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At least 37 records · Page 2Linked to original sources
PubMed1986

External ear canal cholesteatoma.

External ear canal cholesteatoma (EECC) is a rare otologic entity. Erosion of the inferior canal wall and accumulation of keratin debris are consistent findings. In the past there had been confusion between EECC and keratosis obturans, and they were thought to represent the same disease process. Currently, based on clinical and pathologic findings, it is believed that they are two different entities. In this article we present our experience in treating eight patients with EECC. For limited lesions, local debridement and curettage of necrotic bone is effective management. For more extensive lesions, canalplasty or tympanomastoidectomy is indicated.

Adult↗
PubMed1997

An improved method for the recovery of mycoplasmas from the external ear canal of goats.

The efficacy of ear canal flushing and ear canal and mouth swabbing methods for the isolation of mycoplasmas was investigated in 39 goats. Of the 19 goats positive for Mycoplasma spp., 14 (73.7%) were positive with the ear canal flushing method, 4 (21.0%) were positive with both ear canal flushing and mouth swabbing methods, and 1 (5.3%) was positive by the mouth swabbing method. Mycoplasma arginini, M. mycoides subsp. mycoides, and M. mycoides subsp. capri were identified by direct immunofluorescence and growth inhibition tests. Previous reports on the isolation of M. arginini from the ear canal of goats were not found in the literature.

Animals↗
PubMed1981

An evaluation of tympanometric estimates of ear canal volume.

The accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based: (a) ear canal volume does not change when ear canal pressure is varied, and (b) an ear canal pressure of 200 daPa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 daPa can be attributed to the ear canal volume alone. The first assumption was tested by measuring the changes in ear canal volume in eight normal subjects for ear canal pressures between +/- 400 daPa using a manometric procedure based on Boyle's gas law. The data did not support the first assumption. Ear canal volume changed by a mean of .113 ml over the +/- 400 daPa pressure range with slightly larger volume changes occurring for negative ear canal pressures than for positive ear canal pressures. Most of the volume change was attributed to movement of the probe and to movement of the cartilaginous walls of the ear canal. The second assumption was tested by comparing estimates of ear canal volume from susceptance tympanograms with a direct measurement of ear canal volume adjusted for changes in volume due to changes in ear canal pressure between +/- 400 daPa. These data failed to support the second assumption. All tympanometric estimates of ear canal volume were larger than the measured volumes. The largest error (39%) occurred for an ear canal pressure of 200 daPa at 220 Hz, whereas the smallest error (10%) occurred for an ear canal pressure of -400 daPa at 660 Hz. This latter susceptance value (-400 daPa at 660 Hz) divided by three is suggested to correct the 220-Hz tympanogram to the plane of the tympanic membrane. Finally, the effects of errors in estimating ear canal volume on static immittance and on tympanometry are discussed.

Acoustic Impedance Tests↗
PubMed1996

[Postmortem changes in ear canal resonance and tympanic membrane impedance in the human ear].

BACKGROUND: The human temporal bone preparation is a common model for research of physical processes of the ear canal and middle ear. In the past decade only a few reports were published discussing changes of the vibration behaviour of the tympanic membrane, as well as the ear canal resonance, during the time between death and preparation of the temporal bone. The aim of our study is to verify whether measurements at the temporal bone of dead humans can be really applied to the in vivo situation. METHODS: We investigated whether changes of the ear canal resonance and the vibration of the tympanic membrane depend on temperature and time after death. In a female human body we defined the resonance of the outer ear and the impedance of the tympanic membrane using a tympanometer and a real ear measurement system during nine hours post mortem. RESULTS: We were able to prove that before the preparation of the temporal bone none of the parameters changed significantly. CONCLUSIONS: In conclusion, the method of preserving the bone after its preparation is decisive for the validity of measurements at the isolated (post mortem) human temporal bone.

Acoustic Impedance Tests↗
PubMedDate not supplied

Pulse volume recordings in outer ear canal in pulse synchronous tinnitus. A comparison between ears with Glomus tumour, serous otitis media, and normal ears.

