Multiple frequency tympanometry: effects of ear canal volume compensation on static acoustic admittance and estimates of middle ear resonance

Three methods for compensating multiple frequency acoustic admittance measurements for ear canal volume were studied in 26 men with normal middle ear transmission systems. Peak compensated static acoustic admittance (magnitude of y) and phase angle (phi) were calculated from sweep frequency tympanograms (226-1243 Hz in 113 Hz increments). Of the procedures used to compensate for volume in rectangular form, the ear canal pressure used to estimate volume had the largest effect on the estimate of middle ear resonance. Median resonance was 800 Hz for admittance measurements compensated at 200 daPa versus 1100 Hz for measurements compensated at -350 daPa. The remaining two methods, compensation of susceptance only versus both susceptance and conductance and compensation using the minimum volume versus separate volumes at each frequency, did not affect estimates of middle ear resonance. Estimates of middle ear resonance from compensated phase angle measurements also were compared with estimates of resonance from admittance and phase difference curves. Although resonance could not be estimated from the phase difference curve, resonance estimated from the admittance difference curve agreed with the estimate from compensated phase angle.     

Middle ear mucosa pathophysiology and healing processes in children with otitis media with effusion (OME)

Most otitis media with effusion (OME) in children heals spontaneously, but it is sometimes persistent and intractable. The major factors determining these different courses of OME are unknown. Identifying such factors would be clinically helpful. Factors affecting on the outcome of OME were studied experimentally and clinically. In animal experiment OME was induced in rabbit by occluding the Eustachian tube. Clinical study was conducted by investigating a histology of the middle ear mucosa, sampled from 64 children with OME (87 ears) who underwent middle ear tube ventilation. Furthermore, these cases studied how the degree of mastoid pneumatization before and after treatment, changes in the volume of the middle ear air cavity and the course after removal of the middle ear ventilation tube affected lesions in the middle ear mucosa. In animals, histology of the middle ear mucosa showed that in the early stages, the subepithelial layer of the middle ear mucosa was characterized by edematous hypertrophy and enlarged blood vessels. In later stages, it became fibrous as a result of chronic inflammation. These results suggest that lesions of the subepithelial layer are unlikely to recover. In clinical cases, histological changes in mucosal samples were rated on a two-point scale: changes in the epithelium and changes in the subepithelial layer. Re-pneumatization, a sign of healing of middle ear mucosal inflammation, was seen 12 months to 18 months after surgery. Among patients in whom the tube was left inserted for more than 18 months, only 11% had unfavorable outcomes and the recurrence rate was low. All patients who had recurrence of disease despite more than 18 months of tube insertion had prolonged inflammation in the middle ear mucosa. There results indicate that the air cavity returns to approximately normal degree of pneumatization more than 18 months after surgery, and that the extent of lesions in the middle ear mucosa, especially the subepithelial layer, is closely related to the healing of OME.     

Influence of the gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases

To investigate the influence of gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases, the authors examined the mastoid pneumatization among patients with sniffing habit using computed tomography, and also examined the change of negative middle ear pressure induced by sniffing using tympanogram. In 20 ears with cholesteatoma or adhesive otitis media, the areas of mastoid cavity measured at the level of the lateral semicircular canal were significantly smaller than those in 26 ears with otitis media with effusion (OME) or attic retraction and in eight normal ears with sniffing habit (P < .01 and P < .0001, respectively). In 26 ears with OME or attic retraction, the areas of mastoid cavity were significantly smaller than those in eight normal ears with sniffing habit (P < .0001). By contrast, in the four ears with sniff-induced middle ear disease, the recovery of negative middle ear pressure in 5 minutes without swallowing was less than 10 mm H2O, whereas in all seven ears with normal eardrum, negative middle ear pressure recovered by more than 20 mm H2O in 5 minutes. These findings suggested that impairment of gas exchange function through the middle ear mucosa, as well as eustachian tube dysfunction, might be closely related to the development of sniff-induced middle ear diseases.     

