Traumatic Neuroma in the External Auditory Canal.

Traumatic neuroma is the reparative proliferation of axons and Schwann cells at the proximal end of a severed nerve following injury or surgery. Traumatic neuromas with or without clinical symptoms have rarely been reported in the external auditory canal. A 50-year-old woman with a history of trauma visited our otorhinolaryngology clinic with a 7 × 5-mm mass localized on the anterior wall of the external auditory canal. The mass was easily removed via surgical excision and was histopathologically diagnosed as a neuroma. No signs of recurrence were observed after excision. Herein, the authors present this case, along with a review of the literature.

Comparison of Gait Parameters during Forward Walking under Different Visual Conditions Using Inertial Motion Sensors.

PURPOSE: Gait evaluation in patients with dizziness is essential during both initial evaluation and vestibular rehabilitation. Inertial measurement unit (IMU)-based gait analysis systems are clinically applicable in patients with dizziness. Since dizzy patients can utilize visual inputs to compensate for vestibular deficits, it is more difficult for them to walk with their eyes closed (EC). In this study, we compared gait characteristics during forward walking with both eyes open (EO) and EC between healthy subjects and dizzy patients. MATERIALS AND METHODS: Forty-nine healthy controls (mean age 37.18±10.71 years) and 23 patients with dizziness (mean age 49.25±15.16 years) were subjected to vestibular and gait analyses. Medical histories, physical examinations, and vestibular function tests ruled out possible vestibular deficits in the controls. Subjects were instructed to walk at a comfortable pace for 10 m under two conditions (EO or EC). Spatiotemporal parameters, kinematics, and simulated kinetics of each gait recording were recorded using a shoe-type IMU system and analyzed. RESULTS: Although gait speeds were slower, stride lengths were smaller, and double support times were increased under the EC, compared to the EO condition, in both healthy subjects and dizzy patients, the difference was more prominent in dizzy patients. Phase coordination index values did not differ significantly in either group. Gait asymmetry (GA) increased significantly under the EC condition, compared to the EO condition, in dizzy patients. CONCLUSION: GA during forward walking was greater in dizzy patients under an EC condition than under an EO condition.

Limitation of Conventional Audiometry in Identifying Hidden Hearing Loss in Acute Noise Exposure.

PURPOSE: The concept of hidden hearing loss can explain the discrepancy between a listener's perception of hearing ability and hearing evaluation using pure tone audiograms. This study investigated the utility of the suprathreshold auditory brainstem response (ABR) for the evaluation of hidden hearing loss in noise-exposed ear with normal audiograms. MATERIALS AND METHODS: A total of 15 patients (24 ears) with normal auditory thresholds and normal distortion product otoacoustic emissions were included in a retrospective analysis of medical records of 80 patients presenting with histories of acute noise exposure. The control group included 12 subjects (24 ears) with normal audiograms and no history of noise exposure. Pure tone audiometry and suprathreshold ABR testing at 90 dB peSPL were performed. The amplitudes and latencies of ABR waves I and V were compared between the noise-exposed and control groups. RESULTS: We found no significant difference in the wave I or V amplitude, or the wave I/V ratio, between the two groups. The latencies of ABR wave I, V, and I-V interpeak interval were compared, and no significant intergroup difference was observed. CONCLUSION: The results suggest that either hidden hearing loss may not be significant in this cohort of patients with acute noise exposure history, or the possible damage by noise exposure is not reflected in the ABRs. Further studies are needed to inquire about the role of ABR in identification of hidden hearing loss.

Audiologic Status of Children with Confirmed Cytomegalovirus Infection: a Case Series.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is the most common non-genetic cause of sensorineural hearing loss (SHNL) in children. Only about 10% to 15% of children with congenital CMV are symptomatic, and most are not diagnosed at birth. About 7% to 15% of clinically asymptomatic patients may develop later complications, including SNHL, which is the most common sequela in clinically asymptomatic patients. In this study, hearing status was investigated in children with confirmed CMV infection and neonatal hearing screening (NHS) histories were reviewed to explore hearing loss caused by CMV. METHODS: The medical records of 58 children who were diagnosed with confirmed CMV infection were reviewed for clinical symptoms and signs of CMV infection. Hearing status was evaluated with age-appropriate audiological test batteries. RESULTS: A total of 58 children (M:F = 32:26 patients; age at study: mean, 5.62 years, range, 1-10 years) were diagnosed serologically with CMV infection (14 patients, 21.1%), or diagnosed via PCR of serum (5, 7.9%) and/or PCR from urine (19, 26.8%). Hearing loss was confirmed in 11 children (19.0%), being bilateral in 6 (54.5%), and unilateral in 5 (45.5%). Note that 7 of 17 ears with hearing loss passed NHS and were diagnosed only after re-evaluation when CMV infection was identified. CONCLUSION: Hearing loss is a serious complication of CMV infection in children. Our results highlight the importance of timely audiological evaluation in children with clinically symptomatic CMV infection even if they pass NHS.

