Practice Effects Predict Cognitive Outcome in Amnestic Mild Cognitive Impairment

Department of Neurology, University of Utah, Salt Lake City, 84108, USA.
The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry (Impact Factor: 4.24). 11/2011; 19(11):932-9. DOI: 10.1097/JGP.0b013e318209dd3a
Source: PubMed


Practice effects on cognitive tests have been shown to further characterize patients with amnestic mild cognitive impairment (aMCI) and may provide predictive information about cognitive change across time. We tested the hypothesis that a loss of practice effects would portend a worse prognosis in aMCI.
Longitudinal, observational design following participants across 1 year.
Community-based cohort.
Three groups of older adults: 1) cognitively intact (n = 57), 2) aMCI with large practice effects across 1 week (MCI + PE, n = 25), and 3) aMCI with minimal practice effects across 1 week (MCI - PE, n = 26).
Neuropsychological tests.
After controlling for age and baseline cognitive differences, the MCI - PE group performed significantly worse than the other groups after 1 year on measures of immediate memory, delayed memory, language, and overall cognition.
Although these results need to be replicated in larger samples, the loss of short-term practice effects portends a worse prognosis in patients with aMCI.

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    • "Duff (2012) indicates that on repeated testing, improvements may occur due to natural recovery or intervention, but improvements can also occur because of prior exposure to test materials; the latter are typically referred to as practice effects. Practice effects are improvements in cognitive test performance due to repeated exposure to a test; such artificial improvement has traditionally been viewed as error (Duff, Beglinger, Moser, Schultz, & Paulsen, 2010; Duff et al., 2011; McCaffrey, Duff, & Westervelt, 2000). Smaller practice effects occur on less novel subtests, ones based on crystallized abilities. "
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    ABSTRACT: This study compared performance in two groups of older adults, one healthy and another with mild cognitive impairment (MCI), in order to determine whether or not they exhibit plasticity and to analyze whether or not plastic and non-plastic participants differed after a delay. To measure cognitive plasticity, the Spain-Complutense Verbal Learning Test (TAVEC) was applied to a total of 113 participants over 65 who were divided into two groups: MCI (N = 51) and control (N = 62). It was concluded that healthy participants performed better, but impaired participants also demonstrated some capacity for learning and plasticity, and it was shown that these improvements were maintained after a delay. Therefore, TAVEC seems a fitting, simple procedure with which to measure cognitive plasticity, and an effective indicator of impairment.
    Full-text · Article · Aug 2013 · Archives of Clinical Neuropsychology
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    • "Interestingly, there were few PE for the oldest participants when alternate forms were used consistently. In fact, similar to the findings from the 5-year Personnes Agées QUID (PAQUID) study [30], these participants tended to do worse over time, which may support the hypothesis that a lack of PE may signal early cognitive decline [8,31,32]. "
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    ABSTRACT: Background Practice effects are a known threat to reliability and validity in clinical trials. Few studies have investigated the potential influence of practice on repeated screening measures in longitudinal clinical trials with a focus on dementia prevention. The current study investigates whether practice effects exist on a screening measure commonly used in aging research, the Memory Impairment Screen (MIS). Methods The PREADViSE trial is a clinical intervention study evaluating the efficacy of vitamin E and selenium for Alzheimer’s disease prevention. Participants are screened annually for incident dementia with the MIS. Participants with baseline and three consecutive follow-ups who made less than a perfect score at one or more assessments were included in the current analyses (N=1,803). An additional subset of participants with four consecutive assessments but who received the same version of the MIS at baseline and first follow-up (N=301) was also assessed to determine the effects of alternate forms on mitigating practice. We hypothesized that despite efforts to mitigate practice effects with alternate versions, MIS scores would improve with repeated screening. Linear mixed models were used to estimate mean MIS scores over time. Results Among men with four visits and alternating MIS versions, although there is little evidence of a significant practice effect at the first follow-up, mean scores clearly improve at the second and third follow-ups for all but the oldest participants. Unlike those who received alternate versions, men given the same version at first follow-up show significant practice effects. Conclusion While increases in the overall means were small, they represent a significant number of men whose scores improved with repeated testing. Such improvements could bias case ascertainment if not taken into account.
    Full-text · Article · Nov 2012 · Trials
    • "A failure to demonstrate (benefit from) practice effects, for example, may serve as a prognostic indicator of a patient's future cognitive functioning (Duff et al., 2007), and may distinguish changes in cognitive functioning associated with healthy aging from changes that occur in persons diagnosed with Alzheimer's disease (Ivnik et al., 2000). In a group of patients initially diagnosed with mild cognitive impairment, those who showed minimal practice effects after 1 week were at greater risk for cognitive decline 1 year later compared with patients who showed large short-term practice effects (Duff et al., 2011). A patient's failure to demonstrate practice-related gains can be a concurrent or predictive indicator of cognitive decline. "
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    ABSTRACT: In neuropsychological assessment, and many areas of research, it is common for the same test to be administered on more than one occasion to measure change. Measured changes are presumed to reflect true changes in the construct being measured by the test; for example, cognitive changes due to processes such as aging, advancing neurological disease, or treatment interventions. However, practice effects, defined as score increases due to factors such as memory for specific test items, learned strategies, or test sophistication, complicate the interpretation of change. This review presents meta-analyses of nearly 1600 individual effect sizes representing changes in mean-level performance on tests commonly used to assess core domains of neuropsychological function, with the goal of quantitatively summarizing the magnitude of practice effects on such tests. The use of alternate forms, the ages of participants, clinical diagnoses of study participants, and length of the test-retest interval were associated with the magnitude of change in many cases. These findings have important implications for the practice of clinical neuropsychology, as well as for research applications, and highlight the need for practice effects to be taken into account in interpreting change across time with multiple measurements.
    No preview · Article · Apr 2012 · The Clinical Neuropsychologist
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