[Analysis of intrusion errors in free recall]

Area of Science:

• Neuropsychology
• Cognitive Psychology
• Geriatric Psychiatry

Background:

• Extra-list intrusion errors are common in verbal recall tasks, particularly in older adults and those with cognitive impairment.
• The Amsterdam Dementia Screening Test (ADST) includes a list-learning task to assess verbal memory.
• Understanding the cognitive underpinnings of these errors is crucial for diagnosing and managing neurocognitive disorders.

Purpose of the Study:

• To investigate the occurrence and predictors of extra-list intrusion errors in a large cohort of psychogeriatric patients.
• To determine whether episodic memory deficits or executive control (inhibitory control) deficits are more strongly associated with intrusion errors.

Main Methods:

• Examined five trials of an eight-word list-learning task from the ADST in 823 psychogeriatric patients.
• Assessed intrusion errors, verbal recall, recognition memory, and executive control using various neuropsychological tests.
• Employed bivariate and hierarchical multiple regression analyses to identify independent predictors of intrusion errors.

Main Results:

• 45.9% of participants made at least one intrusion error.
• Intrusion errors were associated with poorer performance on recognition memory and executive control measures.
• Hierarchical regression indicated that only free recall and delayed visual recognition (episodic memory measures) independently predicted intrusion errors.

Conclusions:

• Deficits in episodic memory, specifically the strength of memory traces, are sufficient to explain intrusion errors in free recall.
• Inhibitory control deficits do not significantly contribute to intrusion errors in this population, suggesting memory trace weakness as the primary cause.
• Findings highlight the importance of assessing episodic memory function in psychogeriatric patients exhibiting verbal recall difficulties.