Width of the Internal Auditory Canal

1979 ◽  
Vol 88 (3) ◽  
pp. 316-323 ◽  
Author(s):  
Francisco Pérez Olivares ◽  
Harold F. Schuknecht
Keyword(s):  
Hearing Loss ◽  
Soft Tissue ◽  
Sensorineural Hearing Loss ◽  
Internal Auditory Canal ◽  
Middle Region ◽  
Soft Tissue Lesion ◽  
Histological Evidence ◽  
The Mean ◽  
Temporal Bones ◽  
Canal Syndrome

Vertical and horizontal measurements were made of the widths of the internal auditory canals of 435 histologically prepared temporal bones. The mean vertical width, measured at the porus acusticus, was 3.68 mm (range 2.10 to 5.26 mm), and the mean horizontal width, measured in the middle region of the canal, was 3.72 mm (range 2 to 5.8 mm). The 144 ears selected for study because they exhibited slowly progressive sensorineural hearing loss showed a distribution of canal widths similar to that of the group as a whole. Histological examination of the internal auditory canals failed to show any type of soft tissue lesion which might have contributed to narrowing of the canals. The study provides no anatomical or histological evidence for the existence of a small internal auditory canal syndrome.

Enlarged vestibular aqueducts and other inner-ear abnormalities in patients with Down syndrome

2016 ◽  
Vol 131 (4) ◽  
pp. 298-302 ◽  
Author(s):  
C M Clark ◽  
H H Patel ◽  
S G Kanekar ◽  
H Isildak
Keyword(s):  
Computed Tomography ◽  
Hearing Loss ◽  
Down Syndrome ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Internal Auditory Canal ◽  
Sensorineural Hearing ◽  
Vestibular Aqueduct ◽  
Computed Tomography Images ◽  
Temporal Bones

AbstractBackground:Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features.Methods:A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths.Results:Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size.Conclusion:Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.

Pontine Tegmental Cap Dysplasia

2011 ◽  
Vol 145 (6) ◽  
pp. 992-998 ◽  
Author(s):  
Nilesh K. Desai ◽  
Lindsay Young ◽  
Mario A. Miranda ◽  
Joe Walter Kutz ◽  
Peter S. Roland ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Cochlear Implantation ◽  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Sensorineural Hearing ◽  
Imaging Findings ◽  
Membranous Labyrinth ◽  
Brainstem Response ◽  
Temporal Bones

Objectives. Pontine tegmental cap dysplasia (PTCD) is a rare congenital malformation. Clinical and imaging findings in 3 patients and the authors’ experience with bilateral cochlear implantation in 1 patient are described. Study Design. Retrospective review. Setting. Two tertiary medical centers. Subjects and Methods. Three patients were evaluated by an otolaryngologist and underwent magnetic resonance imaging (MRI) of the temporal bones and brain. High-resolution computed tomography (CT) scanning of the temporal bones was performed in 2 patients. Imaging findings of the brain, the presence and course of resolvable cranial nerves, the membranous labyrinth, and internal auditory canals were reviewed. Clinical data were reviewed. Results. All patients demonstrated typical brain characteristics of PTCD. Mild, bilateral cochlear dysplasia was noted in 2, and all had a normal vestibular labyrinth. The cochleovestibular nerves were universally absent bilaterally. The facial nerves were subjectively deficient bilaterally in 1 patient, unilaterally in the second patient, and normal in the third. An accessory canal for the seventh cranial nerve, referred to as a duplicated internal auditory canal, was present in all patients. Auditory brainstem response testing revealed profound bilateral sensorineural hearing loss in all of the patients; none suffered facial weakness. A single patient underwent bilateral cochlear implantation with only minimal response. Conclusion. The authors report 3 cases of PTCD with emphasis on imaging of the seventh and eighth cranial nerves and clinical neurotologic findings. All patients manifested duplicated internal auditory canals, a previously unreported finding in PTCD. Bilateral profound sensorineural hearing loss is due to absence of the cochleovestibular nerve. Prognosis for cochlear implantation is poor.