Tympanometric detection of middle ear effusion in infants and young children

Tympanometry, a test of middle ear status new to clinical pediatrics, was carried out on 280 subjects, 10 days through 5 years of age. The tympanograms obtained were compared with otoscopic findings and, in 107 of the subjects, with findings at myringotomy. Seven distinct tympanometric curve types were identified and defined, based on their degree of correlation with the presence or absence of middle ear effusion. In subjects 7 months of age and older, curves suggesting normal (high) tympanic membrane compliance in combination with atmospheric or near-atmospheric middle ear air pressure were rarely associated with effusion. Conversely, curves suggesting low tympanic membrane compliance were highly correlated with the presence of effusion. Curves suggesting intermediate compliance or reduced middle ear air pressure were also correlated with effusion, but the degree of correlation was dependent on the shape of the curve. In infants less than 7 months of age, many of the ears with effusion had "normal" tympanograms, presumably because external auditory canal walls in such infants tend to be highly distensible. Tympanometry is a simple, rapid, atraumatic, valid, and objective test, easily administered by paraprofessional personnel. Its use can result in improved detection of middle ear effusion and other middle ear abnormalities, and also appears to promote improvement in diagnostic acumen.     

Determination of complements in serum and middle ear effusion of the patients with secretory otitis media

Complements in serum and middle ear effusion were determined in 20 patients with secretory otitis media, and compared with those in the normal controls. The C5 and C1-INH in serum of the patients were significantly higher. On the contrary, C9 and B factor (Bf) were significantly lower, and the circulatory immunocomplex was also higher. In patients with secretory otitis media, the middle ear effusion levels of C3, C4 and C5 were significantly lower, and Bf and immunocomplex were significantly higher than those in serum. The results suggest that the ability of complements in clearing immunocomplex is low. Therefore, the immunocomplex may deposit in the mucosa of the middle ear. Thus the permeability of capillary will be increased, and the middle ear effusion occurs.     

Evoked otoacoustic emissions in children in relation to middle ear impedance

The influence of changes in middle ear impedance with and without serotympanon on the measurement of evoked otoacoustic emissions (EOAE) was investigated in 108 children between 3 and 12 years of age. Children with proven serotympanon never showed good EOAE. In those who only had changes in middle ear impedance without a serotympanon, the decrease in EOAE amplitude was more related to the magnitude of conductive hearing loss than to the change in impedance itself. These results are compared with those of a neonatal screening project in which some of the 532 healthy fullterm newborns showed poor emissions in the first days of life. It seems reasonable to assume that this is due to incomplete pneumatization of the middle ears of these children, especially as a control audiogram later in their lives showed normal hearing thresholds.     

Diimidazo[1,2-c:4'',5''-e]pyrimidines: adenosine agonist activity demonstrated by microphysiometry

Vertigo and dizziness are not common in childhood, but are probably present more often than was formerly thought. These symptoms caused mainly by o700is media and middle ear effusion, two of the most common diseases in children, have been neglected for a long time, both in the literature and in practice, until recently. The purpose of this study was to determine objectively the incidence of balance-related symptoms in children with long-lasting middle ear effusion and to discover whether these symptoms resolve after the insertion of ventilation tubes. One hundred thirty-six children, ages 4 to 9 years, were given electronystagmographic tests and the Bruininks-Oseretsky tests for motor proficiency before and after tube ventilation of the middle ear. The results were compared with those in 74 healthy children with no history of middle ear diseases. Pathologic findings were found in 58% of the children with chronic middle ear effusion, as compared with only 4% of the control group. The symptoms and signs of balance disturbances resolved in 96% of the children after ventilation tube insertion. The results of this study indicate that balance-related symptoms often encountered in young children may result from chronic middle ear effusion and that these symptoms will resolve after evacuation of the effusion and ventilation of the middle ear.     

