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

Abstract

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.

Mild cognitive impairment: narrative review of taxonomies and systematic review of their prediction of incident Alzheimer's disease dementia

“…18 Although there was not consensus, 7 of 10 studies found that multiple-domain aMCI was better than single domain aMCI in predicting progression, 54,[67][68][69]73,74,76 two showed the opposite 70,77 and one showed no difference. 71 A possible reason for the discrepant findings regarding single-domain aMCI and multiple-domain aMCI in the prediction of Alzheimer's disease dementia is differing definitions of the subtypes. The inconsistent findings within this area highlight the variable implementation of the criteria.…”

“…12 The most consistent finding was that aMCI is associated with an increased risk of progression to Alzheimer's disease dementia. 53,[67][68][69][70][71][72][73][74][75][76][77] Individuals with aMCI are more likely (18-19% per year) to progress to Alzheimer's disease dementia than non-amnestic MCI participants (10-11%) in community- 53 and healthcare-based cohorts. 78 Ten studies compared progression rates between various subtypes within the Winblad taxonomy.…”

“…However, two studies found that single-domain aMCI was associated with the highest risk of progression to dementia due to Alzheimer's disease, 70,77 and one found no difference between single-and multipledomain aMCI. 71 A challenge to the discriminative validity of the Winblad taxonomy is that multiple-domain aMCI was also the best predictor of progression to vascular dementia. 73 Although all studies purported to employ the revised Mayo criteria, these were operationalised in different ways, for example, using hierarchical cluster analysis of neuropsychological data rather than clinical judgement 70 or not including information about subjective memory complaint.…”

Modifiable Predictors of Dementia in Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

“…Two studies reported the association of education with conversion from any type MCI to AD. One found that more education decreased 43;43 and one that it increased 81 risk. Only five of the studies in people with any type MCI (from four datasets) reported years of education in people who did and did not convert from any type MCI to dementia, and the pooled unadjusted effect size from these studies was not significant (-0.30, -0.63 to 0.01) 43;53;59;67;80 .…”

Organization of out-patient psychiatric care in dementia and cognitive impairment in aged. Part II: Clinical and economic efficacy of memory clinics and Alzheimer’s disease centers

“…В другом аспекте было проведено исследование в Центре клинических исследований деменции в Южной Корее [21], где с 2006 по 2010 г. были взяты под наблюдение 504 пациента в возрасте 55 лет и старше с диагнозом МКС при первом визите больных. Длительность катамнеза составляла 12 мес.…”