Using event-related potential P300 as an electrophysiological marker for differential diagnosis and to predict the progression of mild cognitive impairment: a meta-analysis

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.

Adjunct Methods for Alzheimer's Disease Detection: A Review of Auditory Evoked Potentials

The auditory afferent pathway as a clinical marker of Alzheimer's disease (AD) has sparked interest in investigating the relationship between age-related hearing loss (ARHL) and AD. Given the earlier onset of ARHL compared to cognitive impairment caused by AD, there is a growing emphasis on early diagnosis and intervention to postpone or prevent the progression from ARHL to AD. In this context, auditory evoked potentials (AEPs) have emerged as a widely used objective auditory electrophysiological technique for both the clinical diagnosis and animal experimentation in ARHL due to their non-invasive and repeatable nature. This review focuses on the application of AEPs in AD detection and the auditory nerve system corresponding to different latencies of AEPs. Our objective was to establish AEPs as a systematic and non-invasive adjunct method for enhancing the diagnostic accuracy of AD. The success of AEPs in the early detection and prediction of AD in research settings underscores the need for further clinical application and study.

Evaluation of cognitive functions in the elderly with and without central auditory processing disorder

PURPOSE

Evaluate and compare the performance of cognitive functions between elderly with and without auditory processing disorders.

METHODS

Twenty-eight healthy elderly (14 Control group and 14 Auditory Processing Disorder group - APD group) participated in the study. All elderly were submitted to (central) auditory processing evaluation, P300 event-related potential and brief cognitive battery (BCB). In the comparison between subjects, the Mann-Whitney test was applied and in the intra-subjects comparison, the Wilcoxon signed rank test was used. To verify if there was an association between the performance of the PAC and the cognitive variables, Spearman's correlation was used.

RESULTS

There were no statistically significant differences between the Control and APD groups for the cognitive abilities assessed by BCB, as well as for the P300 cognitive potential variables.

CONCLUSION

Elderly with auditory processing disorders do not seem to show greater cognitive difficulties compared to elderly of the same age group without auditory processing disorders, exception of the clock drawing test, whose task involves multiple cognitive functions, including visuospatial processing, executive function, semantic memory, and planning.

Evaluation of hearing levels and vestibular function and the impact on cognitive performance in (pre)-symptomatic patients with DFNA9: protocol for a prospective longitudinal study (Rosetta study)

INTRODUCTION

Untreated hearing loss is the largest potentially modifiable risk factor for dementia. Additionally, vestibular dysfunction has been put forward as a potential risk factor for accelerated cognitive decline. Patients with Deafness Autosomal Dominant 9 (DFNA9) present with progressive sensorineural hearing loss and bilateral vestibulopathy and show significantly worse results in cognitive performance compared with a cognitively healthy control group. This highlights the need for adequate treatment to prevent further cognitive decline. This study aims to determine how hearing and vestibular function evolve in (pre-)symptomatic carriers of the p.Pro51Ser mutation in the COCH gene and how this impacts their cognitive performance and health-related quality of life.

METHODS AND ANALYSIS

A prospective, longitudinal evaluation of hearing, vestibular function and cognitive performance will be acquired at baseline, 1-year and 2-year follow-up. A total of 40 patients with DFNA9 will be included in the study. The study will be a single-centre study performed at the ORL department at the Antwerp University Hospital (UZA), Belgium. The control group will encompass cognitively healthy subjects, already recruited through the GECkO study. The primary outcome measure will be the Repeatable Battery for the Assessment of Neuropsychological Status adjusted for the Hearing-Impaired total score. Secondary outcome measures include Cortical Auditory-Evoked Potentials, vestibular assessments and health-related quality of life questionnaires. The expected outcomes will aid in the development of gene therapy by providing insight in the optimal time window for the application of gene therapy for the inner ear.

ETHICS AND DISSEMINATION

The ethical committee of UZA approved the study protocol on 19 December 2022 (protocol number B3002022000170). All participants have to give written initial informed consent in accordance with the Declaration of Helsinki. Results will be disseminated to the public through conference presentations, lectures and peer-reviewed scientific publications.

Features of event-related potentials during retrieval of episodic memory in patients with mild cognitive impairment due to Alzheimer's disease

Objective

To provide a rigorous comparison between patients with mild cognitive impairment due to Alzheimer's disease (MCI-AD) and healthy elderly, as well as to assess the value of electroencephalography (EEG) in terms of early diagnosis, we conducted a neutral image recognition memory task involving individuals with positive biomarkers including β amyloid deposition, pathologic tau or neurodegeneration.

Methods

The task involving study and test blocks was designed to evaluate participants' recognition memory. Electroencephalogram was recorded synchronously to elicit event-related potentials in patients with MCI-AD and healthy control subjects. We further analyzed differences between groups or conditions in terms of behavioral performance, time domain, and time-frequency domain.

Results

The MCI-AD cohort showed a slower response time to old/new images and had low accuracy regarding behavioral performance. The amplitude of the late positive complex for the old/new effects was significantly suppressed in the MCI-AD cohort when compared with that in the HC cohort. The amplitude of the late old/new effects was correlated with the Auditory Verbal Learning Test recognition score in all participants. The time-frequency domain analysis revealed that correct recognition of old items elicited a decrease in beta power, mainly limited to the HC cohort. Moreover, the combination of behavioral (processing speed and accuracy) and electrophysiological (average amplitude and relative power of delta band) measures contributes to classifying patients with MCI-AD from healthy elderly people.

Conclusion

Changes of old/new effects, accuracy and response time are sensitive to the impairment of recognition memory in patients with MCI-AD and have moderate value in predicting the incipient stage of AD.

Reliability and stability of oddball P300 amplitude in older adults: The role of stimulus sequence effects

The P300 may be an individual difference marker of neuro-cognitive function, which due to age-related cognitive decline may be particularly useful in older adults. Recently, we reported effects of the local stimulus sequence in an oddball task (i.e., the number of non-targets that preceded a target) on P300 amplitude in young and older adults. The same older adults completed a second session of the task 4-8 months after the first session. Here, we examined the effect of the stimulus sequence on the between- and within-session reliability and stability of P300 amplitude and RT, and their intertrial variability, in this sample of older adults. The sequence effects - an inverted U-shape effect of the number of standards preceding a target on parietal P300, and a linear effect on frontal P300 - were stable within and across sessions on the group level. Within individuals, P300 amplitude at frontal and parietal electrodes was generally very reliable and stable, mostly independently of sequence effects, encouraging its use as an individual difference marker of neuro-cognitive function in older adults. However, measures of the strength of the sequence effects themselves showed unacceptable reliability, speaking against their use as individual difference markers, at least in older adults.

