Poster A51, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Neuroanatomical Correlates of Visuoconstruction in the Primary Progressive Aphasias
Christa Watson1, Maria Luisa Mandelli1, Katherine Possin1, Maria Luisa Gorno-Tempini1; 1University of California, San Francisco
The most difficult differential diagnosis among the primary progressive aphasias (PPA) is between the logopenic variant (lvPPA) and the nonfluent variant (nfvPPA) as both often present with non-fluent speech. However, the variants have distinct atrophy patterns: left inferior frontal atrophy in nfvPPA and left temproparietal atrophy in lvPPA. Since temproparietal atrophy is often associated with visuospatial difficulties, we hypothesized that visuospatial tasks might help to differentiate lvPPA from nfvPPA. We compared visuospatial functions in three PPA variants and a neurologically healthy control group using a composite of three well-known visuoconstruction tasks (Beery VMI, Benson Figure Copy, and WAIS-III Block Design). Standardized test scores were averaged to create a visuoconstruction composite, which was regressed with whole brain voxel-wise gray matter after adjusting for age, gender, education, Clinical Dementia Rating scores, and total gray matter volume (proxy for degree of atrophy). The lvPPA and nfvPPA groups performed similarly to one another and significantly worse than control and semantic variant groups on the visuoconstruction composite. There were four regions where the visuoconstruction composite correlated with gray matter volume: left 1) precentral gyrus, 2) postcentral/precuneus, and 3) supplementary motor cortex (SMA); and 4) right posterior superior temporal gyrus (STG). The composite correlated with all regions in the nfvPPA group, but in the lvPPA group correlations were only found with the left SMA and right STG. In conclusion, scores on commonly utilized visuoconstruction measures did not differentiate the lvPPA and nfvPPA variants, but the two variants demonstrated distinct brain-behavior relationships.
Topic Area: LANGUAGE: Other