Gammadelta T cell receptor repertoire in middle ear effusions in children

In order to elucidate the immune response in otitis media with effusion, polymerase chain reaction was employed to examine gammadelta T cell receptor repertoire in the middle ear effusions of patients with otitis media with effusion. RNAs were extracted from 13 middle ear effusions of 10 children with otitis media with effusion. Vgamma2 was the most frequently used Vgamma gene. As for Vdelta gene usage, Vdelta2 amplification gave the strongest signal in 10 out of 13 samples. The results suggest that gammadelta T cells bearing Vgamma2/Vdelta2 T cell receptors accumulate in the middle ear effusions in children, and that these T cells may respond to certain bacteria or bacterial products in the middle ear.     

Gas exchange function of the middle ear in patients with otitis media with effusion

Gas exchange function through the middle ear mucosa was assessed using nitrous oxide (N2O) in patients with otitis media with effusion (OME), as well as in normal ears during elective surgery for unrelated disorders. In all normal ears except one (n = 43), an increase in pressure was observed after N2O inhalation. In 42 of 84 ears with OME, a pressure increase was observed, but not in the remaining 42 ears (50%), indicating that the gas exchange function in these latter ears was impaired. In 21 of the 42 ears showing no middle ear pressure increase following N2O inhalation, the middle ear pressure was again monitored after myringotomy and aspiration of the effusion A pressure increase was found in 16 ears, indicating that the impairment in gas exchange function in ears with OME may be reversible in most cases. Computed tomography of the mastoid was examined preoperatively in 66 ears, with the presence or absence of a middle ear pressure change well correlated in 57 ears with the presence or absence of mastoid aeration.     

Neonatal mesenchyme temporal bone study: typical receding pattern versus increase in Potter's sequence

The fate of mesenchyme, which lines the fetal and newborn bony middle ear, is not well understood. The authors wished to test previous observations that a greater amount of mesenchyme was found in Potter's sequence (renal anomalies, pulmonary hypoplasia, and oligohydramnios). Using celloidin-embedded neonatal temporal bones (68 cases, 123 ears), with clinical and autopsy information, middle ear volumes were compared among diagnostic groups using analysis of variance. In 16 ears of Potter's sequence cases the volume of mesenchyme increased in proportion to the size of the middle ear. Conversely, in all other cases the volume of mesenchyme remained constant compared to increasing middle ear size. Both the volume of the bony middle ear and the volume of the air cavity increased at 15 mm3/500 g of body weight (gbw). Mesenchyme percentage decreased by 2%/500 gbw. Middle ear mesenchyme appears to recede rather than reabsorb. However, in Potter's sequence cases the volume of mesenchyme increases, raising issues of a missing renal signal that inhibits mesenchymal growth under normal circumstances.     

Hypnotic susceptibility order effects in waking analgesia

OBJECTIVE: To develop a measuring apparatus that has the ability to sweep both frequency and external auditory meatus static pressure and can display measurement results in a three-dimensional expression. To measure the middle ear dynamic characteristics of normal-hearing subjects and of patients with this apparatus. DESIGN: Investigate 275 ears of 153 normal-hearing subjects and 72 ears with middle ear diseases. RESULTS: The measurement results show fairly distinctive patterns depending on the middle ear conditions, i.e., normal, ossicular chain separation, ossicular chain fixation, secretory otitis media, tympanic membrane perforation, and tympanic membrane atelectasis. The evaluation of patients with ossicular diseases revealed that the rate of correct diagnosis of ossicular chain separation is 84% and that of ossicular chain fixation is 74%. These diagnoses were confirmed by surgery. CONCLUSION: Displaying the measurement results in a three-dimensional expression is helpful to make correct diagnosis in clinical practice. It is especially easy to make a distinction between the ossicular chain separation and ossicular chain fixation. Therefore, it is concluded that this apparatus has a high degree of clinical applicability to the diagnosis of these diseases.     

