Original Research ARTICLE
Front. Hum. Neurosci., 08 March 2010 | http://dx.doi.org/10.3389/neuro.09.010.2010
Department of Otolaryngology – Head and Neck Surgery, Medical University of South Carolina, Charleston, SC, USA
Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
Department of Electrical and Computer Engineering, University of New Mexico, and the Mind Research Network, Albuquerque, NM, USA
Age-related declines in processing speed are hypothesized to underlie the widespread changes in cognition experienced by older adults. We used a structural covariance approach to identify putative neural networks that underlie age-related structural changes associated with processing speed for 42 adults ranging in age from 19 to 79 years. To characterize a potential mechanism by which age-related gray matter changes lead to slower processing speed, we examined the extent to which cerebral small vessel disease influenced the association between age-related gray matter changes and processing speed. A frontal pattern of gray matter and white matter variation that was related to cerebral small vessel disease, as well as a cerebellar pattern of gray matter and white matter variation were uniquely related to age-related declines in processing speed. These results demonstrate that at least two distinct factors affect age-related changes in processing speed, which might be slowed by mitigating cerebral small vessel disease and factors affecting declines in cerebellar morphology.