Memory Impairment, in Mild Cognitive Impairment without Significant Cerebrovascular Disease, Predicts Progression to Alzheimer’s Disease

AIMS: Mild cognitive impairment (MCI) usually represents a transitional phase between normal cognitive function and dementia, but not all people with MCI develop dementia because MCI is a clinically and etiologically heterogeneous grouping. The aim of this study was to compare progression rates to Alzheimer's disease (AD) among various MCI subtypes which show minimal white matter ischemia. METHODS: Our study cohort consisted of 504 patients aged 55 years or older who had a diagnosis of MCI at their baseline visit, and had at least 1 follow-up contact after baseline. RESULTS: Subjects with multiple-domain MCI with amnesia (mdMCI+a) were found to be significantly more likely to progress to AD in comparison to patients with nonamnesic MCI. There was no difference in the progression rate to AD between amnesic MCI and mdMCI+a during the follow-up period. The results of the multivariable Cox proportional hazards model analysis showed the same pattern of results as described above. CONCLUSION: Subjects with mdMCI+a had a statistically significant association with progression to AD. Especially, in cases of degenerative etiologies, impairment of the memory domain is more important than impairment of multiple domains in predicting the progression to dementia.