Proc. American Association of Geriatric Psychiatry (AAGP) 2004, Baltimore Marriott, MD, USA, Feb. 21-24, 2004.
Prabha Siddarth, Linda Ercoli, Paul M. Thompson, Kiralee M. Hayashi, and Gary W. Small
University of California Los Angeles-Neuropsychiatric Institute and Hospital, UCLA School of Medicine, Los Angeles, CA
Objective: Longitudinal in vivo dynamic cortical maps of the brain depict a spreading wave of stage-specific cortical atrophy in Alzheimer's disease (AD). We used dynamic cortical maps to chart gray and white matter changes in nondemented persons with the APOE-4 genetic risk for Alzheimer's disease, compared to persons without APOE-4.
Methods: We recruited 23 adults (age range 50-82 years), 12 with APOE-4 and 11 without APOE-4. MRI brain scans were obtained at baseline and 2-year follow-up. Cortical pattern matching was used to evaluate change in brain shape and tissue distribution over time. Using a cortical flattening process and sulcal matching techniques, an average model of the cortex was built for subject groups, who were then compared on indices of gray matter change.
Results: We found that an interaction of two risk factors for AD - age and APOE-4 - was significantly associated with a decrease in the ratio of gray to white matter volume (F(1,14) = 5.56, p = 0.03). For persons with APOE-4, increasing age was associated with a significant decrease (slope = -0.01, t(14) = -3.52, p = 0.003) in the gray to white matter ratio, which is a 10% decrease in this ratio per decade).
Conclusions: In nondemented persons, APOE-4 may be associated with accelerated brain atrophy. The decline in the gray to white matter ratio differed from expected patterns at this stage of life in healthy controls (Ge et al., 2002), while they parallel patterns of gray matter loss found in persons with AD (Thompson et al., 2003).
Paul Thompson, Ph.D.
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