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At least 181 records · Page 10Linked to original sources
PubMed1993

Preoperative electrical stimulation for cochlear implant selection. The use of ear canal electrodes versus transtympanic electrodes.

Preoperative electrostimulation tests were performed on 43 postlingually deaf and 20 prelingually deaf cochlear implant (CI) candidates. The stimulating electrode was placed at three different locations, i.e. the round window, the promontory and the ear canal and the results were compared. The evoked sensations were reported to be of auditory origin by most of the postlingually deaf CI candidates. Prelingually deaf subjects could not always distinguish clearly and reliably between "hearing" and "feeling". The percentage of stimulated ears of postlingually deaf subjects in whom hearing sensations were evoked was almost identical for the three locations of the stimulating electrode. However, in 5 out of the 7 ears without hearing sensations during ear canal stimulation (ECS), hearing sensations could be evoked during either promontory stimulation (PS) or round window stimulation (RWS). The mean threshold level for "hearing" at a stimulation frequency of 62 Hz was lowest during RWS, 7.7 dB higher during PS and 35.8 dB higher during ECS. The mean electrical dynamic range at 62 Hz was most favourable during RWS (23.9 dB), smaller during PS (15.6 dB) and smallest during ECS (10.0 dB). All differences were statistically significant. Placement of the ear canal electrode was easier, less frightening for the patient and required less time than insertion of the needle electrode for PS or RWS. Therefore we recommend the use of ECS to examine whether the CI candidate can be stimulated, and of RWS if more detailed information is required.

Adolescent↗
PubMed2001

Winer's dilated pore, rare presentation in the external ear canal.

A 51-year-old female patient was admitted to our outpatient department with a discharging right ear of six months duration and not responding to aural toilet and topical antibiotics. Microscopic examination showed a collection of soggy keratin in the floor of the ear canal. Suction cleaning showed a skin defect of about 7 mm in diameter. A CT scan showed rarefaction in the bony canal. Histological diagnosis following an excision biopsy under general anaesthetic showed Winer's dilated pore. Winer's dilated pore is a hair follicle tumour arising from the pilosebaceous apparatus. Hair follicle tumours are relatively rare and their clinical appearance is commonly non-specific. In spite of their non-specific features, they show a keratotic plug grossly which when removed reveals a skin defect and may show bone erosion occasionally if the underlying structure is bone. These features can be misinterpreted for more serious lesions such as squamous cell carcinoma or basal cell carcinoma of the ear canal that can lead to pursuing a more aggressive line of management for a benign lesion. We present this rare lesion illustrating the pathological features, differential diagnosis and management.

Diagnosis, Differential↗
PubMed1992

A look at ear canal changes with jaw motion.

Two procedures were used with one subject to examine changes in the ear canal with jaw motion. Silicone ear impressions were examined to measure the effect of jaw position. Magnetic resonance imaging was used to define the three-dimensional structure of the canal and visualize key underlying tissue. Results showed that inexpensive impressions can detail changes in the cartilaginous region of the canal. Approximately a 25% change in this subject's ear canal with different jaw positions was observed in the anterior/posterior plane with essentially no change in the superior/inferior plane. This is likely related to asymmetric stress from action of the mandibular condyle on neighboring cartilaginous tissue. Solutions to jaw motion-induced feedback problems are suggested.

Ear Canal↗
PubMed1987

Stenosis of the external ear canal: prevention using hydroxylated polyvinyl acetal wicks.

Hydroxylated polyvinyl acetal wicks may be very helpful in preventing postsurgical stenosis of the external ear canal. The wick is inserted into the canal, wetted with Polysporin Otic, and changed periodically until scar tissue becomes stabilized. This method is simple, quick, and well tolerated by the patient. Polyvinyl wicks provide a useful adjunct in preventing stenosis of the external ear canal.

Acetals↗
PubMed1987

Assessment of FM systems with an ear canal probe tube microphone system.

A technique is described to measure the real-ear performance of an FM system using an ear canal probe tube microphone device. The method involves placement of the FM microphone next to the monitoring (compression) microphone of the probe tube assembly to produce a constant sound pressure level input to the FM system. With the probe tube in the ear canal, a hearing aid alone is measured with a 60 dB SPL input and the FM system attached to the hearing aid (personal FM system) is assessed with an 80 dB SPL input to account for the higher input levels that occur due to the 6 inch distance between the speaker's mouth and the FM microphone. This technique permits a rapid comparison of the real-ear response of the hearing aid and the FM system.

Ear Canal↗
PubMed1990

[Fungal flora of the external ear canal--influence of cancer progressing].

