title: Early age noise exposure increases loudness perception - A novel animal model of hyperacusis.
abstract: The neural mechanisms that give rise to hyperacusis, a reduction in loudness tolerance, are largely unknown. Some reports suggest that hyperacusis is linked to childhood hearing loss. However, the evidence for this is largely circumstantial. In order to rigorously test this hypothesis, we studied loudness changes in rats caused by intense noise exposure (12 kHz narrow band noise, 115 dB SPL, 4 h) at postnatal 16 days. Rats without noise exposure were used as controls. The exposed noise group (n = 7) showed a mean 40-50 dB hearing loss compared to the control group (n = 8) at high frequencies (>= 8 kHz) and less hearing loss at lower frequencies. Loudness was evaluated using sound reaction time and loudness response functions in an operant conditioning-based behavioral task using narrow-band noise (40-110 dB SPL, centered at 2, 4 and 12 kHz). Interestingly, the sound reaction time of the noise group was significantly shorter than the control group at supra-threshold levels. The average reaction time was less than 100 ms in the noise group at 100 dB SPL, which was three times shorter than the control group. Our results indicate that early noise-induced hearing loss leads to a significant increase of loudness, a behavior indicative of hyperacusis. Our results are consistent with clinical reports suggesting that hearing loss at an early age is a significant risk factor for hyperacusis.
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA; Department of Communicative Disorders and Sciences, State University of New York at Buffalo, 122 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
authors.forename: Ana'am
authors.initials: A
authors.lastname: Alkharabsheh
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA.
authors.forename: Fen
authors.initials: F
authors.lastname: Xiong
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA.
authors.forename: Binbin
authors.initials: B
authors.lastname: Xiong
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA.
authors.forename: Senthilvelan
authors.initials: S
authors.lastname: Manohar
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA.
authors.forename: Guangdi
authors.initials: G
authors.lastname: Chen
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA; Department of Communicative Disorders and Sciences, State University of New York at Buffalo, 122 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Salvi
authors.affiliation: Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14241, USA; Department of Communicative Disorders and Sciences, State University of New York at Buffalo, 122 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA. Electronic address: weisun@buffalo.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
mesh_terms: D000161:Acoustic Stimulation; D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal; D003216:Conditioning, Operant; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem; D006309:Hearing; D006317:Hearing Loss, Noise-Induced / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D012001:Hyperacusis / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D008144:Loudness Perception; D009622:Noise / Q000009:adverse effects*; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D012307:Risk Factors; D013997:Time Factors
keywords: Hearing loss; Hyperacusis; Loudness; Noise exposure; Sound reaction time