Positive Middle Ear Pressure Research Articles

Can the negative pressures found in obstructive sleep apnea and Eustachian tube dysfunction be related?

ObjectiveThe association between obstructive sleep apnea (OSA) and Eustachian tube dysfunction (ETD) is well known. When both exist in a single pediatric patient, one of the expected culprits is adenoid enlargement. We hypothesize, in contrast, that the negative pharyngeal pressure found in OSA may be transmitted to the middle ear as negative middle ear pressure (MEP), which subsequently results in pathology. The objective of this study was to determine whether the degree of OSA and MEP are associated while using MEP as a quantifiable measurement of ETD. Study designRetrospective chart review. SettingTertiary academic center (Jan 2000–Jan 2018). Subjects and methodsThe relationship between apnea-hypopnea index (AHI) and MEP was examined. A non-anatomic model was utilized to support causality. ResultsThirty-four pediatric patients and twenty-three adult patients were included in the analysis. REM AHI showed a moderate negative correlation with MEP in children (r = -0.265), and a weak positive correlation with MEP in adults (r = 0.171). Children with an AHI in the severe OSA category had a more negative mean MEP than those in the mild category (p = 0.36). Adults with an AHI in the severe OSA category had a more positive mean MEP than those in the mild category (p = 0.11). ConclusionIn children, increasing severity of OSA is associated with a negative MEP, suggesting that negative pressure associated with OSA may be transmitted to the middle ear. In adults, increasing severity of OSA is associated with a more positive MEP.

OCENA ABSORBANCJI SZEROKOPASMOWEJ U DOROSŁYCH Z PODCIŚNIENIEM I NADCIŚNIENIEM W UCHU ŚRODKOWYM

BackgroundMiddle ear pressure plays a vital role in the transmission of sound to the inner ear. However, limited research data exists to understand the effect of abnormal middle ear pressure on wideband absorbance (WBA) tympanometry. The purpose of the study was to evaluate WBA at peak pressure and ambient pressure in adults with abnormal positive and negative middle ear pressure and compare them with normal adult ears having normal middle ear pressure.Material and methodsThree groups of adults – normal middle ear pressure group (56 ears), negative middle ear pressure group (30 ears), and positive middle ear pressure group (15 ears) – in the age range 22 to 50 years were considered. WBA was measured at peak and ambient pressures across the frequencies from 250 to 8000 Hz.ResultsWBA at peak pressure was observed to be higher than at ambient pressure in all the groups, with the difference seen mostly at low and mid-frequencies up to 2000 Hz. The negative middle ear pressure group showed the most considerable difference in mean WBA, seen between 600 Hz and 1000 Hz, followed by the positive middle ear pressure group, with a negligible difference for the normal middle ear pressure group.ConclusionsThe study highlighted the importance of measuring WBA at peak pressure and ambient pressure. The results suggest that the comparison of WBA at peak and ambient pressures, especially from lower to mid-frequencies up to 2000 Hz, would help in differentiating abnormal negative/positive pressure from normal middle ear pressure and also between ears having negative and positive pressure.

The effect of single-ossicle ear flexibility and eardrum cone orientation on quasi-static behavior of the chicken middle ear

In the single-ossicle ear of chickens, the quasi-static displacement of the umbo shows great asymmetry; umbo displacements are much larger for negative than for positive pressure in the middle ear, which is opposite to the typical asymmetry observed in mammal ears. To better understand this behavior, a finite-element model was created of the static response of the chicken middle ear. The role of flexibility of the extracolumella in the model was investigated, and the potential effect of the outward orientation of the tympanic-membrane cone was studied by building two adapted models with a flat membrane and an inverted conical membrane. It is found that the extracolumella must be made of flexible material to explain the large inward displacements of the umbo, and that displacements of the footplate are much smaller due to bending of the flexible extracolumella. However, increasing extracolumellar stiffness mostly reduces umbo displacement rather than increasing footplate displacement. The results suggest that the inverted orientation of the membrane cone is responsible for the change in asymmetry of the umbo displacement curve. The asymmetry of the footplate displacement curve in the normal model is smaller, but increases towards positive middle-ear pressure in the case of a flat or inverted membrane geometry.

Pneumatic low-coherence interferometry otoscope to quantify tympanic membrane mobility and middle ear pressure.

