scholarly journals Beyond the limits: identifying the high-frequency detectors in the anuran ear

2020 ◽  
Vol 16 (7) ◽  
pp. 20200343
Author(s):  
Ariadna Cobo-Cuan ◽  
T. Ulmar Grafe ◽  
Peter M. Narins

Despite the predominance of low-frequency hearing in anuran amphibians, a few frog species have evolved high-frequency communication within certain environmental contexts. Huia cavitympanum is the most remarkable anuran with regard to upper frequency limits; it is the first frog species known to emit exclusively ultrasonic signals. Characteristics of the Distortion Product Otoacoustic Emissions from the amphibian papilla and the basilar papilla were analysed to gain insight into the structures responsible for high-frequency/ultrasound sensitivity. Our results confirm the matching of vocalization spectra and inner ear tuning in this species. Compared to most anurans, H. cavitympanum has a hyperextended hearing range spanning from audible to ultrasonic frequencies, far above the previously established ‘spectral limits’ for the amphibian ear. The exceptional high-frequency sensitivity in the inner ear of H. cavitympanum illustrates the remarkable plasticity of the auditory system and the extent to which evolution can modify a sensory system to adapt it to its environment.

2013 ◽  
Vol 127 (10) ◽  
pp. 952-956 ◽  
Author(s):  
A Goyal ◽  
P P Singh ◽  
A Vashishth

AbstractObjectives:This study aimed to: understand the effect that high intensity noise associated with drilling (during otological surgery) has on hearing in the contralateral ear; determine the nature of hearing loss, if any, by establishing whether it is temporary or persistent; and examine the association between hearing loss and various drill parameters.Methods:A prospective clinical study was carried out at a tertiary centre. Thirty patients with unilateral cholesteatoma and normal contralateral hearing were included. Patients were evaluated pre-operatively and for five days following surgery using high frequency pure tone audiometry, and low and high frequency transient evoked and distortion product otoacoustic emission testing.Results:The findings revealed statistically significant changes in distortion product otoacoustic emissions at high frequencies (p = 0.016), and in transient evoked otoacoustic emissions at both low and high frequencies (p = 0.035 and 0.021, respectively). There was a higher statistical association between otoacoustic emission changes and cutting burrs compared with diamond burrs.Conclusion:Drilling during mastoid surgery poses a threat to hearing in the contralateral ear due to noise and vibration conducted transcranially.


2007 ◽  
Vol 25 (10) ◽  
pp. 1190-1195 ◽  
Author(s):  
Kristin R. Knight ◽  
Dale F. Kraemer ◽  
Christiane Winter ◽  
Edward A. Neuwelt

Purpose The objective is to describe progressive changes in hearing and cochlear function in children and adolescents treated with platinum-based chemotherapy and to begin preliminary evaluation of the feasibility of extended high-frequency audiometry and distortion product otoacoustic emissions for ototoxicity monitoring in children. Patients and Methods Baseline and serial measurement of conventional pure-tone audiometry (0.5 to 8 kHz) and evoked distortion product otoacoustic emissions (DPOAEs) were conducted for 32 patients age 8 months to 20 years who were treated with cisplatin and/or carboplatin chemotherapy. Seventeen children also had baseline and serial measurement of extended high-frequency (EHF) audiometry (9 to 16 kHz). Audiologic data were analyzed to determine the incidence of ototoxicity using the American Speech-Language-Hearing Association criteria, and the relationships between the different measures of ototoxicity. Results Of the 32 children, 20 (62.5%) acquired bilateral ototoxicity in the conventional frequency range during chemotherapy treatment, and 26 (81.3%) had bilateral decreases in DPOAE amplitudes and dynamic range. Of the 17 children with EHF audiometry results, 16 (94.1%) had bilateral ototoxicity in the EHF range. Pilot data suggest that EHF thresholds and DPOAEs show ototoxic changes before hearing loss is detected by conventional audiometry. Conclusion EHF audiometry and DPOAEs have the potential to reveal earlier changes in auditory function than conventional frequency audiometry during platinum chemotherapy in children.


2016 ◽  
Vol 22 ◽  
pp. 2028-2034 ◽  
Author(s):  
Ualace De Paula Campos ◽  
Stavros Hatzopoulos ◽  
Lech K. Śliwa ◽  
Piotr H. Skarżyński ◽  
Wiesław W. Jędrzejczak ◽  
...  

2002 ◽  
Vol 205 (16) ◽  
pp. 2525-2533 ◽  
Author(s):  
Stefan Schuster

SUMMARYGymnotiform weakly electric fish find their way in the dark using a continuously operating active sensory system. An electric organ generates a continuous train of discharges (electric organ discharges, EODs), and tuberous high-frequency electroreceptors monitor the pattern of transcutaneous current flow associated with each EOD. Here, I report that a prior interruption to the continuous train of EODs dramatically affects a response shown by many pulse-type gymnotids. In this so-called novelty response, fish normally raise their electrosensory sampling rate in response to novel sensory stimuli. The gymnotid Gymnotus carapo was induced to pause its EODs briefly, and the novelty response to sensory stimuli given post-pause was analyzed. Mechanosensory stimuli given as early as 20 EODs after a pause elicited clear novelty responses, but strong high-frequency electrical stimuli were ineffective at this time. Moreover, high-frequency electrical stimuli remained less efficient in eliciting normal-sized responses until approximately 2000 EODs, or 40s, after a pause. The post-pause inefficiency of high-frequency stimuli was not due to an inappropriate choice of intensity or their temporal patterning and did not result from the stimulation that caused the pausing. Low-frequency stimuli that also recruited ampullary electroreceptors were more efficient than high-frequency stimuli in eliciting post-pause responses. These findings show that continuous activity is required either to maintain sensitivity to high-frequency electrical stimuli or to ensure that such stimuli are able to modulate efficiently the pacemaker that sets the discharge frequency.


