Syntactic processing in individuals with dyslexia: Using ERP to address the debate

Behavioural and ERP data were collected from university and college students with and without dyslexia to determine if a deficit in syntactic processing in post-secondary students with dyslexia can be explained by the degree of phonological processing deficits. Participants read and listened to sentences of differing syntactic complexity and working memory load, particularly object relative and subject relative sentences. Slow cortical waves showed greater negativity for the objective relative sentences as the sentence progressed for the control participants regardless of presentation format. The same result was seen for the participants with dyslexia when presented with sentences in an auditory format. Analyses revealed that control participants had greater left anterior negativity between 300 and 500 ms for the main verb of the object relative sentences, regardless of presentation format. Participants with dyslexia showed difficulty in processing the written versions of the syntactically complex sentences but they were able to differentiate these syntactic structures when they were presented in an auditory format. An N400 effect was seen by participants with dyslexia for the second article in the object relative structure. The bottleneck for control participants appears to exist at the level of working memory while participants with dyslexia were limited by their phonological processing skills in general and specifically their reading skills for the written syntactic processing tasks. The results support the phonological processing deficit hypothesis in explaining the processing weaknesses of participants with dyslexia