Poster E55, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
A comprehensive examination of language in Parkinson’s disease: Evidence from syntax, morphology, and lexical processing
Jana Reifegerste1, Karim Johari2, Matthew Walenski3, Farzad Ashrafi4, Roozbeh Behroozmand2, Michael Ullman5; 1University of Potsdam, Germany, 2University of South Carolina, 3Northwestern University, 4Shahid Beheshti University of Medical Sciences, Iran, 5Georgetown University
Although Parkinson’s disease (PD), which involves basal-ganglia degeneration, is clearly associated with motor deficits, language has also been implicated. We comprehensively examined several aspects of language, within-subjects, in Farsi-speaking patients with moderate-to-severe PD. On the basis of previous findings and the declarative/procedural model of language, we predicted PD impairments in syntax and regular morphology, which both depend on frontal/basal-ganglia circuits. We expected less impairment in females than males (especially for regular forms, which can be memorized) because of superior female compensation by medial-temporal-lobe-based declarative memory. The PD patients showed deficits, compared to healthy controls, at syntactic judgment, syntactic comprehension (negation, subject-cleft, object-cleft sentences), and the production of regular morphological (Farsi past-tense) forms. Additionally, an interaction between PD/control, male/female participants, and regular/irregular morphology indicated a greater impairment in male than female PDs in regulars, but not irregulars. Right-side hypokinesia (reflecting left frontal/basal-ganglia degeneration) correlated with regulars (across both sexes) but not irregulars, while left-side hypokinesia correlated with neither. Finally, PD patients were impaired at naming commonly-manipulated objects (e.g., hammer), but not non-manipulated items (e.g., mountain), suggesting a dependence of motor-skill object knowledge on frontal/basal-ganglia circuits. Overall, the results reveal a clear pattern of language impairment in moderate-to-severe PD: grammar deficits across syntax and morphology, modulated by sex and particularly dependent on left frontal/basal-ganglia degeneration, but no impairments in lexical processing, at least for words not semantically associated with motor skills. Findings will be compared to other studies of language in PD, including investigations of grammar and lexical processing.
Topic Area: LANGUAGE: Development & aging