title: Suprathreshold measures of auditory function in the aging chinchilla.
abstract: The purpose of this study was to examine the relationship between aging and suprathreshold auditory function in the chinchilla, a rodent with a relatively long life span and a range of hearing similar to that of humans. Subjects were six 11-12-year-old chinchillas and six young controls. Tests of auditory function utilized evoked potential (EVP) recordings from electrodes implanted in the inferior colliculus and measurements of 2f1-f2 distortion product otoacoustic emissions (DPOAEs). Tests of frequency resolution (EVP tuning curves for a 2 kHz probe tone), temporal resolution (EVP forward masking functions using a 2 kHz probe tone), cochlear non-linearity (remote masking), and a DPOAE 'tone challenge', in which DPOAEs at six frequencies were monitored before and after each of five 1-min exposures to a 2 kHz tone at 80 dB SPL, were performed. The results indicate that aged chinchillas can exhibit deficits in suprathreshold tests of auditory function even when the test stimulus is in a region of relatively normal-hearing sensitivity. The results support the notion that aging, independent of hearing loss, can influence suprathreshold auditory function.
authors.affiliation: Department of Communicative Disorders, SUNY at Buffalo, NY 14214-3007, USA. mcfadden@acsu.buffalo.edu
authors.forename: S L
authors.initials: SL
authors.lastname: McFadden
authors.forename: N
authors.initials: N
authors.lastname: Quaranta
authors.forename: D
authors.initials: D
authors.lastname: Henderson
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D002682:Chinchilla; D004567:Electrodes, Implanted; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D007245:Inferior Colliculi / Q000502:physiology; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011304:Presbycusis / Q000209:etiology / Q000503:physiopathology*