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Biomedical subjects

T Frank

Publications and source records attributed to T Frank.

At least 19 recordsLinked to original sources
PubMed1992

Attenuation values for a supra-aural earphone for children and insert earphone for children and adults.

Earphone attenuation values were determined for 17 children (6-14 years old) using supra-aural (TDH-49P/Model 51 cushion) and insert earphones (E-A-Rtone 3A) terminated by an E-A-Rlink 3A (for normal size ear canals) or E-A-Rlink 3B (for small size ear canals) foam eartips, and for 10 adults having small ear canals using insert earphones and E-A-Rlink 3B foam eartips. The test signals were 1/3-octave bands of noise presented in a diffuse sound field (re: ANSI S12.6-1984). The supra-aural earphone attenuation values for the children were slightly higher (more attenuation) or similar to reported adult values, and always lower (less attenuation) compared with insert earphone/E-A-Rlink 3A (IE/3A) or 3B (IE/3B) values for both children and adults. The IE/3B attenuation values were similar between the children and adults and provided slightly more attenuation than the IE/3A. Overall, the results indicated that the ANSI S3.1-1991 maximum permissible ambient noise levels allowed in a test room for ears covered testing with a supra-aural earphone, which were determined using adult values, are appropriate for testing children. Future revisions of ANSI S3.1-1991 may include maximum permissible ambient noise levels for testing with insert earphones. The IE/3A and IE/3B attenuation values could be used for that purpose. In the meantime, because more attenuation was provided by the IE/3A and IE/3B, they can be used for testing both children and adults in higher ambient noise levels than specified in ANSI S3.1-1991.

Acoustic Stimulation↗
PubMed1992

Reference threshold levels for an ER-3A insert earphone.

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.

Adolescent↗
PubMed1991

Hearing aid coupler output level variability and coupler correction levels for insert earphones.

HA coupler type SPLs were independently determined by two experimenters for five repeated measurements with and without replacement of two ER-3A and two EARTONE 3A insert earphones. Measurements were made using a B&K DB-0138 coupler configured as an HA-1, HA-2 earphone coupler and HA-2 earphone coupler with entrance through a rigid tube referred to as the DB-0138 coupler. The HA-1, HA-2, and DB-0138 SPLs were found to be very stable (+/- 0.2 dB) for all intra- and interexperimenter measurements for each insert earphone and coupler type from 125 to 8000 Hz. Averaged across both experimenters and all repeated measurements, the mean HA-1 and HA-2 coupler SPLs were similar for each insert earphone from 125 to 8000 Hz. The mean HA-1, HA-2, and DB-0138 coupler SPLs were similar for each insert earphone from 125 to 2000 Hz; however, from 3000 to 8000 Hz the DB-0138 coupler SPLs were higher than the HA-1 and HA-2 coupler SPLs for each insert earphone. This occurred because of the geometrical differences between the insert earphone to coupler connections and coupler types. The HA-1 minus DB-0138 and HA-2 minus DB-0138 coupler SPL differences, or coupler correction levels, could be explained by quarter-wave resonances and stepped-diameter tubing systems creating acoustic horn effects.

Auditory Threshold↗
PubMed1991

Repeatability of high-frequency thresholds.

High-frequency (10, 12, 14, 16, and 18 kHz) thresholds were obtained for each ear of 50 young adults having normal low-frequency hearing across four test sessions separated by at least 1, but no more than 2, weeks using a Beltone 2000 audiometer. The threshold differences between each possible test session comparison (N = 6) were not significantly (p greater than 0.05) different for ear, test session comparison, or frequency. Overall, intrasubject high-frequency thresholds were found to be repeatable and within a clinically acceptable range of +/- 10 dB for at least 94% of the ears, regardless of test session comparison and frequency.

Adult↗
PubMed1990

Attenuation provided by four different audiometric earphone systems.

The attenuation provided by TDH earphones in MX-41/AR and P/N 51 cushions, Audiocup earphone enclosures and ER-3A insert earphones with ER3-14 foam earplugs was determined for 30 normally hearing subjects using a real-ear attenuation at threshold paradigm. The MX-41/AR and P/N 51 cushions provided about the same amount of attenuation which was less than the attenuation provided by the Audiocup enclosures. The ER-3A/ER3-14 provided the highest amount of attenuation. The MX-41/AR and ER-3A/ER3-14 attenuation values were in agreement with other studies using similar methodology. However, the attenuation provided by the Audiocup enclosures was considerably less, in the lower frequencies, than reported in two other studies. ANSI S3.1-1977 supra-aural earphone cushion attenuation values, which were determined using pure-tones presented in a free-field, should be replaced by earphone cushion attenuation values determined with 1/3 octave bands of noise presented in a diffuse sound field.

Adult↗
PubMed1990

High-frequency hearing thresholds in young adults using a commercially available audiometer.

Test and re-test high-frequency (10-20 kHz) thresholds were obtained for 200 ears of 100 normally hearing (0.25-8 kHz) young adults (18-28 years old) using a Beltone 2000 audiometer and Sennheiser HD 250 earphones referenced to sound pressure levels developed in a Bruel and Kjaer flat-plate coupler. Normative high-frequency thresholds could not be recommended for clinical use due to the very large intersubject threshold variability. This occurred even though test versus re-test thresholds were not significantly different (p greater than 0.05) at any frequency. However, comparisons of the test minus re-test threshold for individual ears were within a clinically acceptable range of +/- 10 dB for at least 95% of the ears at each frequency. Future research should concern intrasubject threshold reliability and variability rather than specifying intersubject normative thresholds.

