Structural and Functional Neuroimaging: Focussing on Mild Cognitive Impairment

10 APPLIED NEUROLOGY February 2006 www.appneurology.com Brain imaging markers have already emerged as important tools in the differential diagnosis of dementia. Parameters derived from brain imaging are being intensively examined as potential predictors to identify persons with only mild cognitive losses who will imminently decline and in whom the full dementia syndrome of AD will develop. As novel, disease-modifying agents emerge, brain-imaging markers also may facilitate drug development1,2 and help monitor drug efficacy in clinical settings. Mild cognitive impairment (MCI) has a variety of definitions, all aimed at expressing an intermediate cognitive state between normal aging and dementia.3 In general, MCI patients have aberrant cognitive skills in 1 or more domains but function adequately in personal, social, and professional contexts. Scientific interest in MCI is rapidly increasing because the annual conversion rate from MCI to dementia is high.4,5 Many imaging studies have sought to identify