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Objectives: We sought to determine how the pathology altered electrically evoked auditory brainstem responses (EABRs) in patients with hearing loss by evaluating EABRs in auditory neuropathy patients with OTOF mutations comparing with various types of congenital deafness. Methods: We included 15 patients with congenital hearing loss, grouped according to pathology: OTOF mutations (n = 4), GJB2 mutations (n = 4), SLC26A4 mutations (n = 4), or cytomegalovirus infections (n = 3). EABRs were recorded when patients underwent cochlear implantation surgery. We evaluated the latencies and amplitudes of the recorded EABRs and compared them statistically between four groups. Results: The EABR latencies of Wave III and Wave V, and of the interval between them, were significantly longer in the OTOF mutation group than in the GJB2 and SLC26A4 mutation groups (Wave III) and in all three other groups (Wave V and Wave III‐V latency); amplitudes were not significantly different between groups. Conclusions: Our results suggest OTOF mutations cause delayed (or slowed) postsynaptic neurotransmission, although the presumed mechanism involved reduced presynaptic transmission between hair cells and spiral ganglion neurons. Level of Evidence: Mainly a case report [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to profile and compare the middle ear microbiomes of human subjects with and without chronic otitis media.Study Design: Prospective multicenter cohort study.Methods: All consecutive patients undergoing tympanoplasty surgery for chronic otitis media or ear surgery for conditions other than otitis media were recruited. Sterile swab samples were collected from the middle ear mucosa during surgery. The variable region 4 of the 16S rRNA gene in each sample were amplified using region-specific primers adapted for the Illumina MiSeq sequencer (Illumina, CA, USA)). The sequences were subjected to local blast and classified using Metagenome@KIN (World Fusion, Tokyo, Japan).Results: In total, 155 participants were recruited from seven medical centers. Of these, 88 and 67 had chronic otitis media and normal middle ears, respectively. The most abundant bacterial phyla on the mucosal surfaces of the normal middle ears were Proteobacteria, followed by Actinobacteria, Firmicutes, and Bacteroidetes. The children and adults with normal middle ears differed significantly in terms of middle ear microbiomes. Subjects with chronic otitis media without active inflammation (dry ear) had similar middle ear microbiomes as the normal middle ears group. Subjects with chronic otitis media with active inflammation (wet ear) had a lower prevalence of Proteobacteria and a higher prevalence of Firmicutes than the normal middle ears.Conclusion: The human middle ear is inhabited by more diverse microbial communities than was previously thought. Alteration of the middle ear microbiome may contribute to the pathogenesis of chronic otitis media with active inflammation.Level Of Evidence: 2b. Laryngoscope, 127:E371-E377, 2017. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis To investigate possible association of hearing loss and SLC26A4 mutations with the subgroups of enlarged vestibular aqueduct (EVA) morphology in Japanese subjects with hearing loss. Study Design Retrospective multicenter study. Methods Forty-seven subjects who had vestibular aqueduct with midpoint diameter >1 mm by computed tomography of the temporal bone were enrolled at multiple sites across Japan, and DNA samples and clinical data were collected. EVA morphology was classified into four subgroups by the pattern of enlargement: aperture, aperture and midpoint, midpoint, and borderline enlargement. Venous blood DNA samples were subjected to polymerase chain reaction-based direct sequencing of all exons and exon-intron boundaries of the SLC26A4. Results Four novel SLC26A4 mutations were identified in the present study. SLC26A4 mutations were detected in almost all subjects with aperture, aperture and midpoint, and midpoint enlargement. In contrast, 71% of subjects with borderline enlargement had no SLC26A4 mutation. No significant difference was found in the distribution of truncating and nontruncating SLC26A4 mutations between the EVA subgroups. In addition, no significant correlation was observed between the EVA subgroups and hearing levels, incidence of hearing fluctuation, or progression of hearing loss. Conclusions Subgroups of EVA morphology were significantly correlated with the presence or absence of SLC26A4 mutation. In a subgroup analysis of subjects with SLC26A4 mutations, however, differences in the EVA subgroups were not correlated with SLC26A4 genotypes or characteristics of hearing loss. Level of Evidence NA. Laryngoscope, 124:E134-E140, 2014 [ABSTRACT FROM AUTHOR]

