Cognitive Event-Related Potentials in Young Adults With Cerebral Palsy: A Proof-of-Concept Study.

Cerebral palsy (CP) is a movement and posture disorder often accompanied by cognitive difficulties which can be assessed using event-related potentials (ERPs), an often-overlooked tool in this population. Here we describe our assessment protocol, examine its feasibility, and validate the use of single-subject ERP analyses in adolescents and young adults with CP, an analysis approach which recognizes the heterogeneity of the clinical population. This study involved a final sample of 9 adolescents/young adults with CP participating in the "MyStory" study (age range 16-29 years, Mage = 25.0 years; 6 female; Gross Motor Function Classification System level I [n = 4], II [n = 2], III [n = 1], IV [n = 1], and V [n = 1]). ERP components were elicited over medial prefrontal and central cortex (error- and correct-related negativities [ERN/CRN], error-positivity [Pe], N100, P200, N200, P300), as well as those generated over occipital cortex (P100, N170). Group and single-subject ERP statistics were computed for ERPs recorded over both areas. Using recently developed data analysis methods (independent components analysis and robust bootstrapped single-subject statistics), we measured the number of participants demonstrating significant condition differences at the timing of each ERP component of interest. We demonstrate good validity for ERPs recorded during 2 of our 3 tasks eliciting frontal activation (eg, 4 of 6 participants with usable data showed a significant single-subject medial frontal negativity condition difference in a context-switching task) and good validity for ERPs derived from a task engaging occipital regions (eg, 8 of 9 participants each showed a significant N170 face-object condition effect).

Perinatal nicotine exposure relates to stimulus-locked event-related potentials in early adolescence during an emotional go/no-go task.

Nicotine exposure is associated with negative consequences on the developing brain, both in utero and after birth. We investigated the relationship between perinatal nicotine exposure and electroencephalographic brain activity recorded during an emotional faces Go/No-Go task among adolescents. Seventy-one adolescents aged 12-15 years completed a Go/No-Go task using fearful and happy faces. Parents completed questionnaire measures of their child's temperament and self-regulation and retrospectively reported on nicotine exposure during the perinatal period. Perinatally exposed children (n = 20) showed increased and prolonged frontal event-related potential (ERP) differentiation in stimulus-locked analyses; that is, greater emotion and condition differentiation in comparison with their non-exposed peers (n = 51). However, non-exposed children showed greater late emotion differentiation recorded over posterior sites. Response-locked ERP differences were not found. ERP effects were not related to temperamental, self-regulatory, or parental education and income-related factors. This study is the first to demonstrate a relationship between perinatal nicotine exposure and ERPs in an emotional Go/No-Go task among adolescents. Findings suggest that while conflict detection remains intact for adolescents with perinatal nicotine exposure, their attentional allocation to behaviourally relevant stimuli may be magnified to beyond optimal levels, particularly when emotion is salient in information processing. Future studies can extend these findings by isolating prenatal nicotine exposure and comparing its effects to isolated postnatal exposure and clarifying the implications of the face and performance processing differences in adolescence.

The relation between belief in a just world and early processing of deserved and undeserved outcomes: An ERP study.

We used event-related potentials (ERPs) to examine how quickly people in general, and certain people in particular, process deservingness-relevant information. Female university students completed individual difference measures, including individual differences in the belief in a just world (BJW), a belief that people get what they deserve. They then read stories in which an outcome was deserved, undeserved, or neither deserved nor undeserved (i.e., "neutral") while their ERPs were recorded with scalp electrodes. We found no overall differentiation between early ERP responses (<300 ms post-stimulus onset) to deserved, undeserved, and neutral outcomes. However, BJW correlated with the difference between early ERP responses to these forms of information (rs from |.44| to |.61|; ps from .018 to < .001). The early nature of our effects (e.g., 96 ms after stimulus onset) suggests individual differences in socially-relevant information processing that begins before conscious evaluation of the stimuli. Potential underlying processes include automatic attention to schema-relevant information and to unexpected (and therefore salient) information and automatic processing of belief-consistent information. Our research underscores the importance of the concept of deservingness in human information processing as well as the utility of ERP technology and robust statistical analyses in investigations of complex social stimuli.

