Event-related potentials in adults with Attention-Deficit/Hyperactivity Disorder: An investigation using an inter-modal auditory/visual oddball task

An event-related potential study of P300 in preschool children with attention deficit hyperactivity disorder

Objective

To study the characteristics of event related potential P300 in preschool children with attention deficit hyperactivity disorder (ADHD) aged 4-6 years (4≤ age <6), and to explore the differences in cognitive function compared with healthy children. To explore a new method for the study of cognitive function in preschool children with ADHD.

Methods

A total of 73 preschool children aged 4-6 years were selected from the outpatient clinic of Neurology Department, the ADHD-specialized Clinic and Health Care Department of the Children's Hospital Affiliated to the Capital Institute of Pediatrics from March 2021 to May 2024. They were divided into the ADHD group (45 cases) and healthy children group (28 cases). Event related potential P300 was measured in all children and the amplitude and latency of the wave were compared between the two groups separately.

Results

The latency of P300 at all the recording electrodes (Fz, Cz, Pz, Oz, C3, C4) in the ADHD group was significantly longer than controls (p < 0.05). The wave amplitudes of children with ADHD were significantly higher than controls at Pz and Oz points.

Conclusion

The differences between two groups in P300 test show that preschool children with ADHD present longer latency at central line of the brain and bilateral central lobes compared with healthy children, and higher amplitude at the central parietal lobe and central occipital lobe. It may suggest that attention cognition has already impaired in preschool children with ADHD.

Evaluation of p300 and spectral resolution in children with attention deficit hyperactivity disorder and specific learning disorder

This study aims to examine auditory processing, P300 values and functional impairment levels among children with Attention Deficit and Hyperactivity Disorder (ADHD), Specific Learning Disorder (SLD), ADHD+SLD and healthy controls. Children with ADHD (n = 17), SLD (n = 15), ADHD+SLD (n = 15), and healthy controls (n = 15) between the ages of 7-12 were evaluated with K-SADS, Weiss Functional Impairment Rating Scale, Turgay DSM-IV Disruptive Behavior Disorders Rating Scale, The Mathematics, Reading, Writing Assessment Scale and Children's Auditory Performance Scale (CHAPS). Auditory P300 event-related potentials and Spectral-Temporally Modulated Ripple Test (SMRT) were applied. Three patient groups were found to be riskier than healthy controls according to the CHAPS. There was no significant difference between the groups in the SMRT. In post-hoc analyses of P300 parietal amplitudes, ADHD, SLD, and ADHD+SLD were found to be significantly lower than the control group. The amplitudes of the ADHD+SLD were by far the lowest. It has been shown that auditory performance skills and p300 amplitudes are lower in children diagnosed with only ADHD or SLD compared to the control group, with the lowest values observed in ADHD+SLD. This study suggests that the difficulties with attention and cognitive functions in the ADHD+SLD are more severe than ADHD and/or SLD without comorbidity.

Electrophysiological evidence for increased auditory crossmodal activity in adult ADHD

Background

Attention deficit and hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by core symptoms of inattention, and/or impulsivity and hyperactivity. In order to understand the basis for this multifaceted disorder, the investigation of sensory processing aberrancies recently reaches more interest. For example, during the processing of auditory stimuli comparable low sensory thresholds account for symptoms like higher distractibility and auditory hypersensitivity in patients with ADHD. It has further been shown that deficiencies not only exist on an intramodal, but also on a multimodal level. There is evidence that the visual cortex shows more activation during a focused auditory task in adults with ADHD than in healthy controls. This crossmodal activation is interpreted as the reallocation of more attentional resources to the visual domain as well as deficient sensory inhibition. In this study, we used, for the first time, electroencephalography to identify a potential abnormal regulated crossmodal activation in adult ADHD.

Methods

15 adult subjects with clinically diagnosed ADHD and 14 healthy controls comparable in age and gender were included. ERP components P50, P100, N100, P200 and N200 were measured during the performance of a unimodal auditory and visual discrimination task in a block design. Sensory profiles and ADHD symptoms were assessed with inattention as well as childhood ADHD scores. For evaluating intramodal and crossmodal activations, we chose four EEG channels for statistical analysis and group-wise comparison.

Results

At the occipital channel O2 that reflects possible crossmodal activations, a significantly enhanced P200 amplitude was measured in the patient group. At the intramodal channels, a significantly enhanced N200 amplitude was observed in the control group. Statistical analysis of behavioral data showed poorer performance of subjects with ADHD as well as higher discrimination thresholds. Further, the correlation of the assessed sensory profiles with the EEG parameters revealed a negative correlation between the P200 component and sensation seeking behavior.

Conclusion

Our findings show increased auditory crossmodal activity that might reflect an altered stimulus processing resource allocation in ADHD. This might induce consequences for later, higher order attentional deployment. Further, the enhanced P200 amplitude might reflect more sensory registration and therefore deficient inhibition mechanisms in adults with ADHD.