Acoustic mechanisms: canal wall-up versus canal wall-down mastoidectomy

The contribution of the middle ear air spaces to sound transmission through the middle ear in canal wall-up and canal wall-down mastoidectomy was studied in human temporal bones by measurements of middle ear input impedance and sound pressure difference across the tympanic membrane for the frequency range 50 Hz to 5 kHz. These measurements indicate that, relative to canal wall-up procedures, canal wall-down mastoidectomy results in a 1 to 5 dB decrease in middle ear sound transmission below 1 kHz, a 0 to 10 dB increase between 1 and 3 kHz, and no change above 3 kHz. These results are consistent with those reported by Gyo et al. (Arch Otolaryngol Head Neck Surg 1986;112:1262-8), in which umbo displacement was used as a measure of sound transmission. A model analysis suggests that the reduction in sound transmission below 1 kHz can be explained by the smaller middle ear air space volume associated with the canal wall-down procedure. We conclude that as long as the middle ear air space is aerated and has a volume greater than 0.7 ml, canal wall-down mastoidectomy should generally cause less than 10 dB changes in middle ear sound transmission relative to the canal wall-up procedure.     

Acute cardiovascular toxicity of thallium (I) ions

The paper deals with: 1. the protein concentration in the perilymph (PL), the serum and the cerebrospinal fluid (CSF), 2. the protein pattern in the PL and 3. histological findings in the middle and inner ear in unilaterally ear-infected guinea pigs. The studies were performed 6 h to 21 days post infectionem (Fig. 1). The pathological changes in the middle ear, which, in most cases, were limited to the infected ear, were initially evaluated under the operating microscope and divided into 4 stages. The analytical and histological results were presented as functions of these stages. As the inflammation intensity increased, the protein concentration in the PL of the infected ears increased to a level exceeding that of the normal value more than ten times (Fig. 2). However, in the serum and in the CSF this concentration remained unchanged. Likewise, no significant protein increase in the PL of the contralateral ears was detectable in most cases. As the inflammation intensity increased, the number of the precipitation lines detectable immunoelectrophoretically increased in the PL of the infected ears (Fig. 3). An increase in the alpha1- and gamma-globulins and a decrease in Albumin was found by electrophoresis on cellulose acetate strips (Tab. 3). The histological findings correlated with initially established inflammatory stages of the middle ear mucous membrane (Tab. 4). As the inflammation intensity increased, the round window, too, was changed pathologically, so that in some cases of purulent otitis media middle ear secretion could enter the cochlea. The protein increase in the PL immediately after the infection is probably due to an increase in the blood vessel permeability in the inner ear.     

Significance of a diastolic notch in the uterine artery flow velocity waveform induced by uterine embolisation in the pregnant ewe

OBJECTIVE: To determine whether water exposure causes middle ear contamination in patients with collar button tympanostomy tubes (TTs). METHOD AND DESIGN: An in vitro model of a human head that contained an auricle, external auditory canal, tympanic membrane with TT, middle ear, eustachian tube, and mastoid cavity was developed. Two electrodes connected to an external ohmmeter resided in the middle ear to detect water entry. The model was tested with 4 types of water exposure: showering, bathing, hair rinsing, and swimming. Statistical analysis was performed by the Fisher exact test. MAIN OUTCOME MEASURES: A positive test result corresponded to water entering the middle ear via the TT, confirmed by a resistance reading of zero on the ohmmeter. A negative test result indicated no change in the initial high resistance reading. RESULTS: No positive test results were obtained for showering (0 of 60 tests), hair rinsing (0 of 60 tests), or head submersion (12.7 cm) in clean tap water (0 of 60 tests). Ten positive test results were obtained for head submersion in soapy water (10 of 97 tests), which was statistically different from clean water (P< or =.007). Swimming pool depths of 30, 45, 60, and 75 cm elicited positive test results in 2 of 16, 3 of 18, 2 of 20, and 11 of 20 tests, respectively. A higher incidence of water entry into the middle ear occurred at depths of more than 60 cm (P< or =.001). No statistical difference between depths of 60 cm or less occurred (P= .88). CONCLUSIONS: Showering, hair rinsing, and head submersion in clean tap water do not promote water entry into the middle ear. Submersion in soapy water increases the probability of water contamination. Pool water infrequently enters the middle ear with head submersion, but the incidence increases with deeper swimming (>60 cm). These data provide further evidence that many water precautions frequently advised in patients with TTs are unnecessary.     

