scholarly journals Accounting for the Occlusion Effect with Insert Earphones

2018 ◽  
Vol 29 (09) ◽  
pp. 826-834
Author(s):  
Dorothy Neave-DiToro ◽  
Amanda DeSantolo ◽  
Michael Bergen ◽  
Adrienne Rubinstein
Keyword(s):  
Bone Conduction ◽  
Published Data ◽  
Ear Canal ◽  
Within Subjects ◽  
Clinically Significant ◽  
Mean Differences ◽  
The One ◽  
Insert Earphones ◽  
Occlusion Effect ◽  
Spurious Results

AbstractThere are clinical implications associated with knowing when the occlusion effect (OE) must be accounted for during bone conduction (BC) testing because spurious results can occur when errors are made in this regard. The amount of OE produced when insert earphones (IEs) are used varies in the literature; thus, further investigation is warranted.The purpose of this project was to determine the OE during BC threshold measurements under the following occluding conditions used clinically: when using partial insertion (PI) versus full insertion (FI) depth and when occluding one versus both ears.A descriptive within-subjects design was used in this study.Twenty-two adults with mean four-frequency pure tone averages of 24 dB HL, aged 40–83 yr, participated.BC thresholds were obtained at 250, 500, and 1000 Hz under seven conditions: (1) both ears unoccluded, (2) left ear occluded with PI, (3) right ear occluded with PI, (4) both ears occluded with PI, (5) left ear occluded with FI, (6) right ear occluded with FI, (7) both ears occluded with FI. For PI, one half of the length of the IE was beyond the opening of the ear canal. For FI, the lateral edge of the foam insert was flush with the entrance to the ear canal.Mean OEs were compared with previously published data. In addition, variability in the data was examined using frequency distribution plots as well as cumulative frequency and percentile values.Mean OEs of 5–13 dB were present in all but the FI condition at 1000 Hz where the OE was <3 dB. Differences between PI and FI conditions were present at each frequency measured, irrespective of whether one or both ears were occluded. The shifts in threshold were consistently more prevalent and greater for the PI than the FI conditions overall. Mean differences between the one-ear and both-ears conditions were not clinically significant. Clinically significant variability in the data was noted, except when comparing the one-ear versus both-ears conditions.Occluding the ear during initial BC measurements may artificially improve the thresholds and create or exaggerate an air-bone gap. Thus, initial BC testing should be performed unoccluded at 250, 500, and 1000 Hz. There is a need to account for the OE even when the IE is flush with the ear canal to avoid insufficient masking.

The Occlusion Effect in Bone Conduction Hearing

1965 ◽  
Vol 8 (2) ◽  
pp. 137-148 ◽  
Author(s):  
David P. Goldstein ◽  
Claude S. Hayes
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Bone Conduction ◽  
Pressure Level ◽  
Ear Canal ◽  
Significant Difference ◽  
Threshold Measure ◽  
Level Shifts ◽  
Positive Correlations ◽  
Occlusion Effect

This experiment tested the hypothesis that the occlusion effect is accompanied by an increase in sound pressure level in the external auditory canal. Pure tone bone conduction thresholds and sound pressure levels were measured, first with the ear canal open, then with the ear canal closed, at two positions of the bone vibrator and at five frequencies in 28 normal listeners. Statistical analyses revealed a significant difference between measures at 250, 500, and 1 000 cps but not at 2 000 and 4 000 cps. Average sound pressure level shifts tended to be larger than their threshold measure counterparts. The two measures, nevertheless, yielded positive correlations.

Occlusion Effect of the External‐Ear Canal and Its Effect upon Bone Conduction

1964 ◽  
Vol 36 (5) ◽  
pp. 1049-1049 ◽  
Author(s):  
Juergen Tonndorf ◽  
Elliot C. Greenfield ◽  
Roger S. Kaufman
Keyword(s):  
Bone Conduction ◽  
External Ear ◽  
Ear Canal ◽  
External Ear Canal ◽  
Occlusion Effect

Insert Earphone Depth and the Occlusion Effect

2000 ◽  
Vol 9 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Margaret S. Dean ◽  
Frederick N. Martin
Keyword(s):  
Bone Conduction ◽  
Deep Insertion ◽  
Insert Earphones ◽  
Occlusion Effect

Twenty individuals were tested to determine the occlusion effect caused by supraaural earphones and by insert earphones with shallow and deep insertion of its foam eartip. The bone-conduction oscillator was placed both on the forehead and the mastoid. It was concluded that using deeply inserted earphones is the most practical way in which to carry out clinical bone-conduction measurements.