Network-Based Differences in Top-Down Multisensory Integration between Adult ADHD and Healthy Controls-A Diffusion MRI Study

BACKGROUND

Attention-deficit-hyperactivity disorder (ADHD) is a neurodevelopmental disorder neurobiologically conceptualized as a network disorder in white and gray matter. A relatively new branch in ADHD research is sensory processing. Here, altered sensory processing i.e., sensory hypersensitivity, is reported, especially in the auditory domain. However, our perception is driven by a complex interplay across different sensory modalities. Our brain is specialized in binding those different sensory modalities to a unified percept-a process called multisensory integration (MI) that is mediated through fronto-temporal and fronto-parietal networks. MI has been recently described to be impaired for complex stimuli in adult patients with ADHD. The current study relates MI in adult ADHD with diffusion-weighted imaging. Connectome-based and graph-theoretic analysis was applied to investigate a possible relationship between the ability to integrate multimodal input and network-based ADHD pathophysiology.

METHODS

Multishell, high-angular resolution diffusion-weighted imaging was performed on twenty-five patients with ADHD (six females, age: 30.08 (SD: 9.3) years) and twenty-four healthy controls (nine females; age: 26.88 (SD: 6.3) years). Structural connectome was created and graph theory was applied to investigate ADHD pathophysiology. Additionally, MI scores, i.e., the percentage of successful multisensory integration derived from the McGurk paradigm, were groupwise correlated with the structural connectome.

RESULTS

Structural connectivity was elevated in patients with ADHD in network hubs mirroring altered default-mode network activity typically reported for patients with ADHD. Compared to controls, MI was associated with higher connectivity in ADHD between Heschl's gyrus and auditory parabelt regions along with altered fronto-temporal network integrity.

CONCLUSION

Alterations in structural network integrity in adult ADHD can be extended to multisensory behavior. MI and the respective network integration in ADHD might represent the maturational cortical delay that extends to adulthood with respect to sensory processing.

Robust perceptual-load-dependent audiovisual integration in adult ADHD

We perceive our daily-life surrounded by different senses (e.g., visual, and auditory). For a coherent percept, our brain binds those multiple streams of sensory stimulations, i.e., multisensory integration (MI). Dependent on stimulus complexity, early MI is triggered by bottom-up or late via top-down attentional deployment. Adult attention-deficit/hyperactivity disorder (ADHD) is associated with successful bottom-up MI and deficient top-down MI. In the current study, we investigated the robustness of the bottom-up MI by adding additional task demand varying the perceptual load. We hypothesized diminished bottom-up MI for high perceptual load for patients with ADHD. 18 adult patients with ADHD and 18 age- and gender-matched healthy controls participated in this study. In the visual search paradigm, a target letter was surrounded by uniform distractors (low load) or by different letters (high load). Additionally, either unimodal (visual flash, auditory beep) or multimodal (audiovisual) flanked the visual search. Linear-mixed modeling was used to investigate the influence of load on reaction times. Further, the race model inequality was calculated. Patients with ADHD showed a similar degree of MI performance like healthy controls, irrespective of perceptual load manipulation. ADHD patients violated the race model for the low load but not for the high-load condition. There seems to be robust bottom-up MI independent of perceptual load in ADHD patients. However, the sensory accumulation might be altered when attentional demands are high.

Hyperprolactinemia Associated with Attentional Processing and Interference Control Impairments in Patients with Prolactinomas

The cognitive impairment of pituitary adenomas (PAs) has received increasing attention. Hyperprolactinemia and tumor mass effect are the potential causes. The aim of this study was to identify possible cognitive impairment and to further explore the correlation between these indices and prolactin (PRL) levels, based on the control of tumor size. Twenty-seven patients with prolactinomas (patient group) and twenty-six matched health control group (HC group) were enrolled in this study. All participants performed the flanker task while we continuously recorded electroencephalography data. On the behavioral performance level, patients showed a significantly slower reaction time (RT) in both flanker types. Concerning the event-related potentials level, patients elicited reduced P2 and enhanced N2 amplitudes compared with the HC group, suggesting an impairment of attentional processing (P2) and conflict monitoring (N2). Moreover, the patient group also induced lower P3 amplitudes relative to the HC group in both types, indicating that there were deficits in attentional resource allocation ability. We also found a significant correlation between the P3 amplitudes and incongruent condition RTs, as well as the subsequent PRL levels in the patient group. In conclusion, this is an innovative study that reveals the impaired cognition abilities in prolactinomas, and also proposes the possible cognitive toxicity of oversecreted PRL levels, which provides evidence for further research on the cognitive decline in PAs.

ASD and ADHD Comorbidity: What Are We Talking About?

According to the scientific literature, 50 to 70% of individuals with autism spectrum disorder (ASD) also present with comorbid attention deficit hyperactivity disorder (ADHD). From a clinical perspective, this high rate of comorbidity is intriguing. What is the real significance of this dual diagnosis? Is ADHD in fact always present in such cases? Might the attentional impairment reported among our ASD patients actually be a distinct trait of their ASD-namely, impaired joint attention-rather than an ADHD attention deficit? Could their agitation be the consequence of this joint attention impairment or related to a physical restlessness etiologically very different from the agitation typical of ADHD? The neurobiological reality of ASD-ADHD comorbidity is a subject of debate, and amphetamine-based treatment can have paradoxical or undesirable effects in the ASD population. Consequently, does a dual diagnosis, notwithstanding its currency in the literature, prevent us from shedding sufficient light on major physiopathologic questions raised by the clinical picture of ASD?