Increased alpha suppression with age during involuntary memory retrieval.

Recent work suggests that while voluntary episodic memory declines with age, involuntary episodic memory, which comes to mind spontaneously without intention, remains relatively intact. However, the neurophysiology underlying these differences has yet to be established. The current study used electroencephalography (EEG) to investigate voluntary and involuntary retrieval in older and younger adults. Participants first encoded sounds, half of which were paired with pictures, the other half unpaired. EEG was then recorded as they listened to the sounds, with participants in the involuntary group performing a sound localization cover task, and those in the voluntary group additionally attempting to recall the associated pictures. Participants later reported which sounds brought the paired picture to mind during the localization task. Reaction times on the localization task were slower for voluntary than involuntary retrieval and for paired than unpaired sounds, possibly reflecting increased attentional demands of voluntary retrieval and interference from reactivation of the associated pictures respectively. For the EEG analyses, young adults showed greater alpha event-related desynchronization (ERD) during voluntary than involuntary retrieval at frontal and occipital sites, while older adults showed pronounced alpha ERD regardless of intention. Additionally, older adults showed greater ERD for paired than unpaired sounds at occipital sites, likely reflecting visual reactivation of the associated pictures. Young adults did not show this alpha ERD memory effect. Taken together, these data suggest that involuntary memory is largely preserved with age, but this may be due to older adults' greater recruitment of top-down control even when demand for such control is limited.

Developmental changes in external and internal performance monitoring across middle childhood: An ERP study.

Performance monitoring is critical for learning and behavioral adaption and is supported by both externally and internally sourced information. Cross-sectional studies indicate an increase in internal error processing across childhood, suggesting a potential developmental transition from reliance on external information to reliance on internally developed models. However, little research has examined the association between these constructs longitudinally. Data from 339 children assessed annually from kindergarten to 2nd grade were examined to determine the developmental trajectory of ERP indices of performance monitoring, and whether the association between these indices changes across time. EEG data were recorded during an incentivized Go/No-Go task and ERP component amplitudes were extracted as peak measures at Fz. Despite small increases in magnitude, no significant changes were observed in any of the ERPs. Multi-level regression analyses indicated that in kindergarten a more negative feedback-related negativity (FRN) was associated with a more negative error-related negativity (ERN) and a more negative error positivity (Pe). Further, the association between the FRN and Pe changed over time, such that in 2nd grade the FRN and Pe decoupled from one another and were no longer associated. These results suggest that the development of performance monitoring through middle childhood may be a phasic process. More specifically, matured external feedback monitoring processes may first facilitate the development of conscious error recognition, and then the development of internal error monitoring processes. Once internal models of error monitoring are well-established, children may then reduce their utilization of external feedback.

Association between EEG asymmetry and the error-related negativity across middle childhood.

Resting frontal EEG alpha asymmetry has been extensively examined as a marker of motivational disposition. Recent research has examined how this trait-level marker of motivation influences an individual's internal error monitoring (indexed by the error-related negativity; ERN), with mixed findings as to whether more negative ERNs are associated with greater left or right alpha power. Data from 339 children who completed an incentivized Go/No-Go task annually from Kindergarten through 2nd grade were examined for an association between ERN amplitude and EEG asymmetry, and for whether the association was developmentally stable. Results indicate an association between left-dominant activation and a more negative amplitude in Kindergarten, with an inversion of this association emerging by 2nd grade, such that a more negative ERNs were associated with right-dominant activation. We suggest that the association between EEG asymmetry and ERN amplitude is likely modulated by task condition (e.g., incentivization) and experience over time (e.g., habituation).

The reliability of visual ERP components in children across the first year of school.