Electrophysiological and neuropsychological assessment of cognition in spinocerebellar ataxia type 1 patients: a pilot study

BACKGROUND

Event-related potentials (ERPs) reflect cognitive processing: negative early components (N100, N200) are involved in the sensory and perceptual processing of a stimulus, whereas late positive component P300 requires conscious attention. Both neuropsychological and affective disorders are present in patients with spinocerebellar ataxia type 1 (SCA1), but the underlying mechanisms need further clarification.

MATERIALS AND METHODS

In this pilot study, we assessed cognitive processing by recording auditory ERPs in 16 consecutive SCA1 patients and 16 healthy controls (HC) matched for age and sex. Motor and nonmotor symptoms were evaluated using the Scale for the Assessment and Rating of Ataxia (SARA) and an extensive neuropsychological battery. ERPs were recorded using an oddball paradigm, and peak latency and amplitude of N100, N200, and P300 were measured in the averaged responses to target tones.

RESULTS

We found in SCA1 significantly increased latencies of N200 and P300 (p=0.033, p=0.007) and decreased amplitudes of N100 and P300 (p=0.024, p=0.038) compared with HC. Furthermore, P300 latency had the highest AUC in the discrimination of SCA1 in ROC analysis. The expansion of trinucleotide repeats correlated with P300 latency (r=-0.607, p=0.048), whereas both P300 and N100 amplitudes correlated with the severity of motor symptoms (r=-0.692, p=0.003; r=-0.621; p=0.010). Significant correlations between P300 latency and the scores of Emotion Attribution Task (r=-0.633, p=0.027), as well as between N200 latency and the scores of Frontal Assessment Battery and Stroop test (r=-0.520, p=0.047; r=0.538, p=0.039), were observed.

CONCLUSIONS

This research provides for the first time an extensive characterization of ERPs as useful electrophysiological markers to identify early cognitive dysfunction in SCA1.

Predictive Power of Cognitive Biomarkers in Neurodegenerative Disease Drug Development: Utility of the P300 Event-Related Potential

Neurodegenerative diseases, such as Alzheimer's disease (AD), and their associated deterioration of cognitive function are common causes of disability. The slowly developing pathology of neurodegenerative diseases necessitates early diagnosis and monitored long-term treatment. Lack of effective therapies coupled with an improved rate of early diagnosis in our aging population have created an urgent need for the development of novel drugs, as well as the need for reliable biomarkers for treatment response. These issues are especially relevant for AD, in which the rate of clinical trial drug failures has been very high. Frequently used biomarker evaluation procedures, such as positron emission tomography or cerebrospinal fluid measurements of phospho-tau and amyloid beta, are invasive and costly, and not universally available or accessible. This review considers the functionality of the event-related potential (ERP) P300 methodology as a surrogate biomarker for predicting the procognitive potential of drugs in clinical development for neurocognitive disorders. Through the application of standardized electroencephalography (EEG) described here, ERP P300 can be reliably measured. The P300 waveform objectively measures large-scale neuronal network functioning and working memory processes. Increased ERP P300 latency has been reported throughout the literature in disorders of cognition, supporting the potential utility of ERP P300 as a biomarker in many neurological and neuropsychiatric disorders, including AD. Specifically, evidence presented here supports ERP P300 latency as a quantitative, unbiased measure for detecting changes in cognition in patients with AD dementia through the progression from mild to moderate cognitive impairment and after drug treatment.

Cerebral activity manipulation of low-frequency repetitive transcranial magnetic stimulation in post-stroke patients with cognitive impairment

OBJECTIVE

The aim of this study was to evaluate the therapeutic effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) on post-stroke cognitive impairment (PSCI).

METHODS

Thirty-six PSCI patients were randomly divided into treatment and control groups of equal size. Both groups were pre-treated with conventional cognitive rehabilitation training. Subsequently, the treatment group was exposed to 1 Hz low-frequency repetitive transcranial magnetic stimulations for 8 weeks, with 5 days per week. Meanwhile, the control group was treated with placebo stimulations. Patients were evaluated via the LOTCA scale assessments and changes in P300 latencies and amplitudes before and after 8 weeks of treatment.

RESULTS

Before treatment, there were no significant differences between the two groups in LOTCA scores, P300 latencies, and amplitudes (P > 0.05). After treatment, LOTCA scores for both groups improved (P < 0.05), and those of the treatment group were higher than those of the control (P < 0.05). For both groups, P300 latencies were not only shortened but also had greater amplitudes (P < 0.05), and those for the treatment group were significantly shorter and larger than those of the control (P < 0.05).

CONCLUSION

As a therapy, rTMS improved cognitive function in PSCI patients, possibly via regulation of neural electrical activity of the cerebral cortex.

Memory-Enhancing Effect of 8-Week Consumption of the Quercetin-Enriched Culinary Herbs-Derived Functional Ingredients: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Due to great demand for memory enhancers, the memory-enhancing effects and the possible underlying mechanisms of the functional ingredients derived from the combined extract of Polygonum odoratum and Morus alba were investigated. A total of 45 participants randomly received either a placebo or the developed herbal supplement at a dose of 50 or 1500 mg/day. The consumption was done once daily for 8 weeks. Working memory was assessed via both an event-related potential and computerized battery tests at baseline and at the end of the 8-week study period. Acetylcholinesterase (AChE) and monoamine oxidase type A and type B (MAO-A, MAO-B) levels were also measured at the end of the study. The subjects who consumed the supplement containing a developed functional ingredient at a dose of 1500 mg/day showed reduced latencies but increased amplitudes of N100 and P300. An improvement in working memory and the suppression of AChE, MAO-A, and MAO-B activities were also observed. Therefore, this study clearly demonstrates the cognitive enhancing effect of the developed herbal congee, which may be associated with the suppressions of AChE and both types of MAO.