Pneumatic otoscopy to assess the mobility of the tympanic membrane (TM) is a highly recommended diagnostic method of otitis media (OM), a widespread middle ear infection characterized by the fluid accumulation in the middle ear. Nonetheless, limited depth perception and subjective interpretation of small TM displacements have challenged the appropriate and efficient examination of TM dynamics experienced during OM. In this paper, a pneumatic otoscope integrated with low coherence interferometry (LCI) was adapted with a controlled pressure-generating system to record the pneumatic response of the TM and to estimate middle ear pressure (MEP). Forty-two ears diagnosed as normal (n = 25), with OM (n = 10), or associated with an upper respiratory infection (URI) (n = 7) were imaged with a pneumatic LCI otoscope with an axial, transverse, and temporal resolution of 6 µm, 20 µm, and 1 msec, respectively. The TM displacement under pneumatic pressure transients (a duration of 0.5 sec with an intensity of ± 150 daPa) was measured to compute two metrics (compliance and amplitude ratio). These metrics were correlated with peak acoustic admittance and MEP from tympanometry and statistically compared via Welch's t-test. As a result, the compliance represents pneumatic TM mobility, and the amplitude ratio estimates MEP. The presence of a middle ear effusion (MEE) significantly decreased compliance (p<0.001). The amplitude ratio of the OM group was statistically less than that of the normal group (p<0.01), indicating positive MEP. Unlike tympanometry, pneumatic LCI otoscopy quantifies TM mobility as well as MEP regardless of MEE presence. With combined benefits of pneumatic otoscopy and tympanometry, pneumatic LCI otoscopy may provide new quantitative metrics for understanding TM dynamics and diagnosing OM.

Is middle ear pressure affected by continuous positive airway pressure use?

Is middle ear pressure affected by continuous positive airway pressure use?

Wideband Acoustic Immittance Normative Data

This article describes the effect of ethnicity, gender, aging, and instrumentation on wideband acoustic immittance (WAI). This is an important topic to investigate as the goal of any audiological test is optimize the test's sensitivity and specificity. One way to improve the test's sensitivity and specificity is to reduce the variability of the normative data. The impact of the aforementioned demographic characteristics on WAI norms has been reviewed, and where applicable its potential impact on clinical outcome has been discussed. Overall, differences observed between Caucasian and Chinese ethnic groups in adults population may warrant the use of ethnicity-specific norms especially for detection of otosclerosis; however, these differences in the school-aged children are not large enough to warrant the use of ethnicity-specific norms. It is important to explore whether the observed differences between Caucasian and Chinese ethnic groups is due to body-size indices and whether these differences can be replicated in other East Asian ethnic groups that share similar body-size indices. The differences observed between school-aged children and adults could also potentially impact clinical decision analysis. Therefore, use of age-specific norm is recommended. The differences in WAI between different systems are not clinically significant, and the use of instrument-specific norms does not result in improved test performance at least for the detection of otosclerosis. However, measuring WAI at ambient pressure (static) or at pressure corresponding to the peak (dynamic mode) could potentially impact the normative data and may prove to be clinically useful in cases of negative and positive middle ear pressure.

Finite-element analysis of middle-ear pressure effects on static and dynamic behavior of human ear

A finite-element analysis for static behavior of middle ear under variation of the middle-ear pressure was conducted in a 3D model of human ear by combining the hyperelastic Mooney-Rivlin material model and geometry nonlinearity. An empirical formula was then developed to calculate material parameters of the middle-ear soft tissues as the stress-dependent elastic modulus relative to the middle-ear pressure. Dynamic behavior of the middle ear in response to sound pressure in the ear canal was predicted under various positive and negative middle-ear pressures. The results from static analysis indicate that a positive middle ear pressure produces the static displacements of the tympanic membrane (TM) and footplate more than a negative pressure. The dynamic analysis shows that the reductions of the TM and footplate vibration magnitudes under positive middle-ear pressure are mainly determined by stress dependence of elastic modulus. The reduction of the TM and footplate vibrations under negative pressure was caused by both the geometry changes of middle-ear structures and the stress dependence of elastic modulus.

