Cerebrospinal fluid (CSF) TAU protein and Amyloid beta42 were able to distinguish between 28 mild cognitive impairment (MCI) patients and both 38 normal aged and 17 anxious and depressed elderly patients, with good sensitivity/specificity when the two measures were combined. These biological markers are independent predictors of the presence of Alzheimer disease (AD), in addition to memory performance. Low Amyloid beta42 level was predictor of a fast progression of MCI patients to full blown dementia. The TAU protein level tended to correlate with memory performance, presumably in relation with the extent of the bilateral medio-temporal damage in early AD.
"Possibly, a significant correlation between tau protein and neuropsychological scores can be proven only in later stages of the disease. There may be yet another reason why we did not find a correlation between neuropsychological test performance and CSF tau protein, in contrast to previous studies   . The increase of tau in the CSF might be much slower than the decrease of Aβ 1−42 , continuing longer into later stages of the disease. "
[Show abstract][Hide abstract] ABSTRACT: Decreased delayed recall, decreased amyloid-β peptides (Aβ1-42), and increased tau protein concentration in cerebrospinal fluid (CSF) are generally regarded to be valid neuropsychological and biological markers for Alzheimer's disease (AD). Previous studies failed to demonstrate clear-cut correlations between neuropsychological impairment and CSF markers. In this study we test recent models of disease progression, that propose that changes in CSF biomarkers already reach a plateau in a preclinical phase, before cognitive decline begins, that is, even before MCI can be diagnosed. We recruited 73 patients with probable AD (n=36) and mild cognitive impairment (MCI) (amnesic MCI=25; non-amnesic MCI=12). We used the CERAD-NP, a widely used neuropsychological battery with norms for different age and education groups, and additional neuropsychological tests for assessing the cognitive profile of these patient groups. We found a significant correlation between Aβ1-42 in the CSF and memory performance for amnesic MCI patients, but not for non-amnesic MCI and AD patients. All other correlations between cognitive tasks and Aβ1-42 were not significant. Tau protein concentration in the CSF was not correlated with any neuropsychological marker in any of the patients groups. We conclude that the decrease of Aβ1-42 in the CSF mirrors disease progression during the early stages up into AD and therefore is not restricted to the preclinical phase. The decrease of Aβ1-42 reaches a plateau only in the full blown demented syndrome and further functional disease progression is then related to neurodegeneration without further reduction of Aβ1-42 in the CSF.
"Nevertheless, another study did not find any correlations between APOE status and CSF Ttau levels (Maruyama et al. 2001). Another study showed that CSF T-tau levels were negatively correlated with the performance on memory tests (Ivanoiu and Sindic 2005). "
[Show abstract][Hide abstract] ABSTRACT: Diagnosis of mild cognitive impairment (MCI) and its subtypes requires a detailed diagnostic assessment and so may be missed at routine primary-care appointments, since the ordinary dementia screening tests lack sensitivity owing to ceiling effects, especially in highly educated subjects.
The study was undertaken using a cross-sectional assessment of 112 elderly subjects (mean age 67.96+/-5.77 years, and mean education level of 12.8+/-5.7 years) with a semi-structured interview and a neuropsychological battery.
MCI patients did not differ from controls on total MMSE scores (p=0.212). Nevertheless, MCI patients showed worse performance than controls on the verbal memory task (p=0.012), and "drawing a pentagon" (p=0.03). Amnestic MCI patients performed worse only on the "three-word recall" task (p=0.013); non-amnestic MCI patients performed worse on the "three-stage command" task (p=0.001); and multiple-domain MCI patients performed worse on the "drawing a pentagon" task (p=0.001) and had a trend toward performing poorly on the 'three word recall' task (p=0.06).
The analysis of MMSE subtest scores, in addition to MMSE total scores, may increase the sensitivity of the MMSE test in screening for MCI and its subtypes.
International Psychogeriatrics 09/2007; 19(4):647-56. DOI:10.1017/S104161020700542X · 1.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND AND PURPOSE: Mild cognitive impairment (MCI) may affect several cognitive domains, including attention and reasoning, but is often first characterized by memory deficits. The purpose of this study was to ask these 2 questions: 1) Can levels of CSF tau proteins and amyloid beta 42 peptide explain thinning of the cerebral cortex in patients with MCI? 2) How are brain morphometry, CSF biomarkers, and apolipoprotein E (APOE) allelic variation related to episodic memory function in MCI? MATERIALS AND METHODS: Hippocampal volume and cortical thickness were estimated by MR imaging and compared for patients with MCI (n 18) and healthy controls (n 18). In addition, regions of interest (ROIs) were selected in areas where the MCI group had atrophy and which overlapped with the episodic memory network (temporal, entorhinal, inferior parietal, precuneus/posterior cingulate, and frontal). Relationships among morphometry, CSF biomarkers, APOE, and memory were tested. The analyses were repeated with an independent sample of patients with MCI (n 19). RESULTS: Patients with MCI and pathologic CSF values had hippocampal atrophy. However, both patients with pathologic and patients with nonpathologic CSF had a thinner cortex outside the hippocampal area. CSF pathology was related to hippocampal volume, whereas relationships with cortical thickness were found mainly in one of the samples. Morphometry correlated robustly with memory performance across MCI samples, whereas less stable results were found for tau protein. CONCLUSION: The differences in hippocampal volume between the MCI and the healthy control groups were only found in patients with pathologic CSF biomarkers, whereas differences in cortical thickness were also found for patients without such pathologic features. Morphometry in areas in the episodic memory network was robustly correlated with memory performance. It is speculated that atrophy in these areas may be associated with the memory problems seen in MCI.
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