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At least 109 records · Page 6Linked to original sources
PubMed2005

Effects of age and size in the ears of gekkonomorph lizards: middle-ear morphology with evolutionary implications.

The function of the ear depends in part on its absolute size and internal proportions. Thus, in both young individuals and small species, the middle ear is expected to be allometrically enlarged despite its smaller absolute size. Here we aim to compare the ontogenetic allometry of relevant middle-ear structures as observed within gecko (gekkonomorph lizards) species, with the evolutionary allometry observed interspecifically. These observations also provide middle-ear data for future evaluation of variation in auditory sensitivity. The material comprised 84 museum specimens of geckos, representing nine species of three gekkonomorph subfamilies. The results of dissections and measurements show that different reports notwithstanding, the middle-ear ossicular chain is indeed structured as described for geckos by Werner and Wever. Some sexual dimorphism is indicated, but this requires further study. During postnatal ontogeny, the allometric growth in the ratio of the columellar footplate area to body length differed between the intraspecific and interspecific levels, hence species differences in the middle ear do not merely result from animal size. The ratio of the tympanic membrane area to the columellar footplate area increased during ontogeny. In this, geckos resemble birds and probably also mammals. Similarly, when the comparison was among adults representing different species, the ratio of the tympanic membrane area to the columellar footplate area increased with body size. In this, however, the geckos differed from birds and mammals, in which this ratio varied taxonomically, irrespective of body size. It would thus seem that middle-ear proportions have evolved among geckos to produce small interspecific differences, but among amniote tetrapods they have evolved according to different principles in the classes reptiles, birds, and mammals.

Aging↗
PubMed2001

Intralaboratory validation of alternative endpoints in the murine local lymph node assay for the identification of contact allergic potential: primary ear skin irritation and ear-draining lymph node hyperplasia induced by topical chemicals.

We validated a two-tiered murine local lymph node assay (LLNA) with a panel of standard contact (photo)allergens and (photo)irritants with the aim of improving the discrimination between contact (photo) allergenic potential and true skin (photo)irritation potential. We determined ear weights to correlate chemical-induced skin irritation with the ear-draining lymph node (LN) activation potential. During tier I LLNAs, a wide range of concentrations were applied on three consecutive days to the dorsum of both ears. Mice were exposed to UVA light immediately after topical application to determine the photoreactive potential of some test chemicals. Mice were killed 24 h after the last application to determine ear and LN weights and LN cell counts. It was possible to classify the tested chemicals into three groups according to their threshold concentrations for LN activation and skin irritation: (1) chemicals with a low LN activation potential and no or very low skin irritation potential; (2) chemicals with a marked LN activation potential higher than a distinct skin irritation potential; and (3) chemicals with LN activation potential equal to or lower than their skin irritation potential. Group 1 consisted only of contact allergens, indicating that LN activation in the absence of skin irritation points to a contact allergenic activity. Since groups 2 and 3 comprised irritants and contact allergens, a tier II LLNA protocol was used to finally differentiate between true irritants and contact allergens. Briefly, mice were pretreated with mildly to moderately irritating concentrations of the chemical to the shaved back and after 12 days were challenged on the ears as described above in order to elicit a contact allergenic response in the ear skin and the ear-draining LN. With this approach, tier II LLNAs have to be conducted only in cases for which skin irritation potential is in the range of LN activation potential and no structure-activity relationship data indicating a contact allergenic hazard are available.

Administration, Topical↗
PubMed2003

Molding the ears after anterior scoring and concha repositioning: a combined approach for protruding ear correction.

The goal of otoplasty for correction of prominent ears is normalization of shape and position of both pinnas with a certain symmetry. Recreating the antihelical fold and lowering the auriculocephalic angle are the basic processes for achieving a normal-looking ear. Various methods have been described to recreate the antihelical fold. In addition to anterior scoring or abrasion, many involve placement of permanent or absorbable sutures to reform the cartilage to proper shape to correct the deformity. In this study the use of a custom-made silicone mold was described after anterior scoring to recreate the antihelical fold, without using any suture material. Silicone molds provide good shaping of the antihelical fold, scapha, and helical rim while the tissue is healing. Fourteen patients underwent bilateral otoplasty for prominent ears in our clinic over a four-year period. The anthelical fold was created by anterior scoring and the concha-mastoid angle lowered and sutured. After completing the surgical procedure for both ears, custom-made silicone molds were worn by the patient for the first two weeks to maintain proper position. The third week, the patient wore the mold half a day. A head dressing was used for two days and the ears were subsequently supported using a headband. Follow-up ranged from fourteen months to four years. One patient developed a postoperative hematoma in one ear that resorbed spontaneously. Patient satisfaction with the procedure was generally high. Using a shape mold after a combination of anterior scoring and concha repositioning gives predictable results with a natural-looking ear.

Adolescent↗
PubMed2005

Effect of the status after ear surgery and ear pathology on the results of infrared tympanic thermometry.

Most publications that deal with infrared tympanic thermometry (ITT) have performed a comparison between the established temperature measurements and ITT. However, to date an understanding of the influence of pathological ear findings on ITT test results is incomplete. Therefore, in the present study ITT was performed in healthy adults (n =21), adult patients with monaural central perforation (n =31) or strong scar formations (n =24) of the tympanic membrane and 18 adult patients after monaural canal wall down surgery. Right and left ear and oral temperature were measured three times by one investigator in a room with a constant temperature of 20-22 degrees C. Between every measurement there was a free time interval of 2 min. In healthy adults (36.50 degrees C vs. 36.51 degrees C) patients with monaural central perforation of the tympanic membrane (36.41 degrees C vs. 36.34 degrees C) and with monaural strong scar formations in the tympanic membrane (36.39 degrees C vs. 36.45 degrees C), no significant difference between the right and left ear could be proved. In contrast to this, a significantly higher temperature in the surgically treated ear compared to the healthy side (36.97 degrees C vs. 36.31 degrees C; P <0.001) occurred in patients with a status of after monaural canal wall down surgery. In summary, it could be demonstrated that, in contrast to minor ear surgery, major ear surgery such as canal wall down has a significant influence on the results of ITT. If a patient's history gives reference to previous ear surgery, an otoscopic examination is necessary in order to exclude the presence of an after-canal-wall-down surgery status and thus to avoid false ITT test results.

Adult↗
PubMed1999

Gustatory otalgia and wet ear syndrome: a possible cross-innervation after ear surgery.

HYPOTHESIS: The chorda tympani and Arnold's nerves have close approximation to each other and their cross-innervation is possible after ear surgery. STUDY DESIGN: A retrospective study was performed with a temporal bone pathology case and two clinical cases as representatives of such a possibility. Patients had severe otalgia and wet ear during gustatory stimulation. METHODS: A temporal bone pathology case was studied under a light microscope. Earache and/or wet ear were provoked during gustatory stimulation. Wet ear was tested with iodine-starch reaction after the subject tasted lemon juice. RESULTS: The temporal bone specimen has clusters of regenerated fibers in the tympanic cavity in the area of the chorda tympani and Arnold's nerves, suggesting a possibility of mixing. There are regenerated fibers in the iter chordae anterius, showing successful bridging of the chorda tympani nerves across a long gap. Detachment of the skin over the operated mastoid bowl obscured signs in one clinical case. Another clinical case of gustatory wet ear showed objective evidence of cross-innervation with iodine-starch reaction. CONCLUSION: The detachment procedure and iodine-starch reaction were the proofs that the signs were related to regenerated fibers. This is the first report of gustatory otalgia and wet ear after ear surgery.

Adult↗
PubMed1997

Induction of an inner-ear-specific autoreactive T-cell line for the diagnostic evaluation of an autoimmune disease of the inner ear.

