Development of Vestibular Organ and Cochlea / 대한이비인후과학회지

Inner ear is an important organ that is responsible for balance and hearing. It is composed of two complicated major subunits, vestibular organ and cochlea. During development, both functional units require complex genetic interactions to achieve proper patterning and morphology as its purpose. This review comprises three parts. In the first part, general information about technical tools in studying mouse ear development is introduced. In the second part, it is shown how semicircular canals are formed and what genetic interaction is involved in canal formation. In the last part, genetic interactions required for proper development of cochlea are elaborated, focusing on the length of cochlea and morphology of organ of Corti. The study about development of mutant mice provides us useful information about genetic interaction involved in the formation of structures for hearing and balance. The data acquired in the development field could provide a breakthrough to hair cell regeneration and stem cell therapy fields in stuck, which are directly applicable to human.

Spontaneous Bilateral Achilles Tendon Rupture after Local Steroid Injection for Carpal Tunnel Syndrome in a Diabetic Patient: A case report

Achilles tendon injuries are one of the most common tendon injuries in the lower extremities, but spontaneous bilateral achilles tendon rupture without any external force is extremely rare. We present a case of a patient who had spontaneous bilateral achilles tendon rupture related to multiple steroid injections for carpal tunnel syndrome in diabetes. According to this case, we suggest that we should take special precaution to use steroid to the diabetes though it is not applied to the achilles tendon directly.

Skull Base Osteomyelitis Caused by Invasive Candida Infection / 대한이비인후과학회지

Skull base osteomyelitis (SBO )is classically described as an infection of the external auditory canal invading the base of the skull. SBO occurs most commonly in elderly diabetics and is almost uniformly caused by Pseudomonas aeroginosa. Fungal SBO is very rare and usually caused by Aspergillus, and less commonly by Candida. The diagnosis of fungal SBO can be delayed because cultures growing fungal pathogens are slow and often interpreted incorrectly as an opportunistic colonization. This may lead to delayed treatment and greater morbidity. The lack of definitive bacterial cultures and inadequate responses to antipseudomonal therapy should raise the possibility of fungal infection, and biopsy of skull base should be obtained to confirm the causative organism, as well as ruling out an underlying malignancy. Fungal SBO is a medical, not a surgical disease. Surgery may also be indicated if the disease plateaus or doesn't on appropriate antimicrobial therapy. We have recently encountered two rare cases of SBO that were caused by Candida. The patients were much improved following mastoidectomy and intravenous amphotericin B.

Vestibular Evoked Myogenic Potentials Produced by Stimulation with 500 Hz-tone Burst / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potential (VEMP) is muscle reflex caused by surface electrodes following repeated high-intensity auditory stimulation. The current study attempted to determine whether VEMP can be consistently evoked from the sternocleidomastoid muscle (SCM) by the 100 dB air-conducted and 50 dB bone-conducted 500 Hz-tone burst. SUBJECTS AND METHOD: Air-conducted and bone-conducted VEMPs in response to 500 Hz-tone burst were recorded from the SCM of 13 normal volunteers. Subjects were seated on their chairs and made to hold their heads turned up as far as possible towards the side, contralateral to the stimulated ear voluntarily. Two different sound durations (rise/fall time=2 msec, plateau time=2 msec[2/2] and rise/fall time=5 msec, plateau time=5 msec[5/5]) were presented through a insertphone or bone vibrators. Latencies and amplitudes of p13 and n23 responses were measured. RESULTS: All normal volunteers showed p13-n23 responses to 50 dB bone-conducted tone burst as well as to 100 dB air-conducted tone burst. The values of latency of p13 and n23 were the most reliable at 5/5 air-conducted in evaluation by coefficiency of variance. Mean p13 and N23 latencies by airconducted tone burst were significantly longer than those of bone-conducted. Mean p13-n23 amplitudes by air-conducted tone burst were significantly larger than those by bone-conducted at 2/2 sound duration. CONCLUSION: VEMP could be consis-tently evoked by the 100 dB air-conducted and 50 dB bone-conducted 500 Hz-tone burst, especially at 5/5 air-conducted.

