Development of a subjective cognitive decline questionnaire using item response theory: a pilot study

Area of Science:

• Gerontology
• Cognitive Neuroscience
• Psychometrics

Background:

• Subjective cognitive decline (SCD) may signal unhealthy cognitive changes.
• A standardized measurement for SCD is currently lacking.
• This pilot study addresses the need for reliable SCD assessment tools.

Purpose of the Study:

• To identify reliable self-report questions for measuring subjective cognitive decline (SCD).
• To develop a foundation for a standardized SCD screening tool in older adults.

Main Methods:

• 112 cognitively normal, 43 mild cognitive impairment, and 33 ambiguous participants completed 57 self-report SCD questions.
• Psychometric methods, including factor analysis and item response theory (IRT), were used for item reduction.
• Computerized adaptive test (CAT) modeling selected the final nine items.

Main Results:

• Factor analysis removed 19 items due to poor response distribution or trait fit.
• IRT analysis identified and removed 17 low-utility items.
• CAT modeling confirmed nine items effectively represented SCD and differentiated cognitively normal from mild cognitive impairment participants (r=0.94).

Conclusions:

• Item response theory and CAT modeling successfully identified nine reliable SCD items.
• This study represents a significant advancement in refining SCD assessment for older adults.
• Future research should validate these findings and incorporate Alzheimer's disease biomarkers for a comprehensive SCD screener.