Unbiased biocatalytic solar-to-chemical conversion by FeOOH/BiVO4/perovskite tandem structure.

Redox enzymes catalyze fascinating chemical reactions with excellent regio- and stereo-specificity. Nicotinamide adenine dinucleotide cofactor is essential in numerous redox biocatalytic reactions and needs to be regenerated because it is consumed as an equivalent during the enzymatic turnover. Here we report on unbiased photoelectrochemical tandem assembly of a photoanode (FeOOH/BiVO4) and a perovskite photovoltaic to provide sufficient potential for cofactor-dependent biocatalytic reactions. We obtain a high faradaic efficiency of 96.2% and an initial conversion rate of 2.4 mM h-1 without an external applied bias for the photoelectrochemical enzymatic conversion of α-ketoglutarate to L-glutamate via L-glutamate dehydrogenase. In addition, we achieve a total turnover number and a turnover frequency of the enzyme of 108,800 and 6200 h-1, respectively, demonstrating that the tandem configuration facilitates redox biocatalysis using light as the only energy source.

Prognostic Factors Affecting Surgical Outcomes in Squamous Cell Carcinoma of External Auditory Canal.

OBJECTIVES: Carcinomas of the external auditory canal (EAC) are rare, and management remains challenging. Previous studies seeking prognostic factors for EAC cancers included cancers other than carcinomas. In this study, we analyzed the treatment outcomes of, prognostic factors for, and survival rates associated with specifically squamous cell carcinoma (SCC) of the EAC. METHODS: A retrospective review of 26 consecutive patients diagnosed with SCCs of the EAC in a 10-year period was performed in terms of clinical presentation, stage, choice of surgical procedure, and adjunct therapy. Overall survival (OS) and recurrence-free survival (RFS) were calculated and univariate analysis of prognostic factors was performed. RESULTS: The median age of the 26 patients with SCCs of the EAC was 63 years (range, 40 to 72 years), and 16 males and 10 females were included. According to the modified University of Pittsburgh staging system, the T stages were T1 in 11, T2 in six, T3 in four, and T4 in five cases. The surgical procedures employed were wide excision in three cases, lateral temporal bone resection (LTBR) in 17, and extended LTBR in four, and subtotal temporal bone resection in two. Two patients underwent neoadjuvant chemotherapy, and two underwent adjuvant chemotherapy. One patient received preoperative radiation therapy, and eleven received postoperative radiation therapy. Of the possibly prognostic factors examined, advanced preoperative T stage and advanced overall stage were significant predictors of RFS, but not of OS. CONCLUSION: The advanced T stage and overall stage were associated with decreased survival after surgical treatment in patients with SCC of the EAC, highlighting the importance of clinical vigilance and early detection.

Relationship of Vertigo and Postural Instability in Patients With Vestibular Schwannoma.

OBJECTIVES: Growth of vestibular schwannomas (VS) causes progressive vestibular symptoms and postural instability. Since the tumor grows slowly, compensation of decaying vestibular input may decrease subjective symptoms of dizziness. This study aims to estimate the relationship of subjective vestibular symptoms and objective postural instability in patients with VS. METHODS: A retrospective review of 18 patients newly diagnosed with VS and with subjective vertigo symptoms was performed. The results of vestibular function tests including the sensory organization test (SOT) using computerized dynamic posturography, caloric test, and self-report measures of subjective dizziness handicap (Dizziness Handicap Inventory) and visual analogue scale were compared according to the onset of vertigo symptoms. RESULTS: In VS patients, SOT showed decreased equilibrium score for all vestibular function related conditions, condition (C) 5 and 6, and composite (COMP) score. COMP scores were not correlated with visual analogue scale or Dizziness Handicap Inventory scores. Acute onset group included six patients and insidious onset group, 12 patients. Equilibrium scores for C5 and C6, and COMP scores were lower for insidious onset group, but the difference was not statistically significant. CONCLUSION: Our findings confirmed postural instability is prevalent in VS patients. SOT parameters did not differ significantly between acute onset and insidious onset groups, but increased tumor size and canal weakness were noted in the insidious onset group. Clinicians should consider that postural instability is likely present even in patients who do not complain of acute vertigo, and appropriate counseling should be discussed with the patients.

