Published papers

Conclusions: The functional connectivity (FC) between the right and left auditory cortex is weak in tinnitus patients. Transcranial direct current stimulation (tDCS) over the auditory cortex has potential as a tool to modulate auditory-based FC. Objective: This study investigated the effects of applying tDCS in tinnitus patients, and searched for modulation of brain networks in resting-state functional magnetic resonance imaging (rs-fMRI) through an analysis of FC with the stimulated brain region. Subjects and methods: Nine male patients with chronic tinnitus and 10 male volunteers with normal hearing were enrolled. The subjects were evaluated with rs-fMRI immediately before and after tDCS. The tinnitus patients filled out the self-evaluation questionnaires designed to measure tinnitus conditions before tDCS treatment and 1 week afterwards. Results: The FC between the right and left auditory cortex was significantly weaker in tinnitus patients than in controls. After tDCS treatment, in the tinnitus group, the primary auditory cortex showed a reduction in the amount of statistically significant connectivity with the somatosensory area and motor area, but maintained strong significant connectivity (p < 0.005) with the auditory area and insular cortex. In contrast, in the control group, there remained strong significant connectivity between the primary auditory cortex and the somatosensory area, motor area, insular cortex, and auditory area.

Objectives: To determine the long-term prognosis of low-frequency hearing loss and predictive factors for the 10-year outcome of low-frequency hearing loss. Study Design: Case series with chart review. Setting: Tertiary referral center. Subjects and Methods: From 1979 to 1998, 466 consecutive patients with low-frequency hearing loss received initial treatment at the Hearing and Tinnitus Clinic of Keio University Hospital. Of the 49 eligible patients, pure-tone threshold data obtained over a period of 10 years after onset of low-frequency hearing loss were available for analysis. To determine the progression of hearing loss, we analyzed audiometric pattern changes. We also examined how the following factors affected 10-year prognosis: sex, age, side of hearing loss, accompanying dizziness, pre-therapeutic hearing thresholds at low frequencies, initial therapy results, and fluctuation of hearing during the first year after onset. Results: High- and pan-frequency hearing loss increased as time progressed. About half of the cases developed high- or pan-frequency hearing loss within 10 years of onset. Audiometric patterns measured at 10 years significantly correlated with those measured at one (r = 0.57), three (r = 0.73), and five years (r = 0.85). The 10-year prognosis significantly correlated with only two factors: initial therapy results (r = 0.49) and fluctuation of hearing during the first year (r = 0.43). Conclusions: About half of the cases in our study developed high- or pan-frequency hearing loss within 10 years of onset of low-frequency hearing loss. The initial therapy results and fluctuation of hearing during the first year may indicate the long-term prognosis of patients presenting with low-frequency hearing loss. © 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation.

We evaluated the effects of a selective serotonin reuptake inhibitor, paroxetine, on treating tinnitus.Tinnitus patients stratified for the presence of depression and anxiety were studied retrospectively. Fifty-six patients were observed for more than 6 months. They were initially treated with paroxetine only at a dose of 10 mg/day for 2-4 weeks; thereafter, the dose was increased to 20 mg/day. Tinnitus distress was evaluated with the Tinnitus Handicap Inventory (THI) and with visual analog scales (VASs) for tinnitus loudness and annoyance. Depression and anxiety were measured with the Self-Rating Depression Scale (SDS) and the trait section of the State-Trait Anxiety Inventory (STAI). The patients were grouped according to their SDS and STAI scores, and each variable was compared at baseline and the 6-month follow-up. Changes among these variables were also examined to determine whether reduced tinnitus distress was related to the improvement of depression or anxiety. Patients with both depression and anxiety showed better results (decrease in THI, VASs, SDS and STAI scores) than patients with anxiety alone, or patients without depression and anxiety. In patients with depression and anxiety, changes in tinnitus variables and changes in depression and anxiety scores were strongly correlated. In other patients, however, changes in tinnitus variables and changes in depression and anxiety scores were not correlated. These results suggest that paroxetine is effective in treating distressed tinnitus patients with depression and anxiety by reducing their tinnitus severity as well as their depression and anxiety. Copyright © 2009 S. Karger AG, Basel.

