Abstract
Background: Impaired sentence comprehension is observed in the three major subtypes of PPA, with distinct performance patterns relating to impairments in comprehending complex sentences in the agrammatic (PPA-G) and logopenic (PPA-L) variants and word comprehension in the semantic subtype (PPA-S). However, little is known about basic combinatory processes during sentence comprehension in PPA, such the integration of verbs with their subject and object(s) (verb-argument integration). Methods: The present study used visual-world eye-tracking to examine real-time verb-argument integration in individuals with PPA (12 with PPA-G, 10 with PPA-L, and 6 with PPA-S) and neurotypical older adults (15). Two baseline experiments probed eye movement control, using a non-linguistic task, and noun comprehension, respectively. Two verb-argument integration experiments examined the effects of verb meaning on (a) lexical access of the verb's direct object (argument access) and (b) selection of a semantically-appropriate direct object (argument selection), respectively. Eye movement analyses were conducted only for trials with correct behavioral responses, allowing us to distinguish accuracy and online processing. Results: The eye movement control experiment revealed no significant impairments in PPA, whereas the noun comprehension experiment revealed reduced accuracy and eye-movement latencies in PPA-S, and to a lesser extent PPA-G. In the argument access experiment, verb meaning facilitated argument access normally in PPA-G and PPA-L; in PPA-S, verb-meaning effects emerged on an atypical time course. In the argument selection experiment, significant impairments in accuracy were observed only in PPA-G, accompanied by markedly atypical eye movement patterns. Conclusion: This study revealed two distinct patterns of impaired verb-argument integration in PPA. In PPA-S, impaired verb-argument integration was observed in the argument access experiment, indicating impairments in basic semantic combinatory processes which likely relate to damage in ventral language pathways. In contrast, listeners with PPA-G showed marked impairments of argument selection, likely relating to damage to left inferior frontal regions.
| Original language | English (US) |
|---|---|
| Article number | 107192 |
| Journal | Neuropsychologia |
| Volume | 134 |
| DOIs | |
| State | Published - Nov 2019 |
Funding
This research was supported by the National Institutes of Health : R01-DC08552 (Mesulam) , P50-DC012283 (Thompson) , and R01-DC01948 (Thompson) . Control participants were also recruited through the Communication Research Registry at Northwestern University . The authors would like to thank the research participants and their families and caregivers for their contributions to this work, as well as their colleagues at the Mesulam Cognitive Neurology and Alzheimer's Disease Center and the Aphasia and Neurolinguistics Research Laboratory at Northwestern University . In particular the authors wish to thank Jaiashre Sridhar for neuroimaging data analyses, Benjamin Rader for demographic and neuropsychological data, and Sarah Chandler, Stephanie Gutierrez, and Dr. Matthew Walenski for assistance with eye-tracking data collection, data analysis, and helpful discussions. This research was supported by the National Institutes of Health: R01-DC08552 (Mesulam), P50-DC012283 (Thompson), and R01-DC01948 (Thompson). Control participants were also recruited through the Communication Research Registry at Northwestern University. The authors would like to thank the research participants and their families and caregivers for their contributions to this work, as well as their colleagues at the Mesulam Cognitive Neurology and Alzheimer's Disease Center and the Aphasia and Neurolinguistics Research Laboratory at Northwestern University. In particular the authors wish to thank Jaiashre Sridhar for neuroimaging data analyses, Benjamin Rader for demographic and neuropsychological data, and Sarah Chandler, Stephanie Gutierrez, and Dr. Matthew Walenski for assistance with eye-tracking data collection, data analysis, and helpful discussions.
Keywords
- Eye-tracking
- Primary progressive aphasia
- Semantics
- Syntax
- Verb-argument structure
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Cognitive Neuroscience
- Behavioral Neuroscience