We sought to identify magnetic resonance- (MR)-imaged structures
associated with declarative memory in a community-dwelling sample of
elderly Mexican–American individuals with a spectrum of cognitive
decline. Measured structures were the hemispheric volumes of the
hippocampus (HC), parahippocampal gyrus, and remaining temporal lobes,
as well as severity of white matter signal hyperintensities (WMH).
Participants were an imaged subsample from the Sacramento Area Latino
Study of Aging (SALSA), N = 122. Individuals were categorized
as normal, memory impaired (MI), cognitively impaired non-demented
(CIND), or demented. We show that WMH was the strongest structural
predictor for performance on a delayed free-recall task (episodic
memory) in the entire sample. The association of WMH with delayed
recall was most prominent in elderly normals and mildly cognitively
impaired individuals with no dementia or impairment of daily function.
However, the left HC was associated with verbal delayed recall only in
people with dementia. The right HC volume predicted nonverbal
semantic-memory performance. We conclude that WMH are an important
pathological substrate that affects certain memory functions in normal
individuals and those with mild memory loss and discuss how tasks
associated with WMH may rely upon frontal lobe function.
(JINS, 2004, 10, 371–381.)