With the aid of a volume flowmeter it is possible to record pulse synchromous volumetric changes in the outer ear canal. In 7 ears with glomus tumour in the tympanic cavity and in 5 with serous otitis media, such changes were larger than in 125 persons with a normal middle ear. By changing the ambient pressure in a pressure chamber and instructing the patients not to swallow, the drum can be pushed inward or outward. In all the cases of glomus tumour studied the pulse volumetric change was considerably affected when the drum was pushed inward or outward. In the normal patients the change was no change at all. This means that the pulse volume changes in normals are generated mainly by the vessels in the outer ear canal.

Adolescent↗
PubMed2005

Bilateral ear canal neoplasia in three dogs.

Bilateral ear canal infections are common in dogs. Ear canal neoplasia is usually associated with unilateral problems, and is uncommon in dogs. To the best of the author's knowledge, bilateral aural neoplasia has not been reported in dogs, and only four case reports were found in the human literature. This report presents three dogs that had bilateral tumours in their ear canals. They were presented with bilateral otitis externa. All three dogs exhibited tissue proliferation of both ear canals that did not respond to glucocorticoids. Treatment consisted of total ear canal ablation, and tissues were submitted for histopathological evaluation. Case # 1 (a 10-year-old, male cocker spaniel) was diagnosed as ceruminious gland carcinoma. Cases # 2 and 3 were diagnosed as squamous cell carcinoma. Case # 1 was diagnosed 4 years earlier as having keratinization disorder, which was causing its chronic ear problems. Case # 2 (a 5-year-old, female French bulldog) was diagnosed 4 years earlier as having atopic dermatitis, which did not respond to hyposensitization, and only partially responded to glucocorticoids therapy. Case # 3 (a 9-year-old, male German shepherd) was diagnosed by the referring veterinarian as having unilateral ear canal proliferation 2 months prior to presentation. However, otoscopic examination showed bilateral proliferation that obstructed both canals. In summary, bilateral ear canal neoplasia should be considered in cases of nonresponsive, proliferative aural pathology.

Animals↗
PubMed1998

Comparison between intensity and pressure as measures of sound level in the ear canal.

In-the-ear calibration of sound pressure level may be problematic at frequencies above 2 kHz, because the pressure can vary significantly along the length of the ear canal, due to reflection of sound waves at the eardrum. This issue has been investigated by measuring behavioral thresholds to tones in a group of human subjects (N = 61) for two different insertion depths of an insert earphone. The change in insertion depth was intended to alter the distribution of pressure in the ear canal, shifting the frequency at which spectral notches occur. The inset earphone or "probe" (Etymotic ER-10C) also contained a calibrated microphone, allowing the recording of sound pressure levels in the ear canal. Prior to the threshold measurements in each subject, the Thevenin acoustic source characteristics of the probe were determined by a special calibration procedure. This calibration allowed the expression of the sound level at threshold in terms of acoustic intensity (W/m2). The impact of changes in insertion depth was determined by measuring behavioral threshold at each depth. Because cochlear sensitivity remained constant, the level of sound entering the ear at threshold should have been the same (within measurement error) for both insertions. The difference in sound pressure level (SPL) at threshold between the two probe insertions was greatest at the notch frequency of the first insertion. At this notch frequency, the SPL at threshold increased by an average of 11.4 dB. The change in sound intensity level (SIL) at threshold was almost always less than the change in SPL. At the notch frequency, the SIL decreased, on average, by only 0.5 dB. These results suggest that SIL may be a better indicator than SPL of the sound level entering the ear, especially for frequencies in the 4-8 kHz range.

Auditory Perception↗
PubMed1996

Comparison of probe insertion methods on estimates of ear canal SPL.

Real-ear sound pressure levels (SPLs) were compared among three methods used for positioning a probe microphone in the ear canal. The probe insertion techniques included (1) an acoustic method that incorporates use of the quarter-wave anti-resonance property of the ear to determine acoustically the location of the probe tube relative to the eardrum; (2) a constant insertion depth method (25 mm from the intratragal notch); and (3) the earmold +5-mm method, which places the probe 5 mm beyond the tip of the earmold, thereby avoiding problems associated with the transition region where sound exits from the bore of the earmold into the larger ear canal. Measurements were obtained at 32 test frequencies in 24 adults with normal middle ear impedance. Results indicated that the SPLs measured by the acoustic method were modestly higher than those measured by the other two methods. This result was most evident in subjects with long ear canals (> 25 mm) and at high test frequencies (3.0 to 6.3 kHz).

