Abstract # 7913 Event # 186:

Scheduled for Monday, August 28, 2017 09:40 AM-10:00 AM: (Grand Ballroom) Oral Presentation


THE COMMON MARMOSET (CALLITHRIX JACCHUS) AS A MODEL FOR AGE-RELATED HEARING LOSS

M. D. Valero1,2 and R. Ratnam2,3
1Massachusetts Eye and Ear Infirmary/Harvard Medical School, Boston, MA 02114, USA, 2University of Texas at San Antonio, 3University of Illinois, Urbana-Champaign
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     The effects of aging on the auditory system of the common marmoset (Callithrix jacchus) have received limited attention despite the wide-spread use of this species in hearing research. Here, we address this by assaying cochlear and brainstem function in forty seven marmosets between 1-12 yrs old. To assay cochlear function, we measured distortion-product otoacoustic emissions (DPOAEs) and wave-I of the auditory-brainstem response (ABR), which reflect the health of the ‘cochlear amplifier’ (outer hair cells; OHCs) and cochlear nerve fibers, respectively. To assay brainstem function, we analyzed the amplitude and latency of ABR peaks with central generators (waves II-V). In monkeys older than 6 yrs, the severity and pattern of ABR threshold shifts (re young) varied substantially. Older animals with normal ABR thresholds had normal cochlear function, and those with elevated ABR thresholds had degraded cochlear function. Regardless of cochlear status, older animals showed signs of central deficits, including reduced peak II-V amplitudes and prolonged inter-peak intervals. The data suggest that the susceptibility of individual marmosets to age-related cochlear deficits varies, but that central auditory processing may be compromised in older monkeys regardless of the status of the peripheral auditory system.