The Consortium to Establish a Registry for Alzheimer's Disease (CERAD). Part V. A normative study of the neuropsychological battery.
ABSTRACT The neuropsychological tests developed for the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) are currently used to measure cognitive impairments of Alzheimer's disease (AD) in clinical investigations of this disorder. This report presents the normative information for the CERAD battery, obtained in a large sample (n = 413) of control subjects (ages 50 to 89) who were enrolled in 23 university medical centers in the United States participating in the CERAD study from 1987 to 1992. We compared separately the performance of subjects with high (> or = 12) and low (< 12) years of formal education. For many of the individual cognitive measures in the highly educated group, we observed significant age and gender effects. Only the praxis measure showed a significant age effect in the low-education group. Delayed recall, when adjusted for amount of material acquired (savings), was relatively unaffected by age, gender, and level of education. Our findings suggest that the savings scores, in particular, may be useful in distinguishing between AD and normal aging.
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ABSTRACT: The evidence suggesting that gait speed may represent a sensitive marker for cognitive decline in the elderly requires support from diverse racial groups. We investigated the relationship between gait speed and cognitive decline over 2 years in a community dwelling sample of elderly Africans. Data are from the Ibadan study of aging (ISA) conducted among a household multi-stage probability sample of 2149 Yoruba Nigerians aged 65 years or older. Gait speed was measured as the time taken to complete a 3 or 4m distance at normal walking speed. We assessed cognitive functions with a modified version of the 10-word learning list and delay recall test, and examined the relationship between baseline gait speed, as well as gait speed changes, and follow-up cognition using multiple linear regression and longitudinal analyses using random effects. Approximately 71% of 1461 participants who were dementia free and who had their gait speed measured at baseline (2007) were successfully followed up in two waves (2008 and 2009). Along with increasing age, poor health and economic status, a slower baseline gait speed was independently associated with poorer follow-up cognition in both linear regression (1.2 words, 95% CI=0.48-2.0) and longitudinal analyses (0.8 words, 95% CI=0.44-1.2). Also, a greater change in gait speed between 2007 and 2009 was associated with the worst follow-up cognition (0.3 words, 95% CI=0.09-0.51). The finding that a substantial change in gait speed was associated with reduced cognitive performance is of potential importance to efforts aimed at early identification of cognitive disorders in this population. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.Gait & Posture 01/2015; 89. DOI:10.1016/j.gaitpost.2015.01.011 · 2.30 Impact Factor
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ABSTRACT: It is common for some healthy older adults to obtain low test scores when a battery of neuropsychological tests is administered, which increases the risk of the clinician misdiagnosing cognitive impairment. Thus, base rates of healthy individuals’ low scores are required to more accurately interpret neuropsychological results. At present, this information is not available for the German version of the Consortium to Establish a Registry for Alzheimer’s Disease-Neuropsychological Assessment Battery (CERAD-NAB), a frequently used battery in the USA and in German-speaking Europe. This study aimed to determine the base rates of low scores for the CERAD-NAB and to tabulate a summary figure of cut-off scores and numbers of low scores to aid in clinical decision making. The base rates of low scores on the ten German CERAD-NAB subscores were calculated from the German CERAD-NAB normative sample (N = 1,081) using six different cut-off scores (i.e., 1st, 2.5th, 7th, 10th, 16th, and 25th percentile). Results indicate that high percentages of one or more “abnormal” scores were obtained, irrespective of the cut-off criterion. For example, 60.6 % of the normative sample obtained one or more scores at or below the 10th percentile. These findings illustrate the importance of considering the prevalence of low scores in healthy individuals. The summary figure of CERAD-NAB base rates is an important supplement for test interpretation and can be used to improve the diagnostic accuracy of neurocognitive disorders.European Archives of Psychiatry and Clinical Neuroscience 01/2015; DOI:10.1007/s00406-014-0571-z · 3.36 Impact Factor
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ABSTRACT: Measuring and predicting Alzheimer's disease (AD) progression is important in order to adjust treatment and allocate care resources. We aimed to identify a combination of subtests from the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB) that best correlated with AD progression in follow-up as well as to predict AD progression. A total of 236 participants with very mild [Clinical Dementia Rating (CDR) = 0.5] or mild AD (CDR = 1.0) at baseline were followed up for 3 years. The CERAD-NB and Mini-Mental State Examination (MMSE) were used to assess cognition, and the CDR scale sum of boxes (CDR-sb) was employed to evaluate AD progression. Generalized estimating equations were used to develop models to predict and follow up disease progression. Performance declined on all CERAD-NB subtests. The ability of the separate subtests to distinguish between groups (baseline CDR = 0.5 or 1.0) diminished during follow-up. The best combination of subtests that explained 62% of CDR-sb variance in follow-up included verbal fluency, constructional praxis, the clock drawing test, and the MMSE. Baseline values of the same combination predicted 37% of the CDR-sb change. A short version of the CERAD-NB subtests provides a promising and time-efficient alternative for measuring cognitive deterioration during AD follow-up. Although the initial signs of AD include memory difficulties, it may be useful to assess non-memory tasks in follow-up.