Clinical Manifestations.

Area of Science:

• Neuropsychology
• Cognitive Neuroscience
• Neurology

Background:

• Neuropsychological testing strategies offer sensitive measures of cognitive decline in neurodegenerative diseases.
• Temporal contiguity and semantic clustering are key recall strategies in word-list learning tasks.
• Differences in strategy use across mild cognitive impairment (MCI) subtypes and their relation to semantic strategies remain unclear.

Purpose of the Study:

• To compare temporal contiguity and semantic clustering strategies across amnestic MCI (aMCI), non-amnestic MCI (naMCI), and control groups.
• To investigate the relationship between temporal contiguity and semantic clustering in memory recall.
• To determine the association between specific recall strategies and cognitive performance in MCI subtypes.

Main Methods:

• Analyzed recall data from the Word-List subtest of the Kaplan-Baycrest Neurocognitive Assessment in 194 patients.
• Calculated temporal contiguity scores based on the lag between successively recalled words.
• Quantified semantic clustering by the consecutive recall of categorically related words, controlling for chance.

Main Results:

• Non-amnestic MCI patients showed significantly less use of temporal contiguity compared to controls (p=0.02).
• Amnestic MCI patients utilized temporal contiguity, but it was associated with poorer immediate recall.
• Semantic clustering was linked to better immediate and delayed recall in both controls and aMCI patients.

Conclusions:

• Temporal contiguity may be a suboptimal recall strategy for individuals with aMCI.
• Individuals with aMCI and intact semantic processing may maintain memory performance by employing semantic strategies.
• Reduced temporal contiguity use in naMCI may reflect impaired frontal memory organization abilities.