Abstract Details

Title Dissociating Object and Number Knowledge in Temporal and Parietal Disease: Partitioning Semantic Memory and its Functional Consequences

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) S13 - Behavioral and Cognitive Neurology: Behavioral Neurology, Aging, and Dementia (1:44 PM-1:55 PM)

Poster/Presentation
Number 005

Background Number sense and magnitude, associated with the parietal lobe, and object knowledge, associated with the temporal lobe, are two domains of semantic memory. We hypothesized that these anatomically distinct domains of knowledge would be selectively impaired in patients with parietal and temporal disease, and that this would selectively impact functional daily living.

Objective We aim to identify a double dissociation for deficits of object and number knowledge within semantic memory and demonstrate dissociable real-world functional consequences of selectively impaired semantic memory.

Design/Methods We assessed patients with temporal (semantic variant primary progressive aphasia, n=6) and parietal disease (corticobasal syndrome, and posterior cortical atrophy, n=15). Groups were matched for education, disease duration, and age. We derived an object knowledge semantic score by averaging the z scores of object knowledge measures (Pyramids and Palm Trees Test, Forks and Chopsticks Test) and a numerosity knowledge score by averaging the z scores of measures assessing number sense and magnitude (simple mental addition and dot-array-Arabic-numeral matching). Functional assessments included the Activities of Daily Living scale (ADL) and the Perception of Conversation Index-Dementia of the Alzheimer’s type (PCI-DAT).

Results T-tests indicated that the object knowledge score was significantly worse than the numerosity score (p<0.01) in the temporal group, but was significantly better than the numerosity score in the parietal group (p<0.05). The temporal group exhibited a worse object knowledge score (p<0.05) and a significantly better numerosity score (p<0.05) than the parietal group. The PCI-DAT score was significantly worse in the temporal group than the parietal group (p<0.001) and correlated with the object knowledge score (p<0.01). Neither object nor numerosity knowledge was related to ADL.

Conclusions Results suggest a double dissociation within semantic memory of object and numerosity knowledge. Impaired object knowledge entails a functional deficit in communication, but neither semantic impairment impacts activities of daily living.

Authors/Disclosures
Molly B. Ungrady (Penn Frontotemporal Degeneration Center) PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Murray Grossman, MD, FAAN (University of Pennsylvania)	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.

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