Conductive hearing impairiment induced by otosclerosis, a typical otological disease, can be dramatically improved by surgery. This review introduces an original surgical procedure using a ceramic apatite implant, and summarizes successful surgical results involving 160 otosclerotic ears.

kull-base and parapharyngeal tumors require intricate treatments due to its anatomic complexity, variations in histological type, and the site often involves the presence of critical blood vessels and nerves. Diagnostic imaging and fine-needle aspiration cytology are thus essential. We report a case of skull-base meningioma extending to the parapharyngeal space in which we made a definitive diagnosis by biopsy (as grade I) and took a wait-and-see approach. A 52-year-old woman had complained of a headache since June 2006 and was seen in the neurology department at our hospital in July. A tumor from around the left jugular foramen to parapharyngeal space was revealed by magnetic resonance imaging (MRI) and she was referred for consultation to the neurosurgical department and our department. It was difficult to establish the diagnosis from the clinical manifestation and diagnostic images due to the tumor's complicated anatomy, therefore it was confirmed by biopsy instead of cytology. It can be said that biopsy is useful to determine therapeutic measures for the skull-base meningioma because it is less invasive and can verify a histological type compared with the complete removal of the tumor.

Otosclerosis is an otological disease that typicaly causes conductive hearing loss. This disease is an important clinical entity since hearing impairment in these case can be dramatically improved by surgery. In this review paper, we review recent research into the pathophysiology of otosclerosis and summarize clinical features, audiometry and diagnostic imaging examinations in 160 ears with otosclerosis that we treated surgically in our department.

We encountered 6 rare cases of acute-onset unilateral psychogenic hearing loss in adults. All were women in their 20s and 30s. Three cases had severe hearing impairment characterized by hearing loss at every frequency; 2 cases had profound hearing impairment, and 1 case had low-frequency hearing impairment. Of the 6 cases, 3 had a history of hearing loss, and 1 had a history of psychogenic visual disturbance. All 6 cases were initially diagnosed as having idiopathic sudden sensorineural hearing loss; all subsequently received steroid therapy. Three cases were not diagnosed as being psychogenic in origin until otoacoustic emissions and auditory brain responses were performed. Although the presence of distinctive clinical features (age, gender, and past history) is important for suspecting psychogenic hearing loss, objective audiological tests such as otoacoustic emissions are essential for diagnosing some cases. Compared to the existing reports of similar cases, our cases had a poorer prognosis (only 2 cases were cured). Copyright © 2009 S. Karger AG, Basel.

Objective: To evaluate the use of electroneurography (ENoG) as a prognostic indicator in acute peripheral facial paralysis in a general hospital. Design: Retrospective study. Participants: The patients had been treated for a sudden onset unilateral facial paralysis during an 18 month period (2005. 7-2006.12). Main outcome measures: ENoG was performed 7 to 14 days after the onset facial palsy. The recovery of facial nerve function was documented by Yanagihara's grading system. All patients were followed monthly until recovery or up to 6 months after onset. Results: One-hundred ten patients with acute peripheral facial paralysis, including Bell's palsy (86%), Ramsay-Hunt Syndrome (6%), trauma (6%), and others (2%) underwent ENoG test. Patients were divided into 5 classes according to the ENoG value; [40%-] 41%, [20-40%] 24%, [10-20%] 9%, [0-10%] 11%, [0%] 15%. The recovery rate in each group was; [40%-] 98%, [20-40%] 96%, [10-20%] 90%, [0-10%] 58%, [0%] 24%. The patients whose ENoG values were greater than 10 % showed a 96 % chance of recovery (sensitivity 0. 88, specificity 0. 86). Patients with a greater ENoG value recovered significantly faster. Conclusion: ENoG provides accurate information predicting the prognosis and recovery rate of patients with facial palsy.

Outer hair cell (OHC) loss in the auditory sensory epithelium is a primary cause of noise-induced sensory-neural hearing loss (SNHL). To clarify the participation of glial cells in SNHL, we used an Alexander disease (AxD) mouse model. These transgenic mice harbor the AxD causal mutant of the human glial fibrillary acidic protein (GFAP) under the control of the mouse GFAP promoter. It is thought that GFAP aggregates compromise the function of astrocytes. In the auditory pathway, the formation of GFAP aggregates was observed only in GFAP-positive cells of the cochlear nerve. The presence of GFAP aggregates did not change auditory function at the threshold level. To assess the change in vulnerability to auditory excitotoxicity, both transgenic and control mice were treated with intense noise exposure. Auditory threshold shifts were assessed by auditory brainstem responses (ABR) at 1 and 4 weeks after noise exposure, and OHC damage was analyzed by quantitative histology at 4 weeks after exposure. Transgenic mice showed more severe ABR deficits and OHC damage, suggesting that cochlear nerve glial cells with GFAP aggregates play a role in noise susceptibility. Thus, we should focus more on the roles of cochlear nerve glial cells in SNHL. © 2008 Elsevier Ireland Ltd and the Japan Neuroscience Society.

