Article

Several cognitive event-related potential (ERP)
components such as mismatch negativity, P300, N400, and the late positive
component (LPC) have been studied in aphasia. The aim of this study was to
determine whether a modified semantic incongruity paradigm can serve as a more
graded differentiation of ERP changes in patients with mild versus severe
comprehension deficits. METHODS: A total of 20 aphasic patients with minor and
severe comprehension deficits and 20 young and elder healthy controls were
examined while reading 4-word sentences ending in a semantically congruent or
noncongruent word. RESULTS: In contrast to young controls and to patients with
mild comprehension deficits, aphasic patients with severe comprehension deficits
exhibit an early positivity in the time window from 200 to 400 milliseconds and
no N400 after the presentation of nonrecurrent semantically incongruent words.
Patients with mild comprehension deficits were found to have an N400 with
prolonged latency in comparison with the controls. An age effect in the control
groups was detected as well. DISCUSSION: Semantic access and integration are
performed differently in aphasic subjects with severe comprehension deficits.
These differences in lexical-semantic processing must be taken into account in
rehabilitation approaches that aim to improve comprehension deficits. Moreover,
the findings may contribute to the design of therapy studies by employing a
physiological measure that can discriminate among patients at baseline and at the
end of an intervention.

Langue : ANGLAIS