ERPs reveal the temporal dynamics of auditory word recognition in specific language impairment

Abstract

We used event-related potentials (ERPs) to compare auditory word recognition in children with specific language impairment (SLI group; N=14) to a group of typically developing children (TD group; N=14). Subjects were presented with pictures of items and heard auditory words that either matched or mismatched the pictures. Mismatches overlapped expected words in word-onset (cohort mismatches; see: DOLL, hear: dog), rhyme (CONE -bone), or were unrelated (SHELL -mug). In match trials, the SLI group showed a different pattern of N100 responses to auditory stimuli compared to the TD group, indicative of early auditory processing differences in SLI. However, the phonological mapping negativity (PMN) response to mismatching items was comparable across groups, suggesting that just like TD children, children with SLI are capable of establishing phonological expectations and detecting violations of these expectations in an online fashion. Perhaps most importantly, we observed a lack of attenuation of the N400 for rhyming words in the SLI group, which suggests that either these children were not as sensitive to rhyme similarity as their typically developing peers, or did not suppress lexical alternatives to the same extent. These findings help shed light on the underlying deficits responsible for SLI.

Developmental differences in the influence of phonological similarity on spoken word processing in Mandarin Chinese

“…Importantly, this pattern held for both the adults and the children, and can be taken as evidence of incremental processing of spoken words in both groups. The current study thus replicates prior work we have done that has offered evidence for incremental processing in English-speaking adults (Desroches et al, 2009), English-speaking children (Desroches et al, 2013; Malins et al, 2013), and Mandarin-speaking adults (Malins & Joanisse, 2012), but this is the first study to establish these effects in Mandarin-speaking children.…”

“…Namely, we expected to observe a greater attenuation of the late N400 for onset mismatches (that is, words differing in onset from expectations but sharing word-final phonemes with expectations; e.g., tang2 - lang2 ) in adults compared to children (Praamstra et al, 1994; Radeau et al, 1998; Coch et al, 2002; Desroches et al, 2006; Desroches et al, 2009; Desroches et al, 2013; Malins et al, 2013). For this reason, we followed up on significant interactions in the late N400 window with post-hoc analyses that contrasted the onset mismatch condition between groups.…”

“…The idea here is because word-final phonemes are partially active, when they finally arrive in the acoustic signal they are processed more easily than word-final phonemes in non-rhyming forms, which have not received this prior activation. Evidence for facilitated processing of rhyming forms has been observed in numerous studies of Indo-European languages in both adults (Praamstra, Meyer, & Levelt, 1994; Radeau, Besson, Fontenau, & Castro, 1998; Desroches, Newman, & Joanisse, 2009) and children (Coch, Grossi, Coffey-Corina, Holcomb, & Neville, 2002; Desroches, Newman, Robertson, & Joanisse, 2013; Malins et al, 2013). In contrast, rhyme effects in Mandarin speakers have been elusive.…”

“…For both groups, we analyzed the following ERP components: the PMN, the N400, and the late N400, as in prior picture-word matching studies (Desroches et al, 2009; Archibald & Joanisse, 2011; Malins & Joanisse, 2012; Desroches et al, 2013; Malins et al, 2013). Windows of analysis were determined by visual inspection, and were defined as follows: PMN (260-320 ms), N400 (350-500 ms), and late N400 (500-600 ms).…”

“…Importantly, it has been shown that these two components are functionally dissociable in terms of the underlying cortical regions that give rise to these ERP responses (Trébuchon, Démonet, Chauvel, & Liégeois-Chauvel, 2013). Furthermore, previous research has indicated that analysis of these components reveals temporally dissociable effects for different mismatch types, such as onset versus rime competitors (Desroches et al, 2009; Archibald & Joanisse, 2011; Malins & Joanisse, 2012; Desroches et al, 2013; Malins et al, 2013). This approach is therefore well-suited to the current investigation, as we aimed to identify which specific aspects of spoken word recognition differed between children and adults.…”