Deficits in language comprehension in schizophrenia were examined
using event-related potentials (ERPs). Schizophrenic and healthy
participants read sentences in which the first clause ended
with a homograph, and the second clause started with a target
word that was semantically related to the homograph's dominant
meaning (e.g., 1. Diving was forbidden from the bridge because
the river had rocks in it. or 2. The guests played bridge because
the river had rocks in it.). Processing of the targets (e.g.,
“river”) was expected to be primarily influenced
by the preceding overall sentence context (congruent in 1;
incongruent in 2) in healthy participants, but to be
inappropriately affected by the dominant meaning of homographs
(e.g., the “structure” meaning of “bridge”)
in sentences like 2 in schizophrenic patients. The N400 ERP
component that is known to be sensitive to contextual effects
during language processing confirmed these predictions. This
showed that language abnormalities in schizophrenia may be related
to deficient processing of context-irrelevant semantic
representations of words from the discourse.