title: Effects of age and hearing loss on overshoot.
abstract: The detection of a brief, sinusoidal probe in a long broadband, simultaneous masker improves as the probe is delayed from the masker's onset. This improvement ("overshoot") may be mediated by a reduction in cochlear amplifier gain over the timecourse of the masker via the medial olivocochlear (MOC) reflex. Overshoot was measured in younger adults with normal hearing and in older adults with normal and impaired hearing to test the hypothesis that aging and cochlear hearing loss result in abnormal overshoot, consistent with changes in certain structures along the MOC pathway. Overshoot decreased with increasing quiet probe thresholds and was only minimally influenced by increasing age. Marked individual differences in overshoot were observed due to differences in masking thresholds for probes presented near the masker's onset. Model simulations support the interpretation that reduced overshoot in hearing-impaired listeners is due to limited cochlear amplifier gain and therefore less gain to adjust over the timecourse of the masker. Similar overshoot among younger and older adults with normal hearing suggests that age-related changes to mechanisms underlying overshoot do not result in significant differences in overshoot among younger and older adults with normal hearing.
authors: Department of Communication Sciences and Disorders, The University of Utah, 390 South, 1530 East, Behavioral Science Building 1201, Salt Lake City, Utah 84112, USA.
authors: Skyler G
authors: SG
authors: Jennings
authors: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, South Carolina 29425-5500, USA.
authors: Jayne B
authors: JB
authors: Ahlstrom
authors: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, South Carolina 29425-5500, USA.
authors: Judy R
authors: JR
authors: Dubno
mesh_terms: D001309:Auditory Threshold; D006309:Hearing; D034381:Hearing Loss; D006801:Humans; D010470:Perceptual Masking