The Occlusion Effect and Ear Canal Sound Pressure Level

1998 ◽  
Vol 7 (2) ◽  
pp. 50-54 ◽  
Author(s):  
Marc A. Fagelson ◽  
Frederick N. Martin
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Bone Conduction ◽  
Frontal Bone ◽  
Pressure Level ◽  
Mastoid Process ◽  
Ear Canal ◽  
External Canal ◽  
Pure Tones ◽  
Occlusion Effect

Comparisons were made between changes in the audibility of bone-conduction stimuli to differences in the sound pressure present in the external auditory canal when ears were occluded. Fifteen listeners with normal middle ear function were tested using pure tones of 250, 500, and 1000 Hz, delivered via a bone-conduction oscillator placed on the mastoid process and the frontal bone. At all three frequencies, and both sites of stimulation, ear canal sound pressures were greater in the occluded than in the unoccluded conditions. Concurrently, the test signals were detected at lower intensities, although the changes in audibility and external canal sound pressure levels were not unity. The occlusion effect was attenuated slightly when the skull was vibrated from the frontal bone.

The Occlusion Effect in Unilateral Functional Hearing Loss

1970 ◽  
Vol 13 (1) ◽  
pp. 37-40
Author(s):  
Gary Thompson ◽  
Marie Denman
Keyword(s):  
Hearing Loss ◽  
Bone Conduction ◽  
Low Frequency ◽  
Clinical Implications ◽  
The Right ◽  
Occlusion Effect

Bone-conduction tests were administered to subjects who feigned a hearing loss in the right ear. The tests were conducted under two conditions: With and without occlusion of the non-test ear. It was anticipated that the occlusion effect, a well-known audiological principle, would operate to draw low frequency bone-conducted signals to the occluded side in a predictable manner. Results supported this expectation and are discussed in terms of their clinical implications.

scholarly journals Review of Bone Conduction Hearing Devices

2021 ◽  
Vol 11 (2) ◽  
pp. 207-219
Author(s):  
Susan E. Ellsperman ◽  
Emily M. Nairn ◽  
Emily Z. Stucken
Keyword(s):  
Hearing Aid ◽  
Bone Conduction ◽  
Sound Transmission ◽  
Ear Canal ◽  
Hearing Devices ◽  
Bone Conduction Hearing ◽  
Single Sided Deafness

Bone conduction is an efficient pathway of sound transmission which can be harnessed to provide hearing amplification. Bone conduction hearing devices may be indicated when ear canal pathology precludes the use of a conventional hearing aid, as well as in cases of single-sided deafness. Several different technologies exist which transmit sound via bone conduction. Here, we will review the physiology of bone conduction, the indications for bone conduction amplification, and the specifics of currently available devices.

Thorough QT Study to Evaluate the Effect of Zoliflodacin, a Novel Therapeutic for Gonorrhea, on Cardiac Repolarization in Healthy Adults

2021 ◽  
Author(s):  
Lori M. Newman ◽  
Martin Kankam ◽  
Aya Nakamura ◽  
Tom Conrad ◽  
John Mueller ◽  
...  
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Cardiac Repolarization ◽  
Cardiac Safety ◽  
Double Blind ◽  
Thorough Qt Study ◽  
Regulatory Guidelines ◽  
Clinically Significant ◽  
The One ◽  
Global Threat

Zoliflodacin is a novel spiropyrimidinetrione antibiotic being developed as single oral dose treatment to address the growing global threat of Neisseria gonorrhoeae . To evaluate the cardiac safety of zoliflodacin, a thorough QT/QTc (TQT) study was performed in healthy subjects. In this randomized, double-blind, placebo-controlled, 4-period crossover study, 72 subjects in a fasted state received a single dose of zoliflodacin 2 g (therapeutic), zoliflodacin 4 g (supratherapeutic), placebo, and moxifloxacin 400 mg as a positive comparator. Cardiac repolarization was measured by duration of the corrected QT interval by Fridericia’s formula (QTcF). At each time point up to 24 hours after zoliflodacin administration, the upper limit of the one-sided 95% confidence interval (CI) for the placebo-corrected change from the pre-dose baseline in QTcF (ΔΔQTcF) was less than 10 ms, indicating an absence of a clinically meaningful increase in QT prolongation. The lower limit of the one-sided multiplicity-adjusted 95% CI of ΔΔQTcF for moxifloxacin was longer than 5 ms at four time points from 1-4 hours after dosing, demonstrating adequate sensitivity of the QTc measurement. There were no clinically significant effects on heart rate, PR and QRS intervals, ECG morphology, or laboratory values. Treatment-emergent adverse events (AEs) were mild or moderate in severity and transient. This was a negative TQT study according to regulatory guidelines (E14) and confirms that a single oral dose of zoliflodacin is safe and well-tolerated. These findings suggest zoliflodacin is not proarrhythmic and contribute to the favorable assessment of cardiac safety for a single oral dose of zoliflodacin.

