The role of processing support in the remediation of aphasic language production disorders

Abstract

Performance factors such as resource or memory limitations, as opposed to loss of linguistic knowledge per se, are increasingly implicated in aphasic language impairments. Here we investigate the consequences of this hypothesis for the remediation of aphasic language production. Two nonfluent aphasic subjects used a computerised communication system (CS) to practice narrative production. The CS serves primarily as a processing prosthesis, allowing the user to record spoken sentence elements, replay these elements, and build them up into larger structures by manipulating icons on the screen. Use ofthe CS in conjunction with explicit training of syntactic structure has been reported to bring about gains in unaided language production. Here we examine the treatment impact or CS-based processing support alone. Eleven weeks of independent home use of the CS resulted in some marked changes in one subject's production of unaided spoken narratives. The most striking and consistent changes involved more structured and informative speech. The second subject, who presented with far more severe lexical impairments, did not show comparable gains in the structural properties of his unaided speech, but was able to produce markedly more structured narratives when aided by the CS. These results support the performance hypothesis because the CS provided no structure-modelling or feedback. In addition, the first subject's treatment gains indicate that practising narrative production with processing support may be effective in bringing about increased structural complexity and informativeness in aphasic speech. This is congruent with other claims in the literature that increasing the complexity or difficulty of the training material may in some cases increase the efficacy of the treatment.