The authors undertook a prospective evaluation of an inception cohort of 1167 ethnically diverse elders recruited from an urban community-based sample monitored with clinical and neuropsychological testing for an average of 4.5 years (standard deviation, 0.8 year). A subset of the subjects underwent MRI. We compared four groups of MCI patients: single-domain amnestic and dysexecutive MCI, and multiple-domain MCI with and without executive dysfunction.
Compared with aMCI, dMCI was less likely to involve other areas of cognition over time and progress to dementia. None of the 33 single-domain dMCI patients progressed to dementia. The presence of executive dysfunction in multiple-domain MCI did not increase risk of progression to dementia. Patients with multiple-domain MCI with executive dysfunction who progressed to dementia were less likely to have an Alzheimer's-type dementia than MCI patients without executive dysfunction. Patients with dMCI were more likely to experience stroke, but not white matter hyperintensity, detected via MRI than patients with aMCI.
dMCI appears to follow a different course, and is less associated with Alzheimer's disease and more associated with stroke than aMCI.