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Cognitive differences between early- and late-onset Alzheimer's disease
Eliot A Licht1, Aaron M McMurtray, Ronald E Saul
1Neurobehavior Unit, VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA. eliotlicht@sbcglobal.net
Summary
Early-onset Alzheimer's disease (EAD) and late-onset Alzheimer's disease (LAD) show cognitive differences primarily due to age, not the disease itself. Alzheimer's disease heterogeneity is linked to age-related vulnerabilities.
Area of Science:
- Neurology
- Geriatrics
- Cognitive Science
Background:
- Neuropathology suggests early-onset Alzheimer's disease (EAD) and late-onset Alzheimer's disease (LAD) are indistinguishable.
- Clinical observations indicate potential cognitive distinctions between EAD and LAD.
Purpose of the Study:
- To investigate cognitive differences between EAD and LAD by comparing patients at the extremes of age of onset.
- To identify age-related cognitive variations in Alzheimer's disease.
Main Methods:
- Comparison of 44 men with EAD (onset < 65 years) and 44 men with LAD (onset ≥ 84 years).
- Assessment using an intake cognitive screening examination upon initial presentation.
- Analysis focused on dementia and various cognitive variables, including verbal fluency and motor-executive functions.
Main Results:
- No significant differences were found between EAD and LAD groups in overall dementia or most cognitive variables.
- The LAD group exhibited worse verbal fluency and motor-executive functions compared to the EAD group.
- These observed cognitive differences diminished upon accounting for age disparities between the groups.
Conclusions:
- Alzheimer's disease presents as a clinically heterogeneous disorder.
- Cognitive manifestations of Alzheimer's disease can vary based on the age of onset.
- Observed differences highlight potential age-related vulnerabilities in the progression of Alzheimer's disease.
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