Abstract # 4242 Event # 89:

Scheduled for Friday, June 22, 2012 10:15 AM-10:30 AM: Session 12 (Magnolia) Oral Presentation


THE AUDITORY SYSTEM OF THE AGING COMMON MARMOSET (CALLITHRIX JACCHUS)

M. D. Valero1 and R. Ratnam1,2
1University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA, 2Texas Biomedical Research Institute
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     The common marmoset (Callithrix jacchus) relies heavily on vocal communication for group cohesion in the wild, particularly because they are an arboreal species with limited visual contact. Thus, we examined whether aged marmosets experience age-related hearing loss, which could hinder their communication. We measured distortion-product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs) in 10 aged and 10 young marmosets to assess the effects of age on cochlear and auditory brainstem function, respectively. The observed increase in hearing threshold (estimated using ABRs) observed in aged marmosets suggests that age-related hearing loss does occur in marmosets. DPOAEs were weaker in aged marmosets (re: young), primarily at low stimulus intensities and high frequencies. ABRs measured with high-intensity tone-bursts indicated no age-related difference in wave I latency, which reflects peripheral conduction velocity. However, the wave II-V interpeak interval, which reflects central conduction velocity, was longer in aged marmosets when compared to the young. Together these data suggest that there is a minimal effect of age on cochlear and auditory-nerve function at suprathreshold stimulus levels, but that a central auditory-brainstem dysfunction may impair hearing in aged marmosets.