P300 Event-Related Potentials Mediate the Relationship Between Child Physical Abuse and Externalizing Behavior

The psychophysiological mechanism linking early childhood experiences to behavior problems remains unclear. This study aimed to examine the association of child physical abuse with P300 event-related potentials (ERP), and to test the mediating effect of P300 amplitude and latency in the relationship between child physical abuse and externalizing behaviors. Cross-sectional secondary data were obtained from 155 children (55.5% boys, mean age: 11.28 ± 0.57 years) who participated in the China Jintan Child Cohort Study. Children self-reported maternal and paternal physical abuse and externalizing behaviors, as well as P300 were obtained in 2013. Additionally, parents and teachers reported child externalizing behaviors in preschool in 2007. P300 were recorded during a standard novel auditory oddball task. Path analysis shows that after controlling for child sex, socioeconomic status, area of residence, IQ, and child externalizing behavior in preschool, children exposed to maternal physical abuse exhibited increased novelty P300 amplitude, which links to more externalizing behavior. Novelty P300 amplitude partially mediated the relationship between maternal physical abuse and externalizing behavior. These findings are the first to document the partial mediating effect of P300 amplitude on the abuse-externalizing relationship and are consistent with the view that physical abuse affects the attention bias to novel cues that likely places them at increased risk for the development and maintenance of externalizing behavior.

On the physiology of cognitive decline in type 1 diabetes

OBJECTIVES

Type 1 diabetes mellitus (T1DM) may be associated with cognitive impairment and notably a decline in psychomotor speed, information processing speed and attention. The mechanism for this decline is uncertain. Previous studies by our group and others have demonstrated a decline in EEG-power and event-related potential amplitude in T1DM. The objectives of the present study were to explore whether 1) the association between event-related potential (N100) amplitude and psychomotor speed is different between T1DM and healthy subjects, and 2) the decline in N100 amplitude depends on duration of diabetes.

METHODS

Patients with T1DM (N = 204) and healthy control subjects (N = 358) were included in a cross-sectional study. Event-related brain potentials were recorded with auditory reaction tasks. Psychomotor speed was evaluated with the Grooved Pegboard test in a subset of the patients (N = 70) and the healthy control subjects (N = 89).

RESULTS

Patients with T1DM had a decrease in the N100 amplitude that correlated with a decline in psychomotor speed, longer duration of diabetes and increasing age. In healthy controls, the N100 amplitude did not decrease with age and the association between psychomotor speed and N100 amplitude was absent.

CONCLUSION

The association between psychomotor speed and N100 amplitude is likely to be a specific trait for T1DM since it was not found in healthy controls and was dependent on diabetes duration. Our findings indicate that the pathogenesis of cognitive decline in T1DM may involve a disease-related factor with a long-term influence on the N100 amplitude.

FUNCTIONAL NEUROMARKERS IN PARKINSON’S DISEASE (PD)

New neurotechnologies which help to study not only the structure but also brain work, especially in milliseconds, allow for a more accurate diagnosis of a given disease entity. The aim of our study was to characterize the functional neuromarkers, including a new neuromarker, that is high rolandic beta, in Parkinson’s disease (PD). A 76-year-old male patient, a university professor, a widower, in an intimate relationship with a beloved partner, was tested in the Reintegration and Training Center of the Polish Society of Neuropsychology. Five years earlier (when he was 71 years old), following long-term stress, he had had a transient ischemic attack (TIA). In the following years he experienced two neurological episodes, and was diagnosed, on the basis of MRI findings and clinical symptoms, with vascular (multi-infarct) Parkinsonism. A sudden deterioration in his functioning, including hand tremors at rest, bradykinesia (motor slowdown), asymmetrical gait difficulties, postural instability, and falls typical for PD, as well as MRI finding (the appearance of ‘a swallow tail ’ on the left side, and the lack on the right of the substantia nigra within the midbrain) was the cause of further differential diagnosis. He was assessed using the HBI methodology (Kropotov 2016; Pąchalska, Kaczmarek, Kropotov 2014). EEG was recorded from 19 scalp sites, in resting state conditions, with eyes open and eyes closed, and during the cued GO/NOGO tasks with animal/plants as GO/NOGO stimuli. The electrodes were applied according to the International 10-20 system. The EEG was recorded referentially to linked ears, allowing for a computational re-referencing of the data (remontaging). Event related potentials (ERPs) were used to assess the functional changes manifested by the patient. To compare our patient with healthy controls we used the normative Human Brain Index (HBI), a database obtained through joint research by Swiss, Norwegian, Polish and Russian neuroscientists (Kropotov 2018). This database included behavioral parameters and ERP measures in 6 different neuropsychological tasks for 1000 healthy subjects. What is striking, no signs of cognitive dysfunction was found; however observed were an asymmetrical frontal lobe alpha (a neuromarker of depression) and excessive Rolandic beta (a neuromarker of Parkinson’s disease). We will discuss the results on the basis of recent subject literature findings, including the personal factors that might influenced the process of the diagnosis and treatment of this patient, ones which should be also taken into account in any differential diagnosis. The obtained results show the importance of using HBI methodology in clinical practice. Physicians involved in the diagnosis and treatment of those with progressive ambulatory impairment and an abnormal white matter (WM) signal on neuroimaging, should when formulating any differential diagnosis consider the use of this approach. ------------------------------------------------------------------------------------------------------------------------------------

EEG event related potentials in sustained, focused and divided attention tasks: Potential biomarkers for cognitive impairment in HIV patients

OBJECTIVES

The objective of this study was to assess the usability of event-related-potentials (ERPs) during sustained, focused, and divided attention tasks as biomarkers for cognitive decline in HIV patients.