The reliability of P300 and the influence of age, gender and education variables in a 50 years and older normative sample

OBJECTIVES

The present study aims to investigate the effects of age, gender, and level of education on P300 in a healthy population, aged 50 years and over; and determine the reliability metrics for different conditions and measurement methods.

METHOD

Auditory and visual oddball recordings of 171 healthy adults were investigated. A fully automated preprocessing was applied to elicit ERP P300. Maximum peak amplitude, latency and mean amplitudes were measured. Data were stratified by age, gender, and education to determine group-level differences by using repeat measures of ANOVA. The internal consistency of P300 was calculated by a split-half method using odd-even segments. Test-retest reliability was assessed by calculating the intraclass correlation coefficient (ICC).

RESULTS

Maximum peak P300 amplitudes were higher in the 50-64 years age group compared to the >65 years age group; and females showed increased P300 amplitudes compared to males. P300 measures showed fair to good internal consistency and poor to good test-retest reliability.

CONCLUSION

Age and gender should be taken into account when designing ERP studies with elderly individuals. P300 showed good internal consistency in general, between gender groups and age groups. Long-term test-retest reliability was lower but acceptable. These findings can be interpreted as the strength of P300 by being an objective and reliable method independent of cultural differences. Here we underline several factors that may affect P300 measures and discuss other possible factors that should be standardized for P300 to be used in clinical settings.

Impairment of executive functions due to sleep alterations: An integrative review on the use of P300

Objective

Cognitive impairment due to sleep deprivation (SD) is an important global health concern as part of the growing rates of sleep disorders and sleep deprivation worldwide. Amongst the affected cognitive processes, the effects of SD on the executive functions (EFs) show diverse methods and inconclusive or contradictory results, highlighting the importance of further research in this field. Considering this scenario, we evaluate one of the most used methods for objectively evaluating EFs on SD: the event-related potential (ERP) P300.

Methods

Our study provides a comprehensive review on the use of P300 for evaluating executive functions in sleep alterations on subjects of all ages, as well as an analysis on the efficiency of P300 as an assessment method for executive functions compared to traditional neurocognitive batteries. We review the benefits of P300 application for multiple sleep/wake alterations, whether evoked in laboratory or as part of pre-existing sleep disorders.

Results

We assess the diverse protocols used to elicit and complement P300, the most identified alterations in amplitude and latency, and suggest new lines of study that could benefit from P300 within the field.

Conclusion

We conclude that P300 is a valuable asset for evaluating executive dysfunction under sleep deprivation both as a standalone protocol and in conjunction with subjective methods, with consistently significant results in assessing executive dysfunction in a diversity of subjects and etiologies.

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.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of the Positive Modulator of HGF/MET, Fosgonimeton, in Healthy Volunteers and Subjects with Alzheimer's Disease: Randomized, Placebo-Controlled, Double-Blind, Phase I Clinical Trial

Background:

Fosgonimeton (ATH-1017) is being developed as a first-in-class regenerative therapy for people with Alzheimer’s disease (AD) and dementia; potentially improving dementia symptoms and altering disease progression by reversing synaptic disconnection and neuronal loss.

Objective:

This randomized, double-blind, placebo-controlled phase I trial (NCT03298672) evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of fosgonimeton.

Methods:

Fosgonimeton was administered once daily via subcutaneous injection to 88 subjects. The single ascending dose study enrolled healthy young male subjects (n = 48; age, 33.4±6.3 years; dose, 2, 6, 20, 40, 60, or 90 mg); the multiple ascending dose study enrolled healthy elderly subjects (n = 29; age, 63.8±4.0 years; dose, 20, 40, 60, or 80 mg; 9-day duration); and the fixed-dose study enrolled AD subjects (n = 11; age, 69.2±7.1 years; dose, 40 mg; 9-day duration). Quantitative electroencephalogram (qEEG) and event-related potential (ERP) P300 measured neurophysiological signals following fosgonimeton treatment, supporting brain penetration and target engagement.

Results:

Fosgonimeton and placebo were shown to be safe and well-tolerated across all doses. Pharmacokinetic results for fosgonimeton were dose-proportional, with no sex effect or accumulation over 9 days. The main effect of fosgonimeton on qEEG was acute and sustained gamma power induction. In AD subjects, there was a significant effect toward ERP P300 latency normalization compared with placebo (p = 0.027; n = 7 at 40 mg fosgonimeton versus n = 4 placebo).

Conclusion:

These results support the continued development of fosgonimeton as a novel therapeutic for people with AD and dementia. The fast-onset normalization of ERP P300 latency in AD subjects suggests enhancement of synaptic function and potential procognitive effects.

Relationship Between Depression After Hemorrhagic Stroke and Auditory Event-Related Potentials in a Chinese Patient Group

PURPOSE

Post-stroke depression (PSD) is the most common psychiatric sequelae of stroke. Numerous studies revealed that event-related potentials (ERP) can reflect depression severity to a certain extent, while there is almost no research on depression after hemorrhagic stroke. Therefore, we employed a prospective cross-sectional study to explore the relationship between ERP and depression after hemorrhagic stroke.

METHODS

A total of 74 patients with intracranial hemorrhage were included in this study. Neurological deficits were evaluated using the National Institutes of Health Stroke Scale (NIHSS) on admission. Depression severity and cognitive impairment were measured using the 17-item Hamilton Depression Scale (HAMD-17) and the Chinese version of the Montreal Cognitive Assessment (MoCA) after two weeks of treatment. All patients were conducted auditory Oddball paradigm for event-related potential mismatch negativity (MMN) and P300.

RESULTS

In total, 36 patients were diagnosed with PSD at the two weeks of treatment, for a percentage of 48.6%. Depression severity of ICH patients correlated positively with both the latency of MMN (r = 0.376, P = 0.001) and P300 (r = 0.325, P = 0.005), and correlated negatively with both the amplitude of MMN (r=-0.385, P = 0.001) and P300 (r=-0.311, P = 0.007). Depression severity was negatively correlated with cognitive function after hemorrhagic stroke (r=-0.347, P = 0.002).

CONCLUSION

The latency and amplitude of MMN and P300 can well reflect the degree of depression after hemorrhagic stroke, which may help in the early diagnosis and effective treatment of PSD.

