Brodtmann Amy, Puce Aina, Syngeniotis Ari, Darby David, Donnan Geoffrey
National Stroke Research Institute, Austin & Repatriation Medical Centre, and Department of Medicien, University of Melbourne, Melbourne, Australia.
Neuroimage. 2003 Sep;20(1):520-8. doi: 10.1016/s1053-8119(03)00237-4.
The effects of aging on blood oxygen level dependent signal changes and the hemodynamic response (HDR) remain controversial. Using functional magnetic resonance (MR) imaging, we examined the HDR properties and activated voxel counts in striate and extrastriate cortex in 18 healthy elderly subjects in response to a simple visual paradigm. Subjects of equal number and gender were prospectively separated into groups from the seventh, eighth, and ninth decades. Activation data were compared with those of 6 healthy subjects aged 30-39 under the same conditions. We found no systematic difference in HDR amplitude, shape, or latency across these groups. However, increasing age over 60 was associated with a significant decline in activated voxel counts, relative to the young controls. The results are discussed in comparison with previously published studies and in the context of the effects of aging on MR signal change. While robust activation can be produced in the striate and extrastriate cortices until the end of the ninth decade, caution should be exercised when comparing data from subjects in different decades. As functional magnetic resonance imaging is increasingly being used to examine patients with stroke and dementia, these results emphasize the importance of careful selection and age matching of control subjects when comparing with a patient population affected by disease processes associated with aging.
