UNLABELLED: Amyloid-β (Aβ) deposition is a pathologic hallmark of Alzheimer disease (AD). Although the typical spatial distribution pattern of Aβ deposition in early AD mainly involves regions distant from the hippocampus, the predominant clinical feature is impairment of hippocampus-dependent memory. We aimed at elucidating the relationship between neocortical Aβ load, regional neuronal function, and memory impairment. METHODS: Thirty patients with early AD underwent combined (11)C-Pittsburgh compound B ((11)C-PIB) and (18)F-FDG PET and memory assessments. Composite measures of hemispheric Aβ load were calculated by volume-weighted mean values of neocortical (11)C-PIB binding. Voxelwise (18)F-FDG uptake was used as a measure of regional glucose metabolism reflecting neuronal activity. We investigated the relationship between left- and right-hemispheric Aβ load and regional glucose metabolism (voxelwise analyses). In addition, we assessed the correlations of hemispheric Aβ load (region-of-interest-based analyses) and regional glucose metabolism (voxelwise analysis) with memory performance. Analyses were corrected for age and sex. RESULTS: Higher Aβ load in the left hemisphere was associated with reduced glucose metabolism of the left medial temporal lobe (MTL; r(2) = 0.38) and correlated with worse wordlist recall (r = -0.37; partial correlation controlled for sex and age). Furthermore, wordlist recall correlated with regional glucose metabolism in the bilateral MTL and precuneus-posterior cingulate cortex and right lingual gyrus (r(2) = 0.24). CONCLUSION: We demonstrated an association between the left-hemispheric Aβ load and impairment of the left MTL in AD at 2 different levels: regional hypometabolism and verbal memory. This correlation suggests that neocortical amyloid deposition is connected to or even drives neuronal dysfunction and neurodegeneration of the MTL, which is associated with impaired episodic memory processing as a clinical core symptom of AD.
UNLABELLED: Amyloid-β (Aβ) deposition is a pathologic hallmark of Alzheimer disease (AD). Although the typical spatial distribution pattern of Aβ deposition in early AD mainly involves regions distant from the hippocampus, the predominant clinical feature is impairment of hippocampus-dependent memory. We aimed at elucidating the relationship between neocortical Aβ load, regional neuronal function, and memory impairment. METHODS: Thirty patients with early AD underwent combined (11)C-Pittsburgh compound B ((11)C-PIB) and (18)F-FDG PET and memory assessments. Composite measures of hemispheric Aβ load were calculated by volume-weighted mean values of neocortical (11)C-PIB binding. Voxelwise (18)F-FDG uptake was used as a measure of regional glucose metabolism reflecting neuronal activity. We investigated the relationship between left- and right-hemispheric Aβ load and regional glucose metabolism (voxelwise analyses). In addition, we assessed the correlations of hemispheric Aβ load (region-of-interest-based analyses) and regional glucose metabolism (voxelwise analysis) with memory performance. Analyses were corrected for age and sex. RESULTS: Higher Aβ load in the left hemisphere was associated with reduced glucose metabolism of the left medial temporal lobe (MTL; r(2) = 0.38) and correlated with worse wordlist recall (r = -0.37; partial correlation controlled for sex and age). Furthermore, wordlist recall correlated with regional glucose metabolism in the bilateral MTL and precuneus-posterior cingulate cortex and right lingual gyrus (r(2) = 0.24). CONCLUSION: We demonstrated an association between the left-hemispheric Aβ load and impairment of the left MTL in AD at 2 different levels: regional hypometabolism and verbal memory. This correlation suggests that neocortical amyloid deposition is connected to or even drives neuronal dysfunction and neurodegeneration of the MTL, which is associated with impaired episodic memory processing as a clinical core symptom of AD.
Authors: Edmond Teng; Nicole Chow; Kristy S Hwang; Paul M Thompson; Karen H Gylys; Gregory M Cole; Clifford R Jack; Leslie M Shaw; John Q Trojanowski; Holly D Soares; Michael W Weiner; Liana G Apostolova Journal: Dement Geriatr Cogn Disord Date: 2014-12-24 Impact factor: 2.959
Authors: Zhuang Song; Philip S Insel; Shannon Buckley; Seghel Yohannes; Adam Mezher; Alix Simonson; Sarah Wilkins; Duygu Tosun; Susanne Mueller; Joel H Kramer; Bruce L Miller; Michael W Weiner Journal: J Neurosci Date: 2015-02-18 Impact factor: 6.167
Authors: Manuel Sanchez-Alavez; Patricia Robledo; Derek N Wills; James Havstad; Cindy L Ehlers Journal: Brain Res Date: 2014-03-02 Impact factor: 3.252
Authors: Daniel A Stevens; Clifford I Workman; Hiroto Kuwabara; Meryl A Butters; Alena Savonenko; Najilla Nassery; Neda Gould; Michael Kraut; Jin Hui Joo; Jessica Kilgore; Vidya Kamath; Daniel P Holt; Robert F Dannals; Ayon Nandi; Chiadi U Onyike; Gwenn S Smith Journal: Brain Commun Date: 2022-02-07