PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “EAR, MIDDLE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1999

Middle ear reconstructive techniques.

Middle ear reconstructive techniques have increased to such an extent that the otolaryngologist is faced with a bewildering number of surgical options. The literature, however, has yet to demonstrate any technique to be optimal in every surgical scenario. This is because of the lack of direct comparisons between techniques and dissimilar criteria for measuring success. This article uses hearing results and the ability to resist extrusion as the principle measures of success, and provides middle ear reconstructive techniques proven to be successful for commonly faced surgical dilemmas.

Ear, Middle↗
PubMed2005

Otoacoustic emissions at compensated middle ear pressure in children.

Middle ear pathology has a negative effect on the detectability of otoacoustic emissions. In this study, we investigated the effect of compensating a deviant static middle ear pressure while measuring transient evoked otoacoustic emissions (TEOAEs). In 59 children (mean age 4 years, 5 months) TEOAEs were measured twice in one session: first at ambient pressure and than at compensated middle ear pressure. On average, TEOAE amplitudes increased by 1.9 dB as a result of middle ear pressure compensation. The amplitude increase was largest in frequency bands centred at 1 and 2 kHz and a statistically significant correlation was found between the amount of compensated pressure and the TEOAE amplitude increase. In the higher frequency bands centred at 3 and 4 kHz, TEOAE amplitudes were almost insensitive to pressure compensation. These results show that measuring OAEs at compensated middle ear pressure enhances the amplitude of TEOAEs, and thus improves the detectability.

Acoustic Impedance Tests↗
PubMed1994

Primary poorly differentiated adenocarcinoma of the middle ear.

Adenocarcinoma of the middle ear is seldom encountered in clinical practice. In the past 20 years, nearly 20 cases of primary adenocarcinoma of the middle ear have been reported, and most cases of these tumors have been described without histologic presentation. To our knowledge, only one case of adenocarcinoma originating in the postoperative middle ear has been reported. We describe a case of primary poorly differentiated adenocarcinoma in the middle ear which was surgically treated for chronic otitis media 50 years ago. Planning diagnostic and therapeutic procedures in connection with middle ear tumors is also discussed.

Adenosarcoma↗
PubMed1992

T cell subsets in round window membrane after middle ear immunostimulation.

In secondary middle ear immune response, kinetics of immunocytes, especially T cell subsets, was examined in the round window membrane (RWM) using immunohistochemical methods. Healthy BALB/c mice and keyhole limpet hemocyanin (KLH) antigen were employed in this study. The inflammatory responses of the RWM and middle ear were investigated after antigen challenge into the middle ear bulla. We used antibodies against murine macrophages and granulocytes (anti-Mac-1), murine helper/inducer T cells (anti-Lyt-1 and -L3T4), murine suppressor/cytotoxic T cells (anti-Lyt-2), murine interleukin-2 receptor (7D4), murine immunoglobulins (anti-IgG, -IgM and -IgA) and KLH. In the RWM and middle ear mucosa, inflammatory cells were observed at 6 hours, peaking on days 3-7, whereas these cells were rarely seen in the scala tympani of the basal turn. Luminal effusion with an enormous infiltration of inflammatory cells, which consisted mainly of Mac-1 cells, IgG cells and IgM cells, was observed in the middle ear cavity on days 1-7 post antigen challenge. In the inflamed RWM, Mac-1 cells were the predominant cell type followed by helper T cells, interleukin 2 receptor positive cells and IgG positive cells, though IgM, IgA and Lyt-2 positive cells were rarely observed after antigen challenge. Our results suggest that RWM has the ability to protect inner ear by cellular immune response through activated helper T cells and Mac-1 cells.

Animals↗
PubMed2002

Effect of middle-ear effusion on otoacoustic emissions.

Because otoacoustic emissions (OAEs) are transmitted from the cochlea to the ear canal via the middle ear, the transmission properties of the middle ear directly influence OAEs' characteristics. In general, middle-ear effusion (MEE) reduces measured emission amplitudes and sometimes eliminates the response entirely. The purpose of this study was to establish the relationship between the conduction of the middle ear and OAEs' properties and to elucidate the effect of middle-ear effusion on detecting OAEs. Spontaneous otoacoustic emissions (SOAEs), transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) were recorded from 44 normal ears and 32 ears with middle-ear effusion. DPOAEs were collected in two basic forms consisting of distortion product audiograms (DP grams) and input-output (I-O) functions, elicited by two primary tones F1 and F2 and varying geometric mean frequencies between 1-6 kHz. The results of air and bone conduction hearing levels in pure tone audiogram were also analysed. In 21 ears out of 32 otitis media with effusion (OME) ears, SOAEs were absent. In the 28 ears with middle-ear effusion, the response and wave reproducibility were diminished, and in the 17 ears with middle-ear effusion, the DP gram was diminished or eliminated. In particular, I-O function curves at 3 kH and 4 kHz were diminished by the primary tones of 45 and 55 dB under the condition of MEE. The SOAEs, TEOAEs and DPOAEs (DP gram and I-O function curve) are highly reliable and useful tests for monitoring changes in middle-ear condition in children with OME and in predicting the course of OME.