Different patterns of sensorineural hearing loss with a potential improvement in auditory function following immunosuppressive therapy might be caused by an isolated autoimmune disease of the inner ear. Because of the lack of well-defined detection methods to identify autoimmune processes within the inner ear and the fact that the human inner ear is one of the few organs of the body not amenable to diagnostic biopsy, there has been great interest in developing animal models. Previous studies found evidence that this entity might be cellular mediated. By heterologeous immunization of inbred Lewis rats with inner-ear tissue, an autoreactive inner-ear-specific T-cell line was established. After passive transfer of these cells, a labyrinthitis was induced in recipient animals. The experimental design can serve as an animal model for a cellular-mediated autoimmune disease of the inner ear. Further studies have to split the cochlear proteins and to identify the protein with the strongest autoimmunological potency. After biotechnical production of this protein, a clinical test to diagnose an autoimmune disease of the inner ear in man should be possible.

Animals↗
PubMedDate not supplied

Probe-tube microphone measures in patients with open-mastoid surgery: real-ear-to-coupler differences and real-ear unaided responses.

Real-ear-to-coupler differences (RECDs) and real-ear unaided responses (REURs) were measured using a probe-tube microphone system in 15 patients who underwent open mastoid surgery. The results show that RECDs are significantly smaller at higher frequencies (1.5, 2.0, 3.0, 4.0 and 6.0 kHz) in mastoid ears. The intrasubject variability of RECDs measures in these patients is on average 2.6 dB larger than for controls. For REURs, mastoid surgery significantly reduced the mean peak resonant frequency without affecting the amplitude and bandwidth. In operated ears, mean resonant frequency is by a factor of 1.4 lower than that for normal ears. Reduced responses (negative gains) at frequencies above the resonance peak occurred in 7 out of the 15 patients. These reduced responses corresponded to the smaller RECD at the middle and high frequencies. The results support the need for individual RECD measures to be made in operated ears instead of using average values from normal subjects. Otherwise, real-ear measures of the aided response should be made for each patient with open-mastoid cavity and the fitting should be done in terms of the target response at the eardrum rather than by defining a target insertion gain.

Adolescent↗
PubMed1999

Vestibular responses of normal and hydropic ears of the guinea pig to middle ear pressure application.

The pressure in the middle ears of normal and hydropic guinea pig ears was increased, and nystagmographic recordings were compared. Two-month unilateral hydropic guinea pigs and normal control guinea pigs underwent pressure treatments in which pressure was introduced into the middle ear. Significantly lower pressure was needed to elicit nystagmus in hydropic ears (mean 1.00 psi or 70.3 cm H2O) compared with normal control ears (mean 1.27 psi or 89.3 cm H2O). All of the normal control guinea pigs showed fast phase nystagmus toward the pressure-applied side, while hydropic guinea pigs showed nystagmus toward the normal ear. The duration of nystagmus was slightly longer in hydropic animals than in normal control animals. The slow phase velocity was slightly higher in the hydropic guinea pigs. Histologic examination revealed that the vestibular sensory cells remained normal and that changes in the organ of Corti were similar between the hydropic ears with and without pressure treatment at equal survival times.

Animals↗
PubMed2000

Long-term middle-ear effects of middle-ear/eustachian tube packing after translabyrinthine surgery.

The purpose of this study was to evaluate the long-term effect on middle ear and eustachian tube function following the packing of the middle-ear space to prevent cerebrospinal fluid rhinorrhoea at the termination of translabyrinthine vestibular schwannoma removal. This was an observational study of a sample of 14 patients examined between two and five years post-operatively. Photo-otoscopy and tympanometry were performed bilaterally to evaluate appearance and function. All operated middle ears were air-containing although eight out of 14 showed scarring as evidence of operative intervention. There were no drum retractions. Ten out of 14 middle-ear compliance peaks were lower in the operated ear with four flat traces. Two out of 14 were the same and two out of 14 showed high compliance. The middle-ear pressure was always within the normal range when determinable. This technique appears to have no detrimental effects on the middle ear and does not permanently obliterate the eustachian tube. The reduced compliance in the majority of cases is probably a result of scarring and fibrosis. When drum hypermobility is seen this is accounted for by incus removal.

Acoustic Impedance Tests↗
PubMed1981

Negative middle ear pressure induced by sniffing. A tympanometric study in persons with healthy ears.

