Affiliations: [a] Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA | [b] Department of Medicine, The University of Texas Health Science Center, San Antonio, TX, USA | [c] Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX, USA | [d] GRECC, the South Texas Veterans' Health System Audie L. Murphy Division, San Antonio, TX, USA | [e] Department of Neurology, KU Alzheimer and Memory Program, University of Kansas Medical Center, Kansas City, KS, USA
Correspondence:
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Correspondence to: Donald R. Royall, MD, The University of Texas Health Science Center, San Antonio, TX, USA. Tel.: +1 210 567 1255; Fax: +1 210 567 1269; E-mail: royall@uthscsa.edu.
Abstract: We have employed structural equation models to explicitly distinguish dementia-relevant variance in cognitive task performance (i.e., δ) from the variance that is unrelated to a dementing process (i.e., g'). Together g' and d comprise Spearman's “g”. Although d represents only a minor fraction of the total variance in cognitive task performance, it is more strongly associated with dementia severity than is g'. In this analysis, we replicate δ in a new dataspace, the University of Kansas Brain Aging Project, and associate it specifically with regional grey matter atrophy by voxel-based morphometry of magnetic resonance imaging data. The latent variable d localizes to elements of the default mode network and related structures in the R hemisphere.
Keywords: Aging, cognition, dementia, g, functional status
