Investigating processing delay in interaural time difference discrimination by normal-hearing children

Abstract

Recent work suggests that interaural time difference (ITD) thresholds are adult-like by 8-10 years of age in children with normal hearing (NH). If processing time is considered, however, we hypothesize that the ability to successfully extract ITDs is not fully mature in children. A novel paradigm was designed to simultaneously measure eye gaze with an eye tracker during an ITD discrimination task with mouse-click. Stimuli were 4 kHz transposed tones modulated at 128 Hz, tested with a 3-interval, 2-alternative forced choice task (left- or right-leading ITDs) with feedback. During each trial, gaze position on the computer screen was simultaneously recorded from stimulus onset to the time when a mouse click indicated either a left or right response. Processing times were extracted from the eye gaze data and compared with those from young NH adults. This presentation will focus on the developmental differences observed when threshold estimation is used versus when processing time is assessed via eye gaze measures. Results from this study will provide a better understanding of the developmental trajectory of binaural hearing abilities in NH children. [Work supported by NIDCD (R01DC003083 and R01DC008365 to Ruth Litovsky).]