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Published on: October 13, 2016
Redefining Amnestic Mild Cognitive Impairment as an Early Form of Alzheimer's Disease Based on Assessment of Memory
Background:
It has been suggested that mild cognitive impairment (MCI) can be used to identify patients at risk of developing clinical stages of Alzheimer's disease (AD).
Objective:
The aim of this study was to describe the characteristics of amnesic syndrome of dementia of the Alzheimer's type (DAT) as a continuous degenerative process from normality to amnesic syndrome and provide a classification of the degrees of amnesia.
Methods:
Of 3,800 new incidental cases at the Memory Clinic, 747 were classified as non-demented patients. A 96-month follow-up study was conducted. We described and compared longitudinal outcomes from normality to amnesic syndrome based on immediate memory, verbal learning, free recall, and recognition using the memory scale from the Basic Neuropsychological Battery, version D (BNB-D) and created a new classification of memory impairment.
Results:
Based on differences observed in this longitudinal study, we classified patients in four memory stages: M1, Normal episodic memory; M2, mild impairment in learning and/or free recall; M3, clear impairment in learning and/or free recall; and M4, complete amnesic syndrome. With this new amnesia classification, we studied the chronological progression of all patients diagnosed without dementia from baseline to DAT conversion using the Kaplan-Meier estimator of survival probability (Log Rank/Mantel Cox comparison. χ2 = 171.84, p = 0.001).
Conclusion:
This new classification of memory impairment can help increase the prediction certainty of conversion from amnestic MCI to AD and improve research on AD biomarkers and their relationship with memory as the principal manifestation of AD.
Insights
This study introduces a new classification for memory impairment, aiding in the prediction of Alzheimer's disease (AD) progression from mild cognitive impairment (MCI). This framework enhances early detection and research into AD biomarkers.
Area of Science:
- Neuroscience
- Gerontology
- Cognitive Psychology
Background:
- Mild cognitive impairment (MCI) is a potential precursor to Alzheimer's disease (AD).
- Understanding the progression from normal cognition to amnesic syndrome is crucial for early AD detection.
Purpose of the Study:
- To characterize amnesic syndrome in dementia of the Alzheimer's type (DAT) as a continuum.
- To develop a novel classification system for memory impairment degrees.
Main Methods:
- A 96-month follow-up of 747 non-demented patients from a Memory Clinic.
- Utilized the Basic Neuropsychological Battery (BNB-D) to assess memory functions.
- Applied Kaplan-Meier survival analysis to track progression to DAT.
Main Results:
- A four-stage memory classification (M1-M4) was established, ranging from normal to complete amnesic syndrome.
- Significant chronological progression from baseline to DAT conversion was observed (p<0.001).
Conclusions:
- The new memory impairment classification improves prediction of MCI to AD conversion.
- This framework can advance research on AD biomarkers and their link to memory deficits.
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