Prevalence of verb and sentence impairment in aphasia as demonstrated by cluster analysis
People with aphasia (PWA) often demonstrate verb and sentence processing impairments, in production as well as in comprehension modalities. Meanwhile, patterns of impairment are typically studied at the group level, in groups of PWA with specific aphasia types (e.g., Broca's aphasia), or in case-series with small sample sizes. Our aim was to investigate if there are consistent patterns of impairment on the Russian version of the Verb and Sentence Test (Bastiaanse et al., 2000) in a large group of PWA (N = 54). We used a data-driven classification method that does not require information about aphasia types - k-means cluster analysis - and compared the results with the clinical diagnoses of the PWA. As a follow-up analysis, we used Crawford's single case methodology (Crawford et al., 2010) to further investigate patterns of impairment within the revealed clusters.