The psychometric properties of the English language version of the Aachen Aphasia Test (EAAT)

Abstract

This article reports results of a standardization study of the English language version of the Aachen aphasia test (EAAT). The EAAT was administered to 135 speakers with and 93 without aphasia. Aphasic speakers were divided into four groups (n =30) representing EAAT standard syndrome groups (global, amnestic, Broca's and Wernicke's aphasia), and 15 speakers who could not be classified into the standard groups. Without aphasia were 24 nonhospitalized and 41 hospitalized speakers with no history of neurological illness or speech-language disorder and 28 speakers with a history of neurological illness, but no aphasia. Hierarchical cluster analysis (complete linkage) demonstrated the validity of the linguistically motivated construction of the EAAT. This was further confirmed for the main subtests through nonmetric multidimensional scaling (smallest space analysis). The property of increasing complexity across subparts of subtests was also confirmed. Nonparametric discriminant analyses showed the high differential validity of the EAAT for distinguishing between aphasia-no aphasia and acceptably high validity for separating out subgroups of speakers. Consistency coefficients (Cronbach's f) illustrate the high to very high internal consistency of the subtests. We argue for the applicability to the EAAT of the original German reliability studies which showed retest and inter- and intra-rater reliability to be high. We conclude that the EAAT amply meets criterion levels for a psychometrically robust test.