[Show abstract][Hide abstract] ABSTRACT: Sudden sensorineural hearing loss is characterized by acute, idiopathic hearing deterioration. We report here the development and evaluation of "constraint-induced sound therapy", which is based on a well-established neuro-rehabilitation approach, and which is characterized by the plugging of the intact ear ("constraint") and the simultaneous, extensive stimulation of the affected ear with music. The sudden sensorineural hearing loss patients who received the constraint-induced sound therapy in addition to the standard corticosteroid therapy showed significantly better recovery of hearing function compared to those who had only received corticosteroid treatments. Additionally, the brain activity obtained in a subgroup of patients suggested that the constraint-induced sound therapy could have prevented maladaptive auditory cortex reorganization. Constraint-induced sound therapy thus appears to be an effective, practical, and safe treatment option for sudden sensorineural hearing loss.
[Show abstract][Hide abstract] ABSTRACT: Abstract Conclusions: To establish a system of differential diagnosis for vertigo/dizziness at the Emergency Department (ED), careful history-taking of complications and examinations of nystagmus should be helpful and therefore prepared by ED staff. Objectives: Vertigo/dizziness could come from various kinds of organs for equilibrium, sometimes resulting in an emergency due to the central origin. In the present study, we checked patients' background data at the ED in advance of a definitive diagnosis at the Department of Otolaryngology and examined the significance of the correlation between the data and the diagnosis. Methods: We studied a series of 120 patients with vertigo/dizziness, who visited the Departments of Emergency and Otolaryngology between April 2011 and March 2012. At the ED, we first checked patients' backgrounds and carried out neurologic and neuro-otologic examinations. At the Department of Otolaryngology, we finally diagnosed all the patients according to the criteria and classified the origins of vertigo/dizziness into central and non-central diseases. Results: The ratio of patients with disease of central origin was 12.5% and that for non-central origin was 87.5%. The risk factors for cerebrovascular disease such as hypertension, heart disease, and diabetes were also the risk factors for central vertigo/dizziness by the chi-squared test. To predict a central origin for vertigo/dizziness, only gaze nystagmus was the significant factor by multivariate regression analysis.
[Show abstract][Hide abstract] ABSTRACT: Abstract Conclusions: The present findings suggest that complete control of vertigo after endolymphatic sac decompression surgery (ESDS) does not always depend on improved vestibular function or reduced endolymphatic hydrops. Vertigo control is, however, associated with hearing stability. Objective: Among surgical treatments for intractable Meniere's disease, ESDS is performed to preserve and improve inner ear function. We examined the correlation between changes in vertigo frequency and neuro-otologic function to understand the condition of the inner ear in patients whose vertigo was completely controlled after undergoing ESDS. Methods: This was a retrospective cross-tabulation study. Between 1997 and 2001, we treated 52 patients with intractable vertigo using ESDS and followed the patients regularly for 2 years. Postoperatively we evaluated and recorded changes in vertigo attack frequency, maximum slow phase eye velocity, worst hearing level, and glycerol test results according to modified American Academy of Otolaryngology-Head and Neck Surgery 1995 criteria. Results: We found no correlation between vertigo control and vestibular function. There was also no correlation between vertigo control and negative conversion of the glycerol test. There was a significant correlation between vertigo control and hearing control .
