Older adults experience slowed processing speed and the severity of slowed processing speed is a strong predictor of age-related cognitive decline and independence. In our recent manuscript in the journal Frontiers in Neuroscience we review the structural changes observed in brains of older adults that occur with slowed processing speed. The most consistently observed structural changes occur in frontal brain regions that are susceptible to micro-vascular disease and cerebellar regions that together appear to constitute declines in neural systems important for coordinating and adapting behavior. Frontal/cerebellar systems may therefore be targets for understanding the efficacy of interventions designed to enhance healthy aging.
The most consistent and pronounced factor that affects the cognitive abilities of older adults is a decline in processing speed, or the rate at which people can perform a task. Links between processing speed and changes in frontal lobe cortex, which appear to be mediated in part by cerebral vessel disease, have been reported previously. Similar results are presented in our recent Frontiers of Human Neuroscience paper, as well as evidence that age-related changes in cerebellar cortex uniquely predict age-related changes in processing speed. Cerebellar cortex did not appear to be substantially affected by vessel disease, suggesting different mechanisms for cerebellar and frontal changes that affect processing speed. These results are important because potential lifestyle and intervention programs designed to limit the effects of aging on cognition could have greater efficacy by targeting distinct cerebellar and frontal systems.