Event-related potentials (ERPs) are increasingly used as neurophysiological markers of perceptual and cognitive processes conveying risk for psychopathology. However, little is known about the reliability of ERP components during childhood, a time of substantial brain maturation. In the present study, we examine the early visual ERP components (P1, N170, VPP), frequently examined as indicators of attentional bias, for 110 children at kindergarten (T1) and first grade (T2). Children performed a Go/Nogo task at both time points, with exact stimuli changed to reduce habituation. All components showed increases in absolute amplitude and the P1 and VPP also showed decreases in latency. Retest reliability across time was good to very good for amplitude measures (Pearson rs ranging from .54 for N170 to .69 for P1) and low to very good for latencies (rs from .34 for P1 to .60 for N170), despite the change in visual stimuli. Although there was some evidence of moderation by sex, early visual ERP components appear to be a reliable measure of individual differences in attention processing in middle childhood. This has implications for the use of early visual ERP components as trait-like markers for individual differences in perceptual processes in developmental research.

Medial frontal negativities predict performance improvements during motor sequence but not motor adaptation learning.

Alterations in our environment require us to learn or alter motor skills to remain efficient. Also, damage or injury may require the relearning of motor skills. Two types have been identified: movement adaptation and motor sequence learning. Doyonet al. (2003, Distinct contribution of the cortico-striatal and cortico-cerebellar systems to motor skill learning. Neuropsychologia, 41(3), 252-262) proposed a model to explain the neural mechanisms related to adaptation (cortico-cerebellar) and motor sequence learning (cortico-striatum) tasks. We hypothesized that medial frontal negativities (MFNs), event-related electrocortical responses including the error-related negativity (ERN) and correct-response-related negativity (CRN), would be trait biomarkers for skill in motor sequence learning due to their relationship with striatal neural generators in a network involving the anterior cingulate and possibly the supplementary motor area. We examined 36 participants' improvement in a motor adaptation and a motor sequence learning task and measured MFNs elicited in a separate Spatial Stroop (conflict) task. We found both ERN and CRN strongly predicted performance improvement in the sequential motor task but not in the adaptation task, supporting this aspect of the Doyon model. Interestingly, the CRN accounted for additional unique variance over the variance shared with the ERN suggesting an expansion of the model.

EEG Integrated Platform Lossless (EEG-IP-L) pre-processing pipeline for objective signal quality assessment incorporating data annotation and blind source separation.

BACKGROUND: The methods available for pre-processing EEG data are rapidly evolving as researchers gain access to vast computational resources; however, the field currently lacks a set of standardized approaches for data characterization, efficient interactive quality control review procedures, and large-scale automated processing that is compatible with High Performance Computing (HPC) resources. NEW METHOD: In this paper we describe an infrastructure for the development of standardized procedures for semi and fully automated pre-processing of EEG data. Our pipeline incorporates several methods to isolate cortical signal from noise, maintain maximal information from raw recordings and provide comprehensive quality control and data visualization. In addition, batch processing procedures are integrated to scale up analyses for processing hundreds or thousands of data sets using HPC clusters. RESULTS: We demonstrate here that by using the EEG Integrated Platform Lossless (EEG-IP-L) pipeline's signal quality annotations, significant increase in data retention is achieved when applying subsequent post-processing ERP segment rejection procedures. Further, we demonstrate that the increase in data retention does not attenuate the ERP signal. CONCLUSIONS: The EEG-IP-L state provides the infrastructure for an integrated platform that includes long-term data storage, minimal data manipulation and maximal signal retention, and flexibility in post processing strategies.

EEG-IP: an international infant EEG data integration platform for the study of risk and resilience in autism and related conditions.