Cortical Auditory Evoked Potentials in Cognitive Impairment and Their Relevance to Hearing Loss: A Systematic Review Highlighting the Evidence Gap

Background: Alzheimer’s disease (AD) is the most prevalent cause of dementia which affects a growing number of people worldwide. Early identification of people at risk to develop AD should be prioritized. Hearing loss is considered an independent potentially modifiable risk factor for accelerated cognitive decline and dementia in older adults. The main outcome of interest of this review is the alteration of Cortical Auditory Evoked Potential (CAEP) morphology in an AD or mild cognitive impairment (MCI) population with and without hearing loss.

Methods: Two investigators independently and systematically searched publications regarding auditory processing on a cortical level in people with cognitive impairment (MCI or AD) with and without hearing loss. Only articles which mentioned at least one auditory elicited event-related potential (ERP) component and that were written in English or Dutch were included. Animal studies were excluded. No restrictions were imposed regarding publication date. The reference list of potential sources were screened for additional articles.

Results: This systematic review found no eligible articles that met all inclusion criteria. Therefore, no results were included, resulting in an empty systematic review.

Conclusion: In general, dysfunction – being either from cognitive or auditory origin – reduces CAEP amplitudes and prolongs latencies. Therefore, CAEPs may be a prognostic indicator in the early stages of cognitive decline. However, it remains unclear which CAEP component alteration is due to cognitive impairment, and which is due to hearing loss (or even both). In addition, vestibular dysfunction – associated with hearing loss, cognitive impairment and AD – may also alter CAEP responses. Further CAEP studies are warranted, integrating cognitive, hearing, and vestibular evaluations.

High Intellectual Potential and High Functioning Autism: Clinical and Neurophysiological Features in a Pediatric Sample

High Intellectual Potential (HIP) and High Functioning Autism (HFA) are two different conditions sharing some clinical and neurobiological features. The aim of the present study was to characterize a sample of HIP children (n: 16; M/F: 14/2; median age: 10 years) in comparison to those with HFA (n: 17; M/F: 16/1; median age: 13 years) and to neurotypically developed (NTD) children (n: 10; M/F: 4/6; median age: 11 years) from a clinical and neurophysiological perspective. Specifically, a standardized clinical assessment of cognitive and adaptive skills, autistic symptoms, executive functions and behavioral features was performed. Moreover, event-related potentials (ERPs) were recorded, referring specifically to the mismatch negativity (MMN) and P300 paradigm. Our data highlighted the presence of similarities between the intellectually gifted individuals and the ones with autism (i.e., a nonhomogeneous intellective profile, an adaptive skills impairment, subthreshold autistic symptoms and increased perfectionism). Interestingly, a distinct neurophysiological characterization between groups came out, with evidence of a reduced MMN amplitude only in the HFA group. Furthermore, no differences within groups in the P300 component emerged. Therefore, our results start to provide a more informative characterization of the HIP phenotype in comparison to those of HFA and NTD, highlighting the potential role of the MMN amplitude index in helping clinicians and researchers to distinguish between HIP and HFA. Nevertheless, further research on the topic is strongly needed.

The reduced left hippocampal volume related to the delayed P300 latency in amnestic mild cognitive impairment

BACKGROUND

Amnestic mild cognitive impairment (aMCI) is characterized by delayed P300 latency and reduced grey matter (GM) volume, respectively. The relationship between the features in aMCI is unclear. This study was to investigate the relationship between the altered P300 latency and the GM volume in aMCI.

METHODS

Thirty-four aMCI and 34 well-matched normal controls (NC) were studied using electroencephalogram during a visual oddball task and scanned with MRI. Both tests were finished in the same day.

RESULTS

As compared with the NC group, the aMCI group exhibited delayed P300 latency in parietal cortex and reduced GM volumes in bilateral temporal pole and left hippocampus/parahippocampal gyrus. A remarkable negative correlation was found between delayed P300 latency and reduced left hippocampal volume only in the aMCI group. Interestingly, the mediating analysis found P300 latency significantly mediated the association between right supramarginal gyrus volume and information processing speed indicated by Stroop Color and Word Test A scores.

CONCLUSIONS

The association between delayed P300 latency and reduced left hippocampal volume in aMCI subjects suggests that reduced left hippocampal volume may be the potential structural basis of delayed P300 latency.

Diversity of the gut-microbiome related to cognitive behavioral outcomes in healthy older adults

With the aging of the United States population, age-related cognitive disorders will be more prevalent and will negatively impact society. Differences in factors within and among individuals that influence cognitive decline complicate studies on the topic. One difference among individuals - gut microbiome diversity and composition - changes within the person across their lifespan and varies among individuals. An individual's gut microflora can significantly influence gut-brain communication, brain function, and behavior. Little research has been done to evaluate the gut-brain relation in non-clinical populations, with no previous studies, to our knowledge, in healthy older adults. In the present study, we investigated the relation between microbiome diversity and cognitive decline. The researchers invited sixty-three healthy older adults between 67-83 years of age to provide a fecal sample and complete an electrophysiological assessment of brain potentials (Event-Related Potentials; ERP) and the Cambridge Neuropsychological Test Automated Battery (CANTAB). Electrophysiological and behavioral data were related to alpha diversity, a measure of the variety of species in the gut-microbiome, supporting the hypothesis that a relation exists between gut microbial diversity and cognitive performance in healthy older adults as measured by CANTAB and ERP. To our knowledge, this study is the first to demonstrate the association between ERP outcomes and the gut-microbiome. Our results begin to bridge the gap in our understanding of the connection between behavior and the composition of the gut-microbiome, commonly referred to as the gut-brain connection.

Event-related potentials using the auditory novel paradigm in patients with myotonic dystrophy

Many neuropsychological disorders, especially attentional abnormality, are present in patients with myotonic dystrophy type 1 (DM1), but the underlying mechanisms remain unclear. This study aimed to evaluate attention function by auditory event-related potential (ERP) P3a (novelty paradigm) in DM1 patients. A total of 10 young DM1 patients (mean age 30.4 years) and 14 age-matched normal controls participated in this study. ERPs were recorded using an auditory novel paradigm, consisting of three types of stimuli, i.e., standard sound (70%), target sound (20%), and various novel sounds (10%), and participants pressed buttons to the target sounds. ERP components P3b after the target stimuli and P3a following the novel stimuli were analyzed. Correlations of neuropsychological evaluations with the amplitudes and latencies of P3b and P3a were analyzed in DM1 patients. We found that P3a latency was significantly delayed in patients with DM1 compared with normal controls, although the latency and amplitude of P3b in DM1 patients were comparable with those in normal controls. The achievement rates of both the Symbol Digit Modality Test and the Paced Auditory Serial Addition Test were significantly correlated with P3a amplitude, as well as P3b amplitude. These results suggest that ERPs, including P3a and P3b, provide important insights into the physiological basis of neuropsychological abnormalities in patients with DM1, especially from the viewpoint of the frontal lobe and attention function.

