TY - JOUR
T1 - Vascular and degenerative processes differentially affect regional interhemispheric connections in normal aging, mild cognitive impairment, and alzheimer disease
AU - Lee, Dong Young
AU - Fletcher, Evan
AU - Martinez, Oliver
AU - Zozulya, Natalia
AU - Kim, Jane
AU - Tran, Jeannie
AU - Buonocore, Michael
AU - Carmichael, Owen
AU - DeCarli, Charles
PY - 2010/8
Y1 - 2010/8
N2 - Background and Purpose-: Despite the critical importance of the corpus callosum (CC) to the connection between brain hemispheres, little is known about the independent contribution of degenerative and vascular processes to regional changes in the microstructural integrity of the CC. Here, we examine these changes in subjects with mild cognitive impairment, with Alzheimer disease, and in cognitively normal elderly adults. Methods-: We used 3-dimensional brain MRI with diffusion tensor imaging in 47 Alzheimer disease, 77 mild cognitive impairment, and 107 cognitively normal subjects, and we calculated mean fractional anisotropy (FA) values for 4 CC regions corresponding to 4 homologous regions of cortical gray matter (GM). To assess vascular and degenerative processes, we also measured cortical GM and white matter hyperintensity (WMH) volume in corresponding regions and evaluated their vascular risk. Results-: We found that GM volumes in anterior and posterior regions were significantly related to FA values in the corresponding regions of the CC for all 3 diagnostic groups. Independent of GM volume, frontal WMH volume was also associated with FA values in the corresponding CC regions, but posterior WMH volume was not. Vascular risk was associated with FA of most CC regions, whereas diagnosis of cognitive state was associated only with FA of the anterior and posterior CC regions. Conclusions-: We found differential region-specific associations between degenerative and vascular processes and the structural integrity of the CC across the spectrum of cognitive ability. Based on these results, we propose a model to explain regional disruption in the interhemispheric connection.
AB - Background and Purpose-: Despite the critical importance of the corpus callosum (CC) to the connection between brain hemispheres, little is known about the independent contribution of degenerative and vascular processes to regional changes in the microstructural integrity of the CC. Here, we examine these changes in subjects with mild cognitive impairment, with Alzheimer disease, and in cognitively normal elderly adults. Methods-: We used 3-dimensional brain MRI with diffusion tensor imaging in 47 Alzheimer disease, 77 mild cognitive impairment, and 107 cognitively normal subjects, and we calculated mean fractional anisotropy (FA) values for 4 CC regions corresponding to 4 homologous regions of cortical gray matter (GM). To assess vascular and degenerative processes, we also measured cortical GM and white matter hyperintensity (WMH) volume in corresponding regions and evaluated their vascular risk. Results-: We found that GM volumes in anterior and posterior regions were significantly related to FA values in the corresponding regions of the CC for all 3 diagnostic groups. Independent of GM volume, frontal WMH volume was also associated with FA values in the corresponding CC regions, but posterior WMH volume was not. Vascular risk was associated with FA of most CC regions, whereas diagnosis of cognitive state was associated only with FA of the anterior and posterior CC regions. Conclusions-: We found differential region-specific associations between degenerative and vascular processes and the structural integrity of the CC across the spectrum of cognitive ability. Based on these results, we propose a model to explain regional disruption in the interhemispheric connection.
KW - Alzheimer disease
KW - cerebrovascular disorders
KW - corpus callosum
KW - diffusion tensor imaging
KW - mild cognitive impairment
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U2 - 10.1161/STROKEAHA.110.582163
DO - 10.1161/STROKEAHA.110.582163
M3 - Article
C2 - 20595668
AN - SCOPUS:77955171128
VL - 41
SP - 1791
EP - 1797
JO - Stroke
JF - Stroke
SN - 0039-2499
IS - 8
ER -