Neural correlates of transitive and finite verb production deficits in Primary Progressive Aphasia: the role of inferior parietal and frontal regions.
Poster D31 in Poster Session D with Social Hour, Friday, October 7, 5:30 - 7:15 pm EDT, Millennium Hall
Sladjana Lukic1,3, Elena Barbieri2,3, Emily J. Rogalski4,5, Sandra Weintraub4,5, Marek-Marsel Mesulam4,6, Cynthia K. Thompson2,3,4; 1Adelphi University, Ruth S. Ammon College of Education and Health Sciences, 2Department of Communication Sciences and Disorders, Northwestern University, Evanston, USA, 3Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, USA, 4Mesulam Cognitive Neurology and Alzheimer’s Disease Center, Northwestern University, Chicago, USA, 5Department of Psychiatry and 6Behavioral Sciences, Northwestern University, Feinberg School Medicine, Chicago, USA, 6Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, USA
Verb retrieval deficits are often reported in individuals with Primary Progressive Aphasia (PPA), a clinical dementia syndrome due to neurodegenerative disease affecting (primarily) the left hemisphere perisylvian network. Verb retrieval difficulties can be affected by verb-argument structure complexity (intransitive versus transitive verbs) and verb-morphology (verb tense, regularity, and subject-verb agreement factors); however, cortical atrophy patterns associated with these deficits remain unclear. The present study examined the relationships between regions of cortical atrophy and deficits in production of transitive and finite inflected verbs in 80 patients with PPA (39 nonfluent agrammatic (PPA-G), 26 logopenic (PPA-L), and 15 semantic PPA (PPA-S) subtypes). Verb transitivity and morphology were assessed using the Northwestern Assessment of Verbs and Sentences (NAVS; Thompson, 2011) and the Northwestern Assessment of Verb Inflection (NAVI; Lee and Thompson, 2017) tests, respectively. Across patients, we used surface-based morphometry to measure cortical thickness in perisylvian language regions, including inferior frontal and temporo-parietal regions-of-interest and correlated that with properties of verb production across patients. The PPA-G patients had greater difficulties producing transitive compared to intransitive verbs, and finite compared to nonfinite verbs. However, neither the PPS-L or PPA-S variants showed significant transitivity effect. While deficits across inflection types (inflection of finite verb forms regardless of regularity and agreement) were associated with PPA-G, irregular verb inflection deficits were associated with PPA-S, and subject-verb agreement deficits were associated with PPA-L. Across patients, deficits in producing transitive verbs (adjusted for intransitive verbs) were associated with inferior parietal atrophy (i.e., the left Angular Gyrus), whereas deficits in inflecting finite verbs (adjusted for uninflected nonfinite forms) were associated with posterior inferior frontal atrophy (i.e., the left Inferior Frontal Gyrus). Our results identified distinct brain regions where atrophy was predictive of verb retrieval deficits, supporting the dual-system view for complex lexical-semantic (i.e., multiple thematic roles) and syntactic (i.e., inflectional morphology) information.
Topic Areas: Disorders: Acquired, Language Production