Owen Carmichael, Ph.D.
Associate Professor and Director of Biomedical Imaging
Associate Professor and Director of Biomedical Imaging
The brains of individuals who die with dementia often show evidence of both Alzheimer’s disease (AD) and cerebrovascular disease (CVD)—damage to the blood vessels of the brain. But it is not clear how these two problems develop in relation to each other over time, and it is also not clear whether preventing one of them (say, CVD) would have been adequate to prevent dementia, given that the other (say, AD) was on the way. I have used MRI markers of AD and CVD to assess how AD and CVD relate to cognitive decline in elderly individuals, and thus begin to understand the possible benefits of shutting down one or the other disease.
The most striking finding of this work is that sub-clinical CVD is remarkably prevalent and relevant, even in studies that went to a great deal of effort to exclude individuals with overt CVD. The Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort, for example, was designed to isolate “pure AD” without much CVD. Yet, MRI markers of CVD are not only present in the ADNI cohort, they are also associated with greater cognitive decline, greater brain atrophy over time, and poorer brain metabolism independent of markers of AD. This suggests that clinical trials of therapies for AD should begin to take great caution to account for CVD in their participants, since many of their participants will show evidence of CVD that has the potential to impact their brain health and cognition.
Publications:Josephine Barnes, Owen T Carmichael, Kelvin K Leung, Christopher Schwarz, Gerard R Ridgway, Jonathan W Bartlett, Ian B Malone, Jonathan M Schott, Martin N Rossor, Geert Jan Biessels, Charlie DeCarli, Nick C Fox.Vascular and AD markers independently predict brain atrophy rate in ADNI controls. In press, Neurobiology of Aging, 2013.
Thaddeus Haight, Susan Landau, Owen Carmichael, Christopher Schwarz, Charles DeCarli, William Jagust, for the Alzheimers Disease Neuroimaging Initiative. Dissociable effects of Alzheimer’s Disease and white matter hyperintensities on brain metabolism. Archives of Neurology 2012, In Press.
Guzman, V.A., Carmichael, O.T., Schwarz, C., Tosto, G., Zimmerman, M.E., Brickman, A.M. for the Alzheimer’s Disease Neuroimaging Initiative. White matter hyperintensities and amyloid are independently associated with entorhinal cortex volume among individuals with mild cognitive impairment.Alzheimers and Dementia 2012, In Press.
Owen Carmichael, Christopher Schwarz, David Drucker, Evan Fletcher, Danielle Harvey, Laurel Beckett, Clifford R. Jack Jr., Michael Weiner, Charles DeCarli, and the Alzheimers Disease Neuroimaging Initiative. Longitudinal Changes In White Matter Disease and Cognition in the First Year of the Alzheimers Disease Neuroimaging Initiative. Archives of Neurology, 2010 Nov;67(11):1370-8. DOI
Jasmine Nettiksimmons, Laurel Beckett, Christopher Schwarz, Owen Carmichael, Evan Fletcher, Charles DeCarli, and the Alzheimers Disease Neuroimaging Initiative. Subgroup of ADNI normal controls characterized by atrophy and cognitive decline associated with vascular damage. Psychology and Aging, 2012 In Press.
Jasmine Nettiksimmons, Danielle Harvey, James Brewer, Owen Carmichael, Charles DeCarli, Clifford R Jack, Jr., Ronald Petersen, Leslie M Shaw, John Q Trojanowski, Michael W Weiner, Laurel Beckett. Subtypes based on CSF and MRI markers in normal elderly predict cognitive decline. Neurobiology of Aging, Volume 31, Issue 8, August 2010, Pages 1419-1428. DOI