MEASUREMENT OF WORD RETRIEVAL IN THE DISCOURSE OF PERSONS WITH APHASIA: STANDARD CORE LEXICON ITEM DEVELOPMENT AND PSYCHOMETRIC PROPERTIES

Abstract

Core lexicon measures are a quantitative measure of lexical use in discourse for persons with aphasia. It is intended to provide clinicians with a clinician-friendly means to quantify lexical use in discourse based on normal expectations of discourse production for specific discourse elicitation tasks. The overarching aims of the current study were to develop a reliable and valid outcome measure for discourse-level assessment and to elucidate psychometric properties of the measure. The current investigation presents the early stages of development and validation of core lexicon measures. The aim of Study I was to outline procedures regarding development of core lexicon measures and to explore how well core lexicon measures can capture overall aphasia severity. Study II was to explore the possibility of the extension of core lexicon framework by developing checklists consisting of core function words to quantify function word use in discourse produced by persons with aphasia. Study III focused on demonstrating concurrent validity and inter-rater reliability of core lexicon measures in order to demonstrate potential clinical usability of the measure. Study IV was to investigate construct validity and item-level psychometric properties of core lexicon measures.