We investigated age-related changes in the mode of regeneration in the mouse peripheral olfactory system after olfactotoxic drug-induced damage. Mice at postnatal ages of 10 days, 3 months, and 16 months were given an intraperitoneal injection of methimazole to produce damage in the olfactory neuroepithelium. The olfactory neuroepithelia were harvested and analyzed immunohistochemically at various postlesion timepoints, from 1 day through to 94 days, to investigate neuroepithelial cell proliferation, the time course of neuronal differentiation, the reconstitution of neuroepithelium, and the innervation of the olfactory bulb. Functional recovery was assessed using the vanillin avoidance behavioral test. The chronological pattern in the expression of Ki67, beta III tubulin, and olfactory marker protein, molecular markers for neuronal cell proliferation and differentiation, changed similarly among the different age groups. In contrast, the extent of neuroepithelial cell proliferation after injury decreased with age, and the final histological recovery of the olfactory neuroepithelium and the innervation of the olfactory bulb were significantly smaller in the 16-month-old group compared to the younger age groups. These results suggest that the age-related decline in the capacity of olfactory neuroepithelium to reconstitute neuroepithelium is associated with its age-related decrease in proliferative activity after the neuroepithelial injury rather than changes in the process of neuronal differentiation. In spite of these incomplete anatomical recoveries, 16-month-old mice regained the ability to avoid vanillin solution by 1 month postlesion, suggesting that the extent of anatomical epithelial damage is not necessarily proportional to the threshold of olfactory perception. J. Comp. Neurol. 519:2154-2174, 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Neural prostheses for restoring lost functions can benefit from selective activation of nerves. We previously proposed a multipoint gating stimulation, which can selectively activate a desired portion of a nerve bundle, regardless of the density of the electrode. In this paper, we discuss the design of an electrode array and effective strategies to determine the stimulus parameters. Large electrodes were less affected by the relative location of the electrodes and the nodes of Ranvier, suggesting that a rectangular electrode, whose long side along a nerve bundle is longer than the internodal distance (i.e., on the order of 1 mm), would be more effective than a disk electrode. We were able to estimate an appropriate current at each electrode on the basis of a blocking threshold, above which no spike propagation was permitted. For lateral gating stimulation, the gate current should be set above the threshold, while for depthwise gating stimulation, the gate current should be set below the threshold. The spatial resolutions of lateral and depthwise gating stimulation were theoretically estimated to be at least 50 μm when the grid spacing of the array was 1.2 mm. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(6): 31-40, 2009; Published online in Wiley InterScience (). DOI 10.1002/ecj.10064 [ABSTRACT FROM AUTHOR]

Using magnetoencephalography (MEG), we report here the hemispheric dominance of the auditory cortex that is selectively modulated by unexpected errors in the lyrics and melody of songs (lyrics and melody deviants), thereby elucidating under which conditions the lateralization of auditory processing changes. In experiment 1 using familiar songs, we found that the dipole strength of responses to the lyrics deviants was left-dominant at 140 ms (M140), whereas that of responses to the melody deviants was right-dominant at 130 ms (M130). In experiment 2 using familiar songs with a constant syllable or pitch, the dipole strength of frequency mismatch negativity elicited by oddballs was left-dominant. There were significant main effects of experiment (1 and 2) for the peak latencies and for the coordinates of the dipoles, indicating that the M140 and M130 were not the frequency mismatch negativity. In experiment 3 using newly memorized songs, the right-dominant M130 was observed only when the presented note was unexpected one, independent of perceiving unnatural pitch transitions (i.e., perceptual saliency) and of selective attention to the melody of songs. The consistent right-dominance of the M130 between experiments 1 and 3 suggests that the M130 in experiment 1 is due to unexpected notes deviating from well-memorized songs. On the other hand, the left-dominant M140 was elicited by lyrics deviants, suggesting the influence of top-down linguistic information and the memory of the familiar songs. We thus conclude that the left- lateralized M140 and right-lateralized M130 reflect the expectation based on top-down information of language and music, respectively. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the relationship between hearing level and temporal bone abnormalities in patients with microtia. Study Design: Retrospective case series study between 1992 and 2004. Setting: Academic, tertiary care referral medical center. Patients: We evaluated 115 ears of 89 patients (68 males, 21 females; mean age, 11 yr; range, 5-44 yr) with microtia. Main Outcome Measures: Hearing level was examined in patients with microtia. Developmental abnormalities of the temporal bone were evaluated by Jahrsdoerfer's computed tomography (CT) scoring system using high-resolution CT (HRCT) scans of the temporal bone. Temporal bone malformation scores were divided into four subgroups: ossicular development, windows connected to the cochlea, aeration of the middle ear cavity, and facial nerve aberration. Patients were divided into the stenosis and atresia groups on the basis of the appearance of the external auditory canal (EAC). We also evaluated the relationships between hearing level and four subtotal scores of the HRCT findings in the stenosis and atresia groups. Results: There was no relationship between hearing level and total points of HRCT scoring system or between hearing level and severity of microtia scored by Marx classification. With regard to subtotal points related to ossicles (4 points), the hearing level in ears with low scores (<2) (64.7 +/- 1.6 dB) was significantly different (P = .03) from that in ears with high scores (> or =2) (54.0 +/- 2.8 dB) in the stenosis group. In the atresia group, the hearing level was 64.3 +/- 2.2 dB in ears with low scores and 62.3 +/- 1.1 in ears with high scores (P > .5). As for subtotal points related to the windows connected to cochlea (2 points), the hearing level was 64.8 +/- 2.6 dB in ears with low scores (0) and 55.9 +/- 2.4 dB in ears with high scores (> = 1) in the stenosis group. In the atresia group, the hearing level was 67.7 +/- 2.3 dB in ears with low scores and 61.5 +/- 1.0 in ears with high scores. There was significant difference between ears with low and high scores in the stenosis group (P = .03) and atresia group (P = .009). There was no significant difference between ears with low and high scores with respect to the subtotal points related to aeration of the middle ear cavity and aberration of the facial nerve. Conclusion: The hearing level in microtic ears correlated with the formation of oval/round windows and ossicular development but not with the degree of middle ear aeration, facial nerve aberration, or severity of microtia. The hearing level can also serve as an indictor, such as the HRCT findings, to determine whether a subject's hearing will likely improve after reconstructive surgery. [ABSTRACT FROM AUTHOR]