In routine clinical tympanometry the finding of negative middle ear pressure is not uncommon. The traditional explanation of the negative pressure is that passive gas resorption takes place when the Eustachian tube is blocked. However, recent investigations in patients with middle ear disease have shown that a high negative intratympanic pressure can be actively induced by sniffing. In the present study 100 subjects with healthy ears were investigated by tympanometry in order to evaluate their ability to evacuate the middle ear by sniffing. Fourteen per cent were able to evacuate the middle ear to stable negative pressures ranging from -1.0 to -3.5 kPa, mean value -1.9 kPa (1 kPa corresponds approximately to 100 mm water). The present findings indicate that a sniff-induced negative pressure is not pathological per se. A temporary negative middle ear pressure induced by sniffing can explain the presence of a type C tympanogram in patients with healthy ears. This findings also emphasizes the difficulty in determining the borderline between normal and pathological tympanograms.

Acoustic Impedance Tests↗
PubMed1986

The use of acoustical test fixtures for the measurement of hearing protector attenuation. Part II: Modeling the external ear, simulating bone conduction, and comparing test fixture and real-ear data.

This paper investigates two main features of the human head which influence the measured attenuation of circumaural and intraaural hearing protection devices (HPDs): the external ear and the different pathways of bone conduction. A theoretical model for the external ear shows that its influence on the insertion loss of HPDs, on the sensitivity level of headphones or earphones, and on the insertion gain of hearing aids, all can be described by one equation. While it is not necessary to simulate the eardrum impedance in order to measure the insertion loss of earmuffs and the sensitivity level of headphones with acoustical test fixtures (ATFs), the required accuracy of an ear simulator is more stringent when the same measurements are performed on intraaural devices. For the evaluation of HPDs, bone conduction plays an important role. We have developed a model to estimate HPD-dependent bone conduction effects. The model includes two bone conduction sources: one in the external ear and one in the middle ear. The model explains, for example, the occlusion effect of HPDs and the masking error at low frequencies due to physiological noise that arises when real-ear attenuation at threshold (REAT) measurements are made. Consequently, objectively measured insertion loss can now be used to predict REAT with improved accuracy. ATF and REAT data are compared using nine earmuffs and nine earplugs. In the majority of cases, the two sets of data agree well. Discrepancies are discussed.

Auditory Threshold↗
PubMed1976

Symposium: Congenital anomalies of the middle ear. III. Congenital anomalies of the middle ear.

Congenital anomalies of the middle ear have been considered rare. The tremendous volume of middle ear surgery performed during the last 15 years has brought attention to numerous anomalies of the facial nerve, ossicles, and middle ear cleft, suggesting that middle ear anomalies are not as rare as once believed. This paper discusses anomalies of the descending and horizontal facial nerve which have been previously reported. The literature of anomalies of the ossicles is reviewed. A very rare anomaly of the carotid artery presenting in the middle ear is described and its surgical treatment outlined. Two anomalies of the middle ear associated with other branchial arch anomalies are reported and their treatment results discussed.

Adolescent↗
PubMed1997

[Active electronic cochlear implants for middle and inner ear hearing loss--a new era in ear surgery. I: Basic principles and recommendations on nomenclature].

Hearing aids have fundamental disadvantages: (1) stigmatization of the patient; (2) the sound is often found to be unsatisfactory due to the limited frequency range and undesired distortion; (3) in many patients, the ear canal fitting device generally necessary leads to an occlusion effect; (4) acoustic feedback when amplification is high. Conventional hearing aids transmit sound into the ear canal via a small microphone. Sound has the disadvantage of requiring high output sound pressure levels for its transmission. This along with the necessary miniaturization of the loudspeaker as well as the resonances and reflections in the closed ear canal contribute to the disadvantages mentioned. In contrast, implantable hearing aids do not make sound signals but micromechanical vibrations. An implantable hearing aid has an electromechanical transducer instead of the loudspeaker of a conventional hearing aid. The hearing signal does not leave the transducer as sound but as a mechanical vibration which is directly coupled to the auditory system bypassing the air. This implantable hearing aid is either coupled to the tympanic membrane, the ossicular chain, the perilymph of the inner ear, or the skull. An implantable hearing aid is expected to have: 1 Better sound fidelity than a hearing aid 2 No ear canal fitting device, free ear canal 3 No feedback 4 Invisibility Requirements on electronic hearing implants designed for patients with conductive hearing loss differ from those on implants for sensorineural hearing loss. Conductive hearing loss requires the implant to replace the impedance transformation, thus being an impedance transformation implant (ITI). In various respects, the demands on an ITI are lower than the demands on an electronic hearing aid for patients with sensorineural hearing loss. The latter are mostly patients with a failure of the cochlea amplifier (CA). A damage to the CA is clinically discernible by a positive recruitment and loss of otoacoustic emissions (OAE). Since these patients form the majority of cases with sensorineural hearing loss, an active hearing implant for such patients should partially replace the function of the CA. Therefore, the suggestion is to refer to a CAI (cochlea amplifier implant). The implant expressions ITI (for patients with conductive hearing loss) and CAI (for patients with sensorineural hearing loss) used in this context allow nomenclatural association with the CI (cochlear implant) for complete inner ear failure as well as with the BSI (brainstem implant) in the case of hearing nerve failure.