Adolescent↗
PubMed1989

[Antiphlogistic effect of bromelaine following third molar removal].

A placebo-controlled double-blind study of 100 patients with impacted and/or dislocated lower wisdom teeth was conducted to examine the tolerance and antiphlogistic efficacy of bromelaine--a mixture of proteolytic enzymes from ananas comosus. Treatment was started 1 day prior to third molar surgery with a daily dose of 3 x 80 mg and was continued for a total of 6 days. On the 1st day following surgery, linear measurement (distance: tragus-pogonion) showed swelling to be 7.5% lower under drug treatment than in the placebo group. Two-dimensional image evaluation increased this difference to 15.9%, which however still failed to attain the significance level of 20%. Between the 3rd and the 7th postoperative day no differences were found between the two groups regarding the extent of soft tissue swelling or the speed of edema resolution.

Adolescent↗
PubMed1988

Bone conduction threshold levels for different bone vibrator types.

This study determined if bone conduction (BC) thresholds were influenced by vibrator type. BC thresholds were obtained for 100 subjects using mastoid placement of Radioear B-71 and B-72 and Pracitronic KH 70 bone vibrators. The nontest ear was masked (30 dB EL) and the ear ipsilateral to the vibrator was open except when testing at 3000 and 4000 Hz when the ear canal was occluded with an earplug to guard against acoustic radiation. BC thresholds at 250 Hz obtained with the B-72 and KH 70 were significantly (p less than .05) higher by 10.5 dB and at 500 Hz were significantly (p less than .05) lower by 5.5 dB than for the B-71. BC thresholds at other frequencies (1000, 2000, 3000, and 4000 Hz) were not significantly different among vibrator types. The findings indicated that reference equivalent threshold force levels (RETFLs) for BC audiometry should be specified by bone vibrator type.

Adult↗
PubMed1987

Accuracy of a 40 dB HL Audioscope and audiometer screening for adults.

This study determined the accuracy of an AudioScope (AS) and pure-tone audiometer (PTA) screening at 40 dB HL from 500 to 4000 Hz in reference to a pure-tone threshold (PTT) test on 1210 ears of adult subjects 20 to 96 yr old. The overall results (averaged over age group and frequency) indicated that the AS and PTA screenings were equally accurate in reference to the PTT test. Averaged over the screening tests, the sensitivity was 91.4% with a false negative rate of 8.6% and the specificity was 93.5% with a false positive rate of 6.5%. As a function of age (averaged over frequency), the AS and PTA screenings had similar accuracy and decreased as age increased to about 60 yr old and then remained stable. As a function of frequency (averaged over age), each screening test had similar accuracy for each frequency. It was concluded that the results of a 40 dB HL AS or PTA screening are very accurate in reference to a PTT test.

Adult↗
PubMed1987

Repeatability of high-frequency bone conduction thresholds.

The purpose of this study was to determine the repeatability of high-frequency, bone conduction thresholds and to increase the data base concerning high-frequency, bone conduction threshold levels. Bone conduction thresholds were obtained on 30 subjects having normal, low, and mid frequency (0.25 to 8 kHz) hearing thresholds within and across five test sessions using a Pracitronic KH 70 bone vibrator referenced to a Brüel and Kjaer 4930 mechanical coupler at 1, 4, 8, 10, 12, 14, and 16 kHz. Within and across sessions, the bone conduction thresholds were not significantly (p greater than 0.05) different at each frequency indicating that repeated testing without replacing the bone vibrator (within session) and with replacing the bone vibrator (across session) did not influence the threshold measurements. Clinical implications concerning high-frequency, bone conduction audiometry are discussed.

Adult↗
PubMed1986

Random-clone strategy for genomic restriction mapping in yeast.

An approach to global restriction mapping is described that is applicable to any complex source DNA. By analyzing a single restriction digest for each member of a redundant set of lambda clones, a data base is constructed that contains fragment-size lists for all the clones. The clones are then grouped into subsets, each member of which is related to at least one other member by a significant overlap. Finally, a tree-searching algorithm seeks restriction maps that are consistent with the fragment-size lists for all the clones in each subset. The feasibility of the approach has been demonstrated by collecting data on 5000 lambda clones containing random 15-kilobase inserts of yeast DNA. It is shown that these data can be analyzed to produce regional maps of the yeast genome, extending in some cases for over 100 kilobases. In combination with hybridization probes to previously cloned genes, these local maps are already useful for defining the physical arrangement of closely linked genes. They may in the future serve as building blocks for the construction of a continuous global map.

Chromosome Mapping↗
PubMed1986

Coupler output level differences resulting from repeated transducer placement.

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.

Audiometry↗
PubMed1986

Acoustic radiation produced by B-71, B-72, and KH 70 bone vibrators.

The amount of acoustic radiation produced by two samples of a Radioear B-71, B-72, and Pracitronic KH 70 bone vibrator was determined for 30 normal-hearing subjects at 4000 Hz. The mean amount of acoustic radiation was very similar for both samples of each vibrator type but significantly (p less than 0.05) different between the bone vibrator types. The mean amount of acoustic radiation averaged over both samples was 8.3 dB for the B-72, 4.3 dB for the B-71, and -0.3 dB for the KH 70. Individual subject data indicated that the B-72 produced excessive acoustic radiation (greater than 5 dB) for 80% of the subjects, the B-71 for 38% of the subjects, and the KH 70 for 8% of the subjects which could cause an invalid high-frequency air-bone gap. Precautions should be taken during bone conduction audiometry to eliminate the possibility of acoustic radiation produced by bone vibrators. A need for additional standards in this area is stressed.

Acoustics↗