Objectives: Since 1997, we have performed the autologous transplantation of fascia into the vocal fold (ATFV) procedure on cases of sulcus vocalis. In what follows, we report the long-term results of our new surgical approach and discuss the role of these transplantations. We also review and report some complications that can be caused by ATFV. Finally, we discuss the ATFV technique as a contribution to the phonosurgery of the future. Study Design: Prospective study. Methods: We were able to obtain long-term results from 10 volunteer cases (2 female and 8 male, age: 15-71, mean 46.5 years old) who could be followed up for at least 3 years after transplantation. All were cases of pathologic sulcus vocalis. We measured maximum phonation time (MPT) and carried out pre- and postsurgical clinical observation and laryngeal stroboscopy in all cases. These measurements and observations were made before the ATFV and at 6 months, 1 year, 2 years, and 3 years after surgery. Results: In stroboscopic observation 1 year after the ATFV, satisfactory glottal closure and excellent mucosal wave were observed for all cases, and there was no case with hyperadduction of the false vocal folds. MPT measures remained at an improved level 2 years and 3 years after the transplantations. Paired-sample t tests showed that the improvement relative to preATFV levels was significant for all postsurgical measurements up to 3 years. Conclusions: We conclude that ATFV is a successful surgical procedure for sulcus vocalis and scarred vocal folds. Other phonosurgical clinical applications may also be envisioned. [ABSTRACT FROM AUTHOR]

The authors investigated the effects of chronic kanamycin (KM) administration on the basement membrane (BM) anionic sites in the ampulla by studying the binding of cationic polyethyleneimine (PEI). KM sulfate was administered intramuscularly 'to guinea pigs with normal Preyer's reflexes daily for 10 or 17 days. The PEI distribution was unchanged on the subepithelial BM in the dark cell region and on the capillary BM in the crista ampullaris. However, PEI binding decreased significantly on the subepithelial BM in the sensory cell and transitional cell regions of those guinea pigs administered KM for 17 days. In the sensory cell region, the PEI distribution did not recover until 6 weeks after KM treatment. Findings suggest that chronic administration of KM severely alters the number of subepithelial BM anionic sites in the sensory cell region. [ABSTRACT FROM AUTHOR]