BACKGROUND: Establishing reliable predictive and diganostic biomarkers of autism would enhance early identification and facilitate targeted intervention during periods of greatest plasticity in early brain development. High impact research on biomarkers is currently limited by relatively small sample sizes and the complexity of the autism phenotype. METHODS: EEG-IP is an International Infant EEG Data Integration Platform developed to advance biomarker discovery by enhancing the large scale integration of multi-site data. Currently, this is the largest multi-site standardized dataset of infant EEG data. RESULTS: First, multi-site data from longitudinal cohort studies of infants at risk for autism was pooled in a common repository with 1382 EEG longitudinal recordings, linked behavioral data, from 432 infants between 3- to 36-months of age. Second, to address challenges of limited comparability across independent recordings, EEG-IP applied the Brain Imaging Data Structure (BIDS)-EEG standard, resulting in a harmonized, extendable, and integrated data state. Finally, the pooled and harmonized raw data was preprocessed using a common signal processing pipeline that maximizes signal isolation and minimizes data reduction. With EEG-IP, we produced a fully standardized data set, of the pooled, harmonized, and pre-processed EEG data from multiple sites. CONCLUSIONS: Implementing these integrated solutions for the first time with infant data has demonstrated success and challenges in generating a standardized multi-site data state. The challenges relate to annotation of signal sources, time, and ICA analysis during pre-processing. A number of future opportunities also emerge, including validation of analytic pipelines that can replicate existing findings and/or test novel hypotheses.

A multi-timescale, multi-method perspective on older adult neurocognitive adaptability.

Objective: Ethical and economic values compel us to improve the screening, monitoring, and enhancement of older adult neurocognitive adaptability. Diverse contemporary theoretical and empirical perspectives highlight the multi-timescale, multi-mechanistic nature of neurocognitive adaptability. Still lacking are frameworks and methodologies that demonstrate this convergence to allow for new paradigms that harness the clinical utility of neurocognitive adaptability.Method: We present a multi-method, multi-timescale analysis of neurocognitive adaptability in a group of healthy, community-dwelling older adults from the Victoria, British Columbia region. Each participant completed a 96-trial computerized cognitive flexibility task at 4 to 6 separate laboratory visits spanning about a month. This captured within-person changes at the within-occasion and across-occasion levels (timescales of seconds and days/weeks, respectively). We used standardized clinical assessments of cognitive reserve (i.e., estimated premorbid function) and conscientiousness (a personality dimension) as cross-sectional (time-invariant) predictors in multi-level linear regression to illustrate between-person differences in within-person cognitive performance trajectories.Results: Reserve predicted cognitive performance differences at the timescale of seconds (within occasions) but did not relate to differences at the timescale of days/weeks (across occasions); in contrast, conscientiousness predicted cognitive performance differences at both timescales. Distinct processes operating within the same task (stimulus-classification vs. set-shifting) improved with practice at discrepant rates.Conclusions: Neurocognitive adaptability is underlain by multiple biopsychosocial mechanisms. Certain widely-used clinical indices (e.g., of reserve or conscientiousness) may estimate distinct types of neurocognitive adaptability relevant to maintaining functional independence into old age. Our methodology and theoretical framework assume that neurocognitive adaptability unfolds at multiple hierarchical scales of time.

Does Anxiety Enhance or Hinder Attentional and Impulse Control in Youth With ADHD? An ERP Analysis.

Objective: Youth with ADHD and comorbid anxiety (ADHD+ANX) experience increased social and academic impairment compared with youth with ADHD without anxiety (ADHD). Group differences in attentional and impulse control may underlie this increased impairment. Examination of group differences using behavioral measures of attentional and impulse control has yielded inconsistent findings. This study explored group differences using event-related potentials (ERPs), which provide neural information concerning early information processing. Method: ERPs (early frontal positivity [EFP], N2) were collected while youth aged 11 to 17 with ADHD (n = 31) and ADHD+ANX (n = 35) completed a visual and an auditory computer task. Results: Compared with the ADHD group, the ADHD+ANX group exhibited larger N2 amplitudes to no-go stimuli and larger EFP amplitudes to target auditory stimuli, with variable attention allocation to nontarget stimuli. Conclusion: The addition of anxiety to ADHD appears to alter early attentional processing, which may be an important aspect of this comorbidity.

Neurophysiological evidence for distinct biases in emotional face processing associated with internalizing and externalizing symptoms in children.