Amplifiers, Electronic↗
PubMed2001

Para-aural abscessation following traumatic ear canal separation in a dog.

Traumatic ear canal separation is rare in animals, with only eight dogs and one cat reported with the condition in the English language literature. Para-aural abscessation occurred in six of these nine animals. Diagnosis was made on otoscopic observation of a shortened, abruptly ending external ear canal that was free from advanced disease. Radiographs in those cases which have been described showed a disruption of the normal air opacity of the affected ear canal. Drainage, by creating a separate opening for the horizontal ear canal, or total ear canal ablation and lateral bulla osteotomy (TECA/LBO), have led to resolution of the clinical signs. This report adds a further case to the literature in which TECA/LBO was employed successfully.

Abscess↗
PubMed1997

CT appearances of external ear canal cholesteatoma.

External ear canal cholesteatoma (EECC) is rare in ear, nose and throat (ENT) practice. Two cases, one bilateral, are described. Computed tomography demonstrates the extent of bony involvement. Erosion of the external canal should not be overlooked when reviewing CT of the petrous bone in cases of discharge from the ear. EECC may necessitate surgery and delay in the diagnosis of EECC can result in progressive bony destruction.

Adult↗
PubMed1989

[Effect of radiation on the fungal flora of the external ear canal].

A mycological study of external ear canals was performed in 40 patients with head and neck cancer to observe the radiation effect on the fungal flora in external ear canals. The control group consisted of 30 non-cancer patients. The findings were: 1. More Candida sp. and Aspergillus sp. were noted in cancer patients than control group and C. albicans were also found, which didn't exist in normal persons. 2. There were opportunistic fungal flora, Candida sp. and Aspergillus sp., in at least one side of external ear canals in 32.5% of the post-irradiated patients who had aseptic external ear canals before the radiation therapy. The reasons we inferred that the patients with head and neck cancer during the radiation therapy were predisposed to otitis externa, in addition to radiation injury to the canal skin, were: 1. The different fungal flora in external ear canals of patients with head and neck cancer before the radiation therapy. 2. The changes of fungal flora after the radiation therapy.

Adult↗
PubMedDate not supplied

Bacteria in the middle ear and ear canal of patients with secretory otitis media and with non-inflamed ears.

Aerobic and anaerobic semiquantitative bacteriological cultures were taken from 110 mucoid middle ear effusions and the respective ear canals of 74 patients with secretory otitis media (SOM). Additionally, mucosal pieces from 20 non-inflamed middle ears and swabs from the ear canals were cultured similarly. Bacteria were found in 35 effusions and 65 ear canals with SOM; in both sites the most frequent species were S. epidermidis and S. aureus, and the species distributions were not significantly different in the sites. Ten effusions grew bacteria not culturable in the respective ear canal samples. Anaerobes were found in one effusion only. Nine non-inflamed middle ears revealed bacteria; the species distribution was no different from SOM, and four of the bacteria were not found in the ear canal of the same ear. In conclusion, there may be bacteria in the middle ear in the absence of inflammation and in SOM, but the role of viable bacteria seems to be nil in an established secretory otitis media.

Adolescent↗
PubMedDate not supplied

[Ear canal narrowing: a case report].

BACKGROUND: ear canal narrowing is the thinning or closing of the ear canal. This can damage the sound transmition from the external to the internal ear, which in turn may cause a false hearing loss. AIM: to alert the professionals of the area on how to avoid a miss diagnosis. METHOD: a 47 year old woman, submitted to two audiologic evaluations: one without avoiding ear canal closing and one avoiding it. RESULTS: a decrease of up to 40 dB was observed in the results of the second evaluation. CONCLUSION: in order to obtain reliable results it is extremely important to verify the presence of ear canal narrowing, at any age, and to use appropriate procedures to avoid it from happening during testing.

Audiometry↗