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News in brief

The contribution of brain lesions to ageassociated memory decline was investigated by Adam Brickman and colleagues at Columbia University (NY, USA). Their results indicate that there is a link between vascular lesions and neurodegenerative changes in the hippocampus, which is in turn associated with poorer memory. Silent strokes were also associated with poor memory and cognitive performance independent of hippocampus size. Silent stokes occur without any of the outward symptoms usually associated with stroke, such as slurred speech and muscle weakness. This is because the lesions that cause the damage are in areas of the brain that are not associated with motor control. These regions may be involved in cognitive functioning or memory. The hippocampus region of the brain is associated with memory and so much of the study of memory decline in the elderly focuses on neuro degenerative changes in and around this area. The effect of silent strokes in this area on memory function has, to date, been much less comprehensively studied. The investigation at Columbia University used structural MRI data from 658 elderly participants without dementia. Cortical and subcortical infarcts were identified and hippocampus brain volume was calculated. Scans showed that 174 of the participants had silent strokes. The team then analyzed scores on various cognitive tests, including memory tasks, and used multiple regression analyses to relate performance to infarcts and brain volume. The results indicated a link between the presence of brain infarcts and reduced hippocampus volume, which is associated with decreased memory functioning. Brickman explained: “our research showed that both strokes and hippocampus shrinkage are independently associated with memory functioning among older adults. These findings suggest that in addition to degenerative changes we typically attribute to Alzheimer’s disease, vascular disease in the brain is playing an important role in suboptimal cognitive aging. Strokes are largely preventable through management of vascular risk factors (such as hypertension, diabetes and obesity) and through maintenance of a healthy lifestyle. A clinical focus on stroke prevention may significantly decrease incidence of dementia. It is also important to note that the majority of individuals in our study who had radiological evidence of a stroke did not have a clinical history of stroke. Aggressive clinical screening and neuroradiological examination is important to identify individuals with and at risk for developing stroke.” The indication that both hippocampal volume and silent strokes can independently affect memory loss in the elderly has clinical implications for the prevention and identification of age-associated neurodegenerative conditions and stresses the importance of stroke management.