2016 ◽  
Vol 27 (1) ◽  
pp. 3-7
Author(s):  
Suchetha Rao ◽  
Ranjith Kumar ◽  
Jayashree Bhat ◽  
Nutan Kamath

Context: Vincristine chemotherapy has dose dependent ototoxicity. Early detection of ototoxicity is better with otoacoustic emissions and high frequency audiometry than conventional pure tone audiometry. The study was done to see if vincristine treatment interferes with hearing sensitivity in children.Methods and Material: A prospective study was conducted on twenty-three children with acute lymphoblastic leukemia (ALL) on Multi Center Protocol (MCP 841).These were subjected to conventional audiometry, high frequency audiometry and distortion product otoacoustic emissions (DPOAEs) before starting chemotherapy. The follow up audiological evaluation after early intensive phase chemotherapy (approximately 6 months) was conducted in thirteen children, who received 12 doses of vincristine (1.4 mg/m2), cranial irradiation of 1800cGy (>3 years) as per protocol and antibiotics as per clinical demands.Results: Baseline audiological evaluation was normal. Follow-up evaluation DPOAEs showed a declining tendency, however changes did not reach statistical significance. Differences in median hearing thresholds prior and post treatment in higher frequency audiometry were also minimal which was not statistically significant. Conventional audiometric thresholds were not altered.Conclusions: The reduction in the signal noise ratio of DPOAE, and reduced hearing sensitivity in high frequencies in post chemotherapy in comparison with baseline measures cannot be ignored though it has failed to reach the level of statistical significance. children on vincristine should have a pre chemotherapy and follow up audiological evaluation with DPOAE The results of the present study needs to be strengthened by including larger sample and long term follow up.Bangladesh J Medicine Jan 2016; 27(1) : 3-7


2009 ◽  
Vol 6 (2) ◽  
pp. 278-281 ◽  
Author(s):  
Sebastiaan W. F. Meenderink ◽  
Mirja Kits ◽  
Peter M. Narins

Acoustic communication involves both the generation and the detection of a signal. In the coqui frog ( Eleutherodactylus coqui ), it is known that the spectral contents of its calls systematically change with altitude above sea level. Here, distortion product otoacoustic emissions are used to assess the frequency range over which the inner ear is sensitive. It is found that both the spectral contents of the calls and the inner-ear sensitivity change in a similar fashion along an altitudinal gradient. As a result, the call frequencies and the auditory tuning are closely matched at all altitudes. We suggest that the animal's body size determines the frequency particulars of the call apparatus and the inner ear.


2003 ◽  
Vol 14 (09) ◽  
pp. 510-517 ◽  
Author(s):  
Susan E. Spirakis ◽  
Raymond M. Hurley

This study investigated the characteristics of hearing loss in children with ventriculoperitoneal (VP) shunted hydrocephalus. Twelve hydrocephalic children with patent VP shunts participated. The etiology of the hydrocephalus was either intraventricular hemorrhage or spina bifida. Audiometric examination included pure-tone air conduction thresholds, tympanometry, contralateral and ipsilateral acoustic reflex thresholds (ARTs), and distortion product otoacoustic emissions (DPOAEs). A unilateral, high-frequency, cochlear hearing loss was found in the ear ipsilateral to the shunt placement in 10 (83%) of the 12 shunt-treated hydrocephalic children. No hearing loss was observed in the ear contralateral to shunt placement. Based on the pure-tone audiometric findings, coupled with the decrease in DPOAE amplitude in the shunt ear, the hearing loss appears to be cochlear in nature. We suggest that cochlear hydrodynamics are disrupted as the result of reduced perilymph pressure, a consequence of cerebrospinal fluid (CSF) reduction due to the combined effects of a patent shunt and a patent cochlear aqueduct. In addition, a concomitant brain stem involvement is evidenced in the ART pattern, possibly produced by the patent shunt draining the CSF from the subdural space, resulting in cranial base hypoplasia.


2014 ◽  
Vol 1 (2) ◽  
pp. 140166 ◽  
Author(s):  
Kathrin Kugler ◽  
Lutz Wiegrebe ◽  
Benedikt Grothe ◽  
Manfred Kössl ◽  
Robert Gürkov ◽  
...  

Noise-induced hearing loss is one of the most common auditory pathologies, resulting from overstimulation of the human cochlea, an exquisitely sensitive micromechanical device. At very low frequencies (less than 250 Hz), however, the sensitivity of human hearing, and therefore the perceived loudness is poor. The perceived loudness is mediated by the inner hair cells of the cochlea which are driven very inadequately at low frequencies. To assess the impact of low-frequency (LF) sound, we exploited a by-product of the active amplification of sound outer hair cells (OHCs) perform, so-called spontaneous otoacoustic emissions. These are faint sounds produced by the inner ear that can be used to detect changes of cochlear physiology. We show that a short exposure to perceptually unobtrusive, LF sounds significantly affects OHCs: a 90 s, 80 dB(A) LF sound induced slow, concordant and positively correlated frequency and level oscillations of spontaneous otoacoustic emissions that lasted for about 2 min after LF sound offset. LF sounds, contrary to their unobtrusive perception, strongly stimulate the human cochlea and affect amplification processes in the most sensitive and important frequency range of human hearing.


Sign in / Sign up

Export Citation Format

Share Document