[Show abstract][Hide abstract] ABSTRACT: This study compared long-term speech performance after cochlear implantation (CI) between surgical strategies in patients with chronic otitis media (COM). Thirty patients with available open-set sentence scores measured more than 2 yr postoperatively were included: 17 who received one-stage surgeries (One-stage group), and the other 13 underwent two-stage surgeries (Two-stage group). Preoperative inflammatory status, intraoperative procedures, postoperative outcomes were compared. Among 17 patients in One-stage group, 12 underwent CI accompanied with the eradication of inflammation; CI without eradicating inflammation was performed on 3 patients; 2 underwent CIs via the transcanal approach. Thirteen patients in Two-stage group received the complete eradication of inflammation as first-stage surgery, and CI was performed as second-stage surgery after a mean interval of 8.2 months. Additional control of inflammation was performed in 2 patients at second-stage surgery for cavity problem and cholesteatoma, respectively. There were 2 cases of electrode exposure as postoperative complication in the two-stage group; new electrode arrays were inserted and covered by local flaps. The open-set sentence scores of Two-stage group were not significantly higher than those of One-stage group at 1, 2, 3, and 5 yr postoperatively. Postoperative long-term speech performance is equivalent when either of two surgical strategies is used to treat appropriately selected candidates.
Journal of Korean Medical Science 01/2015; 30(1):82-87. · 1.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to understand the prevalence and molecular genetic etiology of incomplete partition type III (IP type III) anomaly in Koreans. We also attempted to verify the prevalence of genomic deletions in the DFNX2 locus and to look for association between inheritance patterns and mutation type in East Asian IP type III subjects.
Retrospective case review.
Tertiary referral center.
Subjects with IP type III anomaly and their biological mothers.
Sanger sequencing, array-comparative genomic hybridization (aCGH), and PCR were performed. We also analyzed the type and inheritance of the causative genetic abnormality in East Asian DFNX2 patients.
Mutation type and occurrence.
We identified IP type III in 10 (4.8%) of 206 patients with an inner ear abnormality. We confirmed an etiologic homogeneity, DFNX2, of the IP type III in this Korean population. Two (20%) of the 10 DFNX2 carried a large genomic deletion affecting POU3F4, as proved by aCGH. PCR confirmed that the 2 deletions occurred de novo. Genetic alteration occurred de novo in 29.4% (5/17) of all reported Korean IP type III cases. From this study and literature review, we observed a striking difference of de novo occurrence rate (75% versus 12.5%, p = 0.032) between large genomic deletions and point mutations in East Asian population.
Our data suggest that different POU3F4 mutations might show different recurrence rate in siblings of the IP type III families, especially in East Asian population. Genetic counseling should be provided accordingly.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 03/2014; · 1.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to clarify the cause of the air-bone gap in incomplete partition (IP) type III cases according to the POU3F4 gene (DFNX2) mutation type. A retrospective analysis of patient medical records was done in a tertiary referral medical center. Five IP type III patients proved to be carrying a mutation in or affecting POU3F4. The hearing and the middle ear status at either exploratory tympanotomy or cochlear implantation from these DFNX2 cases was reviewed. Four of five unrelated IP type III patients harbored a point mutation of POU3F4 and the fifth patient carried a large genomic deletion upstream to POU3F4. Two of the four DFNX2 patients carrying a point mutation had moderate to severe mixed hearing loss with a substantial amount of air-bone gap. These patients underwent exploratory tympanotomy to identify the cause of their hearing loss. The other three patients, including one carrying a large deletion, had profound hearing loss at presentation and received a cochlear implant. In the exploratory tympanotomy group with a substantial amount of air-bone gap and a point mutation (n = 2), one patient had a perfect ossicular chain with normal mobility, a positive ipsilateral stapedial reflex, and a positive round window reflex. In the cochlear implantation group (n = 3), we found a stapes with normal mobility and a positive round window reflex in one patient who harbored a large genomic deletion upstream to POU3F4. We concluded that the probable presence of the third window effect is not limited to the particular type of POU3F4 mutation.
Archives of Oto-Rhino-Laryngology 02/2013; · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Enlargement of the vestibular aqueduct (EVA) is a commonly detected inner ear anomaly related to hearing loss and often associated with mutations of SLC26A4 encoding pendrin, a transmembrane exchanger of Cl(-), I(-), and HCO(3)(-). Here we describe the phenotypes of 27 Korean EVA subjects and their SLC26A4 genotypes determined by bidirectional nucleotide sequencing.