METHODS

EEG was acquired using a mobile/wireless 9-channel system in 39 persons with HIV, with well-controlled immune function and 63 healthy control participants (HCs) during three ERP tasks: sustained attention, focused attention, and divided attention.

RESULTS

The HIV-group evidenced smaller late positive potential (LPP) and larger P200 amplitudes across the tasks compared to the HC group. P200 amplitude was correlated (r = 0.56) with the estimated duration of infection. Both groups showed higher P200 and LPP amplitudes in response to infrequent stimuli; this effect was not significantly different between groups. In the sustained attention task, the HIV-group showed significantly slower reaction time than controls while maintaining the same level of accuracy. In the divided attention task, the HIV-group showed a trend towards faster/less accurate responses.

CONCLUSIONS

HIV seropositive participants receiving anti-retroviral treatment (ART) demonstrated significantly larger P200 amplitude during three different attention tasks. This may reflect attentional deficits characterized by over-attending to non-target/distracting stimuli.

SIGNIFICANCE

These findings demonstrate the potential benefits of EEG-ERP metrics derived from attention tasks as neurocognitive biomarkers for HIV. This approach may reveal underlying causes of attentional deficits in HIV patients.

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.

Neuropsychological Deficits in Adult ADHD: Evidence for Differential Attentional Impairments, Deficient Executive Functions, and High Self-Reported Functional Impairments

Objective: This study is aimed to investigate neuropsychological deficits in adult ADHD. Method: Neuropsychological deficits in terms of executive functions, divided, selective, and sustained attention, were investigated in a group of adults with ADHD using a series of neuropsychological tests as well as electroencephalography (EEG). Subjective ratings of everyday life attention and memory problems were also collected. Results: Adults with ADHD showed impairments in executive functions, divided attention and sustained attention, compared with adult controls. Performance on selective attention tasks in adults with ADHD was instead no different from control participants' performance. EEG results confirmed neuropsychological findings by showing a selective impairment on P3 event-related potential (ERP) amplitude indicative of sustained attention deficits. Higher subjective ratings of everyday attentional and memory problems were also found in the ADHD group compared with the control group. Conclusion: This pattern of results suggests differential impairments of attentional skills. Impaired executive functions and higher subjective functional impairments were also found.

Impaired early information processing in adult ADHD: a high-density ERP study

BACKGROUND

Children with attention-deficit/hyperactivity disorder (ADHD) often demonstrate sensory processing difficulties in the form of altered sensory modulation, which may contribute to their symptomatology. Our objective was to investigate the neurophysiological correlates of sensory processing deficits and the electrophysiological characteristics of early information processing in adult ADHD, measured by the P1 event-related potential (ERP).

METHODS

We obtained ERPs during a Go/NoGo task from 26 adult patients with ADHD and 25 matched controls using a high-density 128-channel BioSemi ActiveTwo recording system.

RESULTS

ADHD patients had a significantly reduced P1 component at occipital and inferotemporal scalp areas compared to controls. The reduction was associated with inattention and hyperactivity symptom severity, as measured by the Conners' Adult ADHD Rating Scale. ADHD patients with higher inattention scores had significantly smaller P1 amplitudes at posterior scalp sites, while higher hyperactivity scores were associated with higher P1 amplitudes.

CONCLUSIONS

Deficits in early sensory processing, as measured by the P1 ERP component, are present in adult ADHD patients and are associated with symptom severity. These findings are suggestive of bottom-up cognitive deficits in ADHD driven by impairments in early visual processing, and provide evidence that sensory processing problems are present at the neurophysiological level in this population.

A step forward in the quest for a mobile EEG-designed epoch for psychophysiological studies

The aim of this study was to compare a reconfigurable mobile electroencephalography (EEG) system (M-EMOTIV) based on the Emotiv Epoc® (which has the ability to record up to 14 electrode sites in the 10/20 International System) and a commercial, clinical-grade EEG system (Neuronic MEDICID-05®), and then validate the rationale and accuracy of recordings obtained with the prototype proposed. In this approach, an Emotiv Epoc® was modified to enable it to record in the parieto-central area. All subjects (15 healthy individuals) performed a visual oddball task while connected to both devices to obtain electrophysiological data and behavioral responses for comparative analysis. A Pearson's correlation analysis revealed a good between-devices correlation with respect to electrophysiological measures. The present study not only corroborates previous reports on the ability of the Emotiv Epoc® to suitably record EEG data but presents an alternative device that allows the study of a wide range of psychophysiological experiments with simultaneous behavioral and mobile EEG recordings.

Neural Correlates of Working Memory Deficits in Different Adult Outcomes of ADHD: An Event-Related Potential Study

BACKGROUND

We investigated working memory (WM) processing in a longitudinal sample of young adults with persistent and remittent childhood-onset ADHD to investigate the neural correlates of working memory with adult outcomes of ADHD.