Effects of creative expression program on the event-related potential and task reaction time of elderly with mild cognitive impairment

Objectives

This study aimed to evaluate the effects of a 16-week creative expression intervention program (CrExp) on the event-related potential (ERP) and task reaction time in older individuals with mild cognitive impairment (MCI).

Methods

This study is a randomized controlled clinical trial conducted in the Memory Center of Fujian Provincial hospital. Thirty-six MCI patients were randomly distributed into two groups. One group underwent a 16-week creative expression program (CrExp, n = 18) and the other performed as a control group (CG, n = 18) by general social activities. The amplitude and latency of ERP-P300 from the central (Cz), parietal (Pz), frontal (Fz) cortices and task reaction time (RT) were assessed at baseline, post-interventi on, and 24-week follow-up.

Results

The CrExp group showed greater differences than CG of P300 latency in Cz (F = 4.37, P = 0.015), Pz (F = 2.78, P = 0.009), Fz (F = 6.45, P = 0.031) brain area after 16 weeks of intervention and in Fz (F = 3.23, P = 0.028), Cz (F = 3.79, P = 0.024), and Pz (F = 5.60, P = 0.036) at 24 weeks follow-up. Also, we analyzed the task reaction time between two groups and found that a shorten reaction time at post-intervention (F = 4.47, P = 0.011) and 24 weeks follow-up (F = 3.12, P = 0.007) in the CrExp group. However, there was no difference in P300 amplitude in either brain area between the two groups.

Conclusion

The electrophysiological results of the creative expression cognitive therapy group were more obvious than those of the general cognitive therapy group, and the latency and task reaction time may be considered as supported parameters in diagnosing the effects during non-drug therapy intervention in clinical practice.

Cognitive Impairment, P300, and Transforming Growth Factor β1 in Different Forms of Dementia

BACKGROUND

There are currently few biomarkers to assist in early diagnosis of dementias.

OBJECTIVE

To distinguish between different dementias: Alzheimer's disease (AD), vascular dementia (VaD), and Parkinson's disease dementia (PDD) using simple neurophysiologic (P300) and laboratory markers (transforming growth factor β1 "TGF-β1").

METHODS

The study included 15 patients for each type of dementia and 25 age- and sex-matched control subjects. Dementia patients were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders 4th edition-revised (DSM-IV-R). Modified Mini-Mental State Examination (3MS), Memory Assessment Scale (MAS), P300, and TGF-β1 were examined for each participant.

RESULTS

There were no significant differences between groups as regard to age, sex, and education, social, and economic levels. Significant differences between groups were observed in registration and naming variables of the 3MS. Compared with the control group, P300 latency was prolonged in all groups, although to a greater extent in AD and PDD than in VaD. A serum level of TGF-β1 was significantly elevated in all groups but was significantly higher in AD and VaD than in PDD. 3MS tended to correlate with P300 more than TGF-β1, and to be stronger in AD than the other groups.

CONCLUSION

Measurements of P300 latency and serum levels of TGF-β1 can help distinguish AD, PDD, and VaD. P300 was more prolonged in AD and PDD than VaD whereas TGF-β1 was significantly higher in AD and VaD than PDD. Thus P300 and TGF-β1 may be useful biomarkers for detection and evaluation of the extent of cognitive dysfunction.

Impact of hearing loss and vestibular decline on cognition in Alzheimer's disease: a prospective longitudinal study protocol (Gehoor, Evenwicht en Cognitie, GECkO)

INTRODUCTION

Dementia is a prevalent disease affecting a growing number of the ageing population. Alzheimer's disease (AD) is the most common cause of dementia. Previous research investigated the link between hearing loss and cognition, and the effect of vestibular dysfunction on cognition. Hearing loss and, to a lesser extent, vestibular decline both result in a decreasing cognitive function. However, their interaction should not be underestimated. The aim of this study is to assess the effect of hearing loss, vestibular decline and their interaction on cognition in people suffering from mild cognitive impairment (MCI) and dementia due to AD (ADD).

METHODS AND ANALYSIS

We designed a prospective longitudinal study to assess the effect of hearing loss and vestibular decline on cognition. A total of 100 cognitively impaired elderly (between 55 and 84 years of age), consisting of 60 patients with MCI due to AD and 40 patients with ADD will be included. The control group will consist of individuals with preserved cognition group-matched based on age, hearing level and vestibular function. A comprehensive assessment is performed at baseline, 12-month and 24-month follow-ups. The primary outcome measure is the change in the Repeatable Battery for the Assessment of Neuropsychological Status adjusted for Hearing-impaired individuals total score, a cognitive test battery assessing different cognitive domains. Secondary outcome measures include additional neuropsychological assessments, cortical auditory-evoked potentials, and evaluation of general and disease-specific health-related quality of life. Variables include cognitive, audiological and vestibular evaluation. Variance analyses will assess the effect of hearing loss and vestibular decline on cognition. More precisely, the link between hearing loss and non-spatial cognitive functioning, the effect of vestibular decline on spatial cognition and the impact of both factors on the rate of conversion from MCI due to AD to ADD will be investigated.

ETHICS AND DISSEMINATION

The study protocol was approved by the ethical committee of the Antwerp University Hospital on 4 February 2019 with protocol number B300201938949. The findings will be disseminated through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04385225).