Cochlear Implants↗
PubMed2004

Within-ear and across-ear interference in a dichotic cocktail party listening task: effects of masker uncertainty.

Increases in masker variability have been shown to increase the effects of informational masking in non-speech listening tasks, but relatively little is known about the influence that masker uncertainty has on the informational components of speech-on-speech masking. In this experiment, listeners were asked to extract information from a target phrase that was presented in their right ear while ignoring masking phrases that were presented in the same ear as the target phrase and in the ear opposite the target phrase. The level of masker uncertainty was varied by holding constant or "freezing" the talkers speaking the masking phrases, the semantic content used in the masking phrases, or both the talkers and the semantic content in the masking phrases within each block of 120 trials. The results showed that freezing the semantic content of the masking phrase in the target ear was the only reduction in masker uncertainty that ever resulted in a significant improvement in performance. Providing feedback after each trial improved performance overall, but did not prevent the listeners from making incorrect responses that matched the content of the frozen target-ear masking phrase. However, removing the target-ear contents corresponding to the masking phrase from the response set resulted in a dramatic improvement in performance. This suggests that the listeners were generally able to understand both of the phrases presented to the target ear, and that their incorrect responses in the task were almost entirely a result of their inability to determine which words were spoken by the target talker.

Adult↗
PubMed1992

Transcriptional regulation of human apolipoprotein genes ApoB, ApoCIII, and ApoAII by members of the steroid hormone receptor superfamily HNF-4, ARP-1, EAR-2, and EAR-3.

Apolipoproteins B, CIII, and AII are synthesized primarily in the liver and intestine and play an important role in lipid and cholesterol metabolism. It was previously shown that the cis-acting elements (BA1 (-79 to -63), CIIIB (-87 to -63), and AIIJ (-740 to -719) present in the regulatory regions of the human apoB, apoCIII, and apoAII genes, respectively, are recognized by common transcription factors present in hepatic nuclear extracts. This report shows that four members of the steroid receptor superfamily, ARP-1, EAR-2, EAR-3, and HNF-4, bind specifically to the regulatory elements BA1, CIIIB, and AIIJ. Dissociation constant measurements showed that ARP-1, EAR-2, and HNF-4 bind to elements BA1 and CIIIB with similar affinities (Kd 1-3 nM). Cotransfection experiments in HepG2 cells revealed that ARP-1, EAR-2, and EAR-3 repressed the BA1, CIIIB, and AIIJ element-dependent transcription of the reporter gene constructs and the transcription driven by homopolymeric promoters containing either five BA1 or two CIIIB elements. In contrast, HNF-4 activated transcription of reporter genes containing the elements BA1, CIIIB, and AIIJ and reversed the ARP-1-mediated repression of the apoB and apoCIII genes. These results suggested that the opposing transcription effects observed between HNF-4 and ARP-1 may be due to competition for binding to the same regulatory element. Mutations which affected the binding of HNF-4 to elements BA1 and CIIIB affected its ability to activate transcription of the apoB and apoCIII reporter genes, respectively. Transcriptional activation by HNF-4 depended on the presence of elements II (-112 to -94) and III (-86 to -62) of the apoB and H (-705 to -690), I (-766 to -726), and J (-792 to -779) of the apoCIII promoters, indicating that transcriptional activation of apoB and apoCIII genes by HNF-4 requires the synergistic interaction of factors binding to these elements. The finding that HNF-4, ARP-1, EAR-2 and EAR-3 can regulate the expression of the apoB, apoCIII, and apoAII genes suggest that these nuclear hormone receptors may be an important part of the signal transduction pathways modulating lipid metabolism and cholesterol homeostasis.

