Retest effects in a diverse sample: sociodemographic predictors and possible correction approaches

Area of Science:

• Neuroscience
• Gerontology
• Psychometrics

Background:

• Repeated cognitive assessments in longitudinal studies can lead to retest effects, where scores increase at follow-up compared to baseline.
• These retest effects may compromise the accurate evaluation of cognitive decline in aging populations.

Purpose of the Study:

• To investigate the occurrence and magnitude of retest effects in a large, diverse sample undergoing cognitive assessment over four years.
• To evaluate the impact of sociodemographic factors on follow-up cognitive scores.
• To test and compare two methods for correcting retest effects.

Main Methods:

• A longitudinal study involving 5,592 participants assessed twice over four years.
• Testing of two correction approaches: regression difference correction and mean difference correction.
• Calculation of the Reliable Change Index to assess score changes.

Main Results:

• A modest increase in scores was observed at the four-year follow-up, indicating a slight retest effect.
• Regression difference correction effectively generated adjusted follow-up scores.
• Mean difference correction proved ineffective, and sociodemographic characteristics had minimal influence on retest effects.

Conclusions:

• Regression difference correction is recommended to mitigate retest effects in longitudinal cognitive studies.
• Failure to account for retest effects can lead to biased interpretations of cognitive changes in older adults.