Low‐frequency underwater hearing sensitivity in belugas, Delphinapterus leucas

1988 ◽  
Vol 84 (6) ◽  
pp. 2273-2275 ◽  
Author(s):  
Frank T. Awbrey ◽  
Jeanette A. Thomas ◽  
Ronald A. Kastelein
2017 ◽  
Vol 284 (1864) ◽  
pp. 20171670 ◽  
Author(s):  
Molly C. Womack ◽  
Jakob Christensen-Dalsgaard ◽  
Luis A. Coloma ◽  
Juan C. Chaparro ◽  
Kim L. Hoke

Sensory losses or reductions are frequently attributed to relaxed selection. However, anuran species have lost tympanic middle ears many times, despite anurans' use of acoustic communication and the benefit of middle ears for hearing airborne sound. Here we determine whether pre-existing alternative sensory pathways enable anurans lacking tympanic middle ears (termed earless anurans) to hear airborne sound as well as eared species or to better sense vibrations in the environment. We used auditory brainstem recordings to compare hearing and vibrational sensitivity among 10 species (six eared, four earless) within the Neotropical true toad family (Bufonidae). We found that species lacking middle ears are less sensitive to high-frequency sounds, however, low-frequency hearing and vibrational sensitivity are equivalent between eared and earless species. Furthermore, extratympanic hearing sensitivity varies among earless species, highlighting potential species differences in extratympanic hearing mechanisms. We argue that ancestral bufonids may have sufficient extratympanic hearing and vibrational sensitivity such that earless lineages tolerated the loss of high frequency hearing sensitivity by adopting species-specific behavioural strategies to detect conspecifics, predators and prey.


1978 ◽  
Vol 72 (1) ◽  
pp. 43-55 ◽  
Author(s):  
N.H. FLETCHER ◽  
K. G. HILL

The male cicada of the species Cystosoma saundersii has a grossly enlarged, hollow abdomen and emits a loud calling song with a fundamental frequency of about 800 Hz. At the song frequency, its hearing is nondirectional. The female of C. saundersii lacks sound producing organs, has no enlargement of the abdomen, but possesses an abdominal air sac and has well developed directional hearing at the frequency of the species' song. Physical mechanisms are proposed that explain these observations in semi-quantitative detail using the standard method of electrical network analogues. The abdomen in the male, with its enclosed air, is found to act as a system resonant at the song frequency, thus contributing a large gain in radiated sound intensity. Coupling between this resonator and the auditory tympana accounts for the observed hearing sensitivity in the male, but destroys directionality. In the female, the abdominal cavity acts in association with the two auditory tympana as part of a phase shift network which results in appreciable directionality of hearing at the unusually low frequency of the male song.


1999 ◽  
Vol 105 (2) ◽  
pp. 1298-1298 ◽  
Author(s):  
John R. Sims ◽  
David M. Fothergill ◽  
Michael D. Curley

2006 ◽  
Vol 17 (03) ◽  
pp. 168-178 ◽  
Author(s):  
Melinda C. Freyaldenhoven ◽  
Patrick N. Plyler ◽  
James W. Thelin ◽  
Anna K. Nabelek ◽  
Samuel B. Burchfield

The present study investigated the effects of gain compensation and venting on front-to-back ratios (FBRs), speech understanding in noise, and acceptance of noise in 19 listeners with hearing impairment utilizing directional hearing instruments. The participants were separated into two groups based on degree of low-frequency hearing sensitivity. Subjects were fitted binaurally with Starkey Axent II programmable behind-the-ear hearing aids and full-shell earmolds (select-a-vent). Results demonstrated that gain compensation and venting significantly affected FBRs for both groups; however, acceptance of noise was not significantly affected by gain compensation or venting for either group. Results further demonstrated that speech understanding in noise was unaffected by venting but may be improved with the use of gain compensation for some listeners. Clinical implications are discussed.


1990 ◽  
Vol 33 (4) ◽  
pp. 816-821 ◽  
Author(s):  
Craig A. Champlin ◽  
Stephen P. Muller ◽  
Stephen A. Mitchell

Ear canal sound pressure levels were measured from a 38-year-old woman who had experienced objective tinnitus in her right ear for approximately 2 years. The tinnitus sounded like a series of “sighs” that were synchronous with her pulse rate. Because the level of the tinnitus fluctuated in a pulsing manner, it appeared to be of vascular origin. Psychoacoustically, the tinnitus behaved like a low-pass masker (cutoff frequency = 1.5 kHz) of about 40 dB SPL. This masking effect was manifested as a low-frequency hearing loss in the subject’s right ear. A miniature microphone system was used to monitor the tinnitus before, during, and after a jugular-vein ligation. Because the cause of the tinnitus was only generally known, acoustically monitoring the sound as the jugular vein and/or its tributaries were systematically clamped and then released enabled the site of generation to be known exactly. By monitoring the tinnitus during surgery, the effectiveness of the corrective procedure could be immediately evaluated. Hearing sensitivity in the affected ear returned to normal limits following the elimination of the tinnitus. One year after the surgery, the tinnitus was barely audible to the woman, but only when she positioned her head a specific way. The level of the tinnitus measured in this head-turned condition was markedly lower than the level obtained preoperatively.