Five patients with sensorineural hearing loss, who harbored a point mutation in the mitochondrial transfer RNA (tRNA) gene tRNALeu (UUR), from five unrelated family pedigrees were examined. In these families diabetes and deafness were maternally inherited. Bilateral hearing was more severely impaired at higher frequencies. Audiometric test results revealed that hearing loss involved the cochlea. Hearing gradually deteriorated; the progression rate ranged from 1.5 to 7.9 dB per year. Proportion of mutant mitochondrial DNAs (mtDNAs) in the leukocytes was not related to the rate or degree of hearing loss, although hearing loss appeared at a younger age in patients with higher heteroplasmy. We speculate that after the proportion of damaged mtDNAs, mostly as a result of mutation, exceeds the expression threshold for deficiencies in mitochondrial protein synthesis and oxygen consumption, a drop in adenosine triphosphate level could lead to an imbalance of ion concentration, resulting in cell death in the cochlea. [ABSTRACT FROM AUTHOR]

A nonsense monosyllable audiometric test was administered to 15 patients with eighth nerve or brain stem disorders caused by tumor, hemorrhage, encephalitis, and degenerative disease. Auditory brain stem responses (ABR) were abnormal in all patients. ABR abnormalities were defined by the absence of some or all waves or by prolongation of the wave V-I interval. The discrimination scores of the nonsense monosyllables were significantly lower in patients with completely absent ABR, with partial ABR series involving wave I, or with severely prolonged wave V-I intervals (over 3 SD). However, in patients with wave I only or with only moderately prolonged wave V-I intervals (less than 3 SD), test scores were within normal range. It is concluded that: 1. perception of nonsense monosyllables could be, though need not be, affected in patients with brain stem lesions; 2. eighth nerve lesions severely disrupt auditory comprehension as well as perception of nonsense monosyllables. [ABSTRACT FROM AUTHOR]

For assessing comatose patients, the combination of auditory short, middle, and long latency evoked potentials (auditory brain stem response [ABR], middle latency component [MLC], and slow vertex response [SVR] ) is more comprehensive than auditory brain stem response (ABR) only or ABR with slow vertex response (SVR). Fifty-four acutely comatose patients were studied. Thirty-four of the patients had severe head injury and others had coma of varied etiology. Within two months after admission, 25 patients survived, while 29 patients died. Auditory evoked response measurements were conducted usually within 48 to 72 hours after admission. For patients with normal SVR, MLC, and ABR, there was 100% survival; with absent SVR but normal MLC and ABR, survival was 91%; with absent SVR and MLC and normal ABR, it was 60%; with abnormal ABR, it was 10%; no patient survived whose ABR was absent. It is emphasized that a normal MLC is clearly a predictor of survival of comatose patients, but a normal ABR is not always a reliable indicator of survival. [ABSTRACT FROM AUTHOR]

P300 potentials evoked by tones and spoken words were recorded from a 20-year-old man with a House-3M® single-channel cochlear implant. Three months after cochlear implantation, there was a slight appearance of P300 response to both pure-tone stimuli and spoken-word stimuli; 6 months later, clearly identifiable P300 response to both pure-tone stimuli and spoken-word stimuli were obtained. These results are consistent with an encoding improvement for re-establishment of information processing after auditory rehabilitation. [ABSTRACT FROM AUTHOR]

Objective: The standard for studying temporal bone anatomy has been histopathological sectioning for microtome following chemical fixation and deossification of the temporal bone specimen. We can directly synthesize the membranous labyrinth from the conventional CT exam. We evaluated normal anatomy and pathological conditions of the membranous labyrinth. Method: We studied 20 normal subjects, 20 hyperlipidemias, 20 DMs, 4 Ménière diseases, and 2 congenital malformations. To develop a 3D reconstructed image of the membranous labyrinth based on HR‐CT, the axial data were applied to create 3D images on the CT work station for postprocessing with factory presets. Results: 3D visualization of different structures of the membranous labyrinth allowed display of correct anatomy of high detail in all normal subjects. We could observe the cochlear duct, ductus reuniens, saccule, utricle, and ampullae. Otherwise, pathological conditions were revealed as irregular shape of the cochlear duct and/or small or large saccule or utericle. On unilateral Ménière disease, we could find the enlargement of the utricle. The radiation exposure was 0.15mSv. Conclusion: Our method shows promise for observation of the membranous labyrinth. The pathological conditional images showed abnormal shape in comparison with normal conditions. We got a new diagnostic method for vertigo, disequilibrium, hearing loss, and tinnitus. [ABSTRACT FROM AUTHOR]

Presents a case study of an 8-year-old child who presented stridor and urticaria after exercise in grass. Appearance of itchy urticaria papulosa 15 minutes after playing; Treatment of epinephrine inhalation; History of nasal allergy of the patient.