Audiometry, Pure-Tone↗
PubMed2004

Mechanisms of hearing loss resulting from middle-ear fluid.

Fluid in the middle ear, a defining feature of otitis media with effusion (OME), is commonly associated with a 20- to 30-dB conductive hearing loss. The effects and relative importance of various mechanisms leading to conductive hearing loss were investigated in a human temporal bone preparation. Umbo velocity in response to ear-canal sound was measured with a laser vibrometer while saline and silicone fluids of viscosity 5-12,000 cSt were introduced into the middle ear to contact part or all of the tympanic membrane (TM) and fill part or all of the middle ear. At low frequencies, reductions in umbo velocity (deltaVU) of up to 25 dB depended on the percentage of the original middle-ear air space that remained air-filled, which suggests that the primary mechanism in hearing loss at low frequencies is a reduction of the admittance of the middle-ear air space due to displacement of air with fluid. At higher frequencies, deltaVU (of up to 35 dB) depended on the percentage of the TM contacted by fluid, which suggests that the primary mechanism at high frequencies is an increase in tympanic membrane mass by entrained fluid. The viscosity of the fluid had no significant effect on umbo velocity. deltaVU for the fluid-filled middle ear matched hearing losses reported in patients whose middle ear was believed to be completely filled with fluid. The difference between deltaVU for a partly-filled middle ear and hearing losses reported in patients whose middle ear was believed to be incompletely fluid-filled is consistent with the reported effect of middle-ear underpressure (commonly seen in OME) on umbo velocity. Small amounts of air in the middle ear are sufficient to facilitate umbo motion at low frequencies.

Aged↗
PubMedDate not supplied

Primate model for studies of clinical problems of middle ear functions.

Eustachian tube and middle ear function has been studied in the acute and chronically prepared Rhesus monkey preparation. Measures have included observations of tympanometry and input impedance of the middle ear, of transmission of energy through the middle ear, of static middle ear pressure and of threshold and suprathreshold hearing. Positive and negative long and short-term static middle ear pressures, the effects of middle ear fluids, and various aspects of Eustachian tube function in both normal and pathologic preparations have been studied. In general our observations indicate that the Old World monkey may provide a model permitting acquisition of quantitative data of a variety of middle ear functions under carefully controlled laboratory conditions, including those requiring measures simply not possible in man.

Animals↗
PubMedDate not supplied

Evaluation of automatic screening tympanometry in the identification of middle ear pathology.

This study was designed to evaluate the diagnostic sensitivity of a prototype tympanometric screening instrument. Results from automatic tympanometry and complete electroacoustic impedance measurements (tympanometry, static compliance, and acoustic reflex thresholds) were compared to otologic diagnosis in 53 ears with middle ear pathology. Results suggested a high percentage of agreement between screening tympanometry, results from a complete impedance test battery and pneumatic otoscopy. These findings lend support for theuse of screening tympanometry in school hearing-screening programs and in pediatric practice.

Adolescent↗
PubMed1996

Eustachian tube function and middle ear barotrauma associated with extremes in atmospheric pressure.

Eustachian tube (ET) function was studied by means of sonotubometry and tubotympano-aerodynamography (TTAG) prior to and following exposure to hypobaric or hyperbaric conditions. Forty normal adults were subjected to hypobaric pressure. Fifty adults who underwent hyperbaric oxygen (HBO) therapy also were studied. Following hypobaric exposure, 14 of 80 ears (17.5%) exhibited middle ear barotrauma. Following hyperbaric exposure, 34 of 100 ears (34%) exhibited middle ear barotrauma. Dysfunction of the ET, characterized by altered active and passive opening capacity, was more prevalent following exposure to extremes in atmospheric pressure compared to baseline. The ET function, which was impaired after the first HBO treatment, improved gradually over the next 2 hours. Overall, however, ET function was worse after the seventh treatment. The patients who developed barotrauma exhibited worse ET function prior to hypobaric or hyperbaric exposure. Thus, abnormal ET function can be used to predict middle ear barotrauma prior to exposure to hypobaric or hyperbaric atmospheric pressure.