METHODS

Forty-seven young Chinese adults who had been diagnosed with ADHD during childhood underwent follow-up assessments for an average of 9 years. The ADHD sample consisted of 25 ADHD persisters (mean age =18.38 ± 0.5 years) and 22 remitters (mean age = 18.78 ± 1.10 years), who were compared with 25 sex ratio- and IQ-matched healthy adults (mean age = 19.60 ± 1.22 years) in a verbal n-back task.

RESULTS

No differences in behavioral measures were observed across the three groups. Compared with the healthy controls, the ADHD persisters and remitters had larger N1 amplitudes and smaller P2 amplitudes, while no significant differences between the persistence and remission groups were observed. The P3 amplitudes of the remission and control groups were higher than that of the persistence group, but there was no significant difference between the remitters and healthy controls.

CONCLUSION

The P3 amplitudes reflecting postdecisional processing and/or WM updating were sensitive to ADHD remission, as they might improve concurrently with ADHD symptoms. These results indicate that the N1, P2, and P3 components of WM processing might be potential biomarkers for different ADHD outcomes.

Event-Related Potential Analysis of ADHD and Control Adults During a Sustained Attention Task

Background. Event-related potentials (ERPs) of attention deficit hyperactivity disorder (ADHD) population have been extensively studied using the time-domain representation of signals but time-frequency domain techniques are less explored. Although, adult ADHD is a proven disorder, most of the electrophysiological studies have focused only on children with ADHD. Methods. ERP data of 35 university students with ADHD and 35 control adults were recorded during visual continuous performance task (CPT). Gray level co-occurrence matrix-based texture features were extracted from time-frequency (t-f) images of event-related EEG epochs. Different ERP components measures, that is, amplitudes and latencies corresponding to N1, N2, and P3 components were also computed relative to standard and target stimuli. Results. Texture analysis has shown that the mean value of contrast, dissimilarity, and difference entropy is significantly reduced in adults with ADHD than in control adults. The mean correlation and homogeneity in adults with ADHD were significantly increased as compared with control adults. ERP components analysis has reported that adults with ADHD have reduced N1 amplitude to target stimuli, reduced N2 and P3 amplitude to both standard and target stimuli than controls. Conclusions. The differences in texture features obtained from t-f images of ERPs point toward altered information processing in adults with ADHD during a cognitive task. Findings of reduction in N1, N2, and P3 components highlight deficits of early sensory processing, stimulus categorization, and attentional resources, respectively, in adults with ADHD.

Examining individual differences in reading and attentional control networks utilizing an oddball fMRI task

The aim of the current study was to develop an fMRI task capable of characterizing individual differences in reading and attentional domains. Forty-nine students with a range of reading and attentional control abilities completed an event-related fMRI oddball task consisting of printed word and false font stimuli. Reading network activation was assessed by contrasting printed words with false font stimuli. Left inferior frontal gyrus and superior/middle temporal gyrus showed a main effect of stimulus type. The magnitude of the difference in activation between words and false font was correlated with word reading for both regions and reading fluency for superior/middle temporal gyrus. Regions including bilateral middle cingulate, insula and right inferior frontal gyrus showed a main effect of trial type. The difference in activation between oddball and standard trials in the right superior/middle temporal gyrus and left cerebellum was correlated with attentional control measures. Results indicate the task tapped both reading and attentional control resources. Understanding the contribution of the neural networks supporting each of these domains may provide insight into the shared neural deficits underlying the co-morbidity between developmental dyslexia and attention deficit hyperactivity disorder.

Overlaps and distinctions between attention deficit/hyperactivity disorder and autism spectrum disorder in young adulthood: Systematic review and guiding framework for EEG-imaging research

Attention deficit/hyperactivity disorders (ADHD) and autism spectrum disorders (ASD) frequently co-occur. However, we know little about the neural basis of the overlaps and distinctions between these disorders, particularly in young adulthood - a critical time window for brain plasticity across executive and socioemotional domains. Here, we systematically review 75 articles investigating ADHD and ASD in young adult samples (mean ages 16-26) using cognitive tasks, with neural activity concurrently measured via electroencephalography (EEG) - the most accessible neuroimaging technology. The majority of studies focused on event-related potentials (ERPs), with some beginning to capitalise on oscillatory approaches. Overlapping and specific profiles for ASD and ADHD were found mainly for four neurocognitive domains: attention processing, performance monitoring, face processing and sensory processing. No studies in this age group directly compared both disorders or considered dual diagnosis with both disorders. Moving forward, understanding of ADHD, ASD and their overlap in young adulthood would benefit from an increased focus on cross-disorder comparisons, using similar paradigms and in well-powered samples and longitudinal cohorts.

Early Posterior Negativity as Facial Emotion Recognition Index in Children With Attention Deficit Hyperactivity Disorder

Introduction

Studies indicate that children with Attention Deficit Hyperactivity Disorder (ADHD) have deficits in social and emotional functions. It can be hypothesized that these children have some deficits in early stages of facial emotion discrimination. Based on this hypothesis, the present study investigated neural correlates of early visual processing during emotional face recognition in this group compared with typically developing children using the Event-Related Potentials (ERPs).

Methods

Nineteen boys between the ages of 7 and 11 years diagnosed with ADHD (Combined type) based on DSM-IV-TR classification were compared with 19 typically developing children matched on age and gender. The participants performed an emotional face recognition task while their brain activities were recorded using the event-related potentials procedure.