Isolated Sphenoid Sinus Lesion: A Clinical Analysis of 56 Cases / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Isolated lesions of the sphenoid sinus are a rare disease entity that occurs after a wide use of antibiotics. This lesion may have severe complications such as cranial nerve palsies due to its deep location in the skull. The use of endoscopic surgery for the sphenoid sinus has become popular for its several advantages. We report our experiences of 56 case-isolated sphenoid lesions with a review of articles. SUBJECTS AND METHOD: Fifty-six patients with isolated sphenoid lesions who were treated at Seoul National University Hospital from January 1985 through December 2003 were analyzed. Patients who have lesions confined to the sphenoid sinus on radiologic images (CT or MRI) were included. A retrospective chart review was performed with respect to the patient's symptom, pathology and surgical outcome. RESULTS: Thirty-nine of 56 cases were inflammatory lesions, 8 neoplastic lesions, and 9 fibrous dysplasias. Headache was the most common symptom (66%), followed by nasal symptoms such as nasal obstruction and postnasal drip. Ophthalmologic symptoms were observed in 14 cases. Endoscopic transnasal sphenoidotomy was perforemd in 33 of 39 cases of inflammatory diseases. Symptoms were completely improved in 32 cases after the operation and ophthalmologic symptoms were nearly all improved in all cases. CONCLUSION: The wide use of CT and MRI has increased the detection of isolated lesions of the sphenoid sinus. Complications like cranial nerve palsies were uncommon unlike from the reports that came out in the country. Primary physicians must rule out isolated lesions of the sphenoid to account for intractable headaches.

Aging Effect on the Morphology of the Otoconia Using Scanning Electron Microscopy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Displaced otoconia in the semicircular canal from senile otoconial degeneration have been believed as a major cause of benign paroxysmal positional vertigo (BPPV). The otoconia are mainly composed of calcium carbonate, and thus they are susceptible to chemical deformation during the usual process of scanning electron microscopy (SEM). The aims of this study were to present an optimal protocol of otoconial preparation for SEM and to investigate the change of otoconial morphology due to aging. SUBJECTS AND METHOD: The macula in mice were dissected free from the temporal bone and were divided into three groups using different fixatives and buffers: 2.5% glutaraldehyde in phosphate buffer, 2.5% glutaraldehyde in cacodylate buffer and 70% acetone. The duration of storage in buffer differed for each group, and SEM was used to examine the morphology. After the optimal processing protocol was made, we analysed the difference in the otoconial morphology in younger and older rats. RESULTS: The otoconia with shorter storage duration in phosphate buffer had more clear surface, while longer exposures resulted in coarse surface and fused otoconia. The otoconia stored in cacodylate buffer had smooth surface and showed grossly normal morphology regardless of exposure time. The otoconia fixed in acetone had irregular surface and was easily displaced. In older rats, the bodies of many otoconia were pitted, fissured, penetrated and eventually broken into several fragments. The size variation of utricular otoconia was greater in older rats. The giant otoconia were discovered frequently on the outer margin of utricular macula in older rats. The weakened or linked filaments that were cut in the older group were frequently observed. CONCLUSION: The appropriate processing for SEM is needed to observe the intact otoconial morphology. Older rats showed more degeneration of otoconia and linked filaments. This study for morphologic changes of senile otoconia is expected to be helpful in understanding the etiology of BPPV and aging effect.

