Background: Practice effects (PE), after repeated cognitive measurements, may mask cognitive decline and represent a challenge
in clinical and research settings. However, an attenuated practice effect may indicate the presence of brain pathologies. This study
aimed to evaluate practice effects on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) scale, and
their associations with brain amyloid status and other factors in a cohort of cognitively unimpaired older adults enrolled in the
CHARIOT-PRO SubStudy.
Methods: 502 cognitively unimpaired participants aged 60-85 years were assessed with RBANS in both screening and baseline clinic
visits using alternate versions (median time gap of 3.5 months). We tested PE based on differences between test and retest scores
in total scale and domain-specific indices. Multiple linear regressions were used to examine factors influencing PE, after adjusting
for age, sex, education level, APOE‐ε4 carriage and initial RBANS score. The latter and PE were also evaluated as predictors for
amyloid positivity status based on defined thresholds, using logistic regression.
Results: Participants’ total scale, immediate memory and delayed memory indices were significantly higher in the second test than
in the initial test (Cohen’s dz = 0.48, 0.70 and 0.35, P < 0.001). On the immediate memory index, the PE was significantly lower in
the amyloid positive group than the amyloid negative group (P = 0.022). Older participants (≥ 70 years), women, non‐APOE‐ε4
carriers, and those with worse initial RBANS test performance had larger PE. No associations were found between brain MRI
parameters and PE. In addition, attenuated practice effects in immediate or delayed memory index were independent predictors
for amyloid positivity (P < 0.05).
Conclusion: Significant practice effects on RBANS total scale and memory indices were identified in cognitively unimpaired older
adults. The association with amyloid status suggests that practice effects are not simply a source of measurement error but may
be informative with regard to underlying neuropathology.