The importance of age in the search for ERP biomarkers of aMCI

Executive function measures of participants with mild cognitive impairment: Systematic review and meta-analysis of event-related potential studies

OBJECTIVE

Objective measurements of executive functions using event-related potential (ERP) may be used as markers for differentiating healthy controls (HC) from patients with mild cognitive impairment (MCI). ERP is non-invasive, cost-effective, and affordable. Older adults with MCI demonstrate deteriorated executive function, serving as a potentially valid neurophysiological marker for identifying MCI. We aimed to review published ERP studies on executive function in older adults with MCI and summarize the performance differences by component between healthy older adults and older adults with MCI.

METHODS

Eight electronic databases (Web of Science, PubMed, ScienceDirect, American Psychological Association PsycNet, Cochrane Library, Scopus, Embase, and Ovid) were searched for the study. Articles published from January 1 to December 31, 2022, were considered for this review. A random-effects meta-analysis and between-study heterogeneity analysis were conducted using Comprehensive Meta-Analysis V3.0 software.

RESULTS

We identified 7829 articles of which 28 met the full inclusion criteria and were included in the systematic review and analyses. Our pooled analysis suggested that participants with MCI can be differentiated from HC by significant P200, P300, and N200 latencies. The P100 and P300 amplitudes were significantly smaller in participants with MCI when compared with those in the HCs, and the patients with MCI showed increased N200 amplitudes. Our findings provide new insights into potential electrophysiological biomarkers for diagnosing MCI.

Effect of lidocaine on cognitively impaired rats: Anti-inflammatory and antioxidant mechanisms in combination with CRMP2 antiphosphorylation

OBJECTIVE

Studies have shown that lidocaine has antioxidative stress, anti-inflammatory, and nerve-protective effects. The current study investigated the effects of lidocaine on cognitive function in rats with cognitive dysfunction.

METHODS

A total of 48 rats were randomly assigned to four groups of 12 rats each: control group; L (lidocaine) + D (d-galactose) group, d-galactose group (D group); and D + L group. We assessed cognitive function using a Morris water maze (MWM) and pathologic changes of hippocampal sections. An enzyme-linked immunosorbent assay (ELIZA) was used to detect serum malondialdehyde (MDA) and superoxide dismutase (SOD) levels in rats, and protein immunoblotting (western blot) was used to detect brain tissue proteins (collapsing response mediator protein-2 [CRMP2], phosphorylated-collapsing response mediator protein-2 [P-CRMP2], and β-amyloid protein [Aβ]).

RESULTS

The MWM showed that the d-gal group (284.09 ± 20.46, 5.20 ± 0.793) performed worse than the L + D (265.37 ± 22.34, 4.170 ± 0.577; p = .000) and D + L groups (254.72 ± 27.87, 3.750; p = .000) in escape latency and number of platform crossings, respectively. The L + D group (44.94 ± 2.92 pg/mL, 6.22 ± 0.50 pg/mL, and 460.02 ± 8.26 nmol/mL) and D + L group (46.88 ± 2.63 pg/mL, 5.90 ± 0.38 pg/mL, and 465.6 ± 16.07 nmol/mL) had significantly lower serum inflammatory levels of interleukin-6, tumor necrosis factor-α, and MDA than the d-gal group (57.79 ± 3.96 pg/mL, 11.25 ± 1.70 pg/mL, and 564.9 ± 15.90 nmol/mL), respectively. The L + D group (3.17 ± 0.41 μg/mL) and D + L group (3.08 ± 0.09 μg/mL) had significantly higher serum inflammatory levels of SOD than the d-gal group (2.20 ± 0.13 μg/mL) (all p = .000). The levels of CRMP2, P-CRMP2, and Aβ in the brain tissue homogenates of the L + D group (0.87 ± 0.04, 0.57 ± 0.0, and 0.16 ± 0.02) and the D + L group (0.82 ± 0.05, 0.58 ± 0.09, and 0.15 ± 0.02) were significantly different than the d-gal group (0.67 ± 0.03, 0.96 ± 0.040, and 0.29 ± 0.05).

CONCLUSIONS

Lidocaine was shown to reduce cognitive impairment in rats with cognitive dysfunction through anti-inflammatory and antioxidative stress mechanisms in combination with CRMP2 antiphosphorylation.

Synergistic effects of transcutaneous vagus nerve stimulation and inhibitory control training on electrophysiological performance in healthy adults

Transcutaneous vagal nerve stimulation (tVNS) is a non-invasive nerve stimulation technique that exerts a positive “exogenous” online neuromodulatory effect on inhibitory control (IC). Additionally, IC training (ICT) is an effective approach for enhancing IC via the “endogenous” activation of brain regions implicated in this process. The aim of the present study was to examine the synergistic effects of tVNS and ICT on IC enhancement. For this, we measured the changes in neural activity in frontal, fronto-central, and central regions in the time domain of the N2 component and the frequency domain of alpha power during the stop signal task. A total of 58 participants were randomly divided into four groups that received five sessions of either ICT or sham ICT with either online tVNS or sham tVNS. No differences in N2 amplitude were detected after any of the interventions. However, N2 latency shortened after tVNS + ICT in frontal, fronto-central, and central regions. N2 latency shortened after the intervention of sham tVNS + ICT in frontal region. Moreover, alpha power after tVNS + ICT intervention was larger than those of the other interventions in frontal, fronto-central, and central regions. The obtained electrophysiological data suggested that combining tVNS with ICT has synergistic ameliorative effects on IC, and provide evidence supporting the IC-enhancing potential of tVNS combined with ICT.

