Validation of a new language screening tool for patients with acute stroke: the Language Screening Test (LAST).

BACKGROUND AND PURPOSE Standard aphasia scales such as the Boston Diagnosis Aphasia Evaluation are inappropriate for use in acute stroke. Likewise, global stroke scales do not reliably detect aphasia, and existing brief aphasia screening scales suitable for patients with stroke have several limitations. The objective of this study was to generate and validate a bedside language screening tool, the Language Screening Test, suitable for use in the emergency setting. METHODS The Language Screening Test comprises 5 subtests and a total of 15 items. To avoid retest bias, we created 2 parallel versions of the scale. We report the equivalence of the 2 versions, their internal and external validity, and their interrater reliability. We validated the scale by administering it to 300 consecutive patients within 24 hours after admission to our stroke unit and to 104 stabilized patients with and without aphasia using the Boston Diagnosis Aphasia Evaluation as a reference. RESULTS The 2 versions of the Language Screening Test were equivalent with an intraclass correlation coefficient of 0.96. Internal validity was good; none of the items showed a floor or ceiling effect with no redundancy and good internal consistency (Cronbach α 0.88). External validation against the Boston Diagnosis Aphasia Evaluation showed a sensitivity of 0.98 and a specificity of 1. Interrater agreement was near perfect (intraclass correlation coefficient, 0.998). The median time to complete the Language Screening Test was approximately 2 minutes. Importantly, the Language Screening Test does not need to be administered by a speech and language therapist. CONCLUSIONS This comprehensively validated language rating scale is simple and rapid, making it a useful tool for bedside evaluation of patients with acute stroke in routine clinical practice.