Nature-Inspired Synthesis of Nanostructured Electrocatalysts through Mineralization of Calcium Carbonate.

Biomineralization is a biogenic process that produces elaborate inorganic and organic hybrid materials in nature. Inspired by the natural process, this study explored a new mineralization approach to create nanostructured CaCO3 films composed of amorphous CaCO3 hemispheres by using catechol-rich polydopamine (PDA) as a biomimetic mediator. The thus synthesized biomimetic CaCO3 was successfully transformed to nanostructured films of metal-oxide minerals, such as FeOOH, CoCO3 , NiCO3 , and MnOOH, through a simple procedure. The CaCO3 -templated metal-oxide minerals functioned as efficient electrocatalysts; a CaCO3 -templated cobalt phosphate (nanoCoPi) film exhibited high stability as a water-oxidation electrocatalyst with a current density of 1.5 mA cm-2 . The nanostructure of nanoCoPi, consisting of individual nanoparticles (≈70 nm) and numerous internal pores (BET surface area: 3.17 m2 g-1 ), facilitated an additional charge-transfer pathway from the electrode to individual active sites of the catalyst. This work demonstrates a plausible strategy for facile and green synthesis of nanostructured electrocatalysts through biomimetic CaCO3 mineralization.

Catecholamine-functionalized graphene as a biomimetic redox shuttle for solar water oxidation.

In natural photosynthesis, solar energy is converted to chemical energy through a cascaded, photoinduced charge transfer chain that consists of primary and secondary acceptor quinones (i.e., QA and QB). This leads to an exceptionally high near-unity quantum yield. Inspired by the unique multistep architecture of charge transfer in nature, we have synthesized a catecholamine-functionalized, reduced graphene oxide (RGO) film as a redox mediator that can mimic quinone acceptors in photosystem II. We used polynorepinephrine (PNE) as a redox-shuttling chemical. We also used it to coat graphene oxide (GO) and to reduce GO to RGO. The quinone ligands in PNE, which are characterized by a charge transfer involving two electrons and two protons, acted as electron acceptors that facilitated charge transfer in photocatalytic water oxidation. Furthermore, PNE-coated RGO film promoted fast charge separation in [Ru(bpy)3]2+ and increased the activity of cobalt phosphate on photocatalytic water oxidation more than two-fold. The results suggest that our bio-inspired strategy for the construction of a forward charge transfer pathway can provide more opportunities to realize efficient artificial photosynthesis.

Role of Emotional Distress in Prolongation of Dizziness: A Cross-Sectional Study.

BACKGROUND AND OBJECTIVES: Dizziness is a common condition in outpatient clinics. Comorbid conditions such as anxiety and/or depression often complicate a patient's ability to cope with dizziness. The purpose of the present study was to explore the extent of psychiatric distress using the Hospital Anxiety and Depression Scale (HADS) and to compare the results with the subjective severity of dizziness. SUBJECTS AND METHODS: The cross-sectional study included a total of 456 consecutive patients presenting with acute (n=327) and chronic (n=127) dizziness symptoms. The HADS was used to estimate emotional distress and compare between patients with acute and chronic dizziness symptoms. Also, we calculated correlations between subjective dizziness handicap scores and emotional distress using the total and subscale scores of the Dizziness Handicap Inventory (DHI), Disability Scale (DS), and HADS. RESULTS: The HADS total and subscale scores were significantly increased in patients with chronic dizziness (p<0.01) compared with those with acute symptoms. In patients with symptoms of both acute and chronic dizziness, moderate correlations were evident between the DHI and HADS total scores. When we compared DHI subscale scores with the HADS scores, the emotional DHI subscale scores correlated more highly with the HADS total scores and the scores on the anxiety and depression subscales, than did the functional or physical DHI subscale scores. CONCLUSIONS: Increased levels of distress measured using the HADS in patients with chronic symptoms suggest that emotional status of the patients may contribute to prolongation of dizziness symptoms from the acute phase.