Eustachian tube function and tympanic membrane findings after chronic secretory otitis media

Objective: The etiology of secretory otitis media (SOM) is multifactorial. The main factors discussed are infection and tubal dysfunction. This study aimed to detect poor tubal function and tympanic membrane pathology in young adults after extremely long-standing SOM. Methods: Thirty-four patients, 16–25 years old, with previous chronic SOM persisting at least 6 years (mean 11.2 years, range 6.2–18.6 years), were retrospectively examined at a mean of 18 years after their first myringotomy or tube insertion and comparison was made with 15 controls. The medical records were scrutinized, otomicroscopic examination was performed and the Eustachian tube function was studied in a mini pressure chamber. Results: The mean age at SOM onset was 2.4 years (range 0.5–8.4 years) and the mean period from the last myringotomy or when the last tube had disappeared to follow-up was 6.7 years (range 1.3–12.8 years). Tympanic membrane pathology was found in 76% of the ears of SOM patients and in none (0%) of controls ( P<0.001). The youngest patients had more atrophy than the older patients ( P<0.05) and more myringosclerosis was observed in patients with shorter interval between SOM ending and examination. The patients were found to have significantly poorer active tubal function; i.e. higher inability to equilibrate negative or negative and positive middle ear pressure, compared with controls ( P<0.001). The majority of the patients (74%) still experienced some kind of discomfort in their ears at the time of examination. Conclusions: Still in adulthood patients with chronic SOM during childhood exhibit dysfunction of the tube and tympanic membrane pathology to a high extent.

Middle ear influence on otoacoustic emissions. I: Noninvasive investigation of the human transmission apparatus and comparison with model results

Evoked otoacoustic emissions (EOAEs) are generated within the cochlea in response to external sounds, and they can be acoustically detected in the external auditory meatus after backward propagation through the middle ear. In addition to being used to probe the cochlear mechanisms, they are expected to be sensitive to minute changes in middle ear impedance. Systematic measurements of the changes in the vectorial components of EOAEs were carried out after various manipulations of the human middle ear in order to characterize the influence of stiffness and inertia of the stapes and tympanic-membrane systems. For this purpose, stapedius muscle contractions were elicited by high-level contralateral sound, controlled changes in middle ear pressure (range ±100 daPa) were produced and the tympanic membrane was loaded with water droplets. A computer model of the middle ear network was implemented using a standard lumped-element electric analog of the middle ear (Zwislocki’s model). Forward and backward transmission changes were simulated and model predictions were compared to experimental data. Apart from the case of positive middle ear pressures, a close qualitative correspondence was found between model and real-ear results. Each of the effects was characterized by a unique pattern of phase and magnitude changes as a function of frequency, in relation to the mechanical characteristics of the involved subsystem (i.e. stapes stiffness, tympanic-membrane stiffness or mass) and its resonance properties. Owing to their high sensitivity, EOAEs could be helpful for an accurate individual multifrequency analysis of middle ear impedance by comparisons under rest and test conditions.

Effects of Nasal Obstruction on Eustachian Tube Function and Middle Ear Pressure

To evaluate the relationship between nasal obstruction and otitis media, 10 ferrets were studied before and after either unilateral (n=5) or bilateral (n=5) nasal obstruction. Observations included otomicroscopic assessments of middle ear status, tympanometric recordings of middle ear pressure and forced-response, inflation-deflation and continuous monitoring tests of Eustachian tube function. During the 6-8 week post-obstruction follow-up period no animal developed evidence of otitis media. Abnormal positive middle ear pressures lasting for the period of follow-up occurred only in the animals with bilateral nasal obstruction. Eustachian tube function test results showed these pressures to be generated during swallowing. No changes in the passive function of the tube were documented in either group, but changes in active function consistent with alterations in the pressure gradient between the middle ear and the nasopharynx were observed in both groups.

Increases in Middle Ear Pressure Resulting from Counter-Diffusion of Oxygen and Carbon Dioxide into the Middle Ear of Monkeys

The mechanism of middle ear (ME) pressure regulation is incompletely understood. Previously, Hergels and Magnuson reported an unexpected increase in ME pressure for human subjects who partially evacuated their relative positive ME pressures by swallowing. They suggested that a novel, but unknown mechanism for the generation of gas was responsible for the pressure increase. In this experiment, the MEs of rhesus monkeys were inflated with N2 via the eustachian tube and post inflation ME pressures were recorded for up to three hours. Eleven of 20 experiments showed an initial increase in ME pressure caused by the inflation followed by stable pressures for the remainder of the followup period. In 9 of the experiments, a rapid and temporally discrete decrease in ME pressure was observed during the course of followup. Following the observed pressure decrease which was interpreted as a transient eustachian tube opening, ME pressures showed a progressive increase characterized by a kinetic pattern similar to that of the human experiment. To understand the mechanism responsible for this effect, the monkey experiment was simulated using a mathematical model of ME pressure regulation. Free parameters of the model were taken from experimental data for monkeys. The model accurately predicted the time course of pressure change documented in the monkey experiments. The effect is driven by a decrease in the preexisting ME partial pressures of CO2, O2 and H2O consequent to tubal openings at relative positive pressures, with the subsequent counter diffusion of those gases from blood to ME causing the observed increase in total ME pressure. The results reported by Hergels and Magnuson can also be explained by this mechanism.

