• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.227-230
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• 2005

Hearing loss in the contralateral functioning ear is a rare and distressing complication after vetibular schwannoma removal. Various possible mechanisms have been proposed, however, the etiology of hearing loss is not clear. Fortunately, this is an extremely rare occurrence, sporadic case reports have appeared in the literatures. We report two cases of acute contralateral hearing loss after vestibular schwannoma removal and discuss the possible mechanisms of the phenomenon. Although permanent deafness may result, in our cases, the hearing loss was temporary, returning to near preoperative level within one month. The etiology of hearing loss in one case is thought to be cerebrospinal fluid leakage. However, in the other case, the cause of hearing loss is not clear. A better understanding of these events may lead to preventive measures to avoid contralateral hearing loss after vestibular schwannoma removal.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.179-186
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• 2012

The aims of this study are to consider auditory physiological characteristics and to confirm audiological evaluation and interpretation in regards to cases of sensorineural hearing loss that observe an abnormal AB gap. Vestibulosaccular hearing occurs when there is an abnormally large air-bone gap (AB gap) in sensorineural hearing loss, also known as pure cochlear conductive hearing loss. Generally, an AB gap is caused by damage to the external and/or middle ear. In conductive hearing loss, loss of air condition hearing occurs due to a loss of resonance in the outer ear and/or impedance mismatching in the middle ear. Most of these types of hearing loss can be treated medically and surgically. However, there is no medical treatment for an AB gap in sensorineural hearing loss and hearing loss can worsen gradually or suddenly. In addition, many studies have reported that head trauma makes hearing loss even more serious. Therefore, in order to differentiate between conductive hearing losses, it is important to check whether or not there is an enlarged vestibular aqueduct by means of temporal bone computerized tomography and/or magnetic resonance imaging.

• The Journal of Korean Physical Therapy
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• v.11 no.2
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• pp.29-36
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• 1999

This study was carried out to compare the rotation between vestibular function and balance skills in normal and hearing-impaired children. The subjects were 20 normal children (8-10 years) and 20 bearing-impaired children (8-10 years). The SCPNT was used to assess vestibular function, then, one leg stance test was used to compare static balance skill of normal and hearing-impaired children according to existence of visual input and sex. The results were as follows: 1. In SCPNT, normal md hearing-impaired children showed statistical significance in all left-sided and right-sided rotations(p<.01), and the vestibular function responses of hearing-impaired children wore normal $20\%$, abnormal $45\%$, absent $35\%$. 2. To compare balance skills between normal and hearing-impaired according to eye open and eye close, one-leg stance Oat showed statistical significance in eye open(p<.05), but did not show statistical significance in eye close(p>.05). 3. SCPNT, ene-leg stance test did not show statistical significance according to sex(p>.05).

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.286-292
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• 2007

Objective : Gamma Knife Stereotactic Radiosurgery (GK SRS) has become an important treatment modality for vestibular schwannomas. We evaluated the tumor control rate, patterns of tumor volume change and preservation of hearing following low-dose radiation for vestibular schwannomas in a homogeneous cohort group in which the mean marginal dose was 12 Gy. Methods : A total of 59 patients were enrolled in this study. All enrolled patients were followed-up for at least 5 years and the radiation dose was 11-13 Gy. Regular MRI, audiometry and clinical evaluations were done and tumor volumes were obtained from MRI using the OSIRIS program. Results : The tumor control rate was 97%. We were able to classify the patterns of change in tumor volume into three categories. Transient increases in tumor volume were detected in 29% of the patients and the maximum transient increase in tumor volume was identified at 6 to 30 months after GK SRS. The transient increases in tumor volume ranged from 121% to 188%. Hearing was preserved in 4 of the 12 patients who had serviceable hearing prior to treatment. There were no other complications associated with GK SRS. Conclusion : Low-dose GK SRS was an effective and safe mode of treatment for vestibular schwannomas in comparison to the previously used high-dose GK SRS. Transient increases in tumor volume can be identified during the follow-up period after low-dose GK SRS for vestibular schwannomas. Physicians should be aware that these increases are not always indicative of treatment failure and that close observation is required following treatments. Unfortunately, a satisfactory hearing preservation rate was not achieved by reducing the radiation dose. It is thought that hearing preservation is a more sophisticated problem and further research is required.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.33-40
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• 2000