Nasal and middle ear ciliary beat frequency in chronic suppurative otitis media

The middle ear mucociliary system has been shown to have an important function in the clearance of effusions. Little is known, however, about its role in chronic suppurative otitis media (CSOM). The ciliary beat frequencies of middle ear mucosal biopsies and nasal brushings of 27 patients with CSOM were analysed using a computerized photometric technique. The ciliary beat frequency in the middle ear mucosa was significantly less than that in nasal mucosa. Frequency in ears of smoking patients was significantly lower compared with non-smoking patients. Nasal brushings were taken from 27 otherwise healthy age and sex-matched non-smoking controls and the ciliary beat frequency was very similar to nasal samples from patients with CSOM. Ear controls were obtained from otosclerotic patients undergoing tympanotomy and the beat frequency was significantly higher than in the ear of patients with CSOM. It is concluded that middle ear ciliary function is significantly reduced in CSOM, particularly in patients who smoke.     

Early eradication of pathogens from middle ear fluid during antibiotic treatment of acute otitis media is associated with improved clinical outcome

OBJECTIVE: To determine the relation between early bacteriologic eradication and clinical outcome of acute otitis media (AOM) in infants and young children treated with various antibiotics. STUDY DESIGN: The study group consisted of patients ages 3 to 24 months seen at the Pediatric Emergency Room with: (1) symptoms and physical findings consistent with AOM of < or = 7 days duration; (2) no spontaneous perforation or tympanostomy tubes; (3) positive initial middle ear fluid culture; and (4) a follow-up to at least Day 10+/-2 of the study with a second culture performed 72 to 96 h after initiation of antibiotic treatment. Any patient with a positive middle ear fluid culture 72 to 96 h after initiation of antibiotic treatment was considered to have bacteriologic failure. Otologic evaluation was done by an otolaryngologist unaware of the culture results and of the study drug allocation. A clinical score based on body temperature, report of irritability and ear tugging observed by the parents and the appearance and redness of the ear drum as observed by the otolaryngologist was also used for clinical evaluation. RESULTS: The study group consisted of 123 patients, of whom 57 (46%) had positive middle ear fluid 72 to 96 h after initiation of antibiotic treatment. Clinical failure was observed in 21 of 57 (37%) patients in whom bacteriologic eradication did not occur vs. only 2 of 66 (3%) patients with bacteriologic eradication after 3 to 4 days of treatment (P < 0.001). Clinical score for both moderate and severe disease decreased significantly faster in those with bacteriologic eradication than in those in whom middle ear fluid was still culture-positive 72 to 96 h after initiation of treatment. CONCLUSION: Clinical failures in our population were associated with inability to eradicate the causative organisms of AOM from the middle ear fluid within 3 to 4 days after initiation of antibiotic therapy. Most patients (including those without bacteriologic eradication) improved after 3 to 4 days of treatment, but patients with sterile middle ear fluid felt better after 3 to 4 days of treatment than patients in whom middle ear fluid was still culture-positive.     

Involvement of dental occlusion and trigeminal neuralgia: a clinical report

Over a 12-month period 501 children (age range 11 months to 15 years) underwent surgery for a possible middle ear effusion. All had tympanometry performed within 2 h of surgery. The results of tympanometry were correlated with the surgical findings in 955 ears. A type-B tympanogram has a high sensitivity (0.91) in predicting middle ear effusion with good specificity (0.79). A type-A tympanogram has a very high specificity (0.99) in predicting a dry middle ear but low sensitivity (0.34). Both the positive (0.91) and negative (0.84) predictive values of a type-A tympanogram are high. The addition of a type-C tympanogram increases the sensitivity of predicting a dry middle ear to 0.79. The positive predictive value of a peaked (type-A or -C) tympanogram is 0.71 and should be considered strong evidence that the middle ear is dry. Tympanometry is the best clinical test for the presence or absence of a middle ear effusion, and on the basis of preoperative tympanometry alone the need for surgery should be carefully reassessed.     

