Free-listing and Semantic Knowledge: A Tool for Detecting Alzheimer Disease?

Area of Science:

• Neuroscience
• Cognitive Psychology
• Gerontology

Background:

• Semantic knowledge impairment is a hallmark of Alzheimer disease (AD)-related cognitive decline.
• The precise impact of AD on distinct knowledge domains remains under investigation.

Purpose of the Study:

• To examine how Alzheimer disease affects specific semantic categories crucial for daily functioning: living things and man-made objects.
• To assess the utility of a free-listing task in identifying semantic deficits in AD.

Main Methods:

• A written free-listing task was administered to 19 individuals with AD and 15 cognitively normal older adults.
• Performance on the free-listing task was correlated with other cognitive and functional assessments.
• The content of concept lists generated by both groups was compared.

Main Results:

• Group status (AD vs. control) significantly predicted free-listing performance, even after controlling for demographic and intellectual factors.
• Poorer functional status was associated with lower performance on the free-listing task.
• Individuals with AD demonstrated preserved central conceptual knowledge but degraded peripheral conceptual knowledge within categories.

Conclusions:

• The free-listing task is a simple, cost-effective tool for preliminary detection of semantic knowledge dysfunction in Alzheimer disease.
• This task can differentiate preserved core concepts from degraded peripheral concepts, aiding in AD characterization.
• The free-listing task shows potential as a culturally adaptable cognitive assessment tool.