Visual memory predicts Alzheimer's disease more than a decade before diagnosis

Area of Science:

• Neuroscience
• Gerontology
• Cognitive Psychology

Background:

• Alzheimer's disease (AD) may develop years before clinical symptoms manifest.
• Premorbid cognitive function is crucial for understanding AD's early stages.
• The Baltimore Longitudinal Study of Aging (BLSA) provides long-term data on aging and cognition.

Purpose of the Study:

• To investigate if premorbid Benton Visual Retention Test (BVRT) and Wechsler Adult Intelligence Scale-vocabulary (WAIS-voc) scores predict future Alzheimer's disease (AD) diagnosis.
• To determine the predictive value of long-term cognitive deficits for AD development decades in advance.

Main Methods:

• Analysis of 1,425 BLSA participants aged over 60.
• Utilized Cox proportional hazards models to assess AD risk associated with BVRT and WAIS-voc scores.
• Examined test scores at various intervals up to 20 years before AD diagnosis.

Main Results:

• A higher number of BVRT errors (≥6) significantly increased AD risk up to 15 years before diagnosis (relative risks ranging from 1.76 to 5.69).
• The association between BVRT errors and AD risk was not significant beyond 15 years prior.
• WAIS-voc scores showed no significant association with AD risk across any time period.

Conclusions:

• Elevated BVRT errors are linked to increased Alzheimer's disease risk, suggesting visual memory deficits as an early AD indicator.
• These findings support revising the natural history of AD, highlighting a potential extended period for early detection and intervention.
• Premorbid visual-spatial memory assessment may aid in identifying individuals at higher risk for AD.