The detected variants include two novel missense substitutions (p.V138L and p.P542R). We characterized the ability of p.V138L and p.P542R pendrin products to traffic to the plasma membrane in COS-7 cells and to transport Cl(-), I(-), and HCO(3)(-) in Xenopus oocytes. The results indicate that p.P542R is a benign polymorphic variant, whereas p.V138L is a pathogenic mutation. Since this and other studies of East Asian EVA cohorts show that the majority of SLC26A4 mutations affect either or both of two amplicons (exons 7-8 and 19), we developed a hierarchical protocol that integrates direct sequencing with denaturing high-performance liquid chromatography analyses for detection of SLC26A4 mutations in these populations. We validated the cost efficiency of the integrated protocol by a simulated screen of published East Asian EVA cohorts with known SLC26A4 genotypes.
Our study further defines the spectrum of SLC26A4 mutations among East Asians and demonstrates a rapid and efficient protocol for their detection.
[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to characterize the signal intensity (SI) pattern in the endolymphatic duct/sac from T2-weighted spin echo magnetic resonance (MR) images and T2*-weighted 3-dimensional (3-D) constructive interference in steady state (CISS) MR images that were obtained from a homogenous group of patients with an enlarged vestibular aqueduct (EVA) associated with SLC264 (PDS) mutations.
A retrospective study.
Tertiary referral center.
Eleven subjects (22 ears), with at least 1 SLC26A4 mutation and bilateral EVA confirmed by temporal bone computed tomography, were enrolled.
The MR images of 22 ears were reviewed retrospectively.
The SI of the endolymphatic sac (ES) from 2 sequences were compared and reviewed. The presence of anomalies of the vestibule were also evaluated. In addition, the caloric test results were also reviewed to characterize the vestibular function in a subset of our cohort (12 ears).
T2*-weighted 3-D CISS MR images revealed a more variable SI in the enlarged endolymphatic system than did the T2-weighted images. There was a hierarchy for the order of SI loss from the endolymphatic system on the T2*-weighted 3-D CISS MR images. There were 3 cases where the SI loss from the intraosseous ES, on the T2*-weighted 3-D CISS images, was associated with an abnormal caloric response.
The SI of the ES observed on T2*-weighted 3-D CISS images of EVA patients, with SLC26A4 mutations, showed a distinctive pattern, and the results from this study suggest a potential role for the MR imaging in providing physicians with better information about the functional status of the inner ear.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 09/2008; 29(5):593-600. · 1.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cochlear implantation (CI) remains a safe procedure with a low complication rate. Nevertheless, advances in surgical techniques and the optimization of treatment modalities would further reduce complications.
To assess the complications of CI and describe the management of each complication encountered at our hospital.
This study involved 720 patients that underwent implantation from November 1988 through April 2007. Mean age at implantation was 13.6 years (range 12 months to 83 years). Patients were followed up regularly with a mean follow-up of 42 months (range 4-81 months).
No death was attributed to device implantation. Major complications included: device failure in 12 patients, misplaced electrodes in 4, hematoma in 3, flap necrosis in 3, magnet displacement in 2, facial nerve twitching in 2, electrode exposure in 2, external auditory canal keratoma in 1, immediate facial nerve paralysis in 1, and skin flap irritation due to the suture material in 1. The overall major complication rate was 4.2% (30/720), and there were 37 minor complications (5.1%), which were resolved by conservative treatment or minor intervention. Minor complications included temporary vertigo in 17 patients, facial twitching in 11, hematoma in 4, subcutaneous emphysema in 3, and temporary facial nerve paralysis in 2.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the clinical features of cochlear reimplantation due to device failure.
The medical records of 30 patients who had undergone a revision cochlear implantation were retrospectively reviewed. Causes of revision operations, number of electrode channels inserted, and postoperative speech performances were analyzed.
Device failure (N=12, 38.7%) and hematoma (N=3, 9.6%) were the two most common reasons for revision surgery. In patients with device failure, the number of electrode channels reinserted was equal to, or more than the number of channels inserted during initial implantation. Speech performance scores remained the same, or improved after reimplantation in patients with device failure.
Device failure was the most common cause of revision operation in patients with cochlear implantation. Contrary to expectation, new electrodes were fully inserted without difficulty in all reimplantation cases. Intracochlear damage due to reimplantation appeared to be clinically insignificant.