We encountered 185 patients with Bell's palsy at our hospital between January 2003 and December 2005. Of these patients, 60% visited our department within 3 days of the onset, and 90% within 7 days of the onset ; the interval from onset to hospital visit showed no relation with the severity of the paralysis, Complete recovery was obtained in 85.0% of the patients with steroid or steroid + antiviral treatment. Preservation of the stapedius reflex was a statistically significant predictor of good prognosis, with a high positive predictive value (95.5%). Several factors influencing the prognosis were examined with a Cox's proportional hazards model. The factors considered were the sex of the patients, left / right localization, age, postauricular pain, eye symptoms, taste disorder, underlying diabetes, the Yanagihara facial grading system score, and use of antiviral drugs. The analysis revealed only the Yanagihara score and antiviral drug use as statistically important, with hazard ratios of 1.101 and 1.586, respectively. Although this study had several limitations, steroid + antiviral treatment could yield a better prognosis as compared to steroid treatment alone.

We have previously reported on the effects of tinnitus retraining therapy (TRT) involving monaural noise generators (NGs) up to 24 months after the start of treatment (Eur Arch Otorhinolaryngol. 2013 Feb; 270(2): 443-8.) but very few reports exist about the long-term effects of TRT for periods of over 2 years. The aim of this study was to report the effects of TRT involving monaural NGs more than 24 months after the start of treatment. Thirty-three patients with chronic tinnitus were included in this study. All received directive counseling and monaural NGs without any other combination treatment. Effects were evaluated with the Tinnitus Handicap Inventory (THI) at their final visits to our clinic (average 31 months after the start of treatment). The average THI scores significantly improved from 55.3 ± 19.7 at baseline to 33.5 ±23.3 at their final visits. Seventeen patients (52%) improved by more than 20 points from the baseline. Eleven patients who were treated with TRT for more than 3 years were individually observed in a detailed manner. Some of them experienced aggravation of their symptoms after 2 years' successful treatments. This study suggests that, although TRT seems effective more than 2 years after the start of treatment, the clinical course of each patient can vary and we need to follow them periodically depending on their situations and symptoms.

A 68-year-old woman presented dizziness whenever she put her finger into the right ear and also complained of water-streaming tinnitus, which indicated she would have been suffering from perilymph fistula. An exploratory tympanotomy was conducted. Leakage of perilymph from the round window was suspected, although the cochlin-tomoprotein (CTP) results were negative. After the procedure, the patient’s finger-induced dizziness, tinnitus, and vertigo spells disappeared completely. However, her dizzy symptom did not improve. The patient also complained of general fatigue, weight loss, and insomnia, which led us to suspect comorbid depression. Antidepressants and vestibular rehabilitation treatment resulted in a significant improvement in her dizziness. Although it is not apparent whether the patient had a perilymph fistula, this case demonstrates the importance of evaluating not only physical symptoms but also psychological comorbidity, especially when the physical symptoms are intractable despite treatment.

Metformin (N,N-dimethylbiguanidine) is a widely employed oral hypoglycemic agent for the management of type 2 diabetes mellitus. Its antioxidant properties and safe clinical use raise the possibility of preventing gentamicin-induced hearing loss in patients. Therefore, we screened the usefulness of metformin against gentamicin toxicity in murine cochlear explants and in the guinea pig in vivo. We confirmed in organ culture that metformin blocks the gentamicin-induced translocation of endonuclease G into the nucleus of outer hair cells and attenuates hair cell loss. In vivo, gentamicin treatment with 80, 100, or 130 mg/kg body weight for 14 days induced significant threshold shifts as determined by auditory brain stem responses. Metformin (30, 75, or 100 mg/kg for 14 days) was well tolerated without any indication of auditory side effects. However, co-administration of metformin with gentamicin in various permutations did not prevent loss of auditory function. On the contrary, combined treatment at higher dosages aggravated the gentamicin-induced threshold shifts and caused additional adverse reactions including body weight loss and premature deaths in some animals. These results caution against the use of metformin co-treatment with aminoglycosides and confirm the need for in vivo studies in order to evaluate potentially protective agents selected by in vitro screens.