Causes and Types of Sensorineural Hearing Loss. Clinical Manifestations and Basic Principles of Treatment

2020 ◽  
pp. 9-16
Author(s):  
Sergey Armakov
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Clinical Manifestations ◽  
Sensorineural Hearing ◽  
Doppler Imaging ◽  
Comprehensive Treatment ◽  
Impaired Hearing ◽  
Temporal Bones ◽  
The Brain

Sensorineural hearing loss is a disorder associated with the damage to the inner ear structures: the cochlea (cortical organ), dysfunctioning of the vestibule-cochlear nerve or the central part of the auditory analyser (brain stem and cortical representation of the cortical temporal lobe). In recent years, there has been a steady increase in ensorineural hearing loss patients; they account for ca. 70% among the total patients with impaired hearing. The disease has numerous causes and a complex pathogenesis. Among the main factors contributing to hearing loss are genetic predisposition, perinatal pathology, including hypoxia at childbirth, exposure to infectious and toxic agents and metabolic disorders, injuries (mechanical, acoustic and altitude trauma). Vascular-rheological disorders in the vertebro-basilar system play an important part because blood is supplied to the inner ear from the anterior inferior cerebellar artery. There are sudden, acute and chronic sensorineural hearing loss. The ensorineural hearing loss isdiagnosed by examinations that allow to verify the diagnosis and to determine the sound analyser damage level. This complex includes audiometric examinations, including the tuning fork examination, speech audiometry, and acoustic impedancemetry. If necessary, ultrasound Doppler imaging of the main blood vessels of the brain, computed tomography of the temporal bones, and MRI of the brain are prescribed. The pattern of comprehensive treatment should include, first of all, the elimination of the disease cause and anti-hypoxic drugs, anti-oxidants and a number of physiotherapy procedures.

scholarly journals Does Drilling Induce Hearing Loss after Modified Radical Mastoidectomy? A Retrospective Study

2020 ◽  
Vol 42 (3) ◽  
pp. 38-41
Author(s):  
Yogesh Neupane ◽  
Bijaya Kharel ◽  
Heempali Dutta
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Bone Conduction ◽  
Sensorineural Hearing ◽  
Radical Mastoidectomy ◽  
Modified Radical Mastoidectomy ◽  
The Mean ◽  
Sensory Neural ◽  
Mastoid Surgery ◽  
Sensory Neural Hearing Loss

Introduction Incidence of sensory neural hearing loss following mastoid surgery varies from 1.2 – 4.5%.There are various causes for postoperative sensorineural hearing loss during mastoid surgery. This study aims to identify whether there is any correlation between drilling and postoperative sensory neural hearing loss. MethodsA retrospective study was conducted in the Department of ENT from January 2018 to June 2019. A total number of 68 patients above five years of age who underwent modified radical mastoidectomy for chronic otitis media squamous were included. Revision surgery, preoperative sensorineural hearing loss, injury to the ossicular chain during surgery, patients with lack of follow up or doubtful reports in mentally challenged were excluded from the study. The average bone conduction threshold was calculated from 500, 1000, 2000, 4000 Hz and compared using the Wilcoxon signed-rank test. ResultsThere were 43 males and 25 females in the study with a median age of 23.5 years (16-55). The mean preoperative bone conduction threshold in the four frequencies of 500 Hz, 1kHz, 2kHz, 4kHz were -2.06dB, -2.06dB, 3.31dB, 4.63 dB respectively and the mean postoperative bone conduction thresholds were 1.03, 1.32, 5.29, 4.04 respectively. There was a decline of mean of 3.09 dB and 3.38dB only at the low-frequencies (500Hz and 1kHz) BC threshold respectively which were statistically significant, whereas at higher frequency there was no decline in average postoperative BC threshold. ConclusionThere is no definite role of drill in inducing hearing loss and if present other causes of hearing loss should be sought in postoperative sensorineural hearing loss.

scholarly journals Diagnostic Yield of MRI for Sensorineural Hearing Loss – An Audit

2020 ◽  
Vol 47 (5) ◽  
pp. 656-660
Author(s):  
Helen Wong ◽  
Yaw Amoako-Tuffour ◽  
Khunsa Faiz ◽  
Jai Jai Shiva Shankar
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Diagnostic Yield ◽  
Internal Auditory Canal ◽  
Auditory Brainstem ◽  
Sensorineural Hearing ◽  
Vestibular Evoked Myogenic Potentials ◽  
Clinical Indication ◽  
Presenting Symptoms ◽  
Brainstem Response

