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O2‐02‐07: Is the lack of practice effects on neuropsychological tests an early cognitive marker of Alzheimer's disease?
Author(s) -
Monsch Andreas U.
Publication year - 2010
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2010.05.312
Subject(s) - neuropsychology , neuropsychological assessment , cognition , psychology , alzheimer's disease , neuropsychological test , logistic regression , verbal learning , audiology , boston naming test , disease , memory clinic , cognitive test , medicine , clinical psychology , cognitive impairment , psychiatry
Background: The reliable assessment of change from a previous cognitive functioning level is a prerequisite for determining the possible presence of neurodegenerative diseases such as Alzheimer’s disease (AD) and is a diagnostic sign of mild cognitive impairment (MCI). These criteria imply repeated neuropsychological testing. The purpose of our recent research was to assess the ability of different measures of cognitive change to detect very early AD. Methods: Study 1 investigated whether standardized change scores on the Consortium to Establish a Registry for Alzheimer’s DiseaseNeuropsychological Assessment Battery (CERAD-NAB) are superior diagnostic markers of early AD than scores from a single time-point. 374 normal control subjects were assessed at baseline and an average of 2.40 6 0.28 years later. Data from 95 patients with mild probable AD were collected at their first Memory Clinic testing and an average of 1.1 6 0.24 years later (Zehnder et al., 2008). Study 2 compared different longitudinal change measures in 366 cognitively healthy participants (237 men, 129 women) examined with the California Verbal Learning Test at baseline and 2 years later (Study 2; Blaesi et al., 2009). In both studies age, education, gender, and baseline performance were taken into account. Results: In Study 1, binary logistic regression analyses based on practice effects (T1-T0) revealed that the CERAD-NAB subtests MMSE, Word List-Learning-Total, Word ListSavings, and Figures-Savings best distinguished NCs from AD patients; 93.3% NCs and 86.8% AD patients were correctly classified, yielding a 92.0% correct classification rate. Study 2 found marked practice effects in cognitively healthy individuals after 2 years. Normal ranges for change that control for practice effects and regression to the mean proved to be the best change index. This new method allows for more valid interpretation of change in neuropsychological functioning and thus diagnosis of MCI and AD. Conclusions: Evidence of intra-individual decline is a much more reliable indicator of a neurodegenerative pathology than deficits based on interindividual comparisons with age-specific norms. More specifically, lack of practice effects analyzed with the method described here may serve as an early marker of AD.