Clinical and Experimental Otorhinolaryngology 04/2008; 1(1):10-4. · 0.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: When selecting the appropriate surgical approach the pathological type of tumor, the physiological status as well as the functional aspects should be considered. Understanding the strengths and weaknesses of each surgical technique and knowledge of the particular tumor biology facilitates selection of the most appropriate surgical approach and a successful outcome.
The purpose of this study was to review cases that underwent skull base surgery for a variety of tumors that involved the temporal bone. We reviewed a single center's 25-year experience for epidemiologic characteristics, symptoms, treatment type and outcomes.
The medical records and radiological images of 91 patients, who underwent skull base surgery, were retrospectively reviewed.
Among the 91 patients, 61 cases had benign disease and 30 had malignancies. A facial nerve schwannoma was the most common benign intratemporal tumor and a squamous cell carcinoma was the most common malignant tumor. With the facial nerve schwannoma, facial nerve paralysis and hearing loss were the most common presenting complaints; otalgia was the most common presenting symptom for temporal bone cancer. For patients with a glomus tumor, there was a characteristic pulsating tinnitus. A majority of the facial nerve schwannomas were resectable through the transmastoid approach. The infratemporal fossa approach type A was usually required for lower cranial nerve schwannomas and glomus jugulare tumors. However, the fallopian bridge technique with hypotympanectomy was another surgical option. Partial temporal bone resection and subtotal temporal bone resections were performed in cases with temporal bone cancer. The disease free 5-year survival of the temporal bone cancers was 42% and for the squamous cell carcinomas, it was 44%.
[Show abstract][Hide abstract] ABSTRACT: KCNQ1/KCNE1 K(+) channels and P2Y(4) receptors are expressed in the apical membrane of rat strial marginal cells from postnatal day 1 (P1) and maintained throughout development.
The purpose of the present study was to investigate the developmental expression of KCNQ1/KCNE1 K(+) channel and of P2Y(4), which is an important metabotropic regulator of KCNQ1/KCNE1 K(+) channel in strial marginal cells.
Sprague-Dawley rats at different stages of development (P1, P3, P5, P7, P14, and P21) were studied. The spiral ligament with the stria vascularis was detached from the cartilaginous or bony cochlea and prepared for a voltage-sensitive vibrating probe and immunohistochemistry.
Chromanol 293B, a blocker of KCNQ1/KCNE1 K(+) channel, inhibited short-circuit currents (I ( sc )) from P1 to P21. Similarly, I ( sc ) were found to be decreased by uridine 5'-triphosphate at all ages. The antagonist profiles indicated that the apical P2Y receptor is P2Y(4) subtype. KCNQ1, KCNE1, and P2Y(4) were immunolocalized in the apical region of stria vascularis at P1.
[Show abstract][Hide abstract] ABSTRACT: Extracellular adenosine triphosphate (ATP) released from cellular sources plays an important role in variety of the cochlear physiologic processes. The primary purinergic receptor subtype in the cochlea is the P2X2 receptor, which is a subtype of P2X receptor. This receptor appears to mediate a protective decrease in the electrical driving force in response to acoustic overstimulation. Outer sulcus cells (OSCs) in the cochlear lateral wall appear to maintain an adequate K+ concentration in the cochlear endolymph in response to varying intensities of auditory stimulation. However, little is known about developing OSCs. The purpose of this study was to investigate subtypes of purinergic receptors in developing rat OSCs using a voltage-sensitive vibrating probe. Results showed that only two P2 receptors (P2Y4 and P2X2) contributed to the regulation of short circuit currents in neonatal OSCs. ATP increased cation absorption via apical nonselective cation channels after activating P2Y4 receptors in early neonatal OSCs. P2Y4 expression rapidly declined postnatally and reached near adult levels on postnatal day 14. P2X2 was co-expressed with P2Y4 in early neonatal OSCs. Temporal changes in P2Y4 during OSC development might be involved in the establishment of the endolymphatic ion composition needed for normal auditory transduction and/or specific cellular differentiation.
Hearing Research 07/2007; 228(1-2):201-11. · 2.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to examine improvements of cognitive abilities after cochlear implantation in deaf children. We also examined the psychosocial factors that predict good outcomes of cochlear implantation.
A neuropsychological test battery was administered to 17 deaf children (mean age, 7 yr 2 mo) before receiving the cochlear implant, and they were reassessed with the same test at 6-mo follow-up. Their parents completed questionnaires concerning their medical and educational history, parenting style, and parental emotional problems.