Exogenous tumor necrosis factor-alpha (TNF-α) plays a role in auditory hair cell death by altering the expression of apoptosis-related genes in response to noxious stimuli. Little is known, however, about the function of TNF-α in normal hair cell physiology. We, therefore, investigated the cochlear morphology and auditory function of TNF-α-deficient mice. Auditory evoked brainstem response showed significantly higher thresholds, especially at higher frequencies, in 1-month-old TNF-α-/- mice as compared to TNF-α+/- and wild type (WT); hearing loss did not progress further from 1 to 4 months of age. There was no difference in the gross morphology of the organ of Corti, lateral wall, and spiral ganglion cells in TNF-α-/- mice compared to WT mice at 4 months of age, nor were there differences in the anatomy of the auditory ossicles. Outer hair cells were completely intact in surface preparations of the organ of Corti of TNF-α-/- mice, and synaptic ribbon counts of TNF-α-/- and WT mice at 4 months of age were similar. Reduced amplitudes of distortion product otoacoustic emissions, however, indicated dysfunction of outer hair cells in TNF-α-/- mice. Scanning electron microscopy revealed that stereocilia were sporadically absent in the basal turn and distorted in the middle turn. In summary, our results demonstrate that TNF-α-mutant mice exhibit early hearing loss, especially at higher frequencies, and that loss or malformation of the stereocilia of outer hair cells appears to be a contributing factor. © 2013 Association for Research in Otolaryngology.

Loeys-Dietz syndrome is a recently recognized connective tissue disorder characterized by severe craniofacial and skeletal abnormalities as well as arterial tortuosity with aggressive aneurysm formation. Marfan syndrome, a classic connective tissue disorder, is known to be associated with a risk of obstructive sleep apnea, but sleep-related breathing disorders have not been previously documented in Loeys-Dietz syndrome. The propositus had the prototypic features of Loeys-Dietz syndrome with a de novo mutation in TGFBR2. He developed severe obstructive sleep apnea during his infancy. Continuous positive airway pressure was introduced at age 7 years and provided significant improvement in his nocturnal apnea and sleep apnea-related symptoms, such as enuresis. Marfan syndrome is known to be associated with a high risk of sleep apnea because of its characteristic craniofacial and connective tissue abnormalities. Similarly, the severe craniofacial abnormalities in Loeys-Dietz syndrome may predispose patients to severe obstructive sleep apnea, even at a very young age. Despite the severity of obstructive sleep apnea in the propositus, the administration of continuous positive airway pressure was highly effective in alleviating his symptoms. In summary, severe obstructive sleep apnea was successfully treated using continuous positive airway pressure in a patient with Loeys-Dietz syndrome. Careful evaluation and aggressive intervention for the alleviation of obstructive sleep apnea is warranted in Loeys-Dietz syndrome. © 2013 Wiley Periodicals, Inc.

Objective: To verify whether the severity of globus sensation would be affected by the results of investigations on possible underlying serious pathology in the head, neck and esophagus. Methods: Thirty-six patients with globus sensation were enrolled in this study. All the patients suffered relatively persistent globus sensation which remained after conventional laryngoscopy at their family doctors. These patients were investigated for possible underlying oropharyngeal and esophageal lesions using fiberoptic endoscopy. The severity of globus was evaluated by the visual analog scales (VAS), and the degree of anxiety was evaluated by the state section of State Trait Anxiety Inventory (STAI-s). The questionnaires were administered at their first visits, and 9.6. ±. 3.2 months after endoscopy. The follow-up data obtained from 22 patients were incorporated in the further evaluations. Multiple regression analysis was used to evaluate the relationship between the improvement of VAS scores and that of STAI-s scores. Afterwards, Pearson product-moment correlation coefficient was measured. The recorded images of fiberoptic endoscopy were retrospectively verified by an expert of upper gastrointestinal endoscopy. Results: No malignancies were observed in the endoscopic examination. Despite no treatment administered during the follow-up period, significant improvement of VAS scores was observed from the initial scores (40. ±. 21) to follow-up scores (27. ±. 27, p= 0.014) in the patients examined in this study. The multiple linear regression analysis proved that the improvement of STAI-s scores was the only factor significantly affected the improvement of VAS scores (p= 0.029) among the dependent valuables. The retrospective evaluation of the recorded images revealed comorbid esophagitis in 10 out of the 22 patients. When patients were stratified with the presence of comorbid esophagitis, significant improvement of VAS scores was observed only in the group without comorbid esophagitis at their follow up (17. ±. 20, p= 0.026) compared with their initial scores (36. ±. 17). The multiple linear regression analysis proved that the improvement of VAS scores was significantly affected by the improvement of STAI-s scores (p= 0.047) in this group. Moreover, significant positive relationship between the improvement of VAS scores and that of STAI-s scores was observed only in the group without comorbid esophagitis (r= 0.61, p= 0.047). Conclusion: Proper investigation to prove no underlying serious pathology may lead to the improvement of globus sensation in the patients without comorbid esophagitis through the reduction of their anxiety even when their symptoms are relatively persistent. Our results also indicated that some treatments against esophagitis may be helpful for the improvement of globus sensation in the patients with this comorbid disease. © 2012 Elsevier Ireland Ltd.

