Cooling Induces a Decrease in Middle Ear Compliance

Geal-Dor, Miriam; Khvoles, Roza; Sohmer, Haim

doi:10.1515/jbcpp.1997.8.3.127

Cited by 8 publications

(5 citation statements)

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“…For instance, decreasing the body temperature in rats reduces the compliance of the middle ear (Geal-Dor et al 1997), resulting in a small conductive loss with an airborne gap of 6 dB (Khvoles et al 1998). This conductive loss will reduce both the amplitudes of the two stimulus tones upon entering the inner ear, as well as the emission levels that are transmitted to the external ear.…”

Section: Discussionmentioning

confidence: 99%

Temperature Dependence of Anuran Distortion Product Otoacoustic Emissions

Meenderink

Dijk

2006

JARO

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To study the possible involvement of energy-dependent mechanisms in the transduction of sound within the anuran ear, distortion product otoacoustic emissions (DPOAEs) were recorded in the northern leopard frog over a range of body temperatures. The effect of body temperature depended on the stimulus levels used and on the hearing organ under investigation. Low-level DPOAEs from the amphibian papilla (AP) were reversibly depressed for decreased body temperatures. Apparently, DPOAE generation in the AP depends on metabolic rate, indicating the involvement of active processes in the transduction of sound. In contrast, in the other hearing organ, the basilar papilla (BP), the effects of body temperature on DPOAEs were less pronounced, irrespective of the stimulus levels used. Apparently, metabolic rate is less influencing DPOAE generation. We interpret these results as evidence that no amplifier is involved in sound transduction in the BP. The passive functioning of the anuran BP would place this hearing organ in a unique position within tetrapod hearing, but may actually be beneficial to ectothermic species because it will provide the animal with a consistent spectral window, regardless of ambient or body temperature.

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Section: Discussionmentioning

confidence: 99%

Temperature Dependence of Anuran Distortion Product Otoacoustic Emissions

Meenderink

Dijk

2006

JARO

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“…These results converge with previous works indicating the integrity of the tympanic ossicular system. 16,17 In mice, Cordas et al 7 showed that the lack of maternal THs is essential for the development of the tympanic ossicular system. The activation of thyroid receptors TRα1 and TRß is required in the gestational period, and its absence can delay ossicular maturation, leading to middle ear dysfunction.…”

Section: Discussionmentioning

confidence: 99%

“…These results converge with previous works indicating the integrity of the tympanic ossicular system. 16 17 …”

Section: Discussionmentioning

confidence: 99%

The Induction of Hypothyroidism during Gestation Decreases Outer Hair Cell Motility in Rat Offspring

Oliveira

Trindade

Reis

et al. 2022

Int Arch Otorhinolaryngol

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Introduction Perinatal hypothyroidism has a negative repercussion on the development and maturation of auditory system function. However, its long-term effect on auditory function remains unsettled. Objective To evaluate the effect of prenatal hypothyroidism on the auditory function of adult offspring in rats. Methods Pregnant Wistar rats were given the antithyroid drug methimazole (0.02% -1-methylimidazole-2-thiol– MMI) in drinking water, ad libitum, from gestational day (GD) 9 to postnatal day 15 (PND15). Anesthetized offspring from MMI-treated dams (OMTD) and control rats were evaluated by tympanometry, distortion product otoacoustic emission (DPOAE), and auditory brainstem response (ABR) at PNDs 30, 60, 90, and 120. Results Our data demonstrated no middle ear dysfunction, with the OMTD compliance lower than that of the control group. The DPOAE revealed the absence of outer hair cells function, and the ABR showed normal integrity of neural auditory pathways up to brainstem level in the central nervous system. Furthermore, in the OMTD group, hearing loss was characterized by a higher electrophysiological threshold. Conclusion Our data suggest that perinatal hypothyroidism leads to irreversible damage to cochlear function in offspring.

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“…The types of anesthetics used for ABR evaluations can also produce significant decreases in body temperature (Bill, Hughes, & Stephens, 1989). If body temperature is not regulated during anesthesia, hypothermia may occur which can result in reduced middle ear compliance and CNS depression, both causing increases in ABR thresholds (Geal-Dor, Khvoles, & Sohmer, 1997;Hett, Smith, Pilkington, & Abbott, 1995;Rodriguez, Audenaert, Austin, & Edmonds, 1995). Controlling anesthesia and temperature during ABR evaluations will help to increase the quality of the biopotential data collected and decrease threshold variability on study.…”

Section: Abr Evaluation Limitationsmentioning

confidence: 99%