Deaf children showed marked improvement in speedy and delicate motor coordination and visual organization abilities. Their cognitive functions of comprehension, concentration, and sequential processing, as measured by nonverbal tests, were found to have improved from the levels of borderline to mild mental retardation to that of near-normal range. However, their performances on Information, Comprehension and Similarity, and Mathematics subtests requiring verbal abilities did not show significant changes. Deaf children's working memory improved significantly after cochlear implantation. However, they showed more omission errors in the visual attention test at follow-up than before cochlear implantation. Such inattentiveness for visual stimuli in children post-implantation could be attributed to distractibility of these children toward external noise. Mothers' depression was negatively correlated with scores of acquired knowledge of deaf children.
At the 6-mo follow-up after cochlear implant, deaf children showed marked improvement in nonverbal cognitive functions and working memory. Conversely, their verbal abilities did not significantly change. Maternal factors were found to be important for predicting the prognosis of cochlear implantation. The absence of a control group precludes the possibility of drawing any firm conclusions because the effect of the implant cannot be teased apart from the effects of maturation and training. Future studies should address this question with the use of appropriate control groups.
Ear and Hearing 05/2007; 28(2 Suppl):22S-28S. · 2.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The functional status of central neural pathways, in particular their susceptibility to plasticity and functional reorganization, may influence speech performance of deaf cochlear implant users. In this paper, we sought to determine how brain metabolic activity measured before implantation relates to cochlear implantation outcome, that is, speech perception. In 22 prelingually deaf children between 1 and 11 years, we correlated preoperative glucose metabolism as measured by F-18 fluorodeoxyglucose positron emission tomography with individual speech perception performance assessed 3 years after implantation, while factoring out the confounding effect of age at implantation. Whereas age at implantation was positively correlated with increased activity in the right superior temporal gyrus, speech scores were selectively associated with enhanced metabolic activity in the left prefrontal cortex and decreased metabolic activity in right Heschl's gyrus and in the posterior superior temporal sulcus. These results reinforce the notion that implantation should be performed as early as possible to prevent cross-modal takeover of auditory regions and suggest that rehabilitation strategies may be more efficient if they capitalize on general cognitive functions instead of only targeting specialized circuits dedicated to auditory and audiovisual pattern recognition.
[Show abstract][Hide abstract] ABSTRACT: The plastic changes in the auditory cortex after bilateral cochlear ablation are related to the immediate early genes as well as the neural plasticity-related genes. In addition, cross-modal plasticity may play an important role in the early changes in the auditory cortex after bilateral cochlear ablation.
The purpose of this study was to identify candidate genes involved in the normal development of primary auditory cortex during the critical period as well as those genes specifically modulated under conditions of sensory deafferentation by bilateral cochlear ablation.
We produced a bilaterally deaf rat model and used DNA microarray technology to analyze differential gene expression in the primary auditory cortex of bilateral cochlear ablated and sham-operated age-matched control rats. Gene expression in the auditory cortex was compared at 2, 4, and 12 weeks after surgery. For selected genes, the changes in gene expression were confirmed by real-time polymerase chain reaction (PCR).
In the cochlear ablation groups, the expression of immediate early genes (Egr1, 2, 3, 4, c-fos, etc.) and neural plasticity-related genes (Arc, Syngr1, Bdnf, etc.) was decreased at 2 weeks and increased at 4 weeks. The expression of neurotransmission-related genes (Gabra5, Chrnb3, Chrne, etc.) was decreased at 12 weeks.
[Show abstract][Hide abstract] ABSTRACT: Extracellular ATP decreases K+ secretion in strial marginal cells via apical P2Y4 receptors. We investigated the effect of reactive blue 2 (RB-2), an antagonist of rat P2Y4, on rat strial marginal cells using a voltage-sensitive vibrating probe. The application of RB-2 increased K+ secretion in a dose-dependent manner, and this increase was characterized as a peak followed by a partial relaxation to a steady-state. Moreover, this response was similar to that caused by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS). Suramin had no similar effect, except at high concentration. Thus, we tested the effects of these chemicals on P2Y4 receptors in strial marginal cells. Both RB-2 and DIDS had antagonistic activities at P2Y4, and the antagonist potency at P2Y4 paralleled the potency of K+ secretion. Interestingly, 2'- and 3'-O-(4-benzoyl-benzoyl)adenosine 5'-triphosphate (BzATP) exhibited an agonistic effect at P2Y4 receptor, which was blocked by RB-2, but not by pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Based on these results, we speculate that direct and/or indirect inhibitory mechanisms between P2Y4 and KENQ1/KCNE1 K+ channels exist in strial marginal cell.