scholarly journals No Effect of a Single Supratherapeutic Dose of Lersivirine, a Next-Generation Nonnucleoside Reverse Transcriptase Inhibitor, on Corrected QT Interval in Healthy Subjects

2012 ◽  
Vol 56 (5) ◽  
pp. 2408-2413 ◽  
Author(s):  
Manoli Vourvahis ◽  
Rong Wang ◽  
Marie-Noella Ndongo ◽  
Melissa O'Gorman ◽  
Margaret Tawadrous
Keyword(s):  
Upper Bound ◽  
Healthy Subjects ◽  
Vital Signs ◽  
Transcriptase Inhibitor ◽  
Qtc Interval ◽  
Adult Males ◽  
Supratherapeutic Dose ◽  
Nonnucleoside Reverse Transcriptase Inhibitor ◽  
Clinically Significant ◽  
Mean Differences

ABSTRACTThe objective of this study was to investigate the effect of a supratherapeutic dose of lersivirine (LRV) on corrected QT (QTc) interval using Fridericia's equation (QTcF) in healthy subjects. In this randomized, single-dose, placebo- and active-controlled 3-way crossover study, healthy adult males (n= 48) were randomized to receive LRV (2,400 mg), moxifloxacin (400 mg), or placebo for each treatment period. Triplicate 12-lead electrocardiogram measurements were performed, PK samples were collected, and vital signs were measured. Adverse event monitoring and safety laboratory testing were performed. All subjects were white (mean age, 39 years; body mass index [BMI], 25.6 kg/m2) and completed the study. Following LRV administration, the upper bound of the 90% confidence interval (CI) for time-matched adjusted mean differences to placebo QTcF at each time point postdose was below the regulatory threshold of 10 ms, satisfying the criteria for a negative thorough QT/QTc study. The highest upper bound of QTcF 90% CI occurred at 6 h for LRV (3.32 ms; 90% CI, 1.47 to 5.17 ms). The study was deemed adequately sensitive as the lower bound of the 90% CI for the adjusted mean QTcF differences between moxifloxacin and placebo at the moxifloxacin historicalTmaxof 3 h was >5 ms (15.29 ms; 90% CI, 13.44 to 17.14 ms). There was no statistically significant relationship between LRV exposure and placebo-adjusted change from baseline QTcF or clinically significant changes in QRS complex, pulse rate (PR) interval, heart rate, or blood pressure. LRV (2,400 mg) did not prolong the QTcF interval, and no clinically relevant electrocardiogram or vital sign changes were observed in healthy subjects.

scholarly journals Platelet Counts in Stored Donor Blood

1982 ◽  
Vol 10 (3) ◽  
pp. 271-273 ◽  
Author(s):  
W. J. Russell ◽  
L. J. Tunbridge
Keyword(s):  
Blood Platelet ◽  
Platelet Activity ◽  
Normal Range ◽  
Donor Blood ◽  
Platelet Counts ◽  
Before And After ◽  
The Mean ◽  
Clinically Significant ◽  
The One ◽  
Citrate Phosphate

Platelets were counted in eight units each of one- and three-day-old blood. Counts were done both before and after the blood had passed through a standard 170 micron filter. In the one-day-old blood, platelet counts were within the normal range. The mean count was 237,000 platelets/microlitre. Platelet counts on three-day-old blood were lower, but generally still within the normal range. The mean count was 183,000/microlitre. Only a few platelets were retained by the filter in the transfusion set; about 90% of platelets passed the filter in both the one- and three-day-old blood. It appears that whole blood, anticoagulated with citrate/phosphate/dextrose (CPD), and stored under Australian blood bank conditions retains platelets in sufficient numbers for at least the first three days to be clinically significant. However, it remains to be determined whether satisfactory platelet activity can be expected during this time.

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