People with aphasia show stable Cumulative Semantic Interference (CSI) when tested repeatedly in a web-based paradigm: A perspective for longitudinal assessment

Retrieving words quickly and correctly is an important language competence. Semantic contexts, such as prior naming of categorically related objects, can induce conceptual priming but also lexical-semantic interference, the latter likely due to enhanced competition during lexical selection. In the continuous naming (CN) paradigm, such semantic interference is evident in a linear increase in naming latency with each additional member of a category out of a seemingly random sequence of pictures being named (cumulative semantic interference/CSI effect). Extensively studied in neurotypical participants, CSI studies in people with aphasia (PWA) are rare, although some lesions regularly and persistently impair word retrieval. In the present study, 20 PWA with lesions in the extended left hemispheric language network and 20 matched controls underwent a CN paradigm, naming photographs of closely related objects from 24 categories (e.g., birds) with 5 members each. The experiment was conducted web-based (Stark et al., 2022) on three days (day 1, 2, and 8). The main results are: (i) Mild-moderate aphasia does not preclude web-based testing. (ii) The CSI effect in naming latencies (∼21 ms per ordinal position) did not differ significantly between groups but was more variable in the PWA; the effect was stable across days. (iii) Overall response times decreased between day 1 and day 2, but remained stable on day 8. (iv) In PWA, increased error-rates paralleled the latency-based CSI effect, suggesting stronger interference in this group. (v) Exploratory analyses suggest that lesions in a large area, including frontal, inferior parietal, pre- and post-central opercular cortices, are linked to a larger CSI effect. At a more lenient statistical threshold, lesions in occipital and supramarginal cortices were associated with increased overall naming latencies. These results offer an initial step toward identifying the neuronal underpinnings of semantic context effects in PWA. We conclude that web-based assessment is feasible in PWA and yields a stable CSI effect over repetitive testing. While not directly clinically applicable, the findings could serve as a foundation for exploring training-interventions targeting lexical activation, interference resolution, or word selection.