Objective: This study aimed to create a 3‐dimensional anatomy of the round window to hook region to identify the optimal site for cochleostomy in cochlear implantation and other endocochlear surgical procedures. Method: Ten normal ears were studied. To develop 3‐dimensional reconstructed inner ear image based on high‐resolution temporal bone images obtained by a spiral CT. The axial data were applied to create 3‐dimensional images on the CT work station for post‐processing with the use of current workstation software (GE Advantage Navigation). Results: The anatomy of the round window to hook region is complex, and spatial relationships can be difficult to evaluate using 2‐dimensional CT images. Three‐dimensional models of the round window membrane (RWM), cochlear duct, scala vestibule, scala tympani, ductus reuniens, and surrounding structures were generated. The relationship between these structures and the round window membrane (RWM) and adjacent otic capsule was easily identified. Conclusion: This 3‐dimensional model has implications for surgical procedures to the inner ear that aim to minimize insertional trauma and decrease operation time. We can know the anatomic information before cochlear implant. [ABSTRACT FROM AUTHOR]

Cogan's syndrome is a rare disorder first clinically defined in 1945, characterized by nonsyphilitic interstitial keratitis and progressive audiovestibular symptoms. Later, patients with audiovestibular dysfunction and various types of inflammatory eye disease were classified as having atypical Cogan's syndrome. The etiology and pathogenesis of Cogan's syndrome remain largely unknown. Here, we report a case of atypical Cogan's syndrome with a histological assessment of the temporal bone during the acute disease period. Temporal bone histology was compared to age- and gender-matched normal control, and our findings revealed endolymphatic hydrops and degenerative changes in various parts of the inner ear. Laryngoscope, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: Nasal airway remodeling exists in allergic rhinitis, but it appears to be far less extensive than in asthma. However, there has been little study about nasal airway remodeling and no study using mice models. It has been reported that airway hyperresponsiveness decreased after prolonged allergen challenge in a chronic murine asthma model together with the progression of remodeling. However, there has been no study of the relation of remodeling and airway responsiveness in nasal allergy. Therefore, we have undertaken this investigation to characterize nasal airway structural changes after prolonged allergen challenge and to examine the relationship between nasal airway hyperresponsivity and remodeling., Methods: We prepared murine allergic rhinitis for ovalbumin. Mice were subsequently challenged three times a week with ovalbumin from day 19 to days 53, 88, and 130. We examined allergen-induced nasal symptoms and objective nasal hyperresponsiveness using the enhanced pause system. Moreover, the pathologic changes were investigated after allergen challenge., Results: The extended allergen challenge protocol caused significant nasal airway remodeling. Specifically, remodeling was characterized by goblet cell hyperplasia and deposition of collagen in the submucosal area. Allergen-induced nasal hyperresponsiveness was first increased but gradually decreased in nasal symptoms and Penh after prolonged allergen challenge., Conclusions: We have demonstrated that a remodeling of nasal mucosa in a murine allergic rhinitis model prolonged allergen exposure. Moreover, prolonged allergen exposure induced a reduction of nasal hyperresponsiveness together with a progression of nasal remodeling.

Background: Histamine is one of the most important chemical mediators causing nasal allergic symptoms, and H1 receptor antagonist have been used as the treatment first choice in nasal allergy. The presence of H3 receptors has also been determined in the human nasal mucosa, but few studies have investigated the involvement of H3 receptors in nasal allergy., Objective: We used a murine allergic model to investigate the presence of nasal mucosa H3 receptor mRNA and any H3 receptor agonist or antagonist influences on clinical nasal allergic symptoms., Methods: H3 receptor mRNA in nasal mucosa was investigated by reverse-transcription polymerase chain reaction. OVA-sensitized mice were given an intraperitoneal injection of H3 receptor agonist or antagonist, and clinical nasal allergic symptoms were scored over 10 minutes after nasal provocation of OVA. Inhibition of nasal allergic symptoms was also examined using an H1 receptor antagonist alone and using a both an H3 receptor agonist and an H1 receptor antagonist., Results: H3 receptor mRNA was identified in the murine nasal mucosa. The H3 receptor agonist (R)-alpha-metylhistamine significantly inhibited clinical nasal allergic symptoms of OVA-sensitized mice. The H3 receptor agonist and H1 receptor antagonist inhibited clinical nasal allergic symptoms in the murine allergic model more strongly than the single drug., Conclusion: The foregoing results indicate that H3 receptors are involved in modulation of nasal allergy. H3 receptor agonists can also be useful as a novel therapeutic approach in nasal allergy. Both H3 receptor agonist and H1 receptor antagonist may be more effective than a single drug.