ABSTRACT:Purpose:Contrast-enhanced magnetic resonance imaging (CEMRI) of the head is frequently employed in investigations of sensorineural hearing loss (SNHL). The yield of these studies is perceptibly low and seemingly at odds with the aims of wise resource allocation and risk reduction within the Canadian healthcare system. The purpose of our study was to audit the use and diagnostic yield of CEMRI for the clinical indication of SNHL in our institution and to identify characteristics that may be leveraged to improve yield and optimize resource utilization.Materials and methods:The charts of 500 consecutive patients who underwent CEMRI of internal auditory canal for SNHL were categorized as cases with relevant positive findings on CEMRI and those without relevant findings. Demographics, presenting symptoms, interventions and responses, ordering physicians, and investigations performed prior to CEMRI testing were recorded. Chi-squared test and t-test were used to compare proportions and means, respectively.Results:CEMRI studies revealed relevant findings in 20 (6.2%) of 324 subjects meeting the inclusion criteria. Pre-CEMRI testing beyond audiometry was conducted in 35% of those with relevant positive findings compared to 7.3% of those without (p < 0.001). Auditory brainstem response/vestibular-evoked myogenic potentials were abnormal in 35% of those with relevant CEMRI findings compared to 6.3% of those without (p < 0.001).Conclusion:CEMRI is a valuable tool for assessing potential causes of SNHL, but small diagnostic yield at present needs justification for contrast injection for this indication. Our findings suggest preferred referral from otolaryngologists exclusively, and implementation of a non-contrast MRI for SNHL may be a better diagnostic tool.

Hypertrophic Pachymeningitis of the Internal Auditory Canal: A Rare Case of Unilateral Sudden Sensorineural Hearing Loss

2018 ◽  
Vol 127 (9) ◽  
pp. 649-652 ◽  
Author(s):  
Thomas Muelleman ◽  
Hannah Kavookjian ◽  
James Lin ◽  
Hinrich Staecker
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Internal Auditory Canal ◽  
Sudden Sensorineural Hearing Loss ◽  
Sensorineural Hearing ◽  
High Dose ◽  
Hypertrophic Pachymeningitis ◽  
Eighth Cranial Nerve ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri

Objectives: To describe and increase awareness of a rare cause of unilateral sudden sensorineural hearing loss. Methods: Case report and literature review. Results: We present a 66-year-old female who suffered left-sided sudden sensorineural hearing loss and dizziness. Diagnostic magnetic resonance imaging (MRI) did not reveal masses or lesions along the eighth cranial nerve or in the inner ear. Upon eventual referral to neurotology clinic, hypertrophic pachymeningitis of her left internal auditory canal and adjacent middle and posterior fossa dura were identified. The ensuing laboratory workup for autoimmune and infectious etiology revealed mild elevation of ACE 93 (9-67) but otherwise normal results. Conclusions: Idiopathic hypertrophic pachymeningitis is a diagnosis of exclusion. Neoplastic, infectious, and autoimmune causes must be ruled out. The prevailing treatment for this condition is high-dose corticosteroids. This entity should be considered when evaluating MRI scans obtained in the setting of sudden sensorineural hearing loss.

Cavernous angioma of the internal auditory canal

2004 ◽  
Vol 118 (5) ◽  
pp. 368-371 ◽  
Author(s):  
Kristian Aquilina ◽  
Jagdeep S. Nanra ◽  
Francesca Brett ◽  
Rory McConn Walsh ◽  
Daniel Rawluk
Keyword(s):  
Hearing Loss ◽  
Facial Nerve ◽  
Sensorineural Hearing Loss ◽  
Internal Auditory Canal ◽  
Cavernous Angioma ◽  
Dynamic Nature ◽  
First Report ◽  
Cavernous Angiomas ◽  
Nerve Paresis

Cavernous angiomas of the internal auditory canal are rare lesions. The authors present a case of a 29-year-old lady with multiple infratentorial cavernous angiomas, whose sister had previously undergone surgery for a similar supratentorial lesion. She initially presented with an acute brainstem haematoma, secondary to a pontine cavernous angioma. Three years later she developed progressive right-sided sensorineural hearing loss and facial nerve paresis due to an internal auditory canal lesion. This was removed via the translabyrinthine approach and was found to be a cavernous angioma. This report underlines the multiple and dynamic nature of familial cavernous angiomas, as well as the importance of follow up to determine whether new symptoms are due to the enlargement of known angiomas or the development of new ones. As far as the authors are aware, this is the first report describing a cavernous angioma of the internal auditory canal in the context of familial and multiple infratentorial angiomas.