Histopathologic Evaluation of Obliterating Material in the Guinea Pig Temporal Dorsal Bullae / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The present study was undertaken to determine and to compare the characteristics of bone wax, fibrofatty tissues or bone graft materials (Lubboc(R)) as obliterating materials in the guinea pig by morphological observations. MATERIALS AND METHOD: The guinea pigs were used to perform obliteration of the dorsal bullae of the temporal bone using bone wax, fibrofatty tissues or Lubboc(R). Twelve weeks after transplantation, the animals were sacrificed, and histological sections were prepared. Histological evaluations were performed to determine changes of the dorsal bullae mucosa of the temporal bone and the implanted materials. RESULTS: Where bone wax was used for obliteration, histological evidences indicated inflammatory reactions within the dorsal bullae mucosa of the temporal bone. A large amount of absorption was observed in the fibrofatty tissue. On the other hand, in the case using Lubboc(R), real bonds between the new bone and native bone were observed, as well as a mature trabecular bone traversing throughout the entire implant materials. Bone formation as induced by the Lubboc(R) implantation appeared to be a physiological reaction, which was further supported by observation of extensive neovascularization within the graft material. CONCLUSION: Based on our current observations, we consider Lubboc(R) as a superior implant material for bone wax and fibrofatty tissues.

Comparison of Auditory Brainstem Response and Auditory Steady-State Response Thresholds in Infants and Young Children / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The aim of this study was to assess the accuracy of threshold estimates determined by the auditory steady-state response (ASSR) in a group of sedated infants and young children with a range of hearing losses. MATERIALS AND METHOD: Two studies were performed because the behavioral audiometric information was not available from infants and young children. In the first study, a retrospective analysis was performed for 36 children (mean age: 3 years 4 months) who had completed auditory brainstem response (ABR) and pure tone audiometry to verify that ABR threshold is a good predictor for pure tone threshold in our laboratory. The ABR thresholds to 500 Hz, 1000 Hz tone-pip and click were compared with behavioral thresholds. In the second study, a prospective analysis of 23 children (mean age: 12 months), the ABR thresholds to 500 Hz, 1000 Hz tone-pip and click were compared with ASSR thresholds to amplitude and frequency modulated tones. RESULTS: The first study in which strong correlations were found between ABR and pure tone thresholds (r> or =0.92) demonstrated that ABR thresholds could be used to predict the pure tone thresholds. The second study which showed that ASSR thresholds were highly correlated with ABR thresholds (r> or =0.93) indicated that ASSR thresholds provided reliable audiometric information in infants and young children. CONCLUSION: These studies showed that ASSR could be used to estimate hearing thresholds with reliable accuracy in infants and young children.

Subclinical hypothyroidism and coronary risk factors in women above 55 years

BACKGROUND: There are several reports on the association between hypothyroidism and coronary heart disease. But, it is not convincing whether the subclinical hypothyroidism is associated with the coronary heart disease or not. We have attempted to investigate the association between subclinical hypothyroidism and the difference of Framingham risk score between subclinical hypothyroidism and normal control subjects in women above 55 years old, who have higher prevalence in subclinical hypothyroidism. METHODS: This study involved the subjects above age 55, who visited the health promotion center in a university hospital from 1995 to 2000. Subclinical hypothyroidism was defined as a TSH level greater than 4.1 mu1U/7L in the presence of a normal T3 (87-184 mug/dL) and T4 (6.6-13.1 mug/dL) level. We measured thyroid function test (TSH, T3, T4) and the coronary risk factors (systolic and diastolic blood pressure, total cholesterol, LDL cholesterol, HDL cholesterol, triglyceride, fasting glucose, uric acid, C-reactive protein, and body mass index) . Also, we calculated the Framingham risk score from their sum. RESULTS: There were no significant differences of systolic/diastolic blood pressure, fasting g1ucose, total cholesterol, LDL cholesterol, HDL cholesterol, triglyceride, uric acid, C -reactive protein body mass index and Framingham risk score in subclinical hypothyroidism patients and normal control subjects. CONCLUSIONS: There were no significant differences between the subclinical hypothyroidism patients and normal control subjects with coronary risk assessment in women above 56-years -old.

