Abstract Details

Title Interpreting Ambiguous Sentences in Behavioral-Variant Frontotemporal Degeneration

Topic Behavioral Neurology

Presentation(s) P07 - (-)

Poster/Presentation
Number 159

Objective

Background BACKGROUND: One-third of sentences in daily language contain a temporary syntactic ambiguity. Our model of comprehension proposes that the correct interpretation of ambiguous sentences depends in part on decision-making resources. Specifically, decision-making involves assessing the probability of syntactically-mediated relationships between a verb and its sentence context. Previous fMRI work in healthy adults related this to prefrontal cortex. While bvFTD patients are not known to have syntactic deficits, they have decision-making impairments that may be related to prefrontal disease.

Design/Methods DESIGN/METHODS: We assessed 19 patients with FTD, including 9 bvFTD patients and 10 nonfluent/agrammatic-variant primary progressive aphasics (naPPA). We administered 160 coherent, carefully-matched sentences where the verb was highly compatible (e.g. "The busy psychiatrist heard the story briefly") or less compatible ("The naughty boy heard the neighbors were evil") with its sentence structure, based on published norms. Half of the sentences was lengthened with a prepositional phrase to evaluate whether comprehension difficulty could be attributed to a more general working memory impairment. Patients read each sentence in a self-paced phrase-by-phrase manner on a computer. We measured response latencies and probed sentence content in 20% of trials to maintain attention. We also obtained volumetric gray matter imaging and diffusion tensor imaging tractography.

Results RESULTS: bvFTD patients were significantly slower in their responses to low compatibility sentences relative to controls and naPPA, suggesting that decision-making limitations contribute to impaired sentence comprehension in bvFTD. This deficit was equally true for high and low working memory stimuli, demonstrating that sentence comprehension limitations are not attributable to limited working memory.

Conclusions CONCLUSIONS: While language processing is thought to be preserved in bvFTD, our evidence suggests that decision-making limitations associated with prefrontal disease contribute to difficulty interpreting ambiguous sentences.

Authors/Disclosures
Murray Grossman, MD, FAAN (University of Pennsylvania) PRESENTER	Dr. Grossman has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Neurology. The institution of Dr. Grossman has received research support from NIH.
	No disclosure on file
Corey McMillan, PhD (University of Pennsylvania)	Dr. McMillan has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier. The institution of Dr. McMillan has received research support from Biogen. The institution of Dr. McMillan has received research support from NIH.
John Powers	No disclosure on file
Ashley Boller	No disclosure on file
Danielle Weinberg	No disclosure on file
	No disclosure on file
	No disclosure on file

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