Assessing Working Memory in Mild Cognitive Impairment with Serial Order Recall

Area of Science:

• Neuroscience
• Cognitive Psychology
• Gerontology

Background:

• Working memory (WM) is crucial for cognitive function.
• Traditional Backward Digit Span Test (BDT) analysis aggregates performance.
• Prior research has not detailed specific WM error patterns in mild cognitive impairment (MCI).

Purpose of the Study:

• To investigate WM deficits in MCI using detailed serial order analysis of the BDT.
• To differentiate WM performance across MCI subtypes (amnestic MCI, mixed/dysexecutive MCI) and non-MCI individuals.
• To identify specific error types (transpositions, omissions, perseverations) indicative of WM impairment.

Main Methods:

• Sixty-six memory clinic patients were categorized into non-MCI, amnestic MCI (aMCI), and mixed/dysexecutive MCI (mixed/dys MCI) groups.
• Participants completed the BDT, involving repeating five digits backward across seven trials.
• Serial position accuracy, transposition errors, omissions, and perseverations were meticulously recorded.

Main Results:

• A significant group-by-trial interaction was observed, indicating differential performance based on MCI status and serial position.
• Mixed/dys MCI patients exhibited an attenuated recency effect compared to non-MCI and aMCI groups.
• Mixed/dys MCI patients made significantly more transposition errors, omissions, and perseverations than non-MCI patients.

Conclusions:

• The BDT, when analyzed for serial order parameters, can reveal specific working memory deficits in MCI.
• An attenuated recency effect and increased error types are potential diagnostic markers for mixed/dysexecutive MCI.
• This detailed analysis offers enhanced diagnostic information for working memory impairments in MCI.