Postoperative Results of Tympanoplasty Type 1 in Adult / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The objectives of tympanoplasty are the removal of pathology and the reconstruction of transducer mechanism of the middle ear. Aims of this study were to analyze the postoperative hearing results after tympanoplasty type I and to evaluate the prognostic factors related to the postoperative hearing results and complications. MATERIALS AND METHOD: From January 1996 through January 2001, 138 cases of tympanoplasty type I performed by one senior surgeon were reviewed retrospectively. Revision cases or canal down mastoidectomy cases were excluded. RESULTS: Out of 138 cases, 120 cases (87%) showed air-bone gap of less than 20 dB in postoperative 1-year, the postoperative 1-year air-bone gap (ABG) was 9.6+/-8.6 dB and postoperative 1-year hearing gain was 12.2+/-10.4 dB. The postoperative reperforation rate was 14%, and the recurrent drainage developed in 5%. There was no deterioration of bone conduction. Patients with large perforation had more hearing gain following operation. Postoperative reperforation developed more frequently when the middle ear mucosa was inflamed preoperatively. The postoperative hearing deterioration was mainly due to infection that was uncontrolled preoperatively. CONCLUSION: Postoperative hearing gain was related to the size of perforation. It is important to control the infection preoperatively for the improvement of the result following tympanoplasty type I.

HRCT Findings of Otosclerosis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: With advances in techniques in the field of otology, we can now offer better treatment to patients with the conductive hearing loss. Otosclerosis is rare in the mongoloids so the diagnosis and treatment modality are not well established yet. In this study, we reviewed high resolution computerized tomography (HRCT) of patients with otsclerosis who were confirmed through explotympanotomy and found that there were specific radiological finding relevant to otsclerosis. The purpose of this study was to understand the HRCT findings of otosclerosis in order to provide more information about the disease. MATERIALS AND METHODS: We selected 42 HRCT available patients of 126 patients who were operated in the Seoul National university hospital from January 1981 to December 2000. We used GE HIGH SPEED ADVANTAGE (scan thickness 1 mm, scan interval 1 mm) CT scanner. RESULTS: There were radiolucent lesions in 48 ears(62%). The lesions were found in the fissula ante fenestram, cochlea, and the semicircular canal. CONCLUSIONS: HRCT could be used as an adjunctive diagnostic tool for the detection of otosclerotic lesion, stapedial or cochlear. We could find positive findings in 62% of the patients who showed progressive and conductive hearing loss.

Outcome of Cochlear Implantation in Postmeningitic Children / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Meningogenic labyrinthitis is a common cause of acquired profound sensorineural hearing loss in childhood. Obliterated cochlea is one of the most challenging problems in cochlear implantation because it limits the insertion of active electrodes. The aims of this study were to review the surgical findings of meningitic deaf children and to compare their speech performance with that of congenitally deaf children of the matching age group (n=20). MATERIALS AND METHOD: Of the 104 children who had implants, 18 (17.3%) were deafened by meningitis. Operative and high resolution CT (HRCT) findings were reviewed retrospectively with medical records. Speech feature discrimination test was performed to evaluate speech performance. RESULTS: Seventeen out of 18 patients (94%) required drilling of the ossified bones at surgery. HRCT findings suggested ossification within the basal turn of 67% (71% sensitivity). Speech perception was tested for in ten cases. In 5 of the ten cases, complete insertion of electrodes was not possible. There were no significant differences in speech feature discrimination between congenital deaf children and meningitic deaf children. Speech perception was not related to the number of the electrodes inserted. CONCLUSION: Most (94%) of postmeningitic deaf children had ossification. When the number of inserted active electrodes was more than 10, the number itself had no influence on the speech performance. Postmeningitic deaf children with ossified cochlear could obtain comparable benefit from having implants as much as non-meningitic children.

Pathologic Findings of Otosclerosis in Korea / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Otosclerosis is known to be rare in orientals, but there have been a few reports of the clinically suspicious otosclerosis cases in Korea. Confirmation of otosclerosis, in theory, should be done by histopathology. However, for LASER stapedotomy, it is very hard to obtain the tissue to conduct such histopathological study. In this research, we had surgical specimens available for a review of otosclerosis case. We aimed to confirm the pathologic findings of otosclerosis in Koreans, and review their clinical information. SUBJECTS AND METHOD: Among 126 otosclerosis patients who were operated in the Seoul National University Hospital from January 1981 to December 2001, three cases were selected for pathologic evaluation. We used the H & E method for staining. RESULTS: There were positive histologic findings in all three cases. Two typical phases (early spongiotic and late sclerotic of otosclerosis) could be observed in specimen. CONCLUSION: In the pathologic specimen from the patients showing progressive conductive hearing loss, we could confirm otosclerosis. Both early and late phase of otsclerotic foci coexisted in the same specimen.

