Electrophysiological Evidence for Sentence Comprehension - Wings

Leonard’s words, of ‘low phonetic substance’ and this makes morphology especially
vulnerable in children with SLI (Montgomery & Leonard, 1998). On the other hand,
children with SLI showed moderate to good results on phonological discrimination test
while their performance on other tests was often poorer. Since all children with SLI
included in the study receive therapy, they all have some sort of ‘explicit phonological
knowledge’ and knew how to discriminate between phonemes. When time was not
critical, as in this test, the results were good. The children with SLI showed lower results
on quick naming, where they had to perform quickly. Together with the
electrophysiological tests this indicates processing difficulty, not a representational one.
‘Inefficient’ processing can also be inferred from broad, weak and long lasting effects
(especially noticeable in the late, broad negative deflection in ‘case-chi’ experiment and a
broad frontal and central negative deflection together with a late and weak P600 effect in
‘tense-chi’ experiment). They can indicate different neural substrate, probably not
optimal for language processing. However, sentence stimuli, which strained child’s
attention and comprehension abilities, may perhaps not be optimal choice for establishing
processing differences between children with TLD and children with SLI. For example,
prefixed words and prefixed pseudowords would perhaps show differences in lexical
access and serve as an indicator of even more complex unification processes that go on in
sentences, but, at the same time, as a lexical decision task it would be more appropriate
experiment for children. In this study sentences were used in order to obtain first
comparable data for adults, children and children with SLI.
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