Prechallenge antibodies: moderators of infection rate, signs, and symptoms in adults experimentally challenged with rhinovirus type 39.

This study determined the influence of serum neutralizing antibody titers on infection rate, symptom manifestations, and provoked signs and pathophysiologies in adults experimentally exposed to rhinovirus type 39 (RV-39). Antibody status was determined for 151 healthy volunteers who were then cloistered in a hotel for 6 days. At the end of the first cloister day, the volunteers were challenged with RV-39 in a median tissue culture infective dose of 100. On each of the 6 days, a nasal examination was performed, symptoms were scored, and objective tests of nasal mucociliary function, nasal airway patency, secretion production, and middle ear pressures were completed. Both subjects and investigators were blinded to the prechallenge serum homotypic antibody titers of the subjects. Four subjects presented with a wild virus and were excluded from the analysis. Of the 147 included subjects, prechallenge serum antibody titers to RV-39 were low (under 2) in 56 subjects, intermediate (2 to 8) in 51 subjects, and high (above 16) in 40 subjects. The high-titer group was significantly different from the low-titer group with respect to viral shedding, symptom load, subjective extent of illness, and secretion production, as well as in the frequency of subjects with abnormal nasal mucociliary clearance and positive middle ear pressures. The study results document that for experimental RV-39 exposure, high levels of homotypic serum neutralizing antibody titers are associated with protection from infection and a lessened degree of disease expression, but not with a reduction of otologic complications.

Effects of intranasal challenge with histamine, bradykinin and prostaglandin on middle ear pressure and blood flow in cynomolgus monkeys.

Previous studies documented a significant increase in middle ear pressure following intranasal challenges with ascaris antigen or histamine in sensitized cynomolgus monkeys. To confirm that effects and investigate the mechanism, 4 monkeys were intranasally challenged at separate sessions with histamine (10 mg), bradykinin (1, 10 mg) and prostaglandin D2 (PgD2, 0.5, 1.0 mg) and followed for 90 min. Before and after challenge, middle ear pressure, mucosal blood flow, heart rate, blood pressure, body temperature and the partial pressures of O2 and CO2 in the venous blood were measured. The results showed that while bradykinin challenge had no effect on these measures, PgD2 provoked increased middle ear pressure, and histamine resulted in a biphasic pattern of increasing pressures followed by decreasing pressures. The pattern of change in middle ear pressure after histamine challenge was explicable by a mechanism involving transmucosal gas exchange, while that for PgD2 was related to increased mucosal inflammation. These results document the development of positive middle ear pressures during provoked nasal inflammation and may have relevance to similar observations in the clinical setting.

The relationship between nasal airway resistance and middle ear pressure in subjects with acute upper respiratory tract infection.

Middle ear pressure and nasal airway resistance were measured over 7 1/2h in 8 subjects (age 18-32) with symptomatic acute upper respiratory tract infection. The mean middle ear pressure was -13 +/- 1.5 daPa (s.e.m.) with a range between 65 to -140 daPa. The mean total nasal resistance was 0.4 +/- 0.02 Pa/cm3/s (s.e.m.) with a range between 0.20 to 1.28 Pa/cm3/s. Unilateral nasal airway resistance exhibited reciprocal fluctuations with a range between 0.18-3.60 Pa/cm3/s. The mean difference between the highest and lowest unilateral nasal resistance values for each subject was 1.48 +/- 0.22 Pa/cm3/s (n = 16). No correlation was found between unilateral nasal airway resistance and middle ear pressure. Total nasal airway resistance had an inverse correlation with middle ear pressure r = 0.32, r2 = 0.11, n = 176 (p < 0.001). The results indicate that the generation of a negative middle ear pressure in acute upper respiratory tract infection occurred in a manner consistent with intermittent obstruction of the Eustachian tube and gradual middle ear gas absorption. Rapid increases in middle ear pressure and the generation of a positive middle ear pressure were associated with nose blowing. No evidence was found to support the hypothesis that negative middle ear pressures are associated with sniffing.

Temporal changes in unilateral middle ear pressure under basal conditions

Spontaneous changes in middle ear pressure were measured tympanometrically in 15 healthy adults over 7.5 h under basal conditions. Despite fluctuation of middle ear pressure no temporal pattern existed and there was no evidence of reciprocal changes in pressure between sides. When awake but at rest the middle ear pressure fluctuates around ambient pressure. Recordings of positive pressure may represent supportive evidence in favour of a net basal tendency to produce a positive middle ear pressure.

