Effect of Lexical-Semantic Cues during Real-Time Sentence Processing in Aphasia

Abstract

Using a visual world eye-tracking paradigm, we investigated the real-time auditory sentence processing of neurologically unimpaired listeners and individuals with aphasia. We examined whether lexical-semantic cues provided as adjectives of a target noun modulate the encoding and retrieval dynamics of a noun phrase during the processing of complex, non-canonical sentences. We hypothesized that the real-time processing pattern of sentences containing a semantically biased lexical cue (e.g., the venomous snake) would be different than sentences containing unbiased adjectives (e.g., the voracious snake). More specifically, we predicted that the presence of a biased lexical cue would facilitate (1) lexical encoding (i.e., boosted lexical access) of the target noun, snake, and (2) on-time syntactic retrieval or dependency linking (i.e., increasing the probability of on-time lexical retrieval at post-verb gap site) for both groups. For unimpaired listeners, results revealed a difference in the time course of gaze trajectories to the target noun (snake) during lexical encoding and syntactic retrieval in the biased compared to the unbiased condition. In contrast, for the aphasia group, the presence of biased adjectives did not affect the time course of processing the target noun. Yet, at the post-verb gap site, the presence of a semantically biased adjective influenced syntactic re-activation. Our results extend the cue-based parsing model by offering new and valuable insights into the processes underlying sentence comprehension of individuals with aphasia.

The effect of time on lexical and syntactic processing in aphasia

“…To complement the growth curve analyses, we also conducted cluster-based permutation analyses to detect the temporal onset and duration of an effect between two time-series. This method was originally developed to account for the multiple comparison problem and autocorrelation arising in EEG and MEG data ( Maris & Oostenveld, 2007 ), and has been increasingly applied to eye-tracking research ( Akhavan et al, 2022 ; Baker & Love, 2021 ; Barr, Jackson, & Phillips, 2014 ; Gerhardstein & Olsen, 2020 ; Weighall, Henderson, Barr, Cairney, & Gaskell, 2017 ). In cluster-based permutation testing, inferential tests are performed on each time-bin over the analysis window and all adjacent, significant bins (i.e., passing a determined threshold) are grouped together into a single cluster and a cluster-level statistic is computed whose null distribution is derived through data permutation.…”

“…Experimental evidence has shown that in neurotypical adults and children (at least as young as 4 years of age), reactivation of the direct object occurs immediately at the gap position, resulting in the real-time formation of a syntactic dependency ( Akhavan, Blumenfeld, & Love, 2020 , 2022 ; Baker & Love, 2021 ; Koring, Mak, & Reuland, 2012 ; T. E. Love, 2007 ; Roberts, Marinis, Felser, & Clahsen, 2007 ; Thompson & Choy, 2009 , 2009 , p. 200). Although object-relative sentences are, in general, correctly comprehended by neurologically healthy adults, studies investigating real-time dependency linking have found that this process can be slowed or made more difficult in certain circumstances ( Gennari & MacDonald, 2008 ; Gibson, 1998 ; Gordon, Hendrick, & Johnson, 2001 , 2002 ; Traxler, Morris, & Seely, 2002 ).…”

“…Investigations measuring processing speed during retrieval have found that the competition from similarity-based interference , slows processing times at the verb and increases retrieval difficulty ( Gordon et al, 2001 , 2002 , 2004 , 2007 ; Van Dyke, 2007 ; Van Dyke & McElree, 2006 ). Retrieval difficulty due to interference is also shown to lead to sentence comprehension deficits in IWA ( Akhavan et al, 2022 ; Lissón et al, 2021 ; Mätzig, Vasishth, Engelmann, Caplan, & Burchert, 2018 ; Patil, Hanne, Vasishth, Burchert, & De Bleser, 2011 ; Sullivan, Walenski, Love, & Shapiro, 2017 ). Resolving interference and achieving successful dependency linking during real-time spoken language comprehension creates tight temporal constraints for processing.…”

“…In the present study, we use the same methodology and temporal manipulations from Baker and Love (2021) to explore if providing additional time for processing the target direct-object noun will 1) enhance lexical processing for both IWA and AMC, 2) facilitate downstream dependency linking (via modulating interference) for both IWA and AMC, and 3) improve sentence comprehension for IWA. Eye-tracking-while-listening in a visual world paradigm allows us to explore how additional time at a specific location in the sentence affects lexical processing, dependency linking, and interference resolution and ( Akhavan et al, 2020 , 2022 ; Baker & Love, 2021 ; Sekerina, Campanelli, & Van Dyke, 2016 ; Sheppard, Walenski, Love, & Shapiro, 2015 ). In this paradigm, participants are presented with an array of four pictures while listening to sentences: two of the pictures depict referents mentioned in the sentence and the other two pictures are distractors.…”

“…The competition arising from similarity-based interference can slow retrieval of the target noun ( Van Dyke & McElree, 2006 ). In eye-tracking data, this interference is shown as an extended activation of both nouns during the post-verb time window and is visualized as overlapping gaze patterns of both nouns ( Akhavan et al, 2020 , 2022 ; Baker & Love, 2021 ). In cases where interference is resolved, eye gazes show a greater divergence between looks to each noun.…”