Attentional bias to threat has been implicated in both internalizing and externalizing disorders. This study utilizes event-related potentials to examine early stages of perceptual attention to threatening (angry or fearful) versus neutral faces among a sample of 200 children ages 6-8 years from a low-income, urban community. Although both internalizing and externalizing symptoms were associated with processing biases, the nature of the bias differed between these two symptom domains. Internalizing symptoms were associated with heightened early attentional selection (P1) and later perceptual processing (P2) of fearful faces. In contrast, externalizing symptoms were associated with reduced early attentional selection (P1) of fearful faces and enhanced perceptual processing (P2) of neutral faces, possibly indicative of a hostile interpretation bias for ambiguous social cues. These results provide insight into the distinct cognitive-affective processes that may contribute to the etiology and maintenance of internalizing and externalizing psychopathology.

Neuropsychological and resting-state electroencephalographic markers of older adult neurocognitive adaptability.

OBJECTIVE: This study was undertaken to explore multimethod neurocognitive screening tools to aid in detection of older adults who may be at heightened risk of pathological cognitive decline (preclinical dementia). In so doing, this study advances the theoretical conceptualization of neurocognitive adaptability in the context of aging and dementia. METHOD: This article reports original data from the baseline measurement occasion of a longitudinal study of healthy, community-dwelling older adults from the Victoria, British Columbia region. Participants were diagnosed as normal, subtle decline, or mild cognitive impairment according to actuarial neuropsychological criteria (adjusted for age only or adjusted for age and premorbid IQ). Diagnostic classification was employed to illustrate group differences in a novel metric of multi-timescale neural adaptability derived from 4-min of resting-state electroencephalographic data collected from each participant (immediately following their neuropsychological evaluation). RESULTS: Prior findings were replicated; adjusting raw neuropsychological test scores for individual differences in estimated premorbid IQ appeared to increase the sensitivity of standardized clinical tasks to subtle cognitive impairment. Moreover, and consistent with prior neuroscientific research, timescale-specific (i.e. at ∼12-20 ms timescales) differences in resting-state neural adaptability appeared to characterize groups who differed in terms of neuropsycholgoical diagnostic classification. CONCLUSIONS: Recently proposed actuarial neuropsychological criteria for subtle cognitive decline identify older adults who show timescale-specific changes in resting brain function that may signal the onset of preclinical dementia. The subtle decline stage may represent a critical inflection point-partial loss of neurocognitive adaptability-on a pathological aging trajectory. These findings illustrate areas of potential future development in neurocognitive health care.

An EEG Investigation of the Attention-Related Impact of Mindfulness Training in Youth With ADHD: Outcomes and Methodological Considerations.

OBJECTIVE: The current study examined the impact of an activity-based mindfulness treatment on EEG indices of attention in youth with ADHD aged 11 to 17 years compared with a waitlist control group. METHOD: Pre- and post-treatment, EEG was recorded as participants completed a single-point focus rest task and two active attention tasks. Theta power, beta power, and theta/beta ratio (TBR) were calculated during each task. RESULTS: A significant group by time by task interaction was found that indicated significant improvement in attentional ability, indexed by decreased TBR, for the treatment group but not controls. CONCLUSION: Findings support the benefit of mindfulness treatment for enhancing attentional control in youth with ADHD and extend the literature by providing evidence of these gains at a neural level. Findings also offer methodological support for the use of active attention tasks when examining mindfulness-related attentional gains in youth with ADHD. Directions for future research are discussed.

Compounding matters: Event-related potential evidence for early semantic access to compound words.

Reading words in a native language triggers a largely obligatory cognitive process that we accept as leading to comprehension of the word - we cannot suppress our understanding of word meaning. In this study, we investigated the early stages of this comprehension process by means of event-related potentials (ERPs) to identify when this processing of meaning - that is, semantic processing - first occurs. We report that, when processing visually presented compound words, semantic access at some level occurs as early as the P100 and persists through to the N400. Specifically, we focused on the P100 ERP component, and utilized the unique features of compound words (i.e. variation in the transparency of meaning) to investigate the speed with which we gain access to information about meaning (i.e. semantic access). Twenty-two participants performed a lexical decision task including 40 English compounds, which varied with respect to their constituent semantic transparency. Compounds ranged from full constituent semantic transparency (e.g. grapeseed) to partial transparency (e.g. grapefruit) to full opacity (e.g. hogwash). Regression analyses predicted ERP components from compound constituent transparency, adjusting for word frequency. Word frequency and transparency of both the first and second constituents each uniquely predicted P100 amplitude. Transparency of the second constituent, but not word frequency, predicted later component amplitudes, including that of the N400. The findings suggest that some level of semantic access occurs as early as the P100. Overall, these results support models which emphasize simultaneous processing of form and meaning as opposed to serial or hierarchical approaches.