The effects of anesthesia of the tympanic membrane on eustachian tube function.

In our previous histological studies of the tympanic membrane, we reported the presence of encapsulated nerve corpuscles that are capable of detecting middle ear pressure. Based on these findings, the relation between sensory receptors in the tympanic membrane and tubal function was examined in a clinical study. Tubal function was tested during Valsalva maneuvers and its active equilibration. Function was recorded as a change of the static compliance of the tympanic membrane on an otoadmittance meter. To paralyze the sensory receptors in the tympanic membrane, iontophoresis was used to induce anesthesia of the drum. Forty ears of 20 subjects were tested. All ears were able to equalize positive middle ear pressure without or with a single swallowing. After anesthesia, 13 ears needed more than two swallows and 4 ears failed to equalize middle ear pressure in spite of repeated swallowings. As eustachian tube function changed following anesthesia of the tympanic membranes, a neural connection between sensory receptors in the tympanic membrane and tubal muscles is suggested.

Morning Pressure in the Middle Ear

Tympanograms were taken in the early morning in 25 persons with healthy ears. A first tympanogram was obtained shortly after waking up while the subject was still recumbent, and a second tympanogram was taken in the upright position after chewing and swallowing. Positive middle-ear pressure was found in a majority of ears, and the pressure was reduced after swallowing. The present results indicate that gas absorption from the middle ear is not important in quantitative terms during sleep. Otherwise the morning pressure would be expected to be negative. Two other experiments showed that the middle-ear pressure increased during shallow "sleep-type" breathing, and decreased during hyperventilation. The present results can be explained by diffusion of carbon dioxide over the middle-ear mucosa, the direction of gas transfer being dependent on the breathing pattern.

Positive middle ear pressure shown by tympanometry.

The incidence and implications of positive middle ear pressure shown by tympanometry have been sparsely reported in the literature. A series of 13 patients (16 ears) exhibited middle ear pressures that exceeded +49 mm H2O. Clinical, otoscopic, audiologic, and pathologic findings are reviewed. Otalgia or fullness and pharyngitis were the most commonly reported symptoms. Acute middle ear pathologic conditions were otoscopically confirmed in 13 ears. Effusion was present in five of six ears that were selected for myringotomy. The clinical implications of positive middle ear pressure would be particularly important when screening in a nonmedical setting and in the examination of infants. These findings are also important for considering the role of positive middle ear pressure in the pathogenesis of otitis media.

Nonhuman primate model of cleft palate and its implications for middle ear pathology.

The present study is a preliminary report on the development of a nonhuman primate model of cleft palate and middle ear (ME) disease. The causal relationship between a surgical cleft of the soft palate only or a cleft of the hard and soft palate and otitis media with effusion (OME) was investigated in rhesus monkeys. Prior to clefting, ME status was documented by pneumatic otoscopy or otomicroscopic examination and tympanometry over a period of at least five months. A minimum of four preoperative eustachian tube (ET) function evaluations were performed employing the inflation-deflation and the forced-response tests. These procedures were repeated following surgery and during a long-term follow-up. Seventeen of the 18 ears developed a recurrent OME. Postoperative ME pressures were initially high negative values. After the first two postoperative months, high positive ME pressures were recorded. The forced-response test showed little to no long-term changes in passive and active tubal resistances or in the efficiency of tubal dilation as a result of surgery. The inflation-deflation test showed higher opening and closing pressures and a limited and more variable ability to equilibrate applied positive and negative ME pressures following surgery. Both ME status and ET function appeared to improve with time. These findings indicated that the pathogenesis of recurrent OME in this animal model may have been due to changes in ET function associated with an abnormal nasopharynx rather than aberrant tensor veli palatini (TVP) muscle function.

Eustachian tube ventilatory function in relation to cleft palate.

The ventilatory function of the Eustachian tube was assessed in a group of infants and children with cleft palate, some of whom had received palatal repair. Those whose palates had been repaired were better able, in general, to equilibrate applied positive middle ear pressures than were those with open clefts. In many of the patients whose palates had been repaired, the results of Eustachian tube function studies were similar to those in normal subjects. Differences in Eustachian tube ventilatory function are assumed to be related to differences in tubal compliance. Excessive compliance probably results in, or exaggerates, functional Eustachian tube obstruction. Improvement in tubal function following palate repair is probably related to factors resulting in greater tubal stiffness.