Treatment effects on event-related EEG potentials and oscillations in Alzheimer's disease

Alzheimer's disease dementia (ADD) is the most diffuse neurodegenerative disorder belonging to mild cognitive impairment (MCI) and dementia in old persons. This disease is provoked by an abnormal accumulation of amyloid-beta and tauopathy proteins in the brain. Very recently, the first disease-modifying drug has been licensed with reserve (i.e., Aducanumab). Therefore, there is a need to identify and use biomarkers probing the neurophysiological underpinnings of human cognitive functions to test the clinical efficacy of that drug. In this regard, event-related electroencephalographic potentials (ERPs) and oscillations (EROs) are promising candidates. Here, an Expert Panel from the Electrophysiology Professional Interest Area of the Alzheimer's Association and Global Brain Consortium reviewed the field literature on the effects of the most used symptomatic drug against ADD (i.e., Acetylcholinesterase inhibitors) on ERPs and EROs in ADD patients with MCI and dementia at the group level. The most convincing results were found in ADD patients. In those patients, Acetylcholinesterase inhibitors partially normalized ERP P300 peak latency and amplitude in oddball paradigms using visual stimuli. In these same paradigms, those drugs partially normalize ERO phase-locking at the theta band (4-7 Hz) and spectral coherence between electrode pairs at the gamma (around 40 Hz) band. These results are of great interest and may motivate multicentric, double-blind, randomized, and placebo-controlled clinical trials in MCI and ADD patients for final cross-validation.

Event-related brain potential indexes provide evidence for some decline in healthy people with subjective memory complaints during target evaluation and response inhibition processing

In the preclinical stage of the Alzheimer's disease (AD) continuum, subjects report subjective memory complaints (SMCs), although with the absence of any objective decline, and have a higher risk of progressing to dementia than the general population. Early identification of this stage therefore constitutes a major focus of current AD research, to enable early intervention. In this study, healthy adult participants with high and low SMCs (HSMCs and LSMCs) performed a Go/NoGo task during electroencephalogram (EEG) recording. Relative to LSMC participants, HSMC participants performed the task slower (longer reaction times) and showed changes in the event-related potential (ERP) components associated with response preparation (lower readiness potential -RP- amplitude in the Go condition), and also related to response inhibition processes (lower N2-P3 amplitude in the NoGo condition). In addition, HSMC participants showed lower Go-N2 and NoGo-N2 peak-to-baseline amplitudes, however these results seem to be influenced by a negative tendency overlapping stimulus-related waveforms. The declines observed in this study are mostly consistent with those observed in aMCI participants, supporting the notion of the AD continuum regarding SMC state.

Elderly Body Movement Alteration at 2nd Experience of Digital Art Installation with Cognitive and Motivation Scores

The prevalence of advanced medical treatment has led to global population aging, resulting in increased numbers of dementia patients. One of the most intractable symptoms of dementia is apathy, or lack of interest and enthusiasm, which can accompany memory and cognitive deterioration. Development of a novel method to ameliorate apathy is desirable. In this feasibility trial, we propose a series of digital art installations as a candidate dementia intervention approach. Seven, three-minute scenes of digital images and sounds were presented to visitors either passively or in response to their reactions (motion and sound). We evaluated the potential of this application as an intervention against apathy in an elderly living home. We collected the dementia global standard Mini-Mental State Examination (MMSE) and questionnaire scores of sensory pleasure and motivation along with behavioral motion data in twenty participants. We further compared responses between the first and second experiences in the thirteen participants that were present for both days. Overall, we found a significant increase in participants’ motivation. In these subjects, head and right hand motion increased over different scenes and MMSE degrees, but was most significant during passive scenes. Despite a small number of subjects and limited evaluations, this new digital art technology holds promise as an apathy intervention in the elderly and can be improved with use of wearable motion sensors.

Prevalence, Incidence, Influence Factors, and Cognitive Characteristics of Amnestic Mild Cognitive Impairment Among Older Adult: A 1-Year Follow-Up Study in China

BACKGROUND

The risk and protective factors of amnestic mild cognitive impairment (aMCI) and its prevalence as well as incidence among old adult in Chinese community are still unclear.

METHODS

We carried out this 1-year longitudinal study to survey a random sample of 3,246 community elders aged 60 and over in China. All subjects were required to complete a comprehensive clinical assessment, physical examination and several neuropsychological tests at baseline and follow-up. What's more, we also collected their lifestyle information by a standardized questionnaire.

RESULTS

We found that the prevalence of aMCI was 17.1%, while the incidence of aMCI among Chinese old adult was 70.57 per 1,000 person-years. By using Cox regression analysis, we found that male sex (p = 0.001, OR = 0.489, 95%CI 0.319~0.751) and reading (p = 0.023, OR = 0.533, 95%CI 0.310~0.917) were protective factors for against aMCI. Old adult who developed aMCI in the future showed multiple cognitive impairments (such as immediate memory, associative learning memory and executive function) in their early stage, and Wechsler's Block Design (p = 0.027, OR = 0.969, 95%CL 0.943~0.996) could predict whether subjects would turn into aMCI in the future.

CONCLUSIONS

The present study suggests that aMCI is a considerable health problem in China. Executive dysfunction may be an indicator of future development of aMCI in the old normal adult.