Objective: Hearing impairment and the often concurrent loss of vestibular function, which is rarely assessed in infants, can both impair sensory integration critical to the development of normal motor coordination. This study demonstrates, for the first time, that vestibular function in infants can be noninvasively assessed using vestibular-evoked myogenic potentials (VEMPs). Our intentions were to demonstrate that VEMPs can be reliably recorded from neonates and to compare neonatal VEMPs with those obtained from normal adults., Study Design: Prospective cohort study., Methods: Myogenic evoked potentials induced by air- and bone-conducted auditory stimuli were recorded from the sternocleidomastoid muscles of 12 normal neonates and 12 neonates with various clinical findings. These included infants with bilateral atresia of the external auditory canals, Treacher-Collins syndrome, and neonates who failed universal neonatal screening., Results: With the exception of one patient with hearing loss, reproducible biphasic VEMPs were recorded from the sternocleidomastoid muscle of all the infants using loud, short tone-burst sounds., Conclusions: The VEMP has characteristics that differentiate it from the postauricular response and the Jaw reflex. The VEMPs were dominant on the side ipsilateral to the stimulated ear. The overall morphology of the neonatal VEMP is quite similar to that of adults. The major neonatal differences are a shorter latency of the n23 peak and higher amplitude variability. Our results suggest that recording of the VEMP in neonates with various audio-vestibular problems provides useful information about vestibular function in this population and may provide information that leads to better care and rehabilitation for neonates at risk of developmental and motor system delay.

Objective: The purpose of this study is to verify the hypothesis that ErbB-2 protein is overexpressed in human middle ear cholesteatomas and to elucidate the relationship between overexpression of ErbB-2 protein, cell proliferation, and apoptosis., Study Design: Prospective review of 20 patients between 2001 and 2003 with middle ear cholesteatoma., Methods: Middle ear cholesteatoma matrix and retroauricular skin were immunostained with anti-ErbB-2, Ki-67, and single-stranded DNA (ssDNA) antibody. The distribution of immunoreactivity to these antibodies and labeling indices were compared between cholesteatoma and retroauricular skin., Results: In matrix of middle ear cholesteatoma, ErbB-2 and ssDNA were expressed in the keratinocytes of all layers and Ki-67 was expressed in the keratinocytes of the basal, lower spinous, and occasionally granular layer. In retroauricular skin, ErbB-2 and Ki-67 were expressed in the keratinocytes of the basal and occasionally lower spinous layer and ssDNA was expressed in the keratinocytes of all layers. Labeling indices against anti-ErbB-2, Ki-67, and ssDNA antibody were significantly greater in cholesteatoma as compared with retroauricular skin., Conclusions: In cases of cholesteatoma, ErbB-2 protein was overexpressed and cell proliferation and apoptosis of keratinocytes were accelerated. ErbB-2 protein could modulate terminal differentiation and apoptosis in the keratinocytes of all layers in cholesteatoma matrix and cell proliferation in the keratinocytes of the basal and lower spinous layer in normal skin.

Objective: To study the difference in the facial canal anatomy in terms of the severity of microtia and deformity of the middle ear in patients with microtia using high-resolution computed tomography (HRCT)., Study Design: Forty-six ears with microtia were examined by HRCT. These ears were graded based on two systems of classification and scoring, respectively. The HRCT findings of each group were compared with those of other groups by multiple comparison using the Tukey honestly significant difference test., Methods: Forty-six ears with microtia (unilateral microtia, n = 12; bilateral microtia, n = 34) were examined by HRCT. These ears were graded based on two systems of classification and scoring, respectively. The HRCT findings and age distribution of each group were compared with those of other groups by multiple comparison using the Tukey honestly significant difference test., Results: The mastoid portion of the facial nerve was 3 mm more anteriorly displaced in patients with grades II and III microtia than in those with grade I microtia (P <.01). From the scoring system that was used, the course of the facial nerve was not significantly different between patients with a score of 5 points or less and those with a score of 6 points or more., Conclusion: The mastoid portion of the facial nerve in patients with grades II and III microtia would be more anteriorly displaced because of hypoplasia of the second genu.