The organization and anatomy of narrative comprehension and expression in Lewy body spectrum disorders.
OBJECTIVE
Patients with Lewy body spectrum disorders (LBSD) such as Parkinson's disease, Parkinson's disease with dementia, and dementia with Lewy bodies exhibit deficits in both narrative comprehension and narrative expression. The present research examines the hypothesis that these impairments are due to a material-neutral deficit in organizational executive resources rather than to impairments of language per se. We predicted that comprehension and expression of narrative would be similarly affected and that deficits in both expression and comprehension of narrative would be related to the same anatomic distribution of prefrontal disease.


METHODS
We examined 29 LBSD patients and 26 healthy seniors on their comprehension and expression of narrative discourse. For comprehension, we measured accuracy and latency in judging events with high and low associativity from familiar scripts such as "going fishing." The expression task involved maintaining the connectedness of events while narrating a story from a wordless picture book.


RESULTS
LBSD patients were impaired on measures of narrative organization during both comprehension and expression relative to healthy seniors. Measures of organization during narrative expression and comprehension were significantly correlated with each other. These measures both correlated with executive measures but not with neuropsychological measures of lexical semantics or grammar. Voxel-based morphometry revealed overlapping regressions relating frontal atrophy to narrative comprehension, narrative expression, and measures of executive control.


CONCLUSIONS
Difficulty with narrative discourse in LBSD stems in part from a deficit of organization common to comprehension and expression. This deficit is related to prefrontal cortical atrophy in LBSD.
University of Pennsylvania, Philadelphia, PA, USA. ash@mail.med.upenn.edu
Sharon
S
Ash
Sharon X
SX
Xie
Rachel Goldmann
RG
Gross
Michael
M
Dreyfuss
Ashley
A
Boller
Emily
E
Camp
Brianna
B
Morgan
Jessica
J
O'Shea
Murray
M
Grossman
D000368:Aged; D000369:Aged, 80 and over; D016000:Cluster Analysis; D003072:Cognition Disorders / Q000209:etiology*; D032882:Comprehension / Q000502:physiology*; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology; D007806:Language Disorders / Q000209:etiology* / Q000473:pathology; D020961:Lewy Body Disease / Q000145:classification / Q000150:complications* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D033262:Narration; D009483:Neuropsychological Tests; D012044:Regression Analysis