Results

A significant reduction in the Early Posterior Negativity (EPN) for happy and angry faces has been revealed in ADHD children compared to normal ones (P<0.05).

Conclusion

The present study supports the notion that individuals with ADHD have some impairments in early stage of emotion processing which can leading to their misinterpretation of emotion in faces.

Event-Related Potentials during a Gambling Task in Young Adults with Attention-Deficit/Hyperactivity Disorder

Attention-deficit hyperactivity disorder (ADHD) is characterized by deficits in executive functions and decision making during childhood and adolescence. Contradictory results exist whether altered event-related potentials (ERPs) in adults are associated with the tendency of ADHD patients toward risky behavior. Clinically diagnosed ADHD patients (n = 18) and healthy controls (n = 18), aged between 18 and 29 (median 22 Yo), were screened with the Conners' Adult ADHD Rating Scales and assessed by the Mini-International Neuropsychiatric Interview, adult ADHD Self-Report Scale, and by the 60-item HEXACO Personality Inventory. The characteristic personality traits of ADHD patients were the high level of impulsiveness associated with lower values of agreeableness. All participants performed a probability gambling task (PGT) with two frequencies of the feedback information of the outcome. For each trial, ERPs were triggered by the self-paced trial onset and by the gamble selection. After trial onset, N2-P3a ERP component associated with the attentional load peaked earlier in the ADHD group than in controls. An N500 component related to the feedback frequency condition after trial onset and an N400-like component after gamble selection suggest a large affective stake of the decision making and an emphasized post-decisional evaluation of the choice made by the ADHD participants. By combining ERPs, related to the emotions associated with the feedback frequency condition, and behavioral analyses during completion of PGT, this study provides new findings on the neural dynamics that differentiate controls and young ADHD adults. In the patients' group, we raise the hypothesis that the activity of frontocentral and centroparietal neural circuits drive the decision-making processes dictated by an impaired cognitive workload followed by the build-up of large emotional feelings generated by the conflict toward the outcome of the gambling choice. Our results can be used for new investigations aimed at studying the fine spatiotemporal distribution of cortical activity, and the neural circuits that underly the generation of that activity, associated with the behavioral deficits characteristic of ADHD.

Shared and Disorder-Specific Event-Related Brain Oscillatory Markers of Attentional Dysfunction in ADHD and Bipolar Disorder

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) often present with overlapping symptoms and cognitive impairments, such as increased fluctuations in attentional performance measured by increased reaction-time variability (RTV). We previously provided initial evidence of shared and distinct event-related potential (ERP) impairments in ADHD and BD in a direct electrophysiological comparison, but no study to date has compared neural mechanisms underlying attentional impairments with finer-grained brain oscillatory markers. Here, we aimed to compare the neural underpinnings of impaired attentional processes in ADHD and BD, by examining event-related brain oscillations during a reaction-time task under slow-unrewarded baseline and fast-incentive conditions. We measured cognitive performance, ERPs and brain-oscillatory modulations of power and phase variability in 20 women with ADHD, 20 women with BD (currently euthymic) and 20 control women. Compared to controls, both ADHD and BD groups showed increased RTV in the baseline condition and increased RTV, theta phase variability and lower contingent negative variation in the fast-incentive condition. Unlike controls, neither clinical group showed an improvement from the slow-unrewarded baseline to the fast-incentive condition in attentional P3 amplitude or alpha power suppression. Most impairments did not differ between the disorders, as only an adjustment in beta suppression between conditions (lower in the ADHD group) distinguished between the clinical groups. These findings suggest shared impairments in women with ADHD and BD in cognitive and neural variability, preparatory activity and inability to adjust attention allocation and activation. These overlapping impairments may represent shared neurobiological mechanisms of attentional dysfunction in ADHD and BD, and potentially underlie common symptoms in both disorders.

Aging Effect on Audiovisual Integrative Processing in Spatial Discrimination Task

Multisensory integration is an essential process that people employ daily, from conversing in social gatherings to navigating the nearby environment. The aim of this study was to investigate the impact of aging on modulating multisensory integrative processes using event-related potential (ERP), and the validity of the study was improved by including “noise” in the contrast conditions. Older and younger participants were involved in perceiving visual and/or auditory stimuli that contained spatial information. The participants responded by indicating the spatial direction (far vs. near and left vs. right) conveyed in the stimuli using different wrist movements. electroencephalograms (EEGs) were captured in each task trial, along with the accuracy and reaction time of the participants’ motor responses. Older participants showed a greater extent of behavioral improvements in the multisensory (as opposed to unisensory) condition compared to their younger counterparts. Older participants were found to have fronto-centrally distributed super-additive P2, which was not the case for the younger participants. The P2 amplitude difference between the multisensory condition and the sum of the unisensory conditions was found to correlate significantly with performance on spatial discrimination. The results indicated that the age-related effect modulated the integrative process in the perceptual and feedback stages, particularly the evaluation of auditory stimuli. Audiovisual (AV) integration may also serve a functional role during spatial-discrimination processes to compensate for the compromised attention function caused by aging.

