Article

Wernicke's aphasia (WA) is the classical neurological model of comprehension
impairment and, as a result, the posterior temporal lobe is assumed to be
critical to semantic cognition. This conclusion is potentially confused by (a)
the existence of patient groups with semantic impairment following damage to
other brain regions (semantic dementia and semantic aphasia) and (b) an ongoing
debate about the underlying causes of comprehension impairment in WA. By directly
comparing these three patient groups for the first time, we demonstrate that the
comprehension impairment in Wernicke's aphasia is best accounted for by dual
deficits in acoustic-phonological analysis (associated with pSTG) and semantic
cognition (associated with pMTG and angular gyrus). The WA group were impaired on
both nonverbal and verbal comprehension assessments consistent with a generalised
semantic impairment. This semantic deficit was most similar in nature to that of
the semantic aphasia group suggestive of a disruption to semantic control
processes. In addition, only the WA group showed a strong effect of input
modality on comprehension, with accuracy decreasing considerably as
acoustic-phonological requirements increased. These results deviate from
traditional accounts which emphasise a single impairment and, instead, implicate
two deficits underlying the comprehension disorder in WA.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS