title: Big brown bats (Eptesicus fuscus) maintain hearing sensitivity after exposure to intense band-limited noise.
abstract: Thresholds to short-duration narrowband frequency-modulated (FM) sweeps were measured in six big brown bats (Eptesicus fuscus) in a two-alternative forced choice passive listening task before and after exposure to band-limited noise (lower and upper frequencies between 10 and 50 kHz, 1 h, 116-119 dB sound pressure level root mean square; sound exposure level 152 dB). At recovery time points of 2 and 5 min post-exposure, thresholds varied from -4 to +4 dB from pre-exposure threshold estimates. Thresholds after sham (control) exposures varied from -6 to +2 dB from pre-exposure estimates. The small differences in thresholds after noise and sham exposures support the hypothesis that big brown bats do not experience significant temporary threshold shifts under these experimental conditions. These results confirm earlier findings showing stability of thresholds to broadband FM sweeps at longer recovery times after exposure to broadband noise. Big brown bats may have evolved a lessened susceptibility to noise-induced hearing losses, related to the special demands of echolocation.
authors.affiliation: Department of Cognitive, Linguistic and Psychological Sciences, Brown University, 190 Thayer Street, Providence, Rhode Island 02912, USA.
authors.forename: Andrea Megela
authors.initials: AM
authors.lastname: Simmons
authors.affiliation: Department of Neuroscience, Brown University, 185 Meeting Street, Providence, Rhode Island 02912, USA.
authors.forename: Kelsey N
authors.initials: KN
authors.lastname: Hom
authors.affiliation: Department of Neuroscience, Brown University, 185 Meeting Street, Providence, Rhode Island 02912, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Simmons
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001305:Auditory Fatigue; D001309:Auditory Threshold; D002685:Chiroptera / Q000502:physiology*; D004455:Echolocation; D005260:Female; D006309:Hearing; D006317:Hearing Loss, Noise-Induced / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D008297:Male; D009622:Noise / Q000009:adverse effects*; D011571:Psychoacoustics; D020127:Recovery of Function; D013997:Time Factors