Associations of childhood experiences with event-related potentials in adults with autism spectrum disorder

Childhood maltreatment is defined as experiencing of physical, emotional and sexual abuse and neglect in childhood. Maltreatment in childhood leads to substantial psychosocial problems later in life in the general population. Individuals with autism spectrum disorder (ASD) have a higher risk of experiencing stressful and traumatic events, such as maltreatment, during childhood. Although childhood maltreatment reportedly leads to psychosocial problems in adults with ASD, the biological associations between childhood experiences and brain function in this population remain understudied. Here, we evaluated the relationships between childhood experiences and event-related potential (ERP) components during the auditory odd-ball task in adults with ASD (N = 21) and typically developed (TD) individuals (N = 22). We found that the higher the severity of sexual abuse, the larger the amplitude of P300 at Fz, Cz, C3, and C4 in individuals with ASD. Conversely, the severity of child maltreatment was associated with P300 latency at Cz and C3 in TD individuals. Moreover, full IQ was significantly associated with the MMN amplitude at Fz, Cz, C3, and C4 in TD individuals. These findings provide the first evidence that ERPs could be used to study the impacts childhood experiences on the brain of individuals with ASD and that childhood sexual abuse has salient impacts on brain function in this population.

Prediction of Cognitive Decline in Temporal Lobe Epilepsy and Mild Cognitive Impairment by EEG, MRI, and Neuropsychology

Cognitive decline is a severe concern of patients with mild cognitive impairment. Also, in patients with temporal lobe epilepsy, memory problems are a frequently encountered problem with potential progression. On the background of a unifying hypothesis for cognitive decline, we merged knowledge from dementia and epilepsy research in order to identify biomarkers with a high predictive value for cognitive decline across and beyond these groups that can be fed into intelligent systems. We prospectively assessed patients with temporal lobe epilepsy (N = 9), mild cognitive impairment (N = 19), and subjective cognitive complaints (N = 4) and healthy controls (N = 18). All had structural cerebral MRI, EEG at rest and during declarative verbal memory performance, and a neuropsychological assessment which was repeated after 18 months. Cognitive decline was defined as significant change on neuropsychological subscales. We extracted volumetric and shape features from MRI and brain network measures from EEG and fed these features alongside a baseline testing in neuropsychology into a machine learning framework with feature subset selection and 5-fold cross validation. Out of 50 patients, 27 had a decline over time in executive functions, 23 in visual-verbal memory, 23 in divided attention, and 7 patients had an increase in depression scores. The best sensitivity/specificity for decline was 72%/82% for executive functions based on a feature combination from MRI volumetry and EEG partial coherence during recall of memories; 95%/74% for visual-verbal memory by combination of MRI-wavelet features and neuropsychology; 84%/76% for divided attention by combination of MRI-wavelet features and neuropsychology; and 81%/90% for increase of depression by combination of EEG partial directed coherence factor at rest and neuropsychology. Combining information from EEG, MRI, and neuropsychology in order to predict neuropsychological changes in a heterogeneous population could create a more general model of cognitive performance decline.

Distinctive Effects of Aerobic and Resistance Exercise Modes on Neurocognitive and Biochemical Changes in Individuals with Mild Cognitive Impairment

Background:

Decreased levels of the neuroprotective growth factors, low-grade inflammation, and reduced neurocognitive functions during aging are associated with neurodegenerative diseases, such as Alzheimer’s disease. Physical exercise modifies these disadvantageous phenomena while a sedentary lifestyle promotes them.

Purpose:

The purposes of the present study included investigating whether both aerobic and resistance exercise produce divergent effects on the neuroprotective growth factors, inflammatory cytokines, and neurocognitive performance, and further exploring whether changes in the levels of these molecular biomarkers are associated with alterations in neurocognitive performance.

Methods:

Fifty-five older adults with amnestic MCI (aMCI) were recruited and randomly assigned to an aerobic exercise (AE) group, a resistance exercise (RE) group, or a control group. The assessment included neurocognitive measures [e.g., behavior and event-related potential (ERP)] during a task-switching paradigm, as well as circulating neuroprotective growth factors (e.g., BDNF, IGF-1, VEGF, and FGF-2) and inflammatory cytokine (e.g., TNF-α, IL-1β, IL-6, IL-8, and IL-15) levels at baseline and after either a 16-week aerobic or resistance exercise intervention program or a control period.

Results:

Aerobic and resistance exercise could effectively partially facilitate neurocognitive performance [e.g., accuracy rates (ARs), reaction times during the heterogeneous condition, global switching cost, and ERP P3 amplitude] when the participants performed the task switching paradigm although the ERP P2 components and P3 latency could not be changed. In terms of the circulating molecular biomarkers, the 16-week exercise interventions did not change some parameters (e.g., leptin, VEGF, FGF-2, IL-1β, IL-6, and IL-8). However, the peripheral serum BDNF level was significantly increased, and the levels of insulin, TNF-α, and IL-15 levels were significantly decreased in the AE group, whereas the RE group showed significantly increased IGF-1 levels and decreased IL-15 levels. The relationships between the changes in neurocognitive performance (AR and P3 amplitudes) and the changes in the levels of neurotrophins (BDNF and IGF-1)/inflammatory cytokines (TNF-α) only approached significance.

Conclusion:

These findings suggested that in older adults with aMCI, not only aerobic but also resistance exercise is effective with regard to increasing neurotrophins, reducing some inflammatory cytokines, and facilitating neurocognitive performance. However, the aerobic and resistance exercise modes likely employed divergent molecular mechanisms on neurocognitive facilitation.

Social support and cognitive processing among elderly caregivers and non-caregivers of other elderly persons

Abstract Objective : to analyze measures of social support and cognitive processing among elderly caregivers and non-caregivers. Method : a comparative, cross-sectional and quantitative study was performed. Participants were divided into two groups: 41 elderly caregivers of other elderly persons (G1) and 41 elderly non-caregivers (G2). Sociodemographic, health and care variables, social support, cognition and cognitive processing (verified by long-latency auditory evoked potential acquisition with the Neuron-Spectrun-4 / EPM device) were assessed. Results : in G1, the majority were female (n=33, 80.5%), married (n=34, 82.9%), with a mean age of 68.5 (± 5.8) years, a mean 4.5 (± 3.7) years of schooling and had provided care on average for 18.0 (± 18.4) years for 6.5 (± 5.1) hours per day. In G2, the majority were female (n=31, 75.6%), widowed (n=23, 56.1%), had a mean age of 69.8 (± 7.2) years and a mean 3.7 (± 2) years of schooling. There were no statistically significant differences between the groups in social support, cognition and cognitive processing. Conclusion : the task of caring did not have a negative influence on social support and cognitive processing. This research may contribute to the planning of actions among primary health care providers and to future research investigating other factors that permeate this relationship.