Emotional Face Recognition in Children With Attention Deficit/Hyperactivity Disorder: Evidence From Event Related Gamma Oscillation

Introduction

Children with attention-deficit/hyperactivity disorder (ADHD) have some impairment in emotional relationship which can be due to problems in emotional processing. The present study investigated neural correlates of early stages of emotional face processing in this group compared with typically developing children using the Gamma Band Activity (GBA).

Methods

A total of 19 children diagnosed with ADHD (Combined type) based on DSM-IV classification were compared with 19 typically developing children matched on age, gender, and IQ. The participants performed an emotional face recognition while their brain activities were recorded using an event-related oscillation procedure.

Results

The results indicated that ADHD children compared to normal group showed a significant reduction in the gamma band activity, which is thought to reflect early perceptual emotion discrimination for happy and angry emotions (P<0.05).

Conclusion

The present study supports the notion that individuals with ADHD have some impairments in early stage of emotion processing which can cause their misinterpretation of emotional faces.

An event related potential study of ihibitory and attentional control in Williams syndrome adults

The primary aim of the current study was to employ event-related potentials (ERPs) methodology to disentangle the mechanisms related to inhibitory control in older adults with Williams syndrome (WS). Eleven older adults with WS (mean age 42), 16 typically developing adults (mean age 42) and 13 typically developing children (mean age 12) participated in the study. ERPs were recorded during a three-stimulus visual oddball task, during which participants were required to make a response to a rare target stimulus embedded in a train of frequent non-target stimuli. A task-irrelevant infrequent stimulus was also present at randomised intervals during the session. The P3a latency data response related to task-irrelevant stimulus processing was delayed in WS. In addition, the early perceptual N2 amplitude was attenuated. These data are indicative of compromised early monitoring of perceptual input, accompanied by appropriate orientation of responses to task-irrelevant stimuli. However, the P3a delay suggests inefficient evaluation of the task-irrelevant stimuli. These data are discussed in terms of deficits in the disengagement of attentional processes, and the regulation of monitoring processes required for successful inhibition.

Executive function and neural activation in adults with β-thalassemia major: an event-related potentials study

In recent years, there has been growing interest in understanding the involvement of the nervous system and neurological complications in β-thalassemia major (β-TM). Several reports have demonstrated β-TM-related neurological abnormalities, and these have been postulated to be responsible for impaired cognitive and neuropsychological functioning. We investigated neural correlates of cognitive function in adults with β-TM and healthy controls using scalp-recorded event-related potentials (ERPs). To date, there have been no ERP studies in β-TM adult patients. We identified ERP correlates of executive function by using a complex task-switching paradigm in which participants have to quickly and effectively switch between two different task sets. The results indicated poorer cognitive performance of β-TM patients, resulting in overall higher error rates, longer response times, and increased switch costs compared with controls. Hemoglobin levels were negatively correlated with error rates and response times. Electrophysiological results indicated significant alterations in peak amplitudes of the ERP components P1, N1, and P2 in β-TM patients relative to controls. P2 amplitude correlated with hemoglobin levels. This novel investigation of executive function and related brain mechanisms and dynamics in adults with β-TM underscores the usefulness of ERP methodology as a sensitive measure for the study of neurocognitive processes in β-TM.

Neurofeedback Therapy for Enhancing Visual Attention: State-of-the-Art and Challenges

We have witnessed a rapid development of brain-computer interfaces (BCIs) linking the brain to external devices. BCIs can be utilized to treat neurological conditions and even to augment brain functions. BCIs offer a promising treatment for mental disorders, including disorders of attention. Here we review the current state of the art and challenges of attention-based BCIs, with a focus on visual attention. Attention-based BCIs utilize electroencephalograms (EEGs) or other recording techniques to generate neurofeedback, which patients use to improve their attention, a complex cognitive function. Although progress has been made in the studies of neural mechanisms of attention, extraction of attention-related neural signals needed for BCI operations is a difficult problem. To attain good BCI performance, it is important to select the features of neural activity that represent attentional signals. BCI decoding of attention-related activity may be hindered by the presence of different neural signals. Therefore, BCI accuracy can be improved by signal processing algorithms that dissociate signals of interest from irrelevant activities. Notwithstanding recent progress, optimal processing of attentional neural signals remains a fundamental challenge for the development of efficient therapies for disorders of attention.

Underarousal in Adult ADHD: How Are Peripheral and Cortical Arousal Related?

In children and adults with attention deficit/hyperactivity disorder (ADHD), a general slowing of spontaneous electroencephalographic (EEG) brain activity and a decrease of event-related potential amplitudes such as the contingent negative variation (CNV) are observed. Additionally, some studies have reported decreased skin conductance level (SCL) in this clinical population leading to the hypothesis of a peripheral hypoarousal, which may be a target of biofeedback treatment in addition to or instead of neurofeedback. To our knowledge, the relationship between SCL and CNV has not been simultaneously investigated in one experiment. Using the theoretical background of the hypoarousal model, this article aims to gain more insight into the differences and correlations of cortical (CNV) and peripheral (SCL) arousal in adults with ADHD. A sample of 23 adults with ADHD and 22 healthy controls underwent an auditory Go-NoGo task with simultaneous 22-channel EEG and SCL recordings. Reaction time (RT) and reaction time variability (RTV) were also measured to assess task performance. Significantly decreased CNV amplitude and significantly higher RTV were observed in the ADHD group, reflecting cortical underarousal and problems with sustained attention. No significant correlation between peripheral underarousal and cortical underarousal was observed in the ADHD group or the control group. The observed cortical underarousal reflected in the decreased CNV supports the notion of a reduced CNV amplitude as a possible biomarker for ADHD. However, the connection between cortical and peripheral arousal is not as clear as is suggested in previous research investigating both separately. Implications of these results for new treatment options for ADHD such as biofeedback are discussed.

