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At least 253 records · Page 14Linked to original sources
PubMed2005

Effective treatment of experimental acute otitis media by application of volatile fluids into the ear canal.

Essential oils are volatile and can have good antimicrobial activity. We compared the effects of oil of basil (Ocimum basilicum) and essential oil components (thymol, carvacrol, and salicylaldehyde) to those of a placebo when placed in the ear canal of rats with experimental acute otitis media caused by pneumococci or Haemophilus influenzae. Progress was monitored by otomicroscopic examination and middle ear cultures. The treatment with oil of basil or essential oil components cured or healed 56%-81% of rats infected with H. influenzae and 6%-75% of rats infected with pneumococci, compared with 5.6%-6% of rats in the placebo group. Essential oils or their components placed in the ear canal can provide effective treatment of acute otitis media.

Acute Disease↗
PubMed1999

[Extracranial meningioma presenting as a polyp of the outer ear canal].

Meningiomas are the most frequent benign intracranial tumor. Up to 20% of these neoplasms may eventually extend beyond the skull, particularly when tumor spread affects the temporal bone. We report a clinicopathological observation of an extracranial meningothelial meningioma that was diagnosed morphologically using immunohistochemical techniques. The tumor presented as polyp in the ear canal of a 70-year-old woman who had a history of ear disease and seizures and was under medical treatment. The growth was associated with a right temporal lobe tumor involving the petrosal bone that had been detected 6 years earlier on computed axial tomography.

Aged↗
PubMed2006

Middle ear cavity and ear canal pressure-driven stapes velocity responses in human cadaveric temporal bones.

Drive pressure to stapes velocity (V(st)) transfer function measurements are collected and compared for human cadaveric temporal bones with the drive pressure alternately on the ear canal (EC) and middle ear cavity (MEC) sides of the tympanic membrane (TM), in order to predict the performance of proposed middle-ear implantable acoustic hearing aids, as well as provide additional data for examining human middle ear mechanics. The chief finding is that, in terms of the V(st) response, MEC stimulation performs at least as well as EC stimulation below 8 kHz, provided that the EC is unplugged. Plugging the EC causes a reduced response for MEC drive below 2 kHz, due to a corresponding reduction of the pressure difference between the two sides of the TM. Between 8 and 11 kHz, the MEC drive transfer functions feature an approximately 17 dB drop in magnitude below the EC drive case, the cause of which remains unknown. The EC drive transfer functions reported here feature significantly less magnitude roll-off above 1 kHz than previous studies [with a slope of -2.3 vs -6.7 dB/octave for Aibara et al., Hear. Res. 152, 100-109 (2001)], and significantly more phase group delay (134 vs 62 micros for Aibara et al.).

Artifacts↗
PubMed1992

Differential effects of ear-canal pressure and contralateral acoustic stimulation on evoked otoacoustic emissions in humans.

The effect of ear canal pressure variation (ECPV) on click evoked otoacoustic emissions (EOAEs) was compared to the suppressive effect observed with contralateral acoustic stimulation (CAS) in 11 healthy subjects. Both total EOAE amplitude and amplitude of 200 Hz frequency bands (22) were analyzed. Our results revealed that the ECPV as the CAS induced a decrease of the total EOAE amplitude; these two factors showed an additive effect when they are conjoint. The study of the EOAE frequency bands showed that the majority of them decreased under CAS and ECPV; however, a few bands are not affected. Moreover, it appeared that amplitude of the EOAE frequency bands were not modified in a similar way between the two factors: indeed some bands around 4.1 kHz did not decrease either by CAS or ECPV. These results suggest that these applied factors exert different actions on EOAEs. Moreover, the lack of a decrease effect for the same bands, both with CAS and ECPV, may explain the vulnerability of some cochlear locations.

Acoustic Stimulation↗
PubMed2005

Effect of tympanic cavity evacuation and flushing on microbial isolates during total ear canal ablation with lateral bulla osteotomy in dogs.

OBJECTIVE: To evaluate differences in bacterial numbers, identity, and susceptibility in samples obtained from the tympanic cavity on entry (preflush) and after evacuation and lavage (postflush) and assess perioperative and empiric antimicrobial selection in dogs that underwent total ear canal ablation (TECA) with lateral bulla osteotomy (LBO) or reoperation LBO. DESIGN: Prospective clinical study. ANIMALS: 34 dogs. PROCEDURE: TECA with LBO or reoperation LBO was performed on 47 ears. Pre- and postflush aerobic and anaerobic samples were obtained from the tympanic cavity. Isolates and antimicrobial susceptibility patterns were compared. RESULTS: Different isolates (31/44 [70%] ears) and susceptibility patterns of isolate pairs (6/44 [14%] ears) were detected in pre- and postflush samples from 84% of ears. Evacuation and lavage of the tympanic cavity decreased the number of bacterial isolates by 33%. In 26% of ears, bacteria were isolated from post-flush samples but not preflush samples. Only 26% of isolates tested were susceptible to cefazolin. At least 1 isolate from 53% of dogs that received empirically chosen antimicrobials postoperatively was resistant to the selected drugs. Anaerobic bacteria were recovered from 6 ears. CONCLUSIONS AND CLINICAL RELEVANCE: Accurate microbiologic assessment of the tympanic cavity should be the basis for selection of antimicrobials in dogs undergoing TECA with LBO. Bacteria remain in the tympanic cavity after evacuation and lavage. Cefazolin was a poor choice for dogs that underwent TECA with LBO, as judged on the basis of culture and susceptibility testing results.

Animals↗
PubMed1985

An ultrastructural study of the skin of the tympanic membrane and external ear canal of the guinea pig.