This study was carried out to compare the relation between vestibular function and balance skills in normal with heating-impaired children. The subjects were 20 normal children (8-10 years) and 20 hearing-impaired children (8-10 years). The SCPNT was used to assess vestibular function, then, functional reach test and backward walking test were usee to compare dynamic balance skills of normal and hearing-impaired children according to existence of visual input. The results were as follows : 1. In SCPNT, normal and hearing-impaired children showed statistical significance in all left-sided and right-sided rotations(p<.01), and the vestibular function responses of healing-impaired children were normal $20\%$, abnormal $45\%$, absent $35\%$. 2, To compare dynamic balance skills between normal and healing-impaired according to eye open and eye close, functional reach test did not show statistical significance in eye open situation(p>.05), but showed statistical significance in eye close situation(p<.05). 3. Backward walking test showed statistical significance in eye open and eye close situation(p<.01).

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.34 no.3
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• pp.80-91
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• 2021

Objective : The purpose of this study is to discriminate the vestibular schwannoma misdiagnosed as Idiopathic Sudden Sensorineural Hearing Loss. Methods : A 46-year-old female patient who was suffering left sudden sensorineural hearing loss(SSNHL), visited after diagnosed as Idiopathic SSNHL by previous hospital. For diagnosing the vestibular schwannoma, we conducted the Puretone audiometry, auditory brainstem response threshold test and magnetic resonance imaging(MRI) for temporal bone with enhancement. Result : Auditory Brainstem Response threshold test was abnormal and in enhanced MRI, the vestibular schwannoma in left side was detected. The patient was discharged from the hospital for tertiary hospital care. Conclusions : When the patient with SSNHL visits a hospital even if after diagnosed as Idiopathic SSNHL by previous hospital, a doctor should keep in mind the possibility of vestibular schwannoma.

• Journal of Korean Neurosurgical Society
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• v.40 no.5
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• pp.336-341
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• 2006

Objective : The authors conducted a retrospective study to evaluate the preservation rates of serviceable hearing and to determine its prognostic factors after gamma knife stereotactic radiosurgery[GK SRS] in the patient with vestibular schwannomas. Methods : Between December 1997 and March 2005, 54 patients with a sporadic vestibular schwannoma and serviceable hearing [Gardner Robertson grade I-II] were enrolled in this study. Electronic database of medical records and radiological examinations before and after GK SRS were investigated to the last follow up. The mean marginal dose was $12.3{\pm}0.7Gy$. The mean maximum dose delivered to the tumor center was 24.7Gy [$22{\sim}30Gy$]. The median tumor volume was 2cc [$0.1{\sim}9.1cc$]. The median follow-up period of magnetic resonance[MR] imaging was 31 months [$6{\sim}99\;months$], and the mean follow-up period of audiometry was 24 months [$4{\sim}70\;months$]. Results : The tumor control rate was 100% in the patients with the follow up period more than 2 years. The trigeminal and facial nerve preservation rates were 98% and 100%, respectively. Twenty-eight [52%] of the 54 patients preserved serviceable hearing and 16 [30%] patients retained their pre-GK G-R grade level after GK SRS. In the univariate and multivariate analysis, there was no significant prognostic factor in preservation of the serviceable hearing. Conclusion : The hearing preservation rate is still unsatisfactory compared with the results of other cranial nerve preservation and tumor control in the treatment of vestibular schwannoma by GK SRS. More sophisticated strategy during and after GK SRS is necessary to improve long-term hearing preservation.

