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Abstract:
Language comprehension deficits are a significant problem for
adults with a history of developmental language disorder (DLD). Yet
the exact nature (phonological, morphological, or semantic) and
potential causes of these deficits remain unresolved. Some
researchers attribute the problem to left hemisphere (LH)
deficiencies, while others suggest that the problem results from
either under-engagement or over-engagement of the right hemisphere
(RH). Atchley, Story, and Buchanon (1999) used a divided visual
field priming paradigm to observe how adults with a history of DLD
access lexically ambiguous words. Results indicated that sustained
semantic access to subordinate word meanings in the RH was
disrupted in the DLD readers relative to controls. Additionally in
the LH, only the most dominant meaning of the ambiguous word showed
sustained priming in both controls and DLD participants. In other
words, for DLD readers the subordinate meanings of words were not
primed in either hemisphere and therefore would not be available
during online processing and integration of discourse. This right
hemisphere lexical access deficit possibly contributes to the
language comprehension difficulties observed in these DLD readers.
The present study further explored the nature of each hemisphere's
contribution to language processing in DLD using dichotic listening
tasks that involve both phonological and semantic processes.
Results suggest that comprehension deficits seen in DLD adults may
result from processing abnormalities primarily in the right
hemisphere.
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