The ultrastructure of the skin covering the tympanic membrane and external ear canal has been studied in eight guinea pigs, to identify any features which could be related to the rapid movement of the epidermal surface at this site. Migratory epidermis showed evidence of reduced intercellular adhesion in the deeper layers and reduced differentiation in all layers. Differentiation was more evident in cell ridges found at the junctional zone between migratory and non-migratory skin. The findings agree with those of previous authors, and indicate that migration is most likely to occur within the deeper layers of the epidermis.

Animals↗
PubMedDate not supplied

Influence of ear canal air pressure on acoustic reflex threshold.

This study was undertaken to investigate the effects of ear canal air pressure variation on the threshold of acoustic reflex. The acoustic reflex threshold was obtained to 500 and 1000 Hz activating signals as pressure was varied between +/- 200 mm H2O. The results demonstrated a reduction in sensitivity of the acoustic reflex with variations in positive or negative air pressure. Observation of the conductance component of admittance consistently required higher intensity levels to elicit the acoustic reflex. Clinical implications are that external air pressure can vary within a range of +/- 80 mm H2O and continue to maintain the acoustic reflex threshold close to its value obtained at maximum compliance.

Adult↗
PubMed2005

Effect of ear canal occlusion on pure-tone threshold sensitivity.

This study sought to quantify the effects of varying the degree of ear canal occlusion on pure-tone threshold sensitivity. Thresholds were obtained from each ear of five normal-hearing adults without occlusion, with complete occlusion, and with partial occlusion estimated to be 40-60% and 60-80%. A commercial lubricant was used in the completely occluded condition to eliminate possible acoustic leakage. Results showed a reduction of threshold sensitivity in all occluded conditions, with the greatest effect in frequencies above 1000 Hz. Only in the completely occluded condition were frequencies below 1000 Hz affected. In the partially occluded conditions, thresholds decreased by an average 7.5 dB and 13.0 dB across frequency for the 40-60% and 60-80% conditions respectively. At frequencies above 1000 Hz, the average threshold shifts for the two partially occluded conditions were 10.0 dB and 16.8 dB respectively. The implications of these findings on routine pure-tone audiometric procedures, with specific relevance for industrial hearing conservation programs, are discussed.

Acoustic Stimulation↗
PubMedDate not supplied

[Exposure to low levels of solvents and noise, ear canal volume and audiometric pattern].

We described a case of a male worker, 62 years old, with a combined exposure to low noise levels (80-85 dB Leq,A) and organic solvents mixture for more than 30 years in the automobile industry as a painter. His ear canal has a diameter of more than 1.3 cm. and determine a peculiar pattern of hearing loss, similar to the noise induced one, but chiefly in the speech frequencies. According to experimental and human studies we speculate that in this patient the peculiar morphology of the audiogram, with the low or mean frequencies maximally affected, may been explained by a synergistic effect of solvents mixture in conjunction with noise exposure and a high ear canal volume.

Audiometry↗
PubMed1994

Eccrine cylindroma of the ear canal--report of a case.

Eccrine cylindroma is a benign tumour arising from sweat glands in the skin. It favours the face, forehead and scalp involving the turban area and hence is called a turban tumour. Amongst a variety of tumours originating from adnexal skin structures, which may appear in the ear canal, eccrine cylindroma forms a very rare entity. We present such a case and discuss its pathological and clinical features.

Adenoma↗
PubMed1995

[Surgery of cholesteatoma of the ear canal].

Aseptic necrosis and cholesteatoma of the external auditory canal can be stages of the same pathological entity. The majority of these patients suffered from symptoms similar to those of external otitis. It is suggested that minor mechanical trauma, e.g. cotton lip swabs, plays a role in the pathogenesis of external ear canal cholesteatoma. During the last 10 years we have been surgically treating 22 patients with diagnosis of aseptic necrosis and cholesteatoma of the bony external auditory canal. All 22 patients registered significant postoperative improvement.

Adult↗
PubMed1985

Nonlinear phenomena as observed in the ear canal and at the auditory nerve.

We report here several measures of nonlinear effects in the mammalian ear made in the external auditory meatus and in single neurons of the auditory nerve. We have measured the 2f1-f2 and the f2-f1 distortion products and we have found that the neural distortion product threshold curve for 2f1-f2 mirrors the low-frequency side of the frequency threshold curve, when the neural distortion product threshold curve of 2f1-f2 is plotted versus log(f2/f1) its slope is about 50 dB/oct and its intercept is 10-20 dB above the frequency threshold at the characteristic frequency CF, substantial 2f1-f2 distortion was seen in all animals studied while the f2-f1 distortion product was only rarely found at substantial levels, and the distortion product pressure observed in the ear canal was at a level equal to that detected at threshold by the neural units under study. We have also made measurements of two-tone rate suppression thresholds using two new and consistent threshold paradigms. We find that for high and intermediate characteristic frequency neural units the suppression threshold is independent of frequency and at a level of about 70 dB SPL, the suppression above CF is much less than below CF, and the tip of the frequency tuning curve can be suppressed by up to 40 dB by a low-frequency suppressor.

Animals↗
PubMed1992

[Incidence of "recurrences" following surgical removal of ear canal exostoses].

A clinical review of 55 patients, who underwent an operative removal of exostosis of the external ear canal during the last 10 years, brought us to two main conclusions. While there are no true recurrences, it is possible in cases of continuous exposure to cold water that in regions which were not touched by the first operations new exostosis will occur. The drilling and sucking noise during the operative procedure might cause an inner ear damage, as the sound transmission is unimpeded. Intraoperative protective measures are recommended.

Adolescent↗