The Effect of Ototoxic Sodium Salicylate on DPOAE and Cochlear Blood Flow in Guinea Pig / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Salicylate is one of the most commonly prescribed drugs although it has been recognized that salicylate induces hearing loss and tinnitus reversibly. There are many presumed mechanisms of salicylate ototoxicity including an impairment of the cochlear blood circulation. But the exact mechanism of salicylate ototoxicity is not known clearly. The purpose of this present study was to determine if the decreased blood flow after salicylate injection could be the possible cause of hearing loss. MATERIAL AND METHODS: We used the ventral approach to expose cochlea in 5 guinea pigs showing normal Preyer reflex. We simultaneously measured cochlear blood flow (CBF) by laser doppler and distortion product otoacoustic emission (DPOAE) after a high dose of salicylate injection (300 mg/kg). RESULTS: After salicylate injection, the cochlear blood flow were decreased by 29.1 % in a 3 hour period and the thresholds of DPOAE were elevated by 5 to 25 dB for 3 kHz, 4 kHz, 6 kHz, 8 kHz. CONCLUSION: Sodium salicylate caused a decrease in cochlear blood flow and an increase in the hearing threshold simultaneously after an intraperitoneal injection of sodium salicylate. These findings suggest that the ototoxic mechanism of sodium salicylate could be explained by a certain damage of out hair cell due to decrease in cochlear blood flow.

Clinical Presentation and Management of Labyrinthine Fistula in Chronic Otitis Media with Cholesteatoma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Labyrinthine fistula is a potentially serious complication of cholesteatoma. During or after surgery, cholesteatoma induced labyrinthine fistula can result in partial or total destruction of cochleovestibular functions.This study aimed to evaluate the efficacy of preoperative tests for predicting fistulas and postoperative hearing results according to surgical management. MATERIALS AND METHODS: A retrospective study of the clinical records of 1,712 patients who were operated for chronic otitis media with cholesteatoma from January 1979 through April 2001 in a tertiary university hospital in Seoul area. Of 1,712 patients studied, patients who were proved to have labyrinthine fistulas during operation for cholesteatoma were collected. The results of the pre- and postoperative bone conduction pure tone average and pure tone threshold at 4 kHz were analyzed in those patients. The fistula test,the temporal bone CT scan (TBCT) and intraoperative findings were also evaluated. RESULTS: Labyrinthine fistulas were found in 140 (8.2%) patients in this study. Fistulas were most commonly found in the lateral semicircular canal (91.7%) and fistulas in lateral semicircular canal were more accurately detected than the fistula of the other sites either by fistula test or by TBCT. Positive fistula test results and positive temporal bone CT findings in labyrinthine fistula cases were recorded in 36.3% and 74.1% of cases, respectively. Canal wall down mastoidectomy procedures were applied in 134 ears (95.7.%). The cholesteatoma matrix was removed in 129 ears (92.1%). The average bone conduction threshold showed no significant difference between pre- and postoperative evaluations overall. But in matrix-removed group, the change in the bone conduction level was significantly different between patients having fistula same or larger than 2 mm and smaller than 2 mm. CONCLUSIONS:The high resolution temporal bone CT scan is highly recommended for detection of labyrinthine fistulas. The postoperative hearing results are not affected by the type of mastoidectomy procedures but may be affected by the management of cholesteatoma matrix when the fistula is large in this study.

