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J T Combs

Publications and source records attributed to J T Combs.

13 recordsLinked to original sources
PubMed1991

Predictive value of the angle of acoustic reflectometry.

Impedance tympanometry and acoustic reflectometry tracings were obtained on 406 ears of children between 4 and 16 years of age. The angle formed by the acoustic reflectometry tracing was measured. The reflectivity and the angle of the curve were compared with tympanometric results. Analysis of data on 182 normal ears and 224 abnormal ears revealed a sensitivity of 76.3% and a specificity of 89.6% when a reflectivity of 5.0 was used as the cut point. Utilizing a cut point of 90 degrees resulted in a sensitivity of 92.8% and a specificity of 93.9%. Using both a 5.0 reflectivity and a 90-degree angle as cut points improved sensitivity to 98.7% and specificity to 94.5%.

Acoustic Impedance Tests↗
PubMed1989

Single vs. double acoustic reflectometry tracings.

Impedance tympanometry and acoustic reflectivity tests were obtained on 503 infants and children ranging from 3 months to 12 years of age during a 6-week period in a solo primary care practice. One hundred eighty-five of 1005 tracings from the acoustic otoscope with recorder demonstrated 2 reflectivities. This phenomenon occurred more commonly in infants than in older children and was not seen with reflectivities higher than 7 units. One hundred thirty-eight of the 185 double reflectivity tracings were associated with abnormal impedance tympanometry. The double reflectivity phenomenon may be important in helping to explain the false negative results occasionally seen with this technology in low and intermediate reflectometry scores. Future clinical research involving acoustic reflectometry should utilize the recording device and single and double reflectivity tracings should be handled separately in any analysis of data. Use of the recorder will also prevent false positive errors in the interpretation of some intermediate reflectivities.

Acoustic Impedance Tests↗
PubMed1988

Precision of acoustic reflectometry with recorder in acute otitis media.

There have been conflicting reports about the accuracy of the acoustic reflectometer in detecting middle ear fluid. A recording device connected to the reflectometer prints a graph showing the value of reflectivity to 0.1 unit. Twenty-four ears of children with suspected acute otitis media were studied. Ten reflectivity values were obtained for each patient. The mean standard deviation was 0.20 unit. Thus the imprecision of the instrument previously reported can be overcome by the recording device.

Acoustic Impedance Tests↗