Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to obtain normal hearing thresholds for an ER-3A insert earphone as a contribution for future standardization and for comparison with previous studies and interim ANSI and ISO insert earphone reference equivalent threshold sound pressure levels (RETSPLs). Hearing thresholds were obtained on each ear of 48 normal-hearing subjects from 125 to 8000 Hz using ER-3A and TDH-49P earphones referenced to a Bruel and Kjaer DB-0138 HA-2 and NBS-9A acoustic coupler, respectively. The mean unadjusted and adjusted ER-3A thresholds were in very good agreement with the mean thresholds averaged over eight other studies. Further, the mean adjusted ER-3A thresholds were in very good agreement with the interim ANSI RETSPLs while the mean unadjusted ER-3A thresholds were slightly higher than the ISO RETSPLs. Also, mean ER-3A thresholds averaged over a nine study data base were in closer agreement with the interim ANSI than the ISO RETSPLS. Overall, the interim ANSI insert earphone RETSPLs were recommended for clinical use.
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PMID:Reference threshold levels for an ER-3A insert earphone. 157 87

Coupler output levels were obtained for six repeated placements of a TDH-49 earphone in a P/N 51 cushion on a NBS 9A coupler and a B-71 and B-72 bone vibrator on a mechanical coupler from 250 to 4000 Hz using experienced (N = 9) and untrained subjects (N = 9) who were later trained. The largest minus the smallest coupler output levels across the repeated placements were determined for each subject and transducer at each frequency. The coupler output level differences were similar across subject group for each transducer at each frequency and were not reduced by training. The median and mean differences for the TDH-49 were less than 1 dB, consistent across frequency, and the highest range score never exceeded ANSI tolerance levels. The median and mean differences for the B-71 and B-72 were higher than for the TDH-49 but did not exceed ANSI tolerance levels and were frequency dependent corresponding to the high frequency resonance slope of the vibrator. However, for some subjects, the differences exceeded ANSI tolerance levels for both vibrators, especially for the B-72 at 250, 2000, and 4000 Hz.
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PMID:Coupler output level differences resulting from repeated transducer placement. 374 20

A transformation was derived to convert sound-pressure levels referenced to an NBS-9A coupler to corresponding eardrum sound-pressure levels. It was found that the same transformation may be used for male and female adults and for both TDH-39 and TDH-49 earphones in MX-41/AR supra-aural cushions. It was determined that from 250-2000 Hz the transformation provides an eardrum sound-pressure level estimate that is within 6 dB of the actual eardrum level for 95% of individuals. However, in the 4000-6300-Hz range, the accuracy deteriorates to +/- 12 dB of actual eardrum level for 95% of individuals.
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PMID:NBS-9A coupler-to-eardrum transformation: TDH-39 and TDH-49 earphones. 394 38