2011 ◽  
Vol 22 (07) ◽  
pp. 393-404 ◽  
Author(s):  
Elizabeth D. Leigh-Paffenroth ◽  
Saravanan Elangovan

Background: Hearing loss and age interfere with the auditory system's ability to process temporal changes in the acoustic signal. A key unresolved question is whether high-frequency sensorineural hearing loss (HFSNHL) affects temporal processing in the low-frequency region where hearing loss is minimal or nonexistent. A second unresolved question is whether changes in hearing occur in middle-aged subjects in the absence of HFSNHL. Purpose: The purpose of this study was twofold: (1) to examine the influence of HFSNHL and aging on the auditory temporal processing abilities of low-frequency auditory channels with normal hearing sensitivity and (2) to examine the relations among gap detection measures, self-assessment reports of understanding speech, and functional measures of speech perception in middle-aged individuals with and without HFSNHL. Research Design: The subject groups were matched for either age (middle age) or pure-tone sensitivity (with or without hearing loss) to study the effects of age and HFSNHL on behavioral and functional measures of temporal processing and word recognition performance. These effects were analyzed by individual repeated-measures analyses of variance. Post hoc analyses were performed for each significant main effect and interaction. The relationships among the measures were analyzed with Pearson correlations. Study Sample: Eleven normal-hearing young adults (YNH), eight normal-hearing middle-aged adults (MANH), and nine middle-aged adults with HFSNHL were recruited for this study. Normal hearing sensitivity was defined as pure-tone thresholds ≤25 dB HL for octave frequencies from 250 to 8000 Hz. HFSNHL was defined as pure-tone thresholds ≤25 dB HL from 250 to 2000 Hz and ≥35 dB HL from 3000 to 8000 Hz. Data Collection and Analysis: Gap detection thresholds (GDTs) were measured under within-channel and between-channel conditions with the stimulus spectrum limited to regions of normal hearing sensitivity for the HFSNHL group (i.e., <2000 Hz). Self-perceived hearing problems were measured by a questionnaire (Abbreviated Profile of Hearing Aid Benefit), and word recognition performance was assessed under four conditions: quiet and babble, with and without low-pass filtering (cutoff frequency = 2000 Hz). Results: The effects of HFSNHL and age were found for gap detection, self-perceived hearing problems, and word recognition in noise. The presence of HFSNHL significantly increased GDTs for stimuli presented in regions of normal pure-tone sensitivity. In addition, middle-aged subjects with normal hearing sensitivity reported significantly more problems hearing in background noise than the young normal-hearing subjects. Significant relationships between self-report measures of hearing ability in background noise and word recognition in babble were found. Conclusions: The conclusions from the present study are twofold: (1) HFSNHL may have an off-channel impact on auditory temporal processing, and (2) presenescent changes in the auditory system of MANH subjects increased self-perceived problems hearing in background noise and decreased functional performance in background noise compared with YNH subjects.


1981 ◽  
Vol 24 (1) ◽  
pp. 108-112 ◽  
Author(s):  
P. M. Zurek ◽  
C. Formby

Thresholds for frequency modulation were measured by an adaptive, two-alternative, forced-choice method with ten listeners: eight who showed varying degrees of sensorineural hearing impairment, and two with normal-hearing sensitivity. Results for test frequencies spaced at octave intervals between 125 and 4000 Hz showed that, relative to normal-hearing listeners, the ability of the hearing-impaired listeners to detect a sinusoidal frequency modulation: (1) is diminished above a certain level of hearing loss; and (2) is more disrupted for low-frequency tones than for high-frequency tones, given the same degree of hearing loss at the test frequency. The first finding is consistent with that of previous studies which show a general deterioration of frequency-discrimination ability associated with moderate, or worse, hearing loss. It is proposed that the second finding may be explained: 1) by differential impairment of the temporal and place mechanisms presumed to, encode pitch at the lower and higher frequencies, respectively; and/or, 2) for certain configurations of hearing loss, by the asymmetrical pattern of cochlear excitation that may lead to the underestimation, from measurements of threshold sensitivity, of hearing impairment for low-frequency tones and consequently to relatively large changes in frequency discrimination for small shifts in hearing threshold.


2020 ◽  
Vol 29 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Margaret T. Dillon ◽  
Emily Buss ◽  
Brendan P. O'Connell ◽  
Meredith A. Rooth ◽  
English R. King ◽  
...  

Purpose The goal of this work was to evaluate the low-frequency hearing preservation of long electrode array cochlear implant (CI) recipients. Method Twenty-five participants presented with an unaided hearing threshold of ≤ 80 dB HL at 125 Hz pre-operatively in the ear to be implanted. Participants were implanted with a long (31.5-mm) electrode array. The unaided hearing threshold at 125 Hz was compared between the preoperative and postoperative intervals (i.e., initial CI activation, and 1, 3, 6, 9, and 12 months after activation). Results Eight participants maintained an unaided hearing threshold of ≤ 80 dB HL at 125 Hz postoperatively. The majority ( n = 5) demonstrated aidable low-frequency hearing at initial activation, whereas 3 other participants experienced an improvement in unaided low-frequency hearing thresholds at subsequent intervals. Conclusions CI recipients can retain residual hearing sensitivity with fully inserted long electrode arrays, and low-frequency hearing thresholds may improve during the postoperative period. Therefore, unaided hearing thresholds obtained within the initial weeks after surgery may not reflect later hearing sensitivity. Routine measurement of postoperative unaided hearing thresholds—even for patients who did not demonstrate aidable hearing thresholds initially after cochlear implantation—will identify CI recipients who may benefit from electric–acoustic stimulation. Supplemental Material https://doi.org/10.23641/asha.11356637


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