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: Meniere's disease is a common inner ear disease characterized by vertigo, hearing loss and tinnitus. Since Meniere's disease is thought to be triggered by an immune insult to inner ear hydrops, we examined endolymphatic sac drainage with intra-endolymphatic sac application of large doses of steroids for intractable Meniere's patients and observed long-term results from 2 years to over a decade until 13 years. METHODS: Between 1998 and 2009, we enrolled and assigned 286 intractable Meniere's patients to two groups: group-I (G-I) included patients who underwent endolymphatic sac drainage with steroid instillation and group-II (G-II) included those who declined endolymphatic sac drainage. Definitive spells and hearing improvement in these two groups were determined for 2-13 years after treatment. RESULTS: According to the established criteria, vertigo was completely controlled in 88% of patients in G-I in the 2nd year, in 73% in the 12th year and in 70% in the 13th year. These results in G-I were significantly better than those in G-II for 13 years after treatment. Hearing was improved in 49% of patients in G-I in the 2nd year, in 27% in the 12th year and in 25% in the 13th year. These results in G-I were significantly better than those in G-II for 12 years after treatment, but this was not significant in the 13th year. CONCLUSIONS: Endolymphatic sac drainage with intra-endolymphatic sac application of large doses of steroids could improve long-term follow-up results of hearing as well as vertigo control. This means that the drainage with local steroids could also improve patients' long-term quality in the prime of life.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: Some patients with sudden sensorineural hearing loss (SSNHL) are frustrated by residual tinnitus even after accomplishment of the treatment for SSNHL. In the present prospective study, we examined patients' backgrounds of sex, laterality and age together with changes in hearing level and the tinnitus score after the onset of SSHNL to determine the prognostic factors of residual tinnitus after the final day of medical treatment for SSNHL. METHODS: Forty-four patients with SSNHL were all treated with systemic administration of steroids for 2weeks and oral intake of vasoactive drugs and vitamin B12 for 6months before accomplishment of the treatment for SSNHL. The hearing improvement rate (HIR) was determined by comparing the hearing level before and 6months after the start of treatment. Tinnitus was subjectively evaluated by the tinnitus scoring questionnaire before, 6 and 24months after the start of treatment. The score of a five-step evaluation of subjective tinnitus feelings, "loudness", "duration" and "annoyance", was recorded. RESULTS: HIR was significantly correlated with tinnitus score improvement (TSI) in "duration" at 6months after the start of treatment compared with before treatment. The tinnitus score of all 3 items was significantly improved 6months after the start of treatment compared with that before treatment but it was not significantly changed between 6 and 24months after the start of treatment. TSI in "duration" between 6 and 24months was significantly correlated with the patients' age and HIR using multiple regression analysis. CONCLUSION: According to the tinnitus scoring questionnaire, "duration" is the most reliable item for subjective evaluation of tinnitus accompanied by SSNHL. Generally, subjective feelings for residual tinnitus 6months after the start of treatment for SSNHL are supposed to be almost the same, even at the 24th post-treatment month. Especially, younger patients with better hearing improvement are predicted to achieve further improvement of tinnitus between 6 and 24months after the start of treatment.
[Show abstract][Hide abstract] ABSTRACT: We performed extracapsular dissection (ECD) on 31 patients with pleomorphic adenoma, including 7 deep lobe cases. ECD is minimally invasive and has limited complications compared with other conventional parotidectomy procedures. This is the first report on performance of ECD in patients with deep lobe parotid pleomorphic adenomas. Surgeons who are capsule-conscious can perform ECD with good results.
Pleomorphic adenoma, the most common benign neoplasm occurring in the parotid gland, has a constant frequency of recurrence and facial paralysis in patients after surgery. ECD is one of the surgical procedures performed on patients with these tumors, but its validity is still unclear because of its similarity to enucleation.
We performed ECD in patients with untreated parotid neoplasms that were clinically diagnosed as benign before surgery. Of these, resected samples from 31 patients were histologically diagnosed as pleomorphic adenoma.
We achieved resection in patients with pleomorphic adenoma with no permanent facial paralysis or tumor recurrence, with a median follow-up time of 61 months (range 18-125 months).
[Show abstract][Hide abstract] ABSTRACT: To look for factors relating to the vertigo control and hearing changes after intratympanic injections of gentamicin (GM).
Tertiary referral medical center.
Twenty-eight patients with intractable Ménière's disease.
Three intratympanic injections of GM (once per day for three consecutive days).
Although five patients needed further GM injections or vestibular neurectomy because of poor control (Group I), 23 patients had their vertigo controlled for more than two years without further treatment (Group II). The number of vertigo spells per month, pure-tone audiometry, electrocochleography, caloric response, post-head shake nystagmus, and plasma vasopressin as a stress marker were examined.
Before GM injections, there was no difference in the number of vertigo spells per month between Groups I and II. However, the hearing thresholds were higher in Group I. Hearing improvement, increase in percentage of canal paresis and induction of post-head shake nystagmus were observed after GM injections only in Group II. Even in the 11 patients who showed an improvement in hearing of more than 10 dB (hearing improvement group), percentage of canal paresis was increased after GM. More, premedication plasma vasopressin levels were lower in the hearing improvement group as compared with the hearing loss/no changes group. Four of eight patients became negative for dominant negative summating potential in electrocochleography after GM injections in the hearing improvement group.
Our data indicate that the frequency of vertigo is not a key factor in the vertigo control after GM injections, that induction of vestibular damage in the injected ear is essential for the control of vertigo and this effect is mostly pronounced in patients with milder hearing loss, and that hearing improvement is not only a consequence of good vertigo control but also affected by the stress level before treatment.