Effects of a specially designed aerobic dance routine on mild cognitive impairment

Background

Mild cognitive impairment (MCI) is known as a transitional stage or phase between normal aging and dementia. In addition, it is associated with an increased risk of dementia. Research has shown that moderate-intensity exercise is associated with a decreased risk of cognitive impairment. Two recent studies demonstrated that dance interventions are associated with improved cognitive function in the elderly with MCI.

Purpose

We evaluated the effect of a moderate-intensity aerobic dance routine on the cognitive function in patients with MCI.

Patients and methods

This is a single-blind randomized controlled trial. Sixty MCI patients were randomized to receive either treatment (aerobic dance routine + usual care) or control (usual care only) for 3 months. All patients received usual care for an additional 3 months thereafter. The aerobic dance routine was a specially designed dance routine which involved cognitive effort for patients to memorize the complex movements. Wechsler memory scale-revised logical memory (WMS-R LM) and event-related evoked potentials (ERPs) P300 latency were used to assess patients’ cognitive function at baseline, 3 months, and 6 months.

Results

Twenty-nine patients received exercise therapy and 31 patients received usual care. Patients in the treatment group showed a greater improvement in memory (difference in WMS-R LM changes over 3 months 4.6; 95% CI 2.2, 7.0; p<0.001) and processing speed (difference in P300 latency changes over 6 months −20.0; 95% CI=−39.5, −0.4; p<0.05) compared to control.

Conclusion

This dance routine improves cognitive function, especially episodic memory and processing speed, in MCI patients and merits promotion in communities.

Implementation of a Brain Training Pilot Study For People With Mild Cognitive Impairment

OBJECTIVE

A pilot study to determine the feasibility of recruiting patients with MCI to test for cognitive interventions.

METHOD

Thirty patients with amnestic MCI were to be divided into two intervention arms and one control group. Participants went to local sites and completed brain training for one hour three times per week for nine weeks. Outcome measures were: recruitment, computer abilities, compliance, task performance, neuropsychological tests, and electroencephalography.

RESULTS

After six months, only 20 participants had been recruited. Seventeen were allocated to one of the two intervention groups. Compliance was good and computer skills were not an obstacle. Participants improved their abilities in the modules, but there were no statistically significant changes on neuropsychological tests or EEG.

CONCLUSIONS

Recruitment of MCI participants for extensive cognitive intervention is challenging, but achievable. This pilot study was not powered to detect clinical changes. Future trials should consider recruitment criteria, intervention duration, scheduling, and study location.

Electrophysiological assessment of the concentration and attention in patient with nasal polyposis

Background

Nasal polyposis is a chronic disease presenting with nasal obstruction as the most frequent complaint. It has been documented that nasal polyposis results in deterioration of quality of life and disturbances of sleep. However, remarkable consequences of nasal polyposis such as psychological and cognitive outcomes are relatively poorly studied.

Objective

The aim of the present study was to evaluate whether there is an impairment of concentration and attention in nasal polyposis patients due to hypoxia caused by nasal obstruction.

Methods

This cross-sectional, case-control study was carried out on 30 male patients with nasal polyps and 30 healthy subjects serving as controls. Participant ages were 41.6 ± 10.2 years in the nasal polyps group and 41.3 ± 6.2 in the control group. All participants underwent systemic, neurological, and otorhinolaryngological examinations together with routine hematological and biochemical tests. Patients with nasal polyposis had bilateral complete obstruction of nasal cavity. P300 component of electroencephalography-derived event related potentials were used to monitor concentration and attention. Nasal polyposis and control groups were compared in terms of amplitude and latency of P300.

Results

There were significant differences between control and nasal polyposis groups in terms of latency of P300 (p < 0.001). Nasal polyposis patient latencies in P300 were longer than controls (345.8 ± 16.6 msec, 309.3 ± 16.6 msec, respectively). However, there were no significant differences between control and nasal polyposis groups in terms of amplitude of P300 (p > 0.05).

Conclusion

Results of the current study indicate that hypoxia due to complete nasal obstruction may result in impairment of attention and concentration in nasal polyposis patients. Assessment of patients with P300 latency subcomponent can be a useful diagnostic tool to detect cognitive and psychological consequences.

On the use of the P300 as a tool for cognitive processing assessment in healthy aging: A review

Changes in patterns of performance for the cognitive functions of memory, processing speed, and focused attention are expected in old age.

Increased N200 and P300 latencies in cognitively impaired elderly carrying ApoE ε-4 allele

OBJECTIVE

To compare the results of neuropsychological tests, evoked potentials N200 and P300 and polymorphisms of ApoE and BDNF rs6265 between patients with normal cognition and those with mild cognitive impairment (MCI) and Alzheimer's dementia (AD).

METHODS

This is a cross-sectional study of elderly individuals with normal cognition and those with MCI and AD, who were submitted to evoked potential tests (N200 and P300) by means of hearing stimuli based on the auditory oddball paradigm. Genotyping was obtained by using the real-time PCR technique.

RESULTS

Sixty-five patients were evaluated as follows: 14 controls, 34 with MCI and 17 with AD. N200 latency and P300 latency and amplitude were not associated with MCI and AD diagnosis. Patients with cognitive impairment (MCI or AD) showed increase in the latencies of P300 and N200. BNDF gene was not associated with cognitive impairment.

CONCLUSION

Latencies of N200 and P300 increased in cognitively impaired patients with the presence of ApoE ε-4 allele.

