Lexical decisions in patients with Alzheimer's disease: some notes on automatic versus controlled processing

Area of Science:

• Neuroscience
• Cognitive Psychology
• Linguistics

Background:

• Alzheimer's disease (AD) is a neurodegenerative disorder impacting cognitive functions.
• Early detection of cognitive deficits in AD is crucial for timely intervention.
• Lexical decision-making tasks are used to assess word processing abilities.

Purpose of the Study:

• To compare lexical decision-making performance between individuals with Alzheimer's disease (AD) and normally aging (NA) individuals.
• To investigate potential subtle disruptions in single-word decoding in early-stage AD.
• To determine if AD affects the processing of real words, pseudowords, and nonwords differently.

Main Methods:

• Recruited age, gender, and education-matched groups of AD patients and NA controls.
• Administered a lexical decision task involving real words, pseudowords, and nonwords.
• Analyzed the accuracy of lexical decisions for each stimulus type.

Main Results:

• AD and NA groups exhibited comparable accuracy for real word stimuli.
• Significant differences in accuracy were observed for pseudoword and nonword stimuli, with AD patients performing less accurately.
• These findings indicate a specific deficit in processing non-lexical or unfamiliar word forms in AD.

Conclusions:

• Alzheimer's disease (AD) may subtly disrupt single-word decoding, particularly for non-real words.
• Lexical decision tasks, especially with pseudowords and nonwords, can reveal early cognitive changes in AD.
• These results highlight the importance of sensitive cognitive assessments for identifying early-stage AD.