In order to observe the influence of host immunity on fungal flora of the external ear canals, a group of 22 patients (44 ears) with stage IV head and neck cancer was investigated. The opportunistic fungi, Candida and Aspergillus, were found to have increased statistically (21.2%----43.1%, P less than 0.025). In addition, C. albicans (11.3%), not existing in the normal ear canal, was found with a tendency of increase. Although a recent report revealed that radiation and chemotherapy appear to be directly or indirectly related to fungal flora, the relevancy of host immune defect seems to be more evident in this study.

Adult↗
PubMed1989

Probe-tube microphone measures of ear-canal sound pressure levels in infants and children.

Probe-tube microphone measures of ear-canal sound-pressure levels were obtained for 31 children under 5 years of age. These data were compared to similar measures from a group of 21 adults. The intrasubject variability was smallest for the frequency range from 750 to 3000 Hz and at no frequency did the mean standard deviation exceed 3 dB. Real ear to coupler differences for the children showed the same pattern as a function of frequency as for adults but were significantly larger. A systematic decrease in real ear to coupler differences was observed with increasing age between 1000 and 3000 Hz. An estimate of ear-canal volume did not appear to be a clinically useful predictor of real ear to coupler differences.

Adolescent↗
PubMed1994

Acoustic impedance in the human ear canal.

For 13 normal-hearing test persons, the acoustic impedance about 6 mm inside the ear canal entrance has been measured in the frequency range 90-20,000 Hz by using standing wave measuring tubes connected to the ear canal via small ear adaptor tubes. The results show good reproducibility but large individual differences.

Acoustic Impedance Tests↗
PubMed1990

[Bacterial flora of the external ear canal. 1. Cancer patients].

The bacterial flora of the external ear canal was investigated in a group of 64 patients with head and neck cancer, to observe why otitis externa frequently occurs in cancer patients. Staphylococcus epidermidis (48.5%), Pseudomonas sp. (18.8%), and Flavobacterium sp. (16.8%) were the prominent isolates from ear samples, and Gram-negative organisms which rarely existed in normal canal, were found to be markedly increased (59.4%). Moreover, about half of all non-sterile ear canals were found to have more than one Gram-negative flora. We have concluded that cancer patients probably suffer from external otitis more frequently because of enhanced colonization by Gram-negative pathogens.

Adolescent↗
PubMed1982

Estimation of acoustical energy reflectance at the eardrum from measurements of pressure distribution in the human ear canal.

At frequencies greater than 2 kHz the acoustic impedance at the human eardrum is an unreliable indicator of the behavior of the middle ear system because of the complicated configuration of the ear canal and tympanic membrane. The energy reflectance at the eardrum, however, when obtained from measurement of the standing wave ratio (SWR) in the canal, is relatively insensitive to irregularities in the anatomical layout at the higher frequencies. Measurements of sound pressure distribution in 13 normal ear canals have been analyzed in a critical manner to provide new values of SWR, with estimates of error, between 5 and 10 kHz. At the higher frequencies these values tend to be appreciably greater than those previously reported. At 8 kHz, for example, the new values of SWR range between 18 and 24 dB as compared with earlier values which are in the vicinity of 13 dB. The correspondingly greater values of energy reflectance (60%-78%, as compared with 40%) are more consistent with known properties (mass, size, vibrational patterns) of the human eardrum. These results are applicable to the development of network models representing the middle ear system.

Acoustic Stimulation↗
PubMed2005

Influence of ear canal occlusion and static pressure difference on bone conduction thresholds: implications for mechanisms of bone conduction.

The effect of air pressure change on bone conduction (BC) hearing thresholds in the occluded ear was investigated. The pump manometer system of an impedance bridge was used to change the air pressure in the ear canal of twenty-two normally hearing subjects. BC thresholds were measured with: (1) open ear; (2) the ear canal occluded with a probe tube and application of 0 daPa air pressure; and (3) the ear canal occluded with a probe tube and application of 350 daPa air pressure. Thresholds were lower in condition 2 than in condition 1, the difference decreasing from 27 dB at 2500 Hz to 4.5 dB at 2000 Hz. Thresholds were higher in condition 3 than in condition 2. The results are interpreted in terms of changes in the relative contribution of the three routes of transmission for BC sound produced by occlusion and by a static pressure difference.

Acoustic Impedance Tests↗
PubMed2006

Cholesteatoma of the external ear canal: etiological factors, symptoms and clinical findings in a series of 48 cases.

