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.