Sunlight-assisted, biocatalytic formate synthesis from CO2 and water using silicon-based photoelectrochemical cells.

We report on a silicon-based photoelectrochemical cell that integrates a formate dehydrogenase from Thiobacillus sp. (TsFDH) to convert CO2 to formate using water as an electron donor under visible light irradiation and an applied bias. Our current study suggests that the deliberate integration of biocatalysis to a light-harvesting platform could provide an opportunity to synthesize valuable chemicals with the use of earth-abundant materials and sustainable resources.

Correlation between the dizziness handicap inventory and balance performance during the acute phase of unilateral vestibulopathy.

PURPOSE: The dizziness handicap inventory (DHI) is widely used to evaluate self-perceived handicap due to dizziness, and is known to correlate with vestibular function tests in chronic dizziness. However, whether DHI reflects subjective symptoms during the acute phase has not been studied. This study aims to investigate the correlations of subjective and objective measurements to highlight parameters that reflect the severity of dizziness during the first week of acute unilateral vestibulopathy. MATERIALS AND METHODS: Thirty-seven patients with acute unilateral vestibulopathy were examined. Patients' subjective perceptions of dizziness were measured using the DHI, Vertigo Visual Analog Scale (VVAS), Disability Scale (DS), and Activity-Specific Balance Scale (ABC). Additionally, the oculomotor tests, Romberg and sharpened Romberg tests, functional reach test, and dynamic visual acuity tests were performed. The correlation between the DHI and other tests was evaluated. RESULTS: DHI-total scores exhibited a moderately positive correlation with VVAS and DS, and a moderately negative correlation with ABC. However, DHI-total score did not correlate with results of the Romberg, sharpened Romberg, or functional reach tests. When compared among four groups divided according to DHI scores, VVAS and DS scores exhibited statistically significant differences, but no significant differences were detected for other test results. CONCLUSION: Our findings revealed that the DHI correlated significantly with self-perceived symptoms measured by VVAS and DS, but not ABC. There was no significant correlation with other balance function tests during the first week of acute vestibulopathy. The results suggest that DHI, VVAS and DS may be more useful to measure the severity of acute dizziness symptoms.

Long-Term Outcomes of Acute Low-Tone Hearing Loss.

BACKGROUND AND OBJECTIVES: Although acute low-tone hearing loss has been associated with cochlear hydrops or early stage Meniere's disease, its prognosis in the short-term has been reported to be better than sudden hearing loss. However, recurrence of hearing loss and possible progression to Meniere's disease remain important concerns in the clinical setting. This study aims to investigate the long-term audiological outcomes of acute low-tone hearing loss. SUBJECTS AND METHODS: A retrospective review of patients presenting with a first attack of acute low-tone hearing loss was performed. Of the 77 patients, 33 were followed up for more than 3 months. Progression, recovery of hearing loss and recurrence of hearing loss were examined. Also, correlation between long-term outcomes and associated clinical factors were analyzed. RESULTS: Twenty-five patients (75.7%) had complete hearing recovery, five patients (15.1%) had partial recovery, two patients (6.0%) had no recovery, and one patient (3.0%) had progression of hearing loss 1 month after initial treatment. Thirty-three patients were followed up for more than 3 months (mean 22 months, range 3-79 months). Recurrences of acute low-tone hearing loss were observed in five patients (15.2%). All of the recurrences occurred during the first 12 months of follow-up. Long-term prognosis correlated with the initial therapy results (R(2)=0.693). CONCLUSIONS: Recurrences of hearing loss were documented in five patients (15.2%), and all of these cases occurred within one year of the first attack. Audiological outcomes after initial therapy may predict the recurrence of acute low-tone hearing loss.

A Case of Incus Vibroplasty: Postoperative Changes in Residual Hearing.

In patients with mild to severe hearing loss, conventional hearing aids offer limited benefits and several problems with feedback and cosmesis. Middle ear implants are a feasible option for patients with moderate to severe hearing loss who are unable to achieve adequate benefit from or cannot tolerate hearing aids for various reasons. Here we present a case of middle ear implant surgery using Vibrant Soundbridge with incus vibroplasty technique, and describe the hearing changes during postoperative follow-up.

