title: Neuropsychological Practice Effects in the Context of Cognitive Decline: Contributions from Learning and Task Novelty.
abstract: Although cognitive decline is typically associated with decreasing practice effects (PEs) (presumably due to declining memory), some studies show increased PEs with declines in cognition. One explanation for these inconsistencies is that PEs reflect not only memory, but also rebounds from adapting to task novelty (i.e., novelty effect), leading to increased PEs. We examined a theoretical model of relationships among novelty effects, memory, cognitive decline, and within-session PEs. Sixty-six older adults ranging from normal to severely impaired completed measures of memory, novelty effects, and two trials each of Wechsler Adult Intelligence Scale, 4 th Edition Symbol Search and Coding. Interrelationships among variables were examined using regression analyses. PEs for Symbol Search and Coding (a) were related to different proposed PE components (i.e., memory and novelty effects), such that novelty effect predicted Symbol Search PE (R2 =.239, p<.001) and memory predicted Coding PE (R2 =.089, p=.015), and (b) showed different patterns across stages of cognitive decline, such that the greatest cognitive decline was associated with smallest Coding PE (R2 =.125, p=.004), whereas intermediate cognitive decline was associated with the greatest Symbol Search PE (R2 =.097, p=.040). The relationship between cognitive decline and PE for Symbol Search was partially mediated by novelty effect among older adults with abnormal cognitive decline (model R2 =.286, p<.001). These findings (a) suggest that PE is not a unitary construct, (b) offer an explanation for contradictory findings in the literature, and (c) highlight the need for a better understanding of component processes of PE across different neuropsychological measures.
authors.affiliation: 1University of Utah,Department of Psychology,Salt Lake City,Utah.
authors.forename: Sommer R
authors.initials: SR
authors.lastname: Thorgusen
authors.affiliation: 1University of Utah,Department of Psychology,Salt Lake City,Utah.
authors.forename: Yana
authors.identifier: http://orcid.org/0000-0001-6513-565X
authors.initials: Y
authors.lastname: Suchy
authors.affiliation: 2University of Utah,Department of Neurology,Salt Lake City,Utah.
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Chelune
authors.affiliation: 1University of Utah,Department of Psychology,Salt Lake City,Utah.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Baucom
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000534:rehabilitation*; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D012044:Regression Analysis; D014706:Verbal Learning / Q000502:physiology; D014888:Wechsler Scales
keywords: Cognition; Cognitive reserve; Learning; Memory; Mild cognitive impairment; Models; Theoretical