Language and auditory-verbal short-term memory impairments: Evidence for common underlying processes

We report an investigation of the short-term memory (STM) impairments of 15 aphasic subjects whose language profiles varied with respect to the relative involvement of lexical-semantic and phonological processes. On the hypothesis that STM is dependent on capacities intrinsic to language processing, repetition span should vary in conjunction with lexical-semantic and phonological impairment: Specifically, when lexical-semantic processing is impaired, phonological abilities provide primary support to span performance; when phonological processing is impaired, there should be increased reliance on lexical-semantic information. Support for this hypothesis was provided by correlating measures of semantic and phonological abilities with effects of imageability and frequency on repetition performance, and with serial position effects in retrieval of phonemes within a word and words within a string. The data are discussed within the framework of an interactive activation model of language processing.