Conserved role of Sonic Hedgehog in tonotopic organization of the avian basilar papilla and mammalian cochlea.

Sound frequency discrimination begins at the organ of Corti in mammals and the basilar papilla in birds. Both of these hearing organs are tonotopically organized such that sensory hair cells at the basal (proximal) end respond to high frequency sound, whereas their counterparts at the apex (distal) respond to low frequencies. Sonic hedgehog (Shh) secreted by the developing notochord and floor plate is required for cochlear formation in both species. In mice, the apical region of the developing cochlea, closer to the ventral midline source of Shh, requires higher levels of Shh signaling than the basal cochlea farther away from the midline. Here, gain-of-function experiments using Shh-soaked beads in ovo or a mouse model expressing constitutively activated Smoothened (transducer of Shh signaling) show up-regulation of apical genes in the basal cochlea, even though these regionally expressed genes are not necessarily conserved between the two species. In chicken, these altered gene expression patterns precede morphological and physiological changes in sensory hair cells that are typically associated with tonotopy such as the total number of stereocilia per hair cell and gene expression of an inward rectifier potassium channel, IRK1, which is a bona fide feature of apical hair cells in the basilar papilla. Furthermore, our results suggest that this conserved role of Shh in establishing cochlear tonotopy is initiated early in development by Shh emanating from the notochord and floor plate.

Gadolinium enhanced 3D proton density driven equilibrium MR imaging in the evaluation of cisternal tumor and associated structures: comparison with balanced fast-field-echo sequence.

OBJECTIVES: Although Gadolinium enhanced bFFE is commonly used to evaluate cisternal tumors, banding artifact may interrupt interpretation and adjacent nerve and vessels differentiation is known to be difficult. We analyzed the qualities of Gd enhanced 3D PDDE in the evaluation of cisternal tumors, comparing with bFFE. MATERIAL AND METHODS: Forty five cisternal tumors (33 schwannoma and 12 meningioma) on both bFFE and PDDE were retrospectively reviewed. For quantitative analysis, contrast ratios of CSF to tumor and tumor to parenchyma (CRC/T and CRT/P) on both sequences were compared by paired t-test. For qualitative analysis, the readers gauged the qualities of the two MR sequences with respect to the degree of demarcating cisternal structures (tumor, basilar artery, AICA, trigeminal nerve, facial nerve and vestibulocochlear nerve). RESULTS: In quantitative analysis, CRC/T and CRT/P on 3D PDDE was significantly lower than that of 3D bFFE (p < 0.01). In qualitative analysis, basilar artery, AICA, facial nerve and vestibulocochlear nerves were significantly better demarcated on 3D PDDE than on bFFE (p < 0.01). The degree of demarcation of tumor on 3D PDDE was not significantly different with that on 3D bFFE (p = 0.13). CONCLUSION: Although the contrast between tumor and the surrounding structures are reduced, Gd enhanced 3D PDDE provides better demarcation of cranial nerves and major vessels adjacent to cisternal tumors than Gd enhanced bFFE.

Spontaneous nystagmus in horizontal canal benign paroxysmal positional vertigo.

OBJECTIVE: Benign paroxysmal positional vertigo of horizontal semicircular canal (HSC-BPPV) is characterized by either geotropic or apogeotropic nystagmus induced by head roll test. Some patients also present with spontaneous nystagmus. The aim of this study is to examine the clinical manifestation of spontaneous nystagmus in HSC-BPPV and evaluate the effect on the treatment outcome. PATIENTS AND METHODS: Electronystagmography and video eye movement recordings of 125 patients diagnosed as HSC-BPPV were reviewed retrospectively. Presence of spontaneous nystagmus was analyzed and treatment outcome after repositioning therapy was compared. RESULTS: Overall, spontaneous nystagmus was observed in 19 patients (15.2%) with HSC-BPPV at initial presentation. In canalolithiasis group (n=64), the treatment outcome did not differ between patients with or without spontaneous nystagmus. However, in cupulolithiasis group (n=61), patients presenting with spontaneous nystagmus (n=10) required more repositioning therapy sessions. CONCLUSION: The presence of spontaneous nystagmus at initial presentation may implicate poorer treatment outcome in cupulolithiasis HSC-BPPV patients.