OBJECTIVE: Clinical heterogeneity in Alzheimer's disease has been widely observed. One factor that may influence the expression of dementia in Alzheimer's disease is premorbid intellectual ability. It has been hypothesized that premorbid ability, as measured by educational experience, reflects a cognitive reserve that can affect the clinical expression of Alzheimer's disease. The authors investigated the relation between estimates of premorbid intellectual function and cerebral glucose metabolism in patients with Alzheimer's disease to test the effect of differing levels of premorbid ability on neurophysiological dysfunction. METHOD: In a resting state with eyes closed and ears occluded, 46 patients with Alzheimer's disease were evaluated with positron emission tomography and [18F]-2-fluoro-2-deoxy-D-glucose to determine cerebral metabolism. Premorbid intellectual ability was assessed by a demographics-based IQ estimate and performance on a measure of word-reading ability. RESULTS: After the authors controlled for demographic characteristics and dementia severity, both estimates of premorbid intellectual ability were inversely correlated with cerebral metabolism in the prefrontal, pre-motor, and left superior parietal association regions. In addition, the performance-based estimate (i.e., reading ability) was inversely correlated with metabolism in the anterior cingulate, paracentral, right orbitofrontal, and left thalamic regions, after demographic and clinical variables were controlled for. CONCLUSIONS: The results suggest that higher levels of premorbid ability are associated with greater pathophysiological effects of Alzheimer's disease among patients of similar dementia severity levels. These findings provide support for a cognitive reserve that can alter the clinical expression of dementia and influence the neurophysiological heterogeneity observed in Alzheimer's disease.
OBJECTIVE: Clinical heterogeneity in Alzheimer's disease has been widely observed. One factor that may influence the expression of dementia in Alzheimer's disease is premorbid intellectual ability. It has been hypothesized that premorbid ability, as measured by educational experience, reflects a cognitive reserve that can affect the clinical expression of Alzheimer's disease. The authors investigated the relation between estimates of premorbid intellectual function and cerebral glucose metabolism in patients with Alzheimer's disease to test the effect of differing levels of premorbid ability on neurophysiological dysfunction. METHOD: In a resting state with eyes closed and ears occluded, 46 patients with Alzheimer's disease were evaluated with positron emission tomography and [18F]-2-fluoro-2-deoxy-D-glucose to determine cerebral metabolism. Premorbid intellectual ability was assessed by a demographics-based IQ estimate and performance on a measure of word-reading ability. RESULTS: After the authors controlled for demographic characteristics and dementia severity, both estimates of premorbid intellectual ability were inversely correlated with cerebral metabolism in the prefrontal, pre-motor, and left superior parietal association regions. In addition, the performance-based estimate (i.e., reading ability) was inversely correlated with metabolism in the anterior cingulate, paracentral, right orbitofrontal, and left thalamic regions, after demographic and clinical variables were controlled for. CONCLUSIONS: The results suggest that higher levels of premorbid ability are associated with greater pathophysiological effects of Alzheimer's disease among patients of similar dementia severity levels. These findings provide support for a cognitive reserve that can alter the clinical expression of dementia and influence the neurophysiological heterogeneity observed in Alzheimer's disease.
Authors: Gene E Alexander; Kaitlin L Bergfield; Kewei Chen; Eric M Reiman; Krista D Hanson; Lan Lin; Daniel Bandy; Richard J Caselli; James R Moeller Journal: Neurobiol Aging Date: 2012-03-08 Impact factor: 4.673
Authors: Nikolaos Scarmeas; Eric Zarahn; Karen E Anderson; John Hilton; Joseph Flynn; Ronald L Van Heertum; Harold A Sackeim; Yaakov Stern Journal: Neuroimage Date: 2003-07 Impact factor: 6.556
Authors: D F Tate; E S Neeley; M C Norton; J T Tschanz; M J Miller; L Wolfson; C Hulette; C Leslie; K A Welsh-Bohmer; B Plassman; Erin D Bigler Journal: Brain Res Date: 2010-12-21 Impact factor: 3.252
Authors: Eric M Reiman; Kewei Chen; Gene E Alexander; Richard J Caselli; Daniel Bandy; David Osborne; Ann M Saunders; John Hardy Journal: Proc Natl Acad Sci U S A Date: 2005-06-02 Impact factor: 11.205
Authors: Eric M Reiman; Kewei Chen; Gene E Alexander; Richard J Caselli; Daniel Bandy; David Osborne; Ann M Saunders; John Hardy Journal: Proc Natl Acad Sci U S A Date: 2003-12-19 Impact factor: 11.205
Authors: Stephen R Rapp; Mark A Espeland; Joann E Manson; Susan M Resnick; Nick R Bryan; Sylvia Smoller; Laura H Coker; Lawrence S Phillips; Marcia L Stefanick; Gloria E Sarto Journal: Int J Psychiatry Med Date: 2013 Impact factor: 1.210