# Practice Effects in Cognitive Aging: Implications for Biomarkers and Early Diagnosis

> **NIH NIH F31** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2020 · $38,401

## Abstract

PROJECT SUMMARY
The field of cognitive aging is increasingly concerned with identifying early cognitive decline and the transition
point from normal aging to the Alzheimer’s Disease (AD) continuum. Longitudinal assessments are necessary
to monitor cognitive change. However, studies that involve repeated testing are subject to practice effects,
which are typically defined as improvements in scores because of prior test exposure. Practice effects are
important for studies of aging because they inflate performance, thereby obscuring the true degree of age-
related cognitive decline expected at mid- and late life. If uncorrected for practice effects, stable performance in
a longitudinal study may indicate cognitive decline that would go undetected based on typical norm-based
classifications of impairment. Although cognitive decline is a likely a continuous process, cut points for
impairment are necessary for determining when to alter patient care and when to enroll subjects in a study. Cut
points for cognitive impairment, like cut points for biomarkers, are set because individuals with that level of
performance are more likely to have other symptoms or a greater likelihood for disease progression. The
misclassification of cognitive change may also obscure the relationship between cognition and biomarkers or
risk factors for AD. Nevertheless, researchers almost always utilize uncorrected data, rely on purely statistical
methods of practice effect correction, or simply covary for the number of visits. To directly address practice
effects across two timepoints, a better method is to include replacement subjects who are naive to the tests,
but age- and demographically-matched to returnees. Using this method, the Vietnam Era Twin Study of Aging
(VETSA), demonstrated practice effects after six years, even when mean performance declined with age.
Moreover, practice effect correction doubled the percentage of mild cognitive impairment (MCI) diagnoses
while reducing the number of participants who reverted to normal. In this proposal I will extend this approach to
practice effect correction by, for the first time, applying it across more than two assessments. Data will be from
the VETSA and the Alzheimer’s Disease Neuroimaging Initiative (ADNI), which differ in participant age, retest
interval, biomarkers, and number of assessments. I now have pilot data on the identification of “pseudo”
replacement subjects in ADNI. The method will be developed within ANDI and cross-validated in VETSA,
which recruited “true” replacement subjects. I hypothesize that accounting for practice effects will lead to earlier
diagnoses of MCI, and a stronger signal between cognitive performance and biomarkers. With earlier detection
of MCI, researchers and clinicians will be better able to track AD progression and monitor the effectiveness of
potential treatments. Beyond the current proposal, a longer-term goal is to develop normative practice effect
data (e.g., with NIH toolbox). By ...

## Key facts

- **NIH application ID:** 9992303
- **Project number:** 1F31AG064834-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** Mark Sanderson-Cimino
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $38,401
- **Award type:** 1
- **Project period:** 2020-09-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9992303

## Citation

> US National Institutes of Health, RePORTER application 9992303, Practice Effects in Cognitive Aging: Implications for Biomarkers and Early Diagnosis (1F31AG064834-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9992303. Licensed CC0.

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