Effect of unilateral vestibular stimulation on histamine release from the hypothalamus of rats in vivo

1. We investigated the effect of unilateral vestibular stimulation on histamine release from the anterior hypothalamic area of urethan-anesthetized rats in vivo, using a brain microdialysis method coupled with high-performance liquid chromatography fluorometry. 2. The histamine release was increased to approximately 180% of the basal release by the electrical stimulation of the inner ear with 1 Hz, 500 microA, and 200 ms for 20 min. This effect was dependent on the current intensity. 3. Activation of the unilateral horizontal semicircular canal by middle ear irrigation for 15 min with 45 degrees C water increased the histamine release to approximately 200% of the basal release. 4. Irrigation of the middle ear with ice water for 15 min increased the histamine release to approximately 190% of the basal release. 5. The histamine release was not changed by the irrigation of the middle ear with 37 degrees C water and the irrigation of the auricle with ice water, which suggests that neither somatosensory stimulation to the middle ear nor nonspecific cold stress affects the histamine release. 6. All these findings suggest that the sensory mismatch signals induced by caloric stimulation and unilateral electrical vestibular stimulation activate the histaminergic neuron system in the brain.     

Thrombolytic therapy in Missouri hospital emergency departments: compliance with the National Heart Attack Alert Program guidelines

Adhesive interactions between leukocytes and endothelium are required for subsequent leukocyte extravasation toward inflammatory sites. Understanding the possible kinetic expression of vascular cell adhesion molecule-1 (VCAM-1) in the middle ear cavity during an inflammatory cascade in vivo may be important for clarifying local immunological responses in otitis media. Two inflammatory models were produced in the rat and involved acute middle ear mucosal and cutaneous inflammation induced after inoculation or intradermal injection of lipopolysaccharide (LPS). After intravenous injection of both 125I-labeled anti-VCAM-1 and 131I-labeled control monoclonal antibody (mAb), the kinetic expression of VCAM-1 in the middle ear and skin was assessed by local radionuclide uptake. The biodistribution of an 125I-labeled anti-VCAM-1 mAb as a potential detector of focal inflammation was examined in normal rats. Both inflammatory lesions were characterized by early and sustained (up to 24 h) expression of VCAM-1, with maximal expression at 4 h after LPS stimulation. The kinetics of VCAM-1 expression was similar among the middle ear mucosa or skin specimens studied and different stimulation methods. A similar biodistribution and clearance of radioactivity between 125I-labeled anti-VCAM-1 mAb and 131I- or 99mTc-labeled control mAb were observed. The present result suggest that functional VCAM-1 induced by LPS is expressed in both middle ear tissue and skin lesions and may play a role in the initial stage of inflammatory response produced. Although VCAM-1 upregulation is a very early event in the inflammatory cascade, 125I-labeled anti-VCAM-1 mAb may be useful for the early detection of focal inflammation in the middle ear.     

Interactions among tympanometric variables

To gain a better understanding of tympanometric results that have been difficult to interpret, such as asymmetrical and W-shaped tympanograms, acoustic susceptance and conductance tympanograms were measured from subjects with normal hearing and from subjects with well-defined middle ear pathology. Acoustic reactance, resistance, and impedance were computed and predicted from the measured data. Asymmetrical tympanograms derive in large part from the marked asymmetry in acoustic resistance as a function of ear canal pressure. W-shaped tympanograms result from interactions between reactance and resistance that occur when the two quantities assume similar absolute values or when reactance is mass controlled. A criterion for distinguishing between W-shaped tympanograms that are normal from those that are abnormal is discussed.