Brain Infarction and the Clinical Expression of Alzheimer Disease-Reply

In Reply. —The analyses of Drs Mirra and Gearing indicate that brain infarcts are not associated with NFTs in the neocortex. Our analyses also indicated that brain infarcts were not associated with the number of NFTs, senile plaques, or neuritic plaques in the neocortex, suggesting that AD lesions and brain infarcts were likely to have occured independently of each other. While AD and brain infarction may represent separate disease processes, their combination may nonetheless increase the likelihood that dementia will occur. Among the participants in our study who met our neuropathologic criteria for AD (ie, abundant senile plaques and some NFTs in the neocortex), those with 1 or 2 lacunar infarcts in the basal ganglia, thalamus, or deep white matter had an especially high prevalence of dementia, compared with those without brain infarcts. The prevalence of dementia was 93% for those with such subcortical lacunar infarcts and 57% in those without infarcts.