STATSLAB: An open-source EEG toolbox for computing single-subject effects using robust statistics.

Research on robust statistics during the past half century provides concrete evidence that classical hypothesis tests that rely on the sample mean and variance are problematic. Even seemingly minor departures from normality are now known to create major problems in terms of increased error rates and decreased power. Fortunately, numerous robust estimation techniques have been developed that circumvent the need for strict assumptions of normality and equal variances, leading to increased power and accuracy when testing hypotheses. Two robust methods that have been shown to have practical value across a wide range of applied situations are the trimmed mean and percentile bootstrap test. To facilitate the uptake of robust methods into the behavioural sciences, especially when dealing with trial-based data such as EEG, we introduce STATSLAB: An open-source EEG toolbox for computing single-subject effects using robust statistics. With the STATSLAB toolbox users can apply the percentile bootstrap test, with trimmed means, to a variety of neural signals including voltages, global field amplitude, and spectral features for both scalp channels and independent components. The toolbox offers a range of analytical strategies and is packaged with a fully functional graphical user interface that includes documentation.

Adverse childhood experiences are associated with self-regulation and the magnitude of the error-related negativity difference.

Trauma and stress, like that which occurs as a result of adverse childhood experiences (ACEs), can change brain structure and function, especially in medial prefrontal and hippocampal areas, and can impact self-regulatory skill. The error-related negativity (ERN) is a medial frontal negative event-related potential (ERP) component that is more negative when a participant makes an erroneous versus correct response. We investigated the association of ACEs to adolescents' ERN and self-regulation. Forty-three 12-15 year olds performed a flanker task while EEG data were recorded. We found an interaction between trial type (correct vs incorrect) and group (low, medium and high trauma groups) on the ERN. The high-trauma group showed a larger Error-Correct difference than the low- and medium-trauma groups. This appeared as trend correlations between overall trauma exposure as a continuous variable and ERN-related variables. Trauma exposure was associated with reduced self-regulatory capacity, and accounting for self-regulation decreased the associations between trauma and the ERN, suggestive of a protective effect for self-regulation.

Characteristics of Healthy Older Adults that Influence Self-rated Cognitive Function.

OBJECTIVES: We sought to clarify the nature of self-reported cognitive function among healthy older adults by considering the short-term, within-person association (coupling) of subjective cognitive function with objective cognitive performance. We expected this within-person coupling to differ between persons as a function of self-perceived global cognitive decline and depression, anxiety, or neuroticism. METHODS: This was an intensive measurement (short-term longitudinal) study of 29 older adult volunteers between the ages of 65 and 80 years without an existing diagnosis of dementia or mild cognitive impairment. Baseline assessment included neuropsychological testing and self-reported depression, anxiety, and neuroticism, as well as self- and informant-reported cognitive decline (relative to 10 years previously). Intensive within-person measurement occasions included subjective ratings of cognitive function paired with performance on a computerized working memory (n-back) task; each participant attended four or five assessments separated by intervals of at least one day. Statistical analysis was comprised of multilevel linear regression. RESULTS: Comparison of models suggested that both neuroticism and self-rated cognitive decline explained unique variance in the within-person, across-occasion coupling of subjective cognitive function with objective working memory performance. CONCLUSIONS: Self-ratings of cognition may accurately reflect day-to-day variations in objective cognitive performance among older adults, especially for individuals lower in neuroticism and higher in self-reported cognitive decline. Clinicians should consider these individual differences when determining the validity of complaints about perceived cognitive declines in the context of otherwise healthy aging. (JINS, 2018, 24, 57-66).