OBJECTIVE: Studies of working memory dysfunction in schizophrenia have
focused largely on prefrontal components. This study investigated the
integrity of auditory sensory ("echoic") memory, a component that shows
little dependence on prefrontal functioning. METHOD: Echoic memory was
investigated in 20 schizophrenic subjects and 20 age- and IQ-matched normal
comparison subjects with the use of nondelayed and delayed tone matching.
RESULTS: Schizophrenic subjects were markedly impaired in their ability to
match two tones after an extremely brief delay between them (300 msec) but
were unimpaired when there was no delay between tones. CONCLUSIONS: Working
memory dysfunction in schizophrenia affects brain regions outside the
prefrontal cortex as well as within.