biological markers of auditory gap detection in young, middle-aged, and older adults检测生物标记的听觉差距在年轻,中年和老年人.pdf

Biological Markers of Auditory Gap Detection in Young, Middle-Aged, and Older Adults 1,2 3 4 1,3 Bernhard Ross *, Bruce Schneider , Joel S. Snyder , Claude Alain 1 Rotman Research Institute, Baycrest Centre, Toronto, Ontario, Canada, 2 Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, 3 Department of Psychology, University of Toronto, Toronto, Ontario, Canada, 4 Department of Psychology, University of Nevada, Las Vegas, Nevada, United States of America Abstract The capability of processing rapid fluctuations in the temporal envelope of sound declines with age and this contributes to older adults’ difficulties in understanding speech. Although, changes in central auditory processing during aging have been proposed as cause for communication deficits, an open question remains which stage of processing is mostly affected by age related changes. We investigated auditory temporal resolution in young, middle-aged, and older listeners with neuromagnetic evoked responses to gap stimuli with different leading marker and gap durations. Signal components specific for processing the physical details of sound stimuli as well as the auditory objects as a whole were derived from the evoked activity and served as biological markers for temporal processing at different cortical levels. Early oscillatory 40-Hz responses were elicited by the onsets of leading and lagging markers and indicated central registration of the gap with similar amplitude in all three age groups. High-gamma responses were predominantly related to the duration of no-gap stimuli or to the duration of gaps when present, and decreased in amplitude and phase locking with increasing age. Correspondingly, low-frequency