Evidence for impaired emotional reactivity in aphasia during naturalistic movie-viewing

Abstract Language is thought to play a fundamental role in how humans experience emotion. Chronic aphasia, a persistent language impairment, provides a unique window for examining predictions about the role of language in shaping emotions. Here, we tested the hypothesis that aphasia is associated with altered patterns of emotional reactivity during naturalistic movie viewing. We analyzed real-time and holistic emotion ratings, and language comprehension, of movie clips, in persons with aphasia (PWA, n=57) and healthy controls (HC, n=43). PWA versus HC showed reduced typicality and temporal complexity of real-time emotion judgements (p<.006), reduced typicality of holistic emotion judgements (p<0.001), and reduced language task accuracy (p<.001). Principal component analysis yielded a primary component that distinguished the groups (p<.001), and in PWA correlated with aphasia (r=0.644) and depression (r=-0.305) scores. Machine learning achieved strong group classification (AUC=0.964, accuracy=86%) and moderate aphasia severity prediction (r=0.589), with both language and emotion contributing features. The findings converge in demonstrating that language and emotion impairments are coupled, during both lexical and discourse level processing. The work highlights that scientific accounts and clinical evaluations of language would benefit from incorporating real-time measures of emotion processing, particularly for improving our understanding of real-world functional communication and impairments.