An acute bout of aerobic or strength exercise specifically modifies circulating exerkine levels and neurocognitive functions in elderly individuals with mild cognitive impairment

Although exercise is an effective way to decrease the risk of developing Alzheimer's disease, the biological basis for such benefits from the different exercise modes remains elusive. The present study thus aimed (i) to investigate the effects of acute aerobic or resistance exercise on neurocognitive performances and molecular markers when performing a cognitive task involving executive functioning in older adults with amnestic mild cognitive impairment (aMCI), and (ii) to explore relationships of acute exercise-induced neurocognitive changes with changes in circulating levels of neuroprotective growth factors (e.g., BDNF, IGF-1, VEGF, and FGF-2, collectively termed 'exerkines'), elicited by different acute exercise modes. Sixty-six older adults with aMCI were recruited and randomly assigned to an aerobic exercise (AE) group, a resistance exercise (RE) group, or a non-exercise-intervention (control) group. The behavioral [i.e., accuracy rate (AR) and reaction time (RT)] and electrophysiological [i.e., event-related potential (ERP) P3 latency and amplitude collected from the Fz, Cz, and Pz electrodes] indices were simultaneously measured when participants performed a Flanker task at baseline and after either an acute bout of 30 min of moderate-intensity AE, RE or a control period. Blood samples were taken at three time points, one at baseline (T1) and two after an acute exercise intervention (T2 and T3: before and after cognitive task test, respectively). The results showed that the acute AE and RE not only improved behavioral (i.e., RTs) performance but also increased the ERP P3 amplitudes in the older adults with aMCI. Serum FGF-2 levels did not change with acute aerobic or resistance exercise. However, an acute bout of aerobic exercise significantly increased serum levels of BDNF and IGF-1 and tended to increase serum levels of VEGF in elderly aMCI individuals. Acute resistance exercise increased only serum IGF-1 levels. However, the exercise-induced elevated levels of these molecular markers returned almost to baseline levels in T3 (about 20 min after acute exercise). In addition, changes in the levels of neurotrophic and angiogenic factors were not correlated with changes in RTs and P3 amplitudes. The present findings of changes in neuroprotective growth factors and neurocognitive performances through acute AE or RE suggest that molecular and neural prerequisites for exercise-dependent plasticity are preserved in elderly aMCI individuals. However, the distinct pattern of changes in circulating molecular biomarkers induced by two different exercise modes in aMCI elderly individuals and the potentially interactive mechanisms of the effects of BDNF, IGF-1, and VEGF on amyloid-β provide a basis for future long-term exercise intervention to investigate whether AE relative to RE might be more effective in prevention/treatment of an early stage neurodegenerative disease.

Contribution of auditory P300 test to the diagnosis of mild cognitive impairment in Parkinson's disease

Abnormalities in auditory P300 test have been observed in patients with Parkinson's disease (PD). We aimed to investigate whether or not additional electrophysiological tests assist in making the clinical diagnosis of mild cognitive impairment in Parkinson's disease (PD-MCI), and we evaluated P300 changes in patients with non-demented PD and analyzed the correlation between the cognitive features and P300 changes. Twenty patients with PD who had been diagnosed with mild cognitive impairment (PD-MCI group) according to the Movement Disorder Society (MDS) 2012 PD-MCI level II criteria, 21 patients with PD without cognitive impairment (PD-Normal group), and 20 control subjects (control group) who were neurologically normal were examined by the standard auditory oddball paradigm. The N100, P200, N200, and P300 latencies and N100-P200, P200-N200, and N200-P300 amplitudes were measured and analyzed. P300 latencies recorded from Fz, Cz, and Pz and N200 latency recorded from Fz were significantly longer in the PD-MCI group than in the PD-Normal and the control group (respectively p < 0.001, p = 0.041). P300 amplitude recorded from Fz was significantly lower in PD-MCI group than those in the other groups (p = 0.038). While P300 was obtained in all patients in the PD-Normal and the control group, it was lost in 35% of PD-MCI patients. The results show that P300 provides a diagnostic tool for detecting PDMCI. We suggest that P300 prolongation and loss of P300 potential could be used as supportive parameter in the diagnosis of PD-MCI.

Mismatch negativity as a potential neurobiological marker of early-stage Alzheimer disease and vascular dementia

Alzheimer's disease (AD) and vascular dementia (VD) are serious, irreversible forms of cognitive impairment, which means that an early diagnosis is essential to slow down their progression. One potential neurophysiological biomarker of these diseases is the mismatch negativity (MMN) event-related potentials (ERP) component, which reflects an automatic detection mechanism at the pre-attentive stages of information processing. We evaluated the auditory MMN response in individuals from two patient groups: those in the prodromal stages of AD (P-AD) and those in the prodromal stages of VD (P-VD). Thirty patients (15 P-AD patients and 15 P-VD patients) and 30 age-matched controls were recruited to undergo electrophysiological recordings during the presentation of an auditory deviant-standard-reverse oddball paradigm that was used to elicit genuine MMN responses. We show that over the frontal-central area, the mean amplitude of the MMN was significantly reduced in both the P-AD (p=0.017) and P-VD groups (p=0.013) compared with controls. The MMN peak latency in P-VD patients was significantly shorter than in controls (p=0.027). No MMN response differences between the P-AD and P-VD were found in either the frontal-central or the temporal areas. These results indicate that P-AD and P-VD patients exhibit impaired pre-attentive information processing mechanisms as revealed by the frontal-central area MMN response, which is associated with sensory memory and cognitive deficits.

P300 amplitude and latency in autism spectrum disorder: a meta-analysis

Autism spectrum disorder (ASD) is an early onset neurodevelopmental disorder. Evidence suggests that ASD patients have abnormalities in information processing. Event-related potential (ERP) technique can directly record brain neural activity in real time. P300 is a positive ERP component which can measure the neuroelectrophysiological characteristics of human beings and has the potential to discover the pathological mechanism of ASD. However, P300 studies on ASD patients are incongruent and the disparities may be caused by several factors. By searching PubMed, Embase and Cochrane Library databases, a meta-analysis of P300 component difference between ASD group and typically developed (TD) control group was conducted. Results of amplitude and latency of P3b and P3a from included studies were synthesized. Random effect model was chosen and standardized mean difference (SMD) was calculated. Subgroup analysis was used to identify the source of heterogeneity and to test the effect of different experiment factors. A total of 407 ASD patients and 457 TD controls from 32 studies were included in this analysis. Reduced amplitude of P3b was found in ASD group (SMD = -0.505, 95 % CI -0.873, -0.138) compared with TD group, but no difference of P3b latency, P3a amplitude, or P3a latency was found between groups. Subgroup analysis showed that oddball paradigm elicited attenuated P3b amplitude in Pz electrode among ASD subjects. This meta-analysis suggests ASD patients have abnormalities in P300 component, which may represent for deficits in cognition, attention orientation and working memory processing, particularly in the decision-making processing condition.