Vascular and degenerative processes differentially affect regional interhemispheric connections in normal aging, mild cognitive impairment, and alzheimer disease

Dong Young Lee, Evan Fletcher, Oliver Martinez, Natalia Zozulya, Jane Kim, Jeannie Tran, Michael Buonocore, Owen Carmichael, Charles DeCarli

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1791-1797
Number of pages7
JournalStroke
Volume41
Issue number8
DOIs
StatePublished - Aug 2010

Keywords

  • Alzheimer disease
  • cerebrovascular disorders
  • corpus callosum
  • diffusion tensor imaging
  • mild cognitive impairment

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Clinical Neurology
  • Advanced and Specialized Nursing

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