Abstract Body

Aims: Associated microvascular pathology has been described in many patients with dementing neurodegenerative disorders including Alzheimer’s disease, Lewy Body dementia, Primary progressive aphasia and frontotemporal dementia. In order to determine the contribution of microvascular pathology to age related cognitive changes we performed several series of autopsy studies.

Methods: Radiopathological and clinicopathological correlations in hospitalized elderly with an average age of 85 years.

Results: Cortical microinfarcts (CMI) were the vascular lesion most closely related to the presence of dementia in this population, representing up to 36% of the clinical variability in cognitive function.

In mixed cases, two relatively simple pathological hallmarks, neurofibrillary tangles (NFT) and CMI, were the most potent correlates of dementia; using a microscopic ischemic score for CMI and Braak NFT staging, we were able to account for 50% of the variability in dementia prevalence. CMI are particularly common in the elderly although many may remain undetected with standard brain autopsy procedures. Using a stereological approach were able to identify CMI in over half of the examined older brains.

Although some studies have been able to identify large CMI on 3 or 7 Tesla MRI, radiopathological correlations in our series indicate that the vast majority of CMI are smaller than 500 microns and cannot be seen on ante-mortem or post-mortem sequences.

Conclusion: Studies in older people with dementia should take into account the frequent occurrence of vascular pathology and its important contribution to cognitive changes in this population. CMI are rarely seen on neuroimaging but their hidden presence may affect therapeutic interventions in old age cognitive disorders.