Volume Measurement of Vestibular Schwannoma Using New Software / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Vestibular schwannomas are intracranial neoplasms that compress adjacent structures as their volume grows. Although the clinically relevant parameter is most likely tumor volume, current clinical decisions are based on two-dimensional measurements of tumor diameter. This study was conducted to introduce a new software for accurate measurement of vestibular schwannoma volume and to determine the relationship between diameter and volume. Material and Method: Twenty-eight patients who had no previous treatment before MRI were included in this study. Diameter of the vestibular schwannoma was measured according to AAO guidelines and spherical volume was calculated from the diameter. For the accurate volume measurement of the vestibular schwannoma, we used a new software (Rapidia, 3D Med Co) developed in Korea. Paired t-test was used for the statistical analysis of correlation between the measured and calculated volumes. RESULTS: The difference between the measured and calculated volumes was statistically not significant (p=.120). However, as tumor size increased greater than 2 cm in diameter, our measured volume result was smaller than the calculated volume, although statistically not significant (p=.067). CONCLUSION: These results were due to tumor configuration, which was wider in the axial plane than in the longitudinal plane. From these results, we can realize that initial tumor growth was spherical, and as the size increased, it was distorted by the adjacent structures. These results suggest that special attention is needed in making clinical decisions on larger tumors, especially greater than 2 cm in diameter.

The Efficacy of the Hearing Threshold Level at 3 kHz I/O Curve in DPOAE in Screening the High Risk Neonates in NICU / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Universal infant hearing screening has been recommended by the National Institutes of Health. Although the distortion-product otoacoustic emissions (DPOAE) hold promise as a screening technique, the validity oftheir input/output function curve (I/O curve) in the screening of neonates has not been fully investigated. The aims of this study were to determine the efficacy of the I/O curve as a hearing screening test and to investigate the prevalence of sensorineural hearing loss (SNHL)(moderate to severe degree) in high risk neonates. MATERIALS AND METHOD: A total of 69 ears of 35 infants at risk for hearing loss were tested with both DPOAE and auditory brainstem responses (BR). Auditory brainstem response results were used as the standard for hearing. The hearing threshold level at 3 kHz in I/O curve and the amplitude of distortion product in the DP audiogram were calculated and compared with the results of ABR. Neonates whose hearing thresholds were worse than 60 dB in the I/O curve were regarded as 'test-positive' and neonates whose hearing thresholds were worse than 60dB in ABR were regarded as 'disease-positive'. The sensitivity and the specificity of each test were calculated and the correlations between the response of each test and ABR threshold were also studied. RESULTS: The prevalence of SNHL in neonates in the SNUH neonatal intensive care unit was 5.79%. The sensitivity and specificity of the screening test using the I/O curve were 100% and 63.1%, respectively. The test using the DP amplitude for SNHL showed the sensitivity of 100% and the specificity of 18.46%. This was much lower than that of the screening test using the I/O curve. There was a positive correlation between the I/O threshold and ABR threshold (r=0.43), but there were no statistically significant correlations between the DP amplitude and the ABR threshold nor between the DP amplitude and the I/O threshold. CONCLUSIONS: The test using the I/O threshold in DPOAE is suitable for the screening of the SNHL in neonates with high sensitivity and relatively high specificity. Moreover, the I/O threshold could predict the audiometric threshold more correctly than the DP amplitude could.

Follow up Hearing and Complication Results of the Two Surgical Techniques in the Treatment of Adult Cholesteatoma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The canal wall down (CWD) precedure provides relatively safer access and lower recidivism rate compared to the canal wall up (CWU) procedure. Choice of initial surgical procedure and staging can be variable according to the surgeon's preference and experience. Aims of this study were to analyze the frequency and causes of reoperation and to analyze postoperative hearing results between two groups according to the status of stapes and staging. MATERIALS AND METHODS: Initial surgical management for 179 cases of cholesteatoma performed by 2 senior authors from 1993 through 1998 were reviewed retrospectively. RESULTS: CWD procedure was the preferred procedure (n=151, 84%) and surgery for hearing gain was performed in 103 cases regardless of staging. The numbers and causes of reoperation were analyzed. In CWD cases, the emergence of recidivism (i.e., residual or recurrent cholesteatoma) persisted during the follow up and annual rate of recidivism was around 2%. Between CWD and CWU group, there was no statistical difference in the annual incidence of recidivism. Hearing results according to the types of mastoidectomy and the status of stapes were analyzed at 1 year of the follow up. Air-bone gap closure (ABG closure) didn't show any differences in both groups. In both groups, there were no statistical differences in the ABG closure according to the status of stapes. CONCLUSION: Even though CWD surgery was mainly performed in extended and advanced cases, the rate of recidivism and postoperative hearing results showed no statistical differences between the two groups. A well-performed primary canal wall down surgery is safe with a few problems requiring no further procedure in cholesteatoma surgery.