[Show abstract][Hide abstract] ABSTRACT: In the present study, we first observed up-regulation in preproenkephalin (PPE)-like immunoreactivity (-LIR), a precursor of Met- and Leu-enkephalin, in the rat ipsilateral medial vestibular nucleus (ipsi-MVN) after unilateral labyrinthectomy (UL). By means of double-staining immunohistochemistry with PPE and Fos, a putative regulator of PPE gene expression, we revealed that some of these PPE-LIR neurons were also Fos immunopositive. The time course of decay of these double-stained neurons was quite parallel to that of UL-induced behavioral deficits. This suggests that these double-labeled neurons could have something to do with development of vestibular compensation. We next examined correlation between Fos and PPE expression in the ipsi-MVN by means of a 15-min pre-UL application of antisense oligonucleotide probes against c-fos mRNA into the ipsi-MVN. Gel shift assay and Western blotting revealed that elimination of Fos expression significantly reduced both AP-1 DNA binding activity and PPE expression in the ipsi-MVN after UL. C-fos antisense study also revealed that depression of Fos-PPE signaling in the ipsi-MVN caused significantly more severe behavioral deficits during vestibular compensation. Furthermore, studies with PPE antisense and naloxone, an opioid receptor antagonist, demonstrated that specific depression of enkephalinergic effects in the ipsi-MVN significantly delayed vestibular compensation. All these findings suggest that, immediately after UL, Fos induced in some of the ipsi-MVN neurons could regulate consequent PPE expression via the AP-1 activation and facilitate the restoration of balance between bilateral MVN activities via the opioid receptor activation, resulting in progress of vestibular compensation.
Journal of Neuroscience Research 07/2006; 83(8):1573-83. · 2.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, we examined the expression of mRNAs for Regenerating gene (Reg)/pancreatitis-associated protein (PAP) family members following hypoglossal nerve injury in rats. In addition to four rat family members (RegI, Reg-2/PAP I, PAP II, and PAP III) that had been identified, we newly cloned and sequenced a type-IV Reg gene in rats. Among these five family members, the expression of Reg-2/PAP I mRNA was predominantly enhanced in injured motor neurons after axotomy. Furthermore, a marked induction of PAP III mRNA was observed in the distal part of the injured nerve. A polyclonal antibody was raised against PAP III, and a Western blotting analysis using this antibody confirmed an increased level of PAP III protein in the injured nerve. These results suggest that Reg family members would be new mediators among injured neurons and glial cells, and may play pivotal roles during nerve regeneration.
Biochemical and Biophysical Research Communications 07/2005; 332(1):126-34. · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aquaporins (AQPs) are a family of small transmembrane water transporters. It has recently been revealed that they play a role in regulating homeostasis in the inner ear fluids. Steroid therapy is usually administered to patients with inner ear disorders; however, the mechanism of steroid effects has not been clearly determined. To elucidate the points of action of steroids in the inner ear, we recently examined the distributions of AQP isoform mRNAs in the rat inner ear and identified AQP1-6 mRNAs in the rat cochlea and AQP1, 3, 4, 5 and 6 mRNAs in the rat endolymphatic sac by means of reverse transcriptase polymerase chain reaction (PCR). In this study, we investigated changes in expression of AQP mRNAs in the rat inner ear after i.p. injections of steroids using real-time quantitative PCR and found that AQP3 mRNA in the endolymphatic sac was significantly upregulated in both dose- and time-dependent manners. This result suggests that steroids may effect water homeostasis in the rat inner ear via AQPs.
[Show abstract][Hide abstract] ABSTRACT: The final aim of the present study is to see if the endolymphatic sac is really available as a drug delivery system to have effect on the inner ear organs. In the present study, we examined effects of a single insertion of dexamethasone into the rat unilateral endolymphatic sac on mRNA expression of the inner ear aquaporin (AQP) family, transmembrane water transporters and putative endolymphatic fluid modulators, by means of real-time quantitative PCR. Only AQP-3 mRNA expression in the ipsilateral cochlea was significantly up-regulated in comparison with controls and the up-regulation was demonstrated both in dose-dependent and time-dependent manners. These findings suggest that the intra-endolymphatic sac steroids could make regulatory effects on the inner ear AQP-3 expression via vestibular aqueduct and modulate the homeostasis of endolymphatic fluids, encouraging the possibility that the endolymphatic sac could be a therapeutic window for the inner ear disease.