Conclusions: Patients with migraine-associated vertigo (MAV) may have a higher incidence of photic-driven electroencephalography (EEG) response. The occurrence of photic-driven responses for stimulation at frequencies of 10, 12, and 15 Hz can be considered a positive indicator for MAV. Although photic driving is not specific to migraine, patients with MAV have a higher incidence of photic driving. The distinction between Ménière's disease and MAV by means of EEG would be another interesting topic of research. Objective: The objective of this study was to distinguish between patients with MAV and patients with other vestibulopathies (VPs) using EEG. Methods: EEG with intermittent photic stimulation (PS) at frequencies between 3 and 24 Hz was recorded to quantify photic driving in patients with MAV (n = 21) and VPs (n = 15). The presence or absence of photic driving was determined; a score of 1 was counted for response to a particular frequency. Results: Total scores were calculated for each patient for statistical comparison. There was a significant difference in the average total score between MAV and VP patients (p < 0.05), and photic-driven responses were observed for 10, 12, and 15 Hz stimulation. © 2013 Informa Healthcare.

Trans-tympanic injection into the middle ear has long been the standard for local delivery of compounds in experimental studies. Here we demonstrate the advantages of the novel method of intra-tympanic injection through the otic bone for the delivery of compounds or siRNA into the adult mouse cochlea. First, a fluorescently-conjugated scrambled siRNA probe was applied via intra-tympanic injection into the middle ear cavity and was detected in sensory hair cells and nerve fibers as early as 6 h after the injection. The fluorescent probe was also detected in other cells of the organ of Corti, the lateral wall, and in spiral ganglion cells 48 h after the injection. Furthermore, intra-tympanic delivery of Nox3 siRNA successfully reduced immunofluorescence associated with Nox3 in outer hair cells 72 h after injection by 20%. Drug or siRNA delivery via intra-tympanic injection does not compromise the tympanic membrane or interfere with noise-induced hearing loss, while trans-tympanic injections significantly altered the cochlear response to noise exposure. In summary, intra-tympanic injection through the otic bone into the middle ear cavity provides a promising approach for delivery of compounds or siRNA to cochlear hair cells of adult mice, relevant for the study of mechanisms underlying inner ear insults and, specifically, noise-induced hearing loss. © 2012 Elsevier B.V.

The aim of this study was to assess how tinnitus retraining therapy (TRT) employing monaural noise generators (NGs) affects tinnitus patients. Ninety-five patients with chronic tinnitus were included in this study. All received directive counseling and monaural NGs without any other combination treatment. Effects were evaluated with the Tinnitus Handicap Inventory (THI) 6, 12, and 24 months after the start of treatment. Multiple regression analysis was used to evaluate factors associated with improvement of THI scores. We observed a significant improvement in the average THI scores, which ranged from 59 at baseline to 36 after 6 months and were stable up to 24 months. Severely distressed (SD) patients experienced more benefits from the therapy than moderately distressed (MD) patients. Multiple regression analysis revealed that the presence of transient anxiety symptoms, measured by the state section of the State Trait Anxiety Inventory at the beginning of treatment, were associated the most to a decline in THI scores in SD patients. Pure-tone average at three mid frequencies was a negatively contributing factor. Analysis of MD patients did not provide a good model. In conclusion, TRT employing monaural NGs was an effective intervention especially for SD patients, although plateau of the effects after 6 months may be indicative of limitation of applying NGs monoaurally. Reducing the patients' hearing handicap may reinforce the effects of TRT in SD patients. Additional evaluation and interventions for both SD and MD patients might be needed. © 2012 Springer-Verlag.