Animals↗
PubMed1990

Hyogo ear bank experience with allograft tympanoplasty--review of tympanoplasties on 68 ears.

Allograft tympanoplasties on 68 ears done between October, 1980 and December, 1986 were analyzed from the viewpoint of graft take rate and hearing improvement, and also the results were compared between draining and nondraining ears as well as among three stabilizing methods of the transplanted tympanic membrane (Type I: allograft tympanic membrane (ATM) covered with reflected epithelium; Type II: entirely covered ATM with fascia; and Type III: ATM reinforced with thin crescent fascia) and four groups of allograft materials (Group I: ATM with attached malleus and incus en bloc; Group II: ATM with attached malleus; Group III: ATM attached malleus and incus columella; and Group IV: two stage surgery with Group III material). Among the three types of stabilization in draining ears, the anatomic success rate of the tympanic membrane transplant was 27% in Type I, 56% in Type II and 90% in Type III, while in nondraining ears it was 81%, 88%, and 100%, respectively. The success rate for hearing improvement in draining ears was 40% in Group A, 44% in Group B, 33% in Group C, and in nondraining ears, it was 82%, 100%, and 82%, respectively. Our results show that allograft tympanoplasty can be successful for a well-controlled middle ear with good utility of the areolar fascia in stabilization.

Graft Survival↗
PubMed2006

Morphometric study of the external and middle ear anatomy in sheep: a possible model for ear experiments.

Sheep are a potentially useful model for otologic surgical training and experimentation, currently limited by the scarcity of morphological comparisons between the structure of the ear in sheep and in humans. A detailed morphometric study of the ear in sheep was carried out using computed tomography. Measurements made with AutoCAD Release 14 were compared with measurements for the human ear reported in the literature. In general, ear structures in sheep are two-thirds the size of those in humans. The important anatomical similarities found in this study between the ear in sheep and in humans suggest that sheep may be a useful model for surgical training and experimentation in some middle ear procedures.

Animals↗
PubMed2000

[Inner ear depression after middle ear interventions].

BACKGROUND: Any type of otosurgical procedure involves the risk of inner ear damage. As middle ear surgery is also performed for functional reasons this risk should be taken into consideration. The aim of this study was to analyse the frequency and the nature of sensorineural hearing loss following chronic ear surgery. PATIENTS: A total of 3989 middle ear cases operated on between 1991 and February 1999 at the Department of Otorhinolaryngology, Head and Neck Surgery, University of Würzburg, Germany were studied retrospectively: 781 type I tympanoplasties, 2408 type III tympanoplasties and 800 cases of stapes surgery. The pre- and the postoperative audiograms in the frequency range between 500 and 8000 Hz were analysed and correlated to the different intraoperative findings. RESULTS: Sensorineural hearing loss occurred in a total of 1.3% of 2224 patients with normal preoperative bone conduction thresholds: 0.2% became deaf, 0.8% acquired a high tone loss at 4 kHz and in 0.3% patients also 2 kHz was affected. None of the documented intraoperative complications such as bleeding, unexpected opening of a semicircular canal, extensive manipulation at the ossicular chain or a gusher phenoma showed a relevant effect on postoperative bone conduction thresholds. The incidence of high tone loss was not increased in cases of extensive drilling of the temporal bone. An unexpected opening of the vestibulum led to a small, but statistically significant change in postoperative bone conduction thresholds. CONCLUSIONS: Our results demonstrated that the risk for sensorineural hearing loss caused by middle ear surgery is low. None of the analysed factors seems to be a relevant prognostic risk factor for postoperative inner ear depression.

Adolescent↗