, the otoconial mass was respectively detached in 2 out of 10 labyrinth preparations, none of the labyrinth preparations, and all of the labyrinth preparations. CONCLUSION Vibration was the most effective stimulus for detaching the otoconia from the cupula in these experimental models of cupulolithiasis.

Relationship between clinical features and therapeutic approach for benign paroxysmal positional vertigo outcomes.

OBJECTIVE To examine the clinical features, age and gender distribution of patients, treatment methods, and outcomes of benign paroxysmal positional vertigo. METHODS This paper reports a review of 357 patients treated for this condition at a single institution over a duration of 5 years. Patients with posterior canal benign paroxysmal positional vertigo were divided into two groups: one group underwent the Epley manoeuvre and the other received medication. The lateral canal canalolithiasis patients were also divided into two groups: one underwent the Lempert manoeuvre and the other received medication. Lastly, the lateral canal cupulolithiasis patients were treated with medication and non-specific physical techniques. RESULTS AND CONCLUSION For patients with posterior canal benign paroxysmal positional vertigo, resolution time was significantly shorter in the Epley manoeuvre group than in the medication group. For the lateral canal canalolithiasis patients, resolution time was significantly shorter in the Lempert manoeuvre group than in the medication group. Resolution time was significantly longer in the lateral canal cupulolithiasis patients than in the other patients. The average age of patients increased with the number of recurrences, as did predominance in females. Average age and rate of sensorineural hearing loss were significantly higher in patients with intractable benign paroxysmal positional vertigo compared with those in the curable benign paroxysmal positional vertigo group.

Model experiments of otoconia stability after canalith repositioning procedure of BPPV

Abstract Conclusion: Postural restrictions are probably not necessary after the canalith repositioning procedure (CRP). Objectives: Epley reported the effect of CRP for benign paroxysmal positional vertigo (BPPV). After CRP, patients are often requested to restrict postural change. However, some studies suggested that CRP may work without postural restrictions. The present study aimed to determine the necessity of post-maneuver postural restriction using the frog labyrinth model. Methods: The otoconial mass from the sacculus was placed on the utricular macular otoconia, mimicking a condition after CRP. The stability of the otoconial mass was observed by tilting the preparation, immediately, 3 min, and 5 min after it was placed on the macular otoconia. The utricular macula was maintained in the vertical plane for 10 s, during which period the behavior of the otoconial mass was observed. In experiment 1 the utricular macula was intact, in experiment 2 otoconia were partially removed, and in experiment 3 they were totally removed from the macula. Results: In experiments 1 and 2, in all preparations the otoconial mass became stabilized after 3 min. Even in experiment 3, in most preparations the otoconial mass became stabilized after 5 min.