scholarly journals Reliability of pure‐tone detection thresholds for clinical and 2IFC procedures in quiet and in a noise background

1990 ◽  
Vol 88 (S1) ◽  
pp. S51-S51
Author(s):  
Lynne Marshall ◽  
Thomas E. Hanna ◽  
Richard H. Wilson
1991 ◽  
Vol 69 (8) ◽  
pp. 2059-2066 ◽  
Author(s):  
J. M. Terhune

In-air pure tone detection thresholds of a harbour seal (Phoca vitulina) were measured using behavioural psychophysical techniques. Thresholds dropped from about 70 dB re 20 μPa at 0.1 kHz to about 35 dB re 20 μ Pa at 4 kHz and then increased to about 45 dB re 20 μPa at 16 kHz. Increased sensitivities at 2 and 8 kHz, which have been reported in other pinnipeds, were not evident. In-air intensity detection thresholds averaged 32 dB above their underwater counterparts (1–16 kHz). Masking studies found the critical ratios at 0.25, 0.5, and 1 kHz to be 24, 15, and 21 dB, respectively (white noise masker). From 0.2 to 1.5 kHz, bandwidths 20 dB below the level of pure tone maskers were 0.16–0.18 kHz. Circumstantial evidence suggests the possibility that blood vascular changes associated with diving might also influence the sensitivity of the auditory systems of seals. Under optimal conditions, a pup's airborne cries may be detected by its mother at ranges of 1 km or more.


1978 ◽  
Vol 63 (S1) ◽  
pp. S64-S64
Author(s):  
L. L. Elliott ◽  
D. R. Katz

2021 ◽  
Vol 15 ◽  
Author(s):  
Miriam I. Marrufo-Pérez ◽  
Peter T. Johannesen ◽  
Enrique A. Lopez-Poveda

The roles of the medial olivocochlear reflex (MOCR) in human hearing have been widely investigated but remain controversial. We reason that this may be because the effects of MOCR activation on cochlear mechanical responses can be assessed only indirectly in healthy humans, and the different methods used to assess those effects possibly yield different and/or unreliable estimates. One aim of this study was to investigate the correlation between three methods often employed to assess the strength of MOCR activation by contralateral acoustic stimulation (CAS). We measured tone detection thresholds (N = 28), click-evoked otoacoustic emission (CEOAE) input/output (I/O) curves (N = 18), and distortion-product otoacoustic emission (DPOAE) I/O curves (N = 18) for various test frequencies in the presence and the absence of CAS (broadband noise of 60 dB SPL). As expected, CAS worsened tone detection thresholds, suppressed CEOAEs and DPOAEs, and horizontally shifted CEOAE and DPOAE I/O curves to higher levels. However, the CAS effect on tone detection thresholds was not correlated with the horizontal shift of CEOAE or DPOAE I/O curves, and the CAS-induced CEOAE suppression was not correlated with DPOAE suppression. Only the horizontal shifts of CEOAE and DPOAE I/O functions were correlated with each other at 1.5, 2, and 3 kHz. A second aim was to investigate which of the methods is more reliable. The test–retest variability of the CAS effect was high overall but smallest for tone detection thresholds and CEOAEs, suggesting that their use should be prioritized over the use of DPOAEs. Many factors not related with the MOCR, including the limited parametric space studied, the low resolution of the I/O curves, and the reduced numbers of observations due to data exclusion likely contributed to the weak correlations and the large test–retest variability noted. These findings can help us understand the inconsistencies among past studies and improve our understanding of the functional significance of the MOCR.


2014 ◽  
Vol 494-495 ◽  
pp. 171-174 ◽  
Author(s):  
Gui Ling Tan ◽  
Yu Ming Qi ◽  
San Peng Deng ◽  
De Hua Miao ◽  
Wen Hua Gao

At present, the detection accuracy of monitoring method by human ears is not satisfying in the pure tone detection of on-vehicle loudspeakers. To solve this problem, a new method is proposed to convert vehicle loudspeakers response signals into a two-dimensional image signal via wavelet packet analysis, which can increase the time-frequency of malfunction information. Through image binaryzation and pretreatment image-edge detection, the resulting signal would be recognized with box-counting dimension acquired in the process of gaining time-frequency image through fractal dimension as malfunctioned indications. Experiments show a rate of fault recognition as high as 95% , which meet the requirements of online vehicle loudspeaker detection.


2001 ◽  
Vol 204 (2) ◽  
pp. 175-183 ◽  
Author(s):  
L.B. Fletcher ◽  
J.D. Crawford

Mormyrid electric fish use sounds for communication and have unusual ears. Each ear has a small gas-filled tympanic bladder coupled to the sacculus. Although it has long been thought that this gas-filled structure confers acoustic pressure sensitivity, this has never been evaluated experimentally. We examined tone detection thresholds by measuring behavioral responses to sounds in normal fish and in fish with manipulations to one or to both of the tympanic bladders. We found that the tympanic bladders increase auditory sensitivity by approximately 30 dB in the middle of the animal's hearing range (200–1200 Hz). Normal fish had their best tone detection thresholds in the range 400–500 Hz, with thresholds of approximately 60 dB (re 1 microPa). When the gas was displaced from the bladders with physiological saline, the animals showed a dramatic loss of auditory sensitivity. In contrast, control animals in which only one bladder was manipulated or in which a sham operation had been performed on both sides had normal hearing.


1994 ◽  
Vol 72 (11) ◽  
pp. 1863-1866 ◽  
Author(s):  
S. D. Turnbull

The masked pure tone thresholds of a harbour seal (Phoca vitulina) were measured at various angles using a white noise masker. The white noise source was placed at 0°, 30°, 60°, and 90° relative to the midline of the seal's head (0°). The masked pure tone thresholds for each angle were determined at 2, 4, 8, and 16 kHz. As the angle separating the signal and noise sources increased from 0° to 90°, the critical ratios of the harbour seal decreased by 1–4 dB. This shift in masked thresholds from a reference point of 0° azimuth was significant (H = 10.374, df = 3,16, p < 0.05). No significant difference was found in masked thresholds between 0° and 30° or between 60° and 90°. This indicates that if a noise source is separated by more than 30° relative to the location of a vocalizing seal, signal detection thresholds will be enhanced and communication distances increased.


1986 ◽  
Vol 24 (3) ◽  
pp. 269-275 ◽  
Author(s):  
Jack B. Kelly ◽  
Gerard L. Kavanagh ◽  
James C.H. Dalton

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