Evaluating spoken word-picture matching: what affects performance?

Abstract

One of the most widely used tasks in the assessment of individuals with aphasia is the spoken word-picture matching subtest from PALPA (subtest 47; Kay, Lesser and Coltheart, 1992). Sub-test 47 requires the individual with aphasia to listento a spoken word and make the correct choice from five pictures (target plus four distractors: close semantic, distant semantic, visually related and semantically unrelated). Kay et al. (1992) state that the choice of distractor reflects the specificity of the individual's semantic comprehension ability. As this test contributes clinically to diagnostic and treatment planning decisions, it is essential to consider factors affecting performance to ensure that clinical assessment of semantic comprehension ability is accurate. This study evaluates the relationship between a number of psycholinguistic variables and the performance on PALPA subtest 47 of 54 individuals with aphasia. Results revealed a complex relationship between factors that influence the performance of the individual with aphasia on this spoken word to picture matching task. For the group, semantic rather than lexical factors were found to affect performance. Howewer, effects of word length and rated semantic similarity of target and close distractor were found on the accuracy of target selection for some individuals. The implications of these results for clinical practice are discussed.