Neurological Research 01/2004; 25(8):865-70. · 1.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Altered gravity environments including both hypo- and hypergravity can elicit motion sickness. Vestibular information is known to be essential for motion sickness, but its other neural substrates are poorly understood. We previously showed that bilateral lesions of the amygdala suppressed hypergravity-induced motion sickness in rats, using pica behavior as an emetic index. We show in the present study that during hypergravity stimulation, vestibular information activated the central nucleus of the amygdala (CeA), as determined by the induction of Fos expression, in comparison between normal and bilaterally labyrinthectomized rats. The finding that Fos expression was confined to the CeA and almost completely absent in other subnuclei of the amygdala contrasted with many previous studies that used other stressful stimuli such as foot shock, restraint and forced swimming, suggesting a specific vestibular effects on the amygdala. Prolongation of hypergravity resulted in reduction of Fos expression in the CeA, suggesting a process of habituation. Such decreases appeared earlier than in the vestibular nucleus, suggesting that adaptive changes in the CeA to hypergravity were independent of changes in the vestibular input. Our results suggest the amygdala is a neural substrate involved in the development of and habituation to motion sickness.
Brain Research 11/2003; 986(1-2):114-23. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although steroid treatment is generally administered for patients with inner ear disorders, including Meniere's disease, the mechanism via which steroids exert their effects remains to be clarified. The aquaporins (AQPs) are a family of small transmembrane water transporters, and it has recently been revealed that they play a role in regulating homeostasis in the inner ear fluids. In order to elucidate the action points of steroids in the inner ear, we firstly identified AQPI, 2, 3, 4, 5 and 6 mRNAs in the rat cochlea and AQP1, 3, 4, 5 and 6 in the rat endolymphatic sac by means of reverse transcription-polymerase chain reaction. Subsequently, we found that intratympanic injections of steroids upregulated AQPI mRNA of the rat cochlea in a dose-dependent manner. These results suggest that steroids may affect water homeostasis in the rat inner ear mainly via AQP1.
[Show abstract][Hide abstract] ABSTRACT: In order to elucidate the role of the vestibulocerebellar neural circuits during two-stage bilateral labyrinthectomy (BL) we examined Fos-like immunoreactive (-LIR) neurons as a marker of neural activation in the rat brainstem after BL and the projections of these neurons into the vestibulocerebellum using retrograde tracing and immunohistochemical techniques. Simultaneous BL did not show any Fos expression in the medial vestibular nucleus (MVe). However, with an interval of > 6 h between the two stages of BL, Fos-LIR neurons were induced in the ipsilateral (ipsi-) MVe of the side operated on second, partially projecting into the ipsi-vestibulocerebellum. A previous study demonstrated that some of the unilateral labyrinthectomy-induced Fos-LIR neurons in the ipsi-MVe projected into the ipsi-vestibulocerebellum and inhibited the contra-MVe neurons, resulting in the restoration of the right-left balance. Taken together with our present data, it is suggested that some of the labyrinthectomy-induced Fos expression in the ipsi-MVe is representative of a switch-on signal for the vestibulo-cerebello-vestibular inhibitory neural circuits, which remain turned off after symmetrical lesions such as simultaneous BL but are turned on after severe asymmetrical lesions in order to restore the balance.
[Show abstract][Hide abstract] ABSTRACT: In order to investigate the mechanisms responsible for adaptation to altered gravity, we assessed the changes in mRNA expression of glutamate receptors in vestibular ganglion cells, medial vestibular nucleus, spinal vestibular nucleus/lateral vestibular nucleus, cerebellar flocculus, and uvula/nodulus from rats exposed to hypergravity for 2 h to 1 week using real-time quantitative RT-PCR methods. The mRNA expression of GluR2 and NR1 receptors in the uvula/nodulus and NR1 receptors in the medial vestibular nucleus increased in animals exposed to 2 h of hypergravity, and it decreased gradually to the control level. The mRNA expression of GluR2 receptors in vestibular ganglion cells decreased in animals exposed to 1 week of hypergravity. Neither the metabotropic glutamate receptor 1 nor delta2 glutamate receptor in flocculus and uvula/nodulus was affected by a hypergravity load for 2 h to 1 week. It is suggested that the animals adapted to the hypergravity by enhancing the cerebellar inhibition of the vestibular nucleus neurons through activation of the NR1 and GluR2 receptors on the Purkinje cells in uvula/nodulus especially at the early phase following hypergravity. In the later phase following hypergravity, the animals adapted to the hypergravity by reducing the neurotransmission between the vestibular hair cells and the primary vestibular neurons via down-regulation of the postsynaptic GluR2 receptors in the vestibular periphery.