Distortion Product and Spontaneous Otoacoustic Emissions in Normal Neonates / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Distortion product otoacoustic emission (DPOAE) offers an alternative to transiently evoked OAE as a neonatal hearing screening, and may provide frequency specific information of the cochlea. The purpose of this study is to establish the relevant characteristics of spontaneous OAE (SOAE) and DPOAE of neonates and their efficacy as a neonatal screening method for hearing loss. MATERIALS AND METHODS: From July to September 1999, 72 healthy newborns (144 ear) were included in this study and test was performed within 3 days after birth at nursery. DP audiogram, input/output (I/O) curve at 3 kHz, and SOAE were recorded. RESULTS: The DP audiogram had characteristics with two broad peaks of amplitude at Fe (geometric mean of two primaries) frequencies of 3 kHz and 6 kHz. From the Fe near 3 and 6 kHz, DPOAE was found over 95% of 144 ears. Median threshold of 3 kHz I/O curve was 40 dB. The threshold in 3 kHz could be obtained even in 7 ears that had failed to pass DP audiogram. The thresholds of the ears that failed in DP audiogram were not statistically different from those that passed the test, The amplitude in DP audiogram was not correlated with the threshold in 3 kHz I/O curve. The positive rate for SOAE was 45% (39% in male, 53% in female, 51% in right ear, 38% in left ear, respectively), All the SOAE positive cases passed DP audiogram test. CONCLUSIONS: DPOAE has a potential for neonatal screening test for hearing loss. Near 3 kHz and 6 kHz, DPOAE were highly positive, and these frequencies can be used in screening test. The duration of a diagnostic test would be shorter by excluding certain frequencies. Using the 3 kHz I/O curve in addition to DP audiogram may increase the validity and the e6cacy of the test. SOAF has limitations as a single modality of neonatal screening test for hearing loss.

Clinical Analysis of Delayed Facial Nerve Palsy after Middle Ear Surgery / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Delayed facial nerve palsy (DFNP) following a middle ear surgery is an uncommon event, and is defined to develop 48 or 72 hours after surgery. The pathogenesis of DFNP is not known clearly, but it is presumed to inflammation, neuronal edema or reactivation of herpes virus. The purposes of this study were to provide the clinical aspect of DFNP after middle ear surgery and to discuss the prognostic factors and treatment plan. MATERIAL AND METHOD: From January 1985 to August 1999, in the course of over 5,670 middle ear surgeries, we experienced 12 ipsilateral delayed facial nerve palsies. We analyzed the course of DFNP according to several clinical factors retrospectively. Degree of facial palsy was evaluated with the House-Brackmann grade (HBG). RESULTS: DFNP was developed from 3 day to 14 day after middle ear surgery. The initial degree of facial palsy was HouseBrackmann grade (HBG) II in 6, HBG III in 4, and HBG IV in 2 patients. All patients were treated with steroid and volume expander. The final recovery were HBG I in 11 of the twelve patients. Remaining one patient was found to be HBG Il after a 5-year follow up. In the group who recovered within 1 month, the initial HBG were II or III. CONCLUSION: We obtained satisfactory results with steroid therapy in most patients. The courses of DFNP after middle ear surgery are favorable. The better initial HRG and HBG at 2 weeks are, the earlier recovery can be expected.