English adaptation, international harmonisation, and normative validation of the Language Screening Test (LAST)

Abstract

Background: The Language Screening Test (LAST) is a unique bedside tool, designed to rapidly and reliably evaluate aphasia during the acute and chronic phases of stroke. Two equivalent reliable and validated versions of the LAST exist in French.Aims: Our objective was to conduct a linguistic adaptation for English (LASTen) through a process of translation, international harmonisation, and normalisation in multiple English-speaking countries.Methods & Procedures: There were four progressive stages in the adaptation of the LASTen including a series of sequential evaluations to identify problematic items, with selection of alternatives by consensus and in collaboration with the original LAST developers. First, three Canadian translators independently adapted the 29 items of the original LAST into English, resolving discrepancies by consensus to produce adaptation I. Evaluations of adaptation I involved ratings of translation difficulty and multidisciplinary expert panel review to produce adaptation II. Evaluations of adaptation II included ratings of translation quality by three different translators followed by healthy native speaker testing in Canada to produce adaptation III. Evaluations of adaptation III included expert review in Australia, Canada, England, and the USA for cultural acceptability and naturalness, followed by healthy native speaker testing in all the four countries to produce adaptation IV. Adaptation IV constituted a linguistically valid LASTen for four English dialects. We documented consensus decisions to modify or retain problematic items. We evaluated group differences using the Kruskal–Wallis test for continuous variables and chi-squared analyses for frequency variables with statistical significance of alpha ≤.05.Outcomes & Results: During the translation and the evaluations, we reconsidered 22 of the 29 items, revising 20 to produce adaptation IV of the LASTen. Normative testing in the four English-speaking countries involved 109 participants (mean age 60 years, SD ±16.1). Fifty-five percent were women, and 32% lacked postsecondary education. Fourteen participants made errors across nine items. There were no significant differences in errors for age, sex, or country. However, participants with postsecondary education made fewer errors than those without (p = .04).Conclusions: We achieved a linguistically compatible adaptation of the French LAST for English, confirming naturalness and cultural appropriateness in healthy native speakers of four English dialects. Our systematic multistep approach delineates rigorous methods for the adaptation of aphasia tools. Our normative validation of the LASTen in healthy native speakers of English provides the impetus for its validation in stroke patients within the four English-speaking countries.