Journal of Neurochemistry 07/2002; 81(6):1308-17. · 3.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We treated 33 cases of intractable Meniere's disease with endolymphatic sac drainage and steroid-instillation surgery (EDSS), attaining good long-term results in vertigo and hearing. To elucidate how EDSS affects the diseased inner ear, we examined changes in plasma inner ear hormones after EDSS. Among inner ear hormones, plasma vasopressin was significantly decreased after EDSS compared to after mastoidectomy. In cases with good long-term results in vertigo and hearing, postoperative plasma vasopressin remained lower over the long term than in cases with poor results. In cases with negative glycerol test results one year after surgery, postoperative plasma vasopressin also remained significantly lower over the long term than in cases with positive results. Previous studies reported that vestibular neurons projected into hypothalamic supraoptic and paraventricular nuclei and that changes in the inner ear pressure were related to plasma vasopressin. Taken together with present findings, this suggests that EDSS may reduce plasma vasopressin through modification of the diseased inner ear environment, resulting in improved inner ear function.
[Show abstract][Hide abstract] ABSTRACT: We studied 28 patients with vestibular neuronitis treated at our hospital between 1997 and 1999. To determine the effects of steroid therapy on long-term canal prognosis and daily activity, we examined caloric tests and gave questionnaires to 12 steroid-treated and 16 nonsteroid-treated patients 2 years after onset. We found that canal improvement was 50% in the nonsteroid-treated group and 75% in the steroid-treated one. In cases with severe canal paresis (CP > or = 60%), canal improvement was 33% in the nonsteroid-treated group and 67% in the steroid-treated one. Steroid therapy at the acute stage of this disease significantly reduced the duration of spontaneous nystagmus and handicap in daily life due to dizziness induced by head and body movement, decreasing mood disturbance.
[Show abstract][Hide abstract] ABSTRACT: Endolymphatic sac surgery is one of the most widely accepted techniques used to treat intractable Meniere's disease. To improve this surgery, we developed the following techniques: A simple mastoidectomy was used to expose the endolymphatic sac between the sigmoid sinus and inferior margin of the posterior semicircular canal. The sac was opened and filled with a mass of prednisolone. A bundle of absorbable gelatin films was then inserted into the sac lumen to expand it, followed by gelatin sponges dipped in a high concentration of dexamethasone. Long-term results (17-32 months) in 20 patients with intractable Meniere's disease treated with endolymphatic sac drainage and steroid-insertion surgery (EDSS) showed that definitive spells were completely controlled in 15 of 20 cases (75%); all reports of vertigo decreased; hearing improved in 12 of 20 cases (60%); and annoyance due to tinnitus decreased in 15 of 20 cases (75%). Steroids directly instilled into the endolymphatic cavity may thus be more effective with the diseased inner ear organs than those applied via any other route. Draining of endolymphatic fluid at the sac into the mastoid cavity also contributed to these satisfactory EDSS results.
[Show abstract][Hide abstract] ABSTRACT: To enhance the effect of treatment for intractable Meniere's disease, we exposed the opened endolymphatic sac to high concentrations of steroids. This technique--endolymphatic sac drainage and steroid instillation surgery--involves the application of a mass of prednisolone followed by absorbable gelatin sponges soaked in a high concentration of dexamethasone into a sac lumen opened and expanded with a bundle of absorbable gelatin film. These sponges are also placed around the sac and coated with biochemical adhesive so that the medicine is slowly delivered into the sac over a prolonged period of time by means of a natural sustained-release vehicle. The short-term results (6 to 14 months) in 12 patients with Meniere's disease, including those in stage IV, treated by the above techniques showed that definitive spells were completely controlled in all cases. Hearing was improved, and annoyance due to tinnitus was decreased in all cases except one.
The Annals of otology, rhinology, and laryngology 03/2001; 110(2):109-12. · 1.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Several lines of evidence have suggested that acetylcholine is a possible neurotransmitter/neuromodulator involved in vestibular compensation. However, details of cholinergic effective sites during vestibular compensation remain unclear. In this study, we selectively damaged the rat vestibulo-floccular cholinergic mossy fibers using ethylcholine mustard aziridinium ion. In these animals, unilateral labyrinthectomy caused more severe vestibulo-ocular deficits, especially in the initial stage. These findings suggest that the vestibulo-floccular cholinergic mossy fibers serve to restore the balance between intervestibular nuclear activities in order to induce vestibular compensation in the initial stage.