| The purpose of this study was to investigate the time line of lexical access in 8--11 year-old children with Specific Language Impairment and with and without deficits in auditory processing. Typically developing children and children with SLI, ages 8--11 years, participated in a Picture-Word Interference (PWI) task and a Picture-Picture Interference (PPI) task. For both tasks, subjects named a familiar target picture while ignoring an auditory word in the PWI task and an interfering picture in the PPI task. The interfering stimuli were presented at four stimulus onset asynchronies (SOAs) relative to the onset of the target picture (-150 ms, 0 ms, +150 ms, +300 ms) and were either unrelated to the target picture or related semantically or phonologically. Reaction time for naming was measured and reaction time differences (Related-Unrelated) were obtained for both tasks. All children also underwent language, cognitive and auditory processing test batteries which included the SCAN 3: C screening test, individual IMAP tests (Moore et al., 2010) and derived measures of temporal and frequency resolution.;Multi-level modeling was employed to investigate relationships between all scores and reaction time in the PWI and PPI tasks. Results demonstrated significant early effects (-150ms SOA) in the lexicalization process in the PWI task and later (+150ms SOA) in the lexicalization process in the PPI task. In the children with SLI, "bottom-up" derived measures of temporal resolution and frequency resolution, contributed to overall reaction time in the PWI task, which employed an auditory distractor, but the derived measures did not contribute to overall reaction time in the PPI task, which employed a picture distractor. For typically developing children, this distinction was not observed. |
