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: Event-related potentials (ERPs) to task-irrelevant novel sounds have been shown to increase in amplitude with increasing task difficulty and might therefore reflect listening effort. Here we investigated whether this effect is similar in two groups of younger and older listeners with normal hearing. Novel sounds were presented during a speech-perception-in noise test and task difficulty was adjusted decreasing the signal-to-noise ratio (SNR) relative to the individual 50% correct speech recognition SNR (easy +10dB, medium +2dB, hard 0dB). Amplitudes of the Novelty P3 and a late positive potential (LPP) were significantly larger in younger compared to older participants. Novelty P3 amplitude increased with increasing task difficulty in both age groups, but the effect was more robust in younger listeners. By contrast, LPP amplitude increases were observed only in older listeners. Novelty P3 and LPP were found to be differently affected by task difficulty in the two age groups indicating sustained and more effortful processing under challenging listening conditions in older listeners. These results confirmed the potential use of novel sounds during an auditory task as an indirect measure of listening effort in younger and older listeners, but the different focus on Novelty P3 and LPP should be taken into account. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 03/2015; DOI:10.1016/j.clinph.2015.02.055 · 2.98 Impact Factor
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ABSTRACT: The neural correlate of anterograde amnesia in Wernicke-Korsakoff syndrome (WKS) is still debated. While the capacity to learn new information has been associated with integrity of the medial temporal lobe (MTL), previous studies indicated that the WKS is associated with diencephalic lesions, mainly in the mammillary bodies and anterior or dorsomedial thalamic nuclei. The present study tested the hypothesis that amnesia in WKS is associated with a disrupted neural circuit between diencephalic and hippocampal structures. High-density evoked potentials were recorded in four severely amnesic patients with chronic WKS, in five patients with chronic alcoholism without WKS, and in ten age matched controls. Participants performed a continuous recognition task of pictures previously shown to induce a left medial temporal lobe dependent positive potential between 250 and 350 ms. In addition, the integrity of the fornix was assessed using diffusion tensor imaging (DTI). WKS, but not alcoholic patients without WKS, showed absence of the early, left MTL dependent positive potential following immediate picture repetitions. DTI indicated disruption of the fornix, which connects diencephalic and hippocampal structures. The findings support an interpretation of anterograde amnesia in WKS as a consequence of a disconnection between diencephalic and MTL structures with deficient contribution of the MTL to rapid consolidation.Brain Topography 08/2014; DOI:10.1007/s10548-014-0391-5 · 2.52 Impact Factor
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ABSTRACT: Working memory, the capacity of actively maintaining task-relevant information during a cognitive task, is a heritable trait. Working memory deficits are characteristic for many psychiatric disorders. We performed genome-wide gene set enrichment analyses in multiple independent data sets of young and aged cognitively healthy subjects (n = 2,824) and in a large schizophrenia case-control sample (n = 32,143). The voltage-gated cation channel activity gene set, consisting of genes related to neuronal excitability, was robustly linked to performance in working memory-related tasks across ages and to schizophrenia. Functional brain imaging in 707 healthy participants linked this gene set also to working memory-related activity in the parietal cortex and the cerebellum. Gene set analyses may help to dissect the molecular underpinnings of cognitive dimensions, brain activity, and psychopathology.Neuron 02/2014; 81(5). DOI:10.1016/j.neuron.2014.01.010 · 15.98 Impact Factor