Modeling practice effects in healthy middle‐aged participants of the Alzheimer and Families parent cohort

Sánchez Benavides, Gonzalo; Gispert López, Juan Domingo; Fauria, Karine; Molinuevo, José Luis; Gramunt Fombuena, Nina

doi:http://dx.doi.org/10.1016/j.dadm.2016.07.001

Modeling practice effects in healthy middle‐aged participants of the Alzheimer and Families parent cohort

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Sánchez‐Benavides G, Gispert JD, Fauria K, Molinuevo JL, Gramunt N. Modeling practice effects in healthy middle‐aged participants of the Alzheimer and Families parent cohort. Alzheimers Dement (Amst). 2016 Jan;4(1):149-58. DOI: 10.1016/j.dadm.2016.07.001

Abstract

Introduction. Repetitive administration of neuropsychological tests can lead to performance improvement merely due to previous exposure. The magnitude of such practice effects (PEs) may be used as a marker of subtle cognitive impairment because they are diminished in healthy individuals subsequently developing Alzheimer's disease (AD). Methods. To explore the relationship between sociodemographic factors, AD family history (FH), and APOE ε4 status, and the magnitude of PE, four subtests of the Wechsler Adult Intelligence Scale-IV were administered twice to 400 middle-aged healthy individuals, most of them first-degree descendants of AD patients. Results. PEs were observed in all measures. Sociodemographic variables did not show a uniform effect on PE. Baseline score was the strongest predictor of change, being inversely related to PE magnitude. Significant effects of the interaction term APOE ε4∗Age in processing speed and working memory were observed. Discussion. PEs exert a relevant effect in cognitive outcomes at retest and, accordingly, they must be taken into consideration in clinical trials. The magnitude of PE in processing speed and working memory could be of special interest for the development of cognitive markers of preclinical AD.