Test-retest stability of word retrieval in aphasic discourse

This study examined the test-retest stability of select word-retrieval measures in the discourses of people with aphasia who completed a 5-stimulus discourse task.

Discourse samples across 3 sessions from 12 individuals with aphasia were analyzed for the stability of measures of informativeness, efficiency, main concepts, noun and verb retrieval, word-finding difficulty, and lexical diversity. Values for correlation coefficients and the minimal detectable change score were used to assess stability for research and clinical decision making.

Measures stable enough to use in group research studies included the number of words; the number of correct information units (CIUs); the number of accurate-complete, accurate-incomplete, and absent main concepts; the percentage of T-units that had word-finding behaviors of any kind; the percentage of T-units that contained empty words; and a lexical diversity measure. Words per minute, CIUs per minute, and the percentage of T-units that contained time fillers or delays were sufficiently stable to use when making clinical decisions about an individual.

Although several of the measures demonstrated acceptable stability for group research studies, relatively few were sufficiently stable for making clinical decisions about individuals on the basis of a single administration.