Adult↗
PubMed1994

Neutrophil oxygen metabolite inhibition of cultured chinchilla middle ear epithelial cell growth.

Middle ear inflammation in acute bacterial otitis media is characterized by accumulation of neutrophils in middle ear effusion. Since neutrophils release products that may injure surrounding tissues, we studied the effect of neutrophil metabolic products on middle ear epithelial cells (MEECs) in vitro. Chinchilla MEECs were incubated with phorbol myristate acetate (PMA)-activated human neutrophils or with hydrogen peroxide (H2O2). Cell growth, which was measured by 3H-thymidine incorporation, was inhibited by activated neutrophils and by H2O2. Unstimulated neutrophils, PMA alone, and catalase alone did not affect the viability of MEECs. Catalase, an enzyme that reduces H2O2, partially blocked the inhibitory effect of activated neutrophils and completely blocked the inhibitory effect of H2O2. Inhibition of MEEC metabolism by neutrophil-reactive oxygen species may contribute to epithelial injury, which may prolong the middle ear inflammatory response and lead to chronic tissue damage.

Animals↗
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

Variability of Eustachian tube function: comparison of ears with retraction disease and normal middle ears.

OBJECTIVE: To explore the short-term and longterm variability of tubal opening and closing in ears with advanced retractions and in healthy ears. STUDY DESIGN/METHODS: Twenty ears with retraction type middle ear disease (R-MED) and 20 normal ears underwent direct recording of the middle ear pressure during repeated forced openings, equalization of +100 daPa and -100 daPa by swallowing, Valsalva inflation, and forceful sniffing. Tests were performed twice (separated by 30 min) on each of 2 days separated by 3 to 4 months. RESULTS: There was considerable intraindividual variability of the forced opening pressure and the closing pressure in both groups, within as well as between sessions and test days. Although the variability was 1.5 to 2 times higher in ears with retraction than in the normal group, mean Po and Pc did not differ between the groups. Compared with normal ears, ears with retraction changed more frequently from a positive to negative test response, or vice versa, when re-tested after 30 minutes. Rates of positive response in the equalization and Valsalva tests were significantly lower in diseased ears compared with normal ears. CONCLUSIONS: Eustachian tube opening and closing functions vary more in ears with retraction disease than in normal ears, which is consistent with the variable clinical course of R-MED and implies that single tubal function tests have little prognostic value on the individual level.

Adolescent↗
PubMed1979

Immunocompetence of the guinea pig's middle ear.

Immunocompetence of the middle ear was studied in guinea pigs in two series of experiments. The first, afferent phase, consisted of grafting iso and allografts in the guinea pig's middle ear to sensitize the animals which were later to receive a skin graft on the back. The second, efferent phase, first sensitized the animals with a skin graft on their back and later in the middle ear. The results show a rather low capacity of the middle ear to elicit a second-set rejection of the skin grafts. This lack of sensitization is explained by the authors by the concept of tolerance.

Animals↗
PubMed1985

Scanning electronic microscopy of sialit-preserved total middle-ear grafts.

Twelve middle ears from human cadavers, prepared for total grafting and preserved in sialit (1:5000) for more than 10-12 months, were studied with the aid of a scanning microscope. Such investigations have not been reported before in the medical literature. The observed de-epithelialization of most of the membrane and of the ossicles and the distortion of the joints in the transmission apparatus are considered to be results of the prolonged preservation in sialit. The mesenchymal structures are well preserved an this may indicate that, after grafting, revascularization occurs along the lumina of the 'empty' vessels. Because of this finding it might be considered that the maximum duration of preservation in sialit should be no longer than 10-12 months.

Ear, Middle↗
PubMed1996

In vitro and in vivo determination of the thermal effect of middle ear endoscopy.

During middle ear endoscopy, patients frequently experience vertigo. We theorized that this effect is secondary to heat produced by the scope. We evaluated two Hopkins rods and two fiberoptic scopes to assess the temperature elevation at the lateral semicircular canal (LSCC) of temporal bones and in a live canine model. These results were compared to the results of a standard 44 degrees C water caloric. We demonstrated in both models that the temperature rise at the LSCC increased relative to the scope diameter and that the Hopkins rods produced the same or greater heating effect than a warm caloric. Direct exposure of the thermocouple to the light produced a greater temperature elevation. We conclude that endoscopes produce sufficient heat to induce caloric stimulation of the LSCC. Care should be exercised to prevent the possibility of thermal injury.

Animals↗