Sudden deafness in vestibular schwannoma

1994 ◽  
Vol 108 (2) ◽  
pp. 116-119 ◽  
Author(s):  
David A. Moffat ◽  
David M. Baguley ◽  
Hubertus von Blumenthal ◽  
Richard M. Irving ◽  
David G. Hardy
Keyword(s):  
Hearing Loss ◽  
Vestibular Schwannoma ◽  
Tumour Size ◽  
Internal Auditory Canal ◽  
Sudden Deafness ◽  
Aetiological Factor ◽  
Caloric Test ◽  
Significant Difference ◽  
Facial Numbness ◽  
The Mean

AbstractTwelve per cent of a series of 284 patients with vestibular schwannoma presented with sudden deafness. If sudden sensorineural hearing loss is present then it is very likely to be the main presenting symptom. The mean length of patients' history is eight months shorter in this group than in the non-sudden deafness group. Sixteen per cent of vestibular schwannoma patients without sudden deafness present with a 'dead' ear whereas 29.5 per cent of those presenting with sudden deafness have total hearing loss. There was no significant difference between the sudden deafness group and the 'all others' group with regard to tumour size, udiogram shape, caloric test, imbalance, and facial numbness. Although the numbers of patients with sudden deafness in this series were too small to reach significance, on the basis of the clinical correlation of vestibular schwannoma morphology it is possible to postulate that compression of the vasculature within the bony internal auditory canal by a laterally arising tumour may be the aetiological factor and may be more likely to occur than in more medially arising tumours.

Use of Contralateral Masking in the Measurement of the Auditory Brainstem Response

1982 ◽  
Vol 25 (4) ◽  
pp. 528-535 ◽  
Author(s):  
Larry E. Humes ◽  
Marleen G. Ochs
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Auditory Brainstem Response ◽  
Mean Amplitude ◽  
Auditory Brainstem ◽  
Normal Hearing ◽  
Brainstem Response ◽  
The Mean ◽  
Intensity Functions ◽  
Contralateral Masking

In the first portion this study, the effects of two levels of contralateral masking on the auditory brainstem response (ABR) were investigated in 10 normal-hearing subjects. No significant changes were observed in the mean latency-intensity functions or the mean amplitude-intensity functions of this group of subjects when noise of various levels was added to the nontest ear. In the second portion of this study, ABRs were also recorded from the poorer ear of four subjects with a profound unilateral sensorineural hearing loss. Results from the latter group revealed a crossed-over wave V in all cases when the stimulus was delivered to the poorer ear and the nontest (better) ear was not masked. Contralateral masking obliterated this "crossed ABB" in all four unilaterally impaired subjects. These results provide support for the use of contralateral masking when recording from the poorer ear of subjects having asymmetrical hearing loss.

Otosclerotic Involvement of the Cochlea: A Histologic and Audiologic Study

1981 ◽  
Vol 89 (2) ◽  
pp. 343-351 ◽  
Author(s):  
Dennis R. Elonka ◽  
Edward L. Applebaum
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Bone Conduction ◽  
Sensorineural Hearing ◽  
The Other ◽  
Poor Correlation ◽  
Stapes Footplate ◽  
Temporal Bones ◽  
Similar Incidence ◽  
Sensorineural Loss

This study sought correlations between sensorineural hearing loss and otosclerotic endosteal involvement in 29 temporal bones examined histologically. The sensorineural hearing loss of the affected parts of the cochlea was determined by the last antemortum bone conduction audiogram available. There were eight temporal bones with only stapes footplate involvement, six with one discrete focus of otosclerotic endosteal involvement, and 15 with two or more foci of endosteal involvement. Analysis of audiometric data showed that the group of bones with two or more foci of endosteal involvement had a similar incidence of 45 dB sensorineural loss (9 of 15 or 60%) as did the group with no endosteal involvement (5 of 8 or 62%). The group with two or more foci had a greater incidence of 60 dB or greater sensorineural loss (46%) compared with the groups with none (12%) or one focus (16%) involved. Correlation between hearing toss and involvement of cochlear endosteum was poor. Correlation existed in only 2 of 15 ears with two or more foci involving the cochlear endosteum. There was no correlation in the other groups. It appears that cochlear endosteal involvement alone may not be sufficient explanation for the sensorineural hearing loss found with otosclerosis, except in the most severely involved ears.

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