title: Difficulty processing temporary syntactic ambiguities in Lewy body spectrum disorder.
abstract: While grammatical aspects of language are preserved, executive deficits are prominent in Lewy body spectrum disorder (LBSD), including Parkinson's disease (PD), Parkinson's dementia (PDD) and dementia with Lewy bodies (DLB). We examined executive control during sentence processing in LBSD by assessing temporary structural ambiguities. Using an on-line word detection procedure, patients heard sentences with a syntactic structure that has high-compatibility or low-compatibility with the main verb's statistically preferred syntactic structure, and half of the sentences were lengthened strategically between the onset of the ambiguity and its resolution. We found selectively slowed processing of lengthened ambiguous sentences in the PDD/DLB subgroup. This correlated with impairments on measures of executive control. Regression analyses related the working memory deficit during ambiguous sentence processing to significant cortical thinning in frontal and parietal regions. These findings emphasize the role of prefrontal disease in the executive limitations that interfere with processing ambiguous sentences in LBSD.
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, United States. mgrossma@mail.med.upenn.edu
authors.forename: Murray
authors.initials: M
authors.lastname: Grossman
authors.forename: Rachel G
authors.initials: RG
authors.lastname: Gross
authors.forename: Peachie
authors.initials: P
authors.lastname: Moore
authors.forename: Michael
authors.initials: M
authors.lastname: Dreyfuss
authors.forename: Corey T
authors.initials: CT
authors.lastname: McMillan
authors.forename: Philip A
authors.initials: PA
authors.lastname: Cook
authors.forename: Sherry
authors.initials: S
authors.lastname: Ash
authors.forename: Andrew
authors.initials: A
authors.lastname: Siderowf
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007802:Language; D020961:Lewy Body Disease / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D013067:Speech Perception / Q000502:physiology*