Structural prediction in aphasia: Evidence from either

•Structural prediction among people with aphasia (PWA) was examined.•PWAs' reading of or and an NP disjunct was speeded by either, showing prediction.•Effect of either decreased across the experiment for older controls.•Findings provide novel evidence of lexically-cued structural prediction in aphasia.•Controls and PWA may adapt on-line to likelihood of structures in the local context.

Young neurotypical adults engage in prediction during language comprehension (e.g., Altmann & Kamide, 1999; Staub & Clifton, 2006; Yoshida, Dickey & Sturt, 2013). The role of prediction in aphasic comprehension is less clear. Some evidence suggests that lexical prediction may be spared in aphasia (Dickey, Warren, Hayes, & Milburn, 2014; Love & Webb, 1977; cf. Mack, Ji, & Thompson, 2013), and there is even indication that structural prediction may be spared in some people with aphasia (PWA; e.g. Hanne, Burchert, De Bleser, & Vashishth, 2015). The current self-paced reading experiment manipulated the presence of either to examine structural prediction among PWA and a set of similar-aged neurotypical control participants. Consistent with intact structural prediction for both groups of participants, when either preceded a disjunction, reading times were faster on the or and second disjunct (cf. Staub & Clifton, 2006). For neurotypical controls, this effect of the presence vs. absence of either shrank reliably as more experimental items were encountered, whereas for PWA there was a non-significant trend for it to grow as more experimental items were encountered. These findings indicate that PWA and older neurotypical individuals can use a lexical cue to predict the structural form of upcoming material during comprehension, but that on-line adaptation to patterns in the local context may be different for the two groups.