BACKGROUND: To evaluate symptoms, clinical findings, and etiological factors in external ear canal cholesteatoma (EECC). METHOD: Retrospective evaluation of clinical records of all consecutive patients with EECC in the period 1979 to 2005 in a tertiary referral centre. Main outcome measures were incidence rates, classification according to causes, symptoms, extensions in the ear canal including adjacent structures, and possible etiological factors. RESULTS: Forty-five patients were identified with 48 EECC. Overall incidence rate was 0.30 cases per year per 100,000 inhabitants. Twenty-five cases were primary, while 23 cases were secondary: postoperative (n = 9), postinflammatory (n = 5), postirradiatory (n = 7), and posttraumatic (n = 2). Primary EECC showed a right/left ratio of 12/13 and presented with otalgia (n = 15), itching (n = 5), occlusion (n = 4), hearing loss (n = 3), fullness (n = 2), and otorrhea (n = 1). Similar symptoms were found in secondary EECC, but less pronounced. In total the temporomandibular joint was exposed in 11 cases, while the mastoid and middle ear was invaded in six and three cases, respectively. In one primary case the facial nerve was exposed and in a posttraumatic case the atticus and antrum were invaded. In primary EECC 48% of cases reported mechanical trauma. CONCLUSION: EECC is a rare condition with inconsistent and silent symptoms, whereas the extent of destruction may be pronounced. Otalgia was the predominant symptom and often related to extension into nearby structures. Whereas the aetiology of secondary EECC can be explained, the origin of primary EECC remains uncertain; smoking and minor trauma of the ear canal may predispose.

Journal Article↗
PubMedDate not supplied

Cosmetic results of a ventrally based advancement flap for closure of total ear canal ablations in 6 cats: 2002-2003.

OBJECTIVE: To report the outcome of a modified total ear canal ablation (TECA) technique to maintain normal ear carriage in cats. STUDY DESIGN: Case series. ANIMALS: Six cats with external ear canal disease. METHODS: Medical records were reviewed to identify cats in which a modified TECA using a single pedicle advancement flap was used to maintain normal ear carriage. Signalment, histopathologic diagnosis, complications, and outcome were retrieved. Owners were contacted to document long-term outcome. RESULTS: Modified TECA procedures (7) were performed in 6 cats. Normal ear carriage was present immediately after surgery and was preserved at follow-up interview. Owners were satisfied with cosmetic appearance. Histopathologic diagnosis of excised ear masses included ceruminous gland adenocarcinoma (2 cats), ceruminous gland adenoma (2 cats, 3 ears), and inflammatory polyp (2 cats). CONCLUSIONS: Modification of the TECA skin incision preserved normal ear carriage in all cats. Owners were satisfied with overall outcome and with cosmetic result. Rate and nature of complications were similar to previously published data. CLINICAL RELEVANCE: A simple modification of the TECA skin incision to create a single pedicle advancement flap maintains normal ear carriage in cats.

Animals↗
PubMedDate not supplied

Care of the ear canal and mastoid.

Zinc sulfate has been used for therapy of granulations of the trachea and ear that have not responded to usual treatment. This paper will report on current indications for zinc sulfate and the resulting success in managing granulomata of the ear canal and mastoid bowl. Some mastoid bowls have been large and hard to clean, especially in the posterior and lateral parts. A method of cleaning using indirect otoscopy and curved aspirators in conjunction with adequate lubrication will be described. Treatment of otalgia in both the ear canal and mastoid bowl due to otitis externa sicca and results of proper lubrication and avoidance of patient instrumentation to restore the normal wax will also be discussed.

Cerumen↗
PubMed1995

[Swollen ear canal, not always innocent].

A swollen ear canal: not to be underestimated. The role of radiology in three patients with problems due to unaccomplished otitis externa is discussed. The choice between CT scanning and MRI in selected cases is balanced.

Aged↗
PubMed1984

Cochlear nonlinearities inferred from two-tone distortion products in the ear canal of the alligator lizard.

Distortion products ( DPs ) evoked by two-tone stimuli at frequencies F1 and F2 were measured in the ear-canal sound pressure of the alligator lizard. The largest sound pressures measured, other than those at F1 and F2, where at the cubic difference frequencies 2F1-F2 and 2F2-F1. All cubic DPs were greatly reduced by destruction of the basilar membrane, which suggests that its nonlinear properties are the source of the DPs . Measurements following acoustic overstimulation show a complex relationship between the magnitude of DPs and cochlear state, as assessed by measurements of cochlear potential, and indicate the existence of multiple nonlinear sources within the inner ear. Relative magnitudes of the DPs and their dependence on stimulus level suggest that the inner-ear DP sources are cubic nonlinearities. The DPs are not highly sensitive to either average stimulus frequency or stimulus frequency separation, suggesting that the nonlinear processes are within the macromechanical processes of the inner ear. Contrary to some interpretations of ear-canal DP measurements in mammals, we conclude that DPs need not be associated with hair-cell processes and are not particularly useful indicators of cochlear health.

Acoustic Stimulation↗