ERP C250 shows the elderly (cognitively normal, Alzheimer's disease) store more stimuli in short-term memory than Young Adults do

Contingent Negative Variation in the Evaluation of Neurocognitive Disorders Due to Possible Alzheimer's Disease

The usefulness of Contingent Negative Variation (CNV) potential as a biomarker of neurocognitive disorders due to possible Alzheimer's disease, is based on its possible physiological correlates. However, its application in the diagnostic evaluation of these disorders is still incipient. The aim of this study is to characterize the patterns of cognitive processing of information in the domain of nonspecific global attention, by recording potential CNV in a group of patients with neurocognitive disorders due to possible Alzheimer's disease. An experimental study of cases and controls was carried out. The sample included 39 patients classified according to DSM-5 with a neurocognitive disorder subtype possibly due Alzheimer's disease, and a Control Group of 53 subjects with normal cognitive functions. CNV potential was registered using standard protocol. The analysis of variance obtained significant differences in mean values and confidence intervals of total CNV amplitude between the three study groups. The late CNV segment amplitudes makes it possible to discriminate between the level of mild and major dysfunction in the group of patients. The CNV total amplitudes of potential allows for effective discrimination between normal cognitive functioning and neurocognitive disorders due to possible Alzheimer's disease.

The effect of mind-body exercise on memory in older adults: a systematic review and meta-analysis

OBJECTIVES

The current systematic review aims to examine the effect of mind-body exercise on different memory types in the elderly population.

METHODS

Four literature databases (Pubmed, Cochrane library, Embase and Sinomed) were searched from inception to March 19, 2019. Randomized controlled trials (RCTs) examining the effect of mind-body exercise on memory in older adults were included. The assessment of risk of bias for the included studies and data synthesis were conducted using the software of review manager 5.3 based on the Cochrane handbook.

RESULTS

Twelve eligible RCTs with a total 1051 participants were identified that met the inclusion criteria for the systematic review. Meta-analysis in elderly adults without known neurological diseases showed mind-body exercise intervention had a large effect on general memory (SMD = 1.24, p = 0.005), a moderate effect on short-term memory (SMD = 0.51, p = 0.02) and long-term memory (SMD = 0.78, p < 0.001), a small effect on working memory (SMD = 0.28, p = 0.009), and a moderate effect on episodic memory (SMD = 0.74, p < 0.001) and semantic memory (SMD = 0.59, p = 0.003) compared to no specific exercise intervention. Similar results were also found in elderly adults with known neurological diseases, showing a moderate effect on general memory (SMD = 0.56, p < 0.001), short-term memory (SMD = 0.68, p = 0.01), and long-term memory (SMD = 0.80, p = 0.003); a small effect on working memory (SMD = 0.46, p < 0.001); and a large effect on episodic memory (SMD = 0.91, p < 0.001).

CONCLUSION

Compared with no specific exercise, mind-body exercise enhances memory in older adults. However, larger, more robust trials with longer follow-up periods and standardized neuropsychological outcome measures are needed before more definitive conclusions can be drawn.

A systematic review of cognitive event-related potentials in mild cognitive impairment and Alzheimer's disease

This systematic review examined whether event-related potentials (ERPs) during higher cognitive processing can detect subtle, early signs of neurodegenerative disease. Original, empirical studies retrieved from PsycINFO and PubMed were reviewed if they analyzed patterns in cognitive ERPs (≥150 ms post-stimulus) differentiating mild cognitive impairment (MCI), Alzheimer's disease (AD), or cognitively intact elders who carry AD risk through the Apolipoprotein-E ε4 allele (ε4+) from healthy older adult controls (HC). The 100 studies meeting inclusion criteria (MCI = 47; AD = 47; ε4+ = 6) analyzed N200, P300, N400, and occasionally, later components. While there was variability across studies, patterns of reduced amplitude and delayed latency were apparent in pathological aging, consistent with AD-related brain atrophy and cognitive impairment. These effects were particularly evident in advanced disease progression (i.e., AD > MCI) and in later ERP components measured during complex tasks. Although ERP studies in intact ε4+ elders are thus far scarce, a similar pattern of delayed latency was notable, along with a contrasting pattern of increased amplitude, consistent with compensatory neural activation. This limited work suggests ERPs might be able to index early neural changes indicative of future cognitive decline in otherwise healthy elders. As ERPs are also accessible and affordable relative to other neuroimaging methods, their addition to cognitive assessment might substantively enhance early identification and characterization of neural dysfunction, allowing opportunity for earlier differential diagnosis and targeting of intervention. To evaluate this possibility there is urgent need for well-powered studies assessing late cognitive ERPs during complex tasks, particularly in healthy elders at risk for cognitive decline.

Temporospatial components of brain ERPs as biomarkers for Alzheimer's disease

Introduction

Developing biomarkers that distinguish individuals with Alzheimer's disease (AD) from those with normal cognition remains a crucial goal for improving the health of older adults. We investigated adding brain spatial information to temporal event-related potentials (ERPs) to increase AD identification accuracy over temporal ERPs alone.

Methods

With two-step principal components analysis, we applied multivariate analyses that incorporated temporal and spatial ERP information from a cognitive task. Discriminant analysis used temporospatial ERP scores to classify participants as belonging to either the AD or healthy control group.

Results

Temporospatial ERPs produced a cross-validated area under the curve of 0.84. Adding spatial information through a formal procedure significantly improves classification accuracy.

Discussion

A weighted combination of temporospatial ERP markers performs well in detecting AD. Because ERPs are noninvasive and inexpensive, they may be promising biomarkers for AD that can add functional information to other biomarker systems while providing the individual's probability of correct classification.