1991 ◽  
Vol 34 (2) ◽  
pp. 386-390 ◽  
Author(s):  
Roanne G. Karzon

Sensitivity and specificity of static acoustic admittance (SAA) and tympanometric width (TW) were assessed for 116 pediatric patients. Otologic examination was the validation criterion. Reliability of immediate repeat tympanometric measures (SAA, TW, peak pressure, and estimate of ear canal volume) was also evaluated. A statistically significant change in SAA, with a larger SAA on measure two than measure one, was observed. No significant change across the two sequential measures was observed for TW, peak pressure, or the estimate of ear canal volume. The sensitivity and specificity data collected are discussed with respect to assisting clinicians in selecting tympanometric criteria suitable to their own clinical situation.


1993 ◽  
Vol 36 (1) ◽  
pp. 178-185 ◽  
Author(s):  
Janet E. Shanks ◽  
Richard H. Wilson ◽  
Nancy K. Cambron

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 (| y |) and phase angle (ø) 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.


2000 ◽  
Vol 16 (3) ◽  
pp. 133-136
Author(s):  
Tzeng-Yuan Chen ◽  
Man-Ge Chen

ABSTRACTThis research applied the method of direct acoustic admittance measurement to investigate effects of the flame character and the burner acoustic admittance on the flame-driving behavior. The acoustic admittance data were obtained by directly measuring the amplitudes of pressure and velocity oscillations, and the phase relations between the pressure and velocity oscillations. Results of this research reveal that the flame-driving characteristic is mainly dominated by the nonreactive burner admittance not the flame. Whether the flame is to drive or damp the acoustic field is detcrmined by the acoustic admittance of the burner system. The flame equivalence ratio plays a role mainly in determining the magnitude of the flame driving/damping.


1994 ◽  
Vol 15 (4) ◽  
pp. 310-323 ◽  
Author(s):  
Robert J. Nozza ◽  
Charles D. Bluestone ◽  
David Kardatzke ◽  
Ruth Bachman

2012 ◽  
Vol 16 (02) ◽  
pp. 186-194 ◽  
Author(s):  
Camila Macedo ◽  
Mariza Feniman ◽  
Tamyne de Moraes

Summary Introduction: The use of conventional tympanometry is not sufficiently sensitive to detect all cases of middle ear changes, and this hinders accurate diagnosis. Objective: To characterize acoustic immittance measures of infants from 0 to 3 months of age using multifrequency tympanometry in a prospective study. Method: 54 infants from 0 to 3 months of age were evaluated. The inclusion criteria included absence of respiratory infections during the evaluation, presence of transient evoked otoacoustic emissions, and absence of risk indicators for hearing loss. The subjects were evaluated by an audiologic interview, a visual inspection of the ear canal, and measures of acoustic immittance at the frequencies of 226 Hz, 678 Hz, and 1,000 Hz. Tympanometric records of the occlusion effect, tympanometric curve type, tympanometric peak pressure, equivalent ear canal volume, and peak compensated static acoustic admittance were collected. Results: The results indicated the presence of an occlusion effect (2.88% at 226 Hz, 4.81% at 678 Hz and 3.85% at 1,000 Hz), predominance of a tympanometric curve with a single peak (65.35% at 226 Hz, 81.82% at 678 Hz, and 77.00% at 1,000 Hz), and tympanometric peak pressure ranging from -155 to 180 daPa. Further, the equivalent ear canal volume increased with the frequency of the probe (0.64 mL at 226 Hz, 1.63 mho at 678 Hz, and 2.59 mmho at 1,000 Hz) and the peak compensated static acoustic admittance values increased with an increase in frequency (0.51 mL at 226 Hz, 0.55 mmho at 678 Hz and 1.20 mmho at 1,000 Hz). 93.06% of the tympanograms were classified as normal at 226 Hz, 81.82% at 678 Hz, and 77.00 % at 1,000 Hz, respectively. Conclusion: Taken together, these results demonstrated that utilizing these evaluations made it possible to characterize the acoustic immittance measures of infants.


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