Feasibility of Predicting MCI/AD Using Neuropsychological Tests and Serum β-Amyloid

Retention and impairment of neurocognitive functions in mild cognitive impairment and Alzheimer's disease with a comprehensive neuropsychological test

AIM

MATRICS Consensus Cognitive Battery was developed by the National Institute of Mental Health to establish acceptance criteria for measuring cognitive changes in schizophrenia and can be used to assess cognitive functions in other psychiatric disorders. We used a Japanese version of MATRICS Consensus Cognitive Battery to explore the changes in multiple cognitive functions in patients with mild cognitive impairment and mild Alzheimer's disease.

METHODS

We administered the Japanese version of MATRICS Consensus Cognitive Battery to 11 patients with mild cognitive impairment (MCI), 11 patients with Alzheimer's disease, and 27 healthy controls. All Japanese versions of MATRICS Consensus Cognitive Battery domain scores were converted to t-scores using sample means and standard deviations and were compared for significant performance differences among healthy control, MCI, and mild Alzheimer's disease groups.

RESULTS

Compared with healthy controls, patients with MCI and mild Alzheimer's disease demonstrated the same degree of impairment to processing speed, verbal learning, and visual learning. Reasoning and problem-solving showed significant impairments only in mild Alzheimer's disease. Verbal and visual abilities in working memory showed different performances in the MCI and mild Alzheimer's disease groups, with the Alzheimer's disease group demonstrating significantly more deficits in these domains. No significant difference was found among the groups in attention/vigilance and social cognition.

CONCLUSIONS

The Japanese version of MATRICS Consensus Cognitive Battery can be used to elucidate the characteristics of cognitive dysfunction of normal aging, MCI, and mild dementia in clinical practice.

Quantifying memory deficits in amnestic mild cognitive impairment

INTRODUCTION

In the present study, we use the item-specific deficit approach (ISDA), a method for characterizing memory deficits in list-learning, to portray the memory deficits in amnestic mild cognitive impairment (aMCI).

METHODS

We applied the ISDA to compare memory performance of patients with aMCI and healthy controls in encoding, consolidation, and retrieval using the Free and Cued Selective Reminding Test.

RESULTS

The results revealed clear differences in recall performance between patients with aMCI and controls. When analyzing the ISDA deficit indices, the results revealed a prominent encoding deficit, followed by a consolidating deficit. A greater sensitivity for the encoding index confirmed that a difficulty with encoding information plays a major role in explaining the episodic memory deficits experienced by patients with aMCI.

DISCUSSION

The present study applying the ISDA reveals great sensitivity and specificity of the encoding deficit index when identifying aMCI. As aMCI constitutes a risk factor to develop Alzheimer's disease, the current findings also confirm the need to concentrate on encoding deficits as an early diagnostic sign of cognitive decline.

APOE ε4 specific imbalance of arachidonic acid and docosahexaenoic acid in serum phospholipids identifies individuals with preclinical Mild Cognitive Impairment/Alzheimer's Disease

This study was designed to explore the influence of apolipoprotein E (APOE) on blood phospholipids (PL) in predicting preclinical Alzheimer's disease (AD). Lipidomic analyses were also performed on blood from an AD mouse model expressing human APOE isoforms (EFAD) and five AD mutations and from 195 cognitively normal participants, 23 of who converted to mild cognitive impairment (MCI)/AD within 3 years. APOE ε4-carriers converting to MCI/AD had high arachidonic acid (AA)/docosahexaenoic acid (DHA) ratios in PL compared to cognitively normal ε4 and non-ε4 carriers. Arachidonic acid and DHA containing PL species, ε4-status and Aβ42/Aβ40 ratios provided 91% accuracy in detecting MCI/AD. Fish oil/omega-3 fatty acid consumption was associated with lower AA/DHA ratios even among ε4 carriers. High plasma AA/DHA ratios were observed in E4FAD compared to EFAD mice with other isoforms. In particular, alterations in plasma AA and DHA containing PL species were also observed in the brains of E4FAD mice compared to E3FAD mice. Despite the small sample size and a short follow-up, these results suggest that blood PL could potentially serve as biomarkers of preclinical MCI/AD.

Plasma microRNA biomarkers for detection of mild cognitive impairment

Early stages of many neurodegenerative diseases, such as Alzheimer's disease, vascular and frontotemporal dementia, and Parkinson's disease, are frequently associated with Mild Cognitive Impairment (MCI). A minimally invasive screening test for early detection of MCI may be used to select optimal patient groups in clinical trials, to monitor disease progression and response to treatment, and to better plan patient clinical care. Here, we examined the feasibility of using pairs of brain-enriched plasma microRNA (miRNA), at least one of which is enriched in synapses and neurites, as biomarkers that could differentiate patients with MCI from age-matched controls. The identified biomarker pairs fall into two sets: the "miR-132 family" (miR-128/miR-491-5p, miR-132/miR-491-5p and mir-874/miR-491-5p) and the "miR-134 family" (miR-134/miR-370, miR-323-3p/miR-370 and miR-382/miR-370). The area under the Receiver-Operating Characteristic curve for the differentiation of MCI from controls using these biomarker pairs is 0.91-0.95, with sensitivity and specificity at 79%-100% (miR-132 family) and 79%-95% (miR-134 family), and p〈0.001. In a separate longitudinal study, the identified miRNA biomarker pairs successfully detected MCI in majority of patients at asymptomatic stage 1-5 years prior to clinical diagnosis. The reported biomarker pairs also appear useful for detecting age-related brain changes. Further testing in a larger study is necessary for validation of these results.