Presentation

Nicoletta Biondo^1,2, Maria Ivanova¹, Simona Mancini², Nina Dronkers^1,3; ¹UC Berkeley, ²BCBL, ³UC Davis

Time impairment is a pervasive phenomenon in aphasia. Many studies (overview in Faroqi-Shah & Friedman, 2015) showed that people with agrammatic aphasia struggle with the production of inflected verbs (e.g., Last night she … went to the movies). Time impairment was also found in agrammatic comprehension (e.g., Wenzlaff & Clahsen, 2004; Clahsen & Ali, 2009; Faroqi-Shah & Dickey, 2009) and in Wernicke’s aphasics (e.g., Jonkers & de Bruin, 2009). Interestingly, the source of this impairment does not seem to be related just to morphological complexity or to the production of tense features per se, but to time reference and the ability to access discourse (Bastiaanse et al., 2011; Bos et al., 2014). Discourse represents an interface between syntax and the cognitive system (e.g., Druks, 2017) that operates by rules that go beyond the level of the sentence (Avrutin, 2006). One question is thus whether this time impairment is purely linguistic or affects more general cognitive abilities. Previous studies have offered a fragmentary picture: They focused only on specific aspects of time processing, which was mainly investigated behaviorally by grouping small cohorts of patients based on lesion site or aphasia type. The main aim of this project is to carry out a systematic investigation of time processing in aphasia, across different domains (linguistic, non-linguistic) and, for the first time, involving the use of structural magnetic resonance imaging (MRI) methods, to uncover the neural underpinnings of time processing. Three questions will be addressed: (i) which aspects of time processing are impaired in individuals with aphasia? (ii) Is this impairment purely linguistic? (iii) What is the neurobiological basis of time processing? To address (i), we designed 3 linguistic tasks investigating: the ability to locate the self in the current moment (temporal orientation test, Benton et al., 1994); the ability of locating an event expressed by the verb in the past/present/future (event location, e.g., “The boy peeled the banana”); the ability to verify temporal coherence (temporal concord, e.g., “Tomorrow the boy peeled the banana”). To address (ii), we designed 3 non-linguistic versions of the same tasks, where events are represented visually, through pictures (e.g., Bastiaanse et al., 2011; Borodisky et al., 2011). To address (iii), we will perform Voxel-based Symptom Lesion Mapping (VSLM) analyses using participant scores on these three tasks coupled with structural MRI data. We anticipate involving 50 participants who are English native speakers with left hemisphere lesions, ≥ 6 months post-stroke, and adequate hearing/vision/motor skills to complete the tasks. This 3-year Marie Skłodowska-Curie project began a few months ago and it is currently in the piloting stage. We expect poor performance in the linguistic tasks if time impairment is purely linguistic, but also in the non-linguistic tasks if the impairment is more domain-general. Through VSLM analyses we also expect to identify regions that may be crucial for different aspects of time processing (e.g., pre-frontal regions for temporal concord, temporal/parietal for event location).

Topic Areas: Disorders: Acquired, Morphology