Hearing Research 10/2006; 219(1-2):66-73. · 2.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Speech perception in face-to-face conversation involves processing of speech sounds (auditory) and speech-associated mouth/lip movements (visual) from a speaker. Using PET where no scanner noise was present, brain regions involved in speech cue processing were investigated with the normal hearing subjects with no previous lip-reading training (N = 17) carrying out a semantic plausibility decision on spoken sentences delivered in a movie file. Multimodality was ensured at the sensory level in all four conditions. Sensory-specific speech cue of one sensory modality, i.e., auditory speech (A condition) or mouth movement (V condition), was delivered with a control stimulus of the other modality whereas speech cues of both sensory modalities (AV condition) were delivered during bimodal condition. In comparison to the control condition, extensive activations in the superior temporal regions were observed bilaterally during the A condition but these activations were reduced in extent and left lateralized during the AV condition. Polymodal region such as left posterior superior temporal sulcus (pSTS) involved in cross-modal interaction/integration of audiovisual speech was found to be activated during the A and more so during the AV conditions but not during the V condition. Activations were observed in Broca's (BA 44), medial frontal (BA 8), and anterior ventrolateral prefrontal (BA 47) regions in the left during the V condition, where lip-reading performance was less successful. Results indicated that the speech-associated lip movements (visual speech cue) rendered suppression on the activity in the right auditory temporal regions. Overadditivity (AV > A + V) observed in the right postcentral region during the bimodal condition relative to the sum of unimodal speech conditions was also associated with reduced activity during the V condition. These findings suggested that visual speech cue could exert an inhibitory modulatory effect on the brain activities in the right hemisphere during the cross-modal interaction of audiovisual speech perception.
[Show abstract][Hide abstract] ABSTRACT: Superficial siderosis (SS) of the central nervous system has been thought to be a rare condition that generates progressive hearing loss, ataxia, pyramidal signs, and dementia. The main cause of hearing loss by SS is thought to be neuronal. Because there is no histopathologic report of the human temporal bone in SS, there is a debate about the possibility of cochlear involvement. We present a 25-year-old man who was investigated for bilateral progressive sensorineural hearing loss and vestibular failure after head trauma. On brain MRI, SS of the central nervous system was detected. Distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) showed no response on both sides. However, integrity of the eighth nerve was proved by the electrical ABR test on the right side and the patient benefited significantly from cochlear implantation. The sensorineural hearing loss in SS seems to be related to cochlear damage as well as neuronal damage. So, cochlear implantation would be a hearing rehabilitation modality for the sensorineural hearing loss caused by SS.
[Show abstract][Hide abstract] ABSTRACT: Cochlear implantation is an established method of auditory rehabilitation for the severe and profoundly hearing impaired; however, it may cause complications. This study focused upon the intraoperative problems and postoperative complications of cochlear implantation. The medical records of 430 patients who underwent cochlear implantation at our center from November 1988 through March 2004 were analyzed retrospectively. Major complications were reported in nine cases (2.1%), which included one device explantation. Minor complications (25 cases, 5.8%) such as dizziness, skin rash and hematoma were self-limited. The mechanical device failures were identified in nine cases (2.1%). The causes of the postoperative complications were examined, and the management methods and the results obtained are described. Surgeons must be prepared to cope with the intra- and postoperative problems associated with cochlear implantation. A careful preoperative evaluation would reduce the frequency of serious complications.
International Congress Series 04/2006; 1273:145–148.
[Show abstract][Hide abstract] ABSTRACT: Evaluation of head-position dependency during the ice-water test is essential when the test is indicated. Because ice-water irrigation (IWI) in the prone position is frequently skipped in many laboratories, we investigated the importance of evaluating position dependency in an ice-water test.
Twenty-five unilateral peripheral vestibulopathy patients showing no nystagmus during warm irrigation were included. IWI was performed in supine and prone positions, and maximum slow-phase velocity and direction of nystagmus were assessed by using video nystagmography.
Eleven cases showed head-position dependency and were interpreted as hypofunctional. Fourteen cases showed no dependency, suggesting the absence of end organ function. In the latter group, 6 patients showing definite nystagmus in supine position could have been misinterpreted as hypofunctional, had it not been for prone-position results.
Evaluation of head position dependency by using IWI is important in the determination of lateral semicircular canal function.
Otolaryngology Head and Neck Surgery 10/2005; 133(3):334-8. · 1.72 Impact Factor