• Journal of Korean Neurosurgical Society
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• v.42 no.3
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• pp.159-167
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• 2007

Vestibular schwannoma (VS) is a benign tumor typically originated in the schwann cell of vestibular nerve and usually accompany hearing symptom. Microsurgical removal and radiosurgery have a great role for the treatment of VS. Recently radiosurgery has been considered as an alternative or primary treatment for VS with the tremendous increase of patients who were treated with gamma knife radiosurgery (GKS) though microsurgery still takes the premier. By many published results, it is proved that GKS is a effective and noninvasive technique for VS, especially small sized tumors with satisfactory tumor control rate. The authors assumed that GKS can be expected to achieve satisfactory tumor control rate for small VS under 5cc in volume. A major interest regarding radiosurgery nowadays is to determine the optimal radiation dose for hearing preservation to improve the quality of life of patients. The more high radiation dose are used for effective tumor growth control, the more radiation-related complications like as hearing deficit, the impairment of other cranial nerve function are increased. Since 1990's the mean radiation dose for tumor margin was more than 18 Gy, but there were high complication rate in spite of good tumor growth control. After the year of 2000, under the influence of advanced neuro-imaging techniques and radiosurgical planning system which enable clinicians to do more precise planning, marginal dose for VS has been decreased to 12-13 Gy and the radiation-related complications has been reduced. But because there may be a unexpected radiation induced complications as time goes by after the latency period, optimal radiation dose for VS should be established on the basis of more long term follow-up observation.

• Journal of Korean Neurosurgical Society
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• v.30 no.11
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• pp.1308-1313
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• 2001

Object : The goals of radiosurgery include preservation of neurological function and prevention of tumor growth. We document the results of gamma-knife radio-surgery for vestibular schwannoma. Method & Object : Eighty-two patients underwent stereotactic radiosurgery for an vestibular schwannoma from October, 1994 to December, 2000. Sixty-five of these patients were followed up for radiological and clinical evaluation. As pregamma-knife modality, surgical resection were done in 23 patients,and V-P shunt in 2 patients. Initial symptoms were headache(n=45), dizziness(n=16), tinnitus(n=17). While normal facial function(House-Brackmann grade 1) was present in 48 patients(73.8%), other patients showed grade 2 function in 8, grade 3 function in 7,and grade 4 function in 2. The Gardner/Robertson scale was used to code hearing function. Male to female ratio was 1:3. Mean tumor volume was $7.98cm^3$. Mean dose delivered to the tumor margin was 14.2Gy,and mean maximal dose was 28.3Gy. Results : Mean follow-up duration of 19.9 months. Thirty-five showed decrease(53.8%) in size, 19 patients(29.2%) stationary, 3(4.6%) initial decrease follow up increase, 5(7.6%) initial increase follow up decrease,and 59 patients (90.8%) were well controlled. Two patients experienced transient facial neuropathy, one transient trigeminal neuropathy, and one transient hearing deterioration. After gamma-knife radiosurgery, ventriculoperitoneal shunt was done in 4 patients. Conclusions : Gamma-knife radiosurgery can be used to treat postoperative residual tumors as well as in patients with concomitant medical problems in patients with preserved hearing function. Gamma-knife radiosurgery is safe and effective method to treat small, medium sized(less than 3cm in extracanalicular diameter), intracanalicular vestibular schwannoma, associated with low rate of cranial neuropathy.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1978.06a
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• pp.7.2-7
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• 1978

There are over 60 types of hereditary hearing loss in man and most of these are distinguished from one another by outstanding associated defects caused the same gene producing hearing loss. However, there are at least 12 types of hereditary hearing loss with no known associated defects. The authors experienced two similar families with hereditary hearing loss. The affected offsprings had inevitably an affected parent in type of transmissin (autosomal dominant) and the hearing loss developed in childhood and progressed. Audiologic findings showed bilateral symmetrical moderate to severe sensori-neural hearing loss with flattened configuration on the audiogram. Vestibular function tests showed no abnormal findings and the associated anomalies could'nt be observed in history or clinical examinations.