Attention-related EEG markers in adult ADHD

ADHD status affects both bottom-up sensory processing and top-down attentional selection, impairing professional and social functioning. The objective of the study was to investigate the functional mechanisms of attention deficits in adult ADHD by examining the electrophysiological activities associated with bottom-up attentional cueing (temporal and spatial orienting of attention) and top-down control (conflict resolution). Continuous EEG was recorded in 21 adult ADHD patients (40.05±9.5 years) and 20 healthy adults (25.5±4 years) during performance of the Attention Network Test (ANT). We examined the cue and target-related P1, N1 and P3 components as well as the contingent negative variation (CNV) developing between cue and target. Oscillatory responses were analyzed in the alpha (8-13Hz) and beta (14-19Hz) frequency bands. ADHD patients performed similarly to controls but showed reduced P3 amplitude, larger early CNV decrementing over time, reduced preparatory activation in both alpha and beta bands, as well as flattened target-related posterior alpha and beta responses. As compared to controls, the inverted CNV pattern suggested peculiar preparatory processing in ADHD patients. The singular pattern of target-related beta response indicated increased inhibitory processes in the case of easier task resolution and more generally, the lack of association between conflict resolution speed and beta activity supported alternative executive processing in ADHD patients. Overall, the reduced activation of the functional networks devoted to bottom-up and top-down attention suggests that adult ADHD patients engage reduced cortical resources in this composite task, compatible with the cortical hypoarousal model.

Disorder-specific and shared neurophysiological impairments of attention and inhibition in women with attention-deficit/hyperactivity disorder and women with bipolar disorder

BACKGROUND

In adults, attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) have certain overlapping symptoms, which can lead to uncertainty regarding the boundaries of the two disorders. Despite evidence of cognitive impairments in both disorders separately, such as in attentional and inhibitory processes, data on direct comparisons across ADHD and BD on cognitive-neurophysiological measures are as yet limited.

METHOD

We directly compared cognitive performance and event-related potential measures from a cued continuous performance test in 20 women with ADHD, 20 women with BD (currently euthymic) and 20 control women.

RESULTS

The NoGo-N2 was attenuated in women with BD, reflecting reduced conflict monitoring, compared with women with ADHD and controls (both p < 0.05). Both ADHD and BD groups showed a reduced NoGo-P3, reflecting inhibitory control, compared with controls (both p < 0.05). In addition, the contingent negative variation was significantly reduced in the ADHD group (p = 0.05), with a trend in the BD group (p = 0.07), compared with controls.

CONCLUSIONS

These findings indicate potential disorder-specific (conflict monitoring) and overlapping (inhibitory control, and potentially response preparation) neurophysiological impairments in women with ADHD and women with BD. The identified neurophysiological parameters further our understanding of neurophysiological impairments in women with ADHD and BD, and are candidate biomarkers that may aid in the identification of the diagnostic boundaries of the two disorders.

Neurofeedback as a nonpharmacological treatment for adults with attention-deficit/hyperactivity disorder (ADHD): study protocol for a randomized controlled trial

BACKGROUND

Neurofeedback has been applied effectively in various areas, especially in the treatment of children with attention-deficit/hyperactivity disorder (ADHD). This study protocol is designed to investigate the effect of slow cortical potential (SCP) feedback and a new form of neurofeedback using near-infrared spectroscopy (NIRS) on symptomatology and neurophysiological parameters in an adult ADHD population. A comparison of SCP and NIRS feedback therapy methods has not been previously conducted and may yield valuable findings about alternative treatments for adult ADHD.

METHODS/DESIGN

The outcome of both neurofeedback techniques will be assessed over 30 treatment sessions and after a 6-month follow-up period, and then will be compared to a nonspecific biofeedback treatment. Furthermore, to investigate if treatment effects in this proof-of-principle study can be predicted by specific neurophysiological baseline parameters, regression models will be applied. Finally, a comparison with healthy controls will be conducted to evaluate deviant pretraining neurophysiological parameters, stability of assessment measures, and treatment outcome.

DISCUSSION

To date, an investigation and comparison of SCP and NIRS feedback training to an active control has not been conducted; therefore, we hope to gain valuable insights in effects and differences of these types of treatment for ADHD in adults.

TRIAL REGISTRATION

This study is registered with the German Registry of Clinical Trials: DRKS00006767 , date of registration: 8 October 2014.

Neuropharmacological effect of atomoxetine on attention network in children with attention deficit hyperactivity disorder during oddball paradigms as assessed using functional near-infrared spectroscopy

The current study aimed to explore the neural substrate for atomoxetine effects on attentional control in school-aged children with attention deficit hyperactivity disorder (ADHD) using functional near-infrared spectroscopy (fNIRS), which can be applied to young children with ADHD more easily than conventional neuroimaging modalities. Using fNIRS, we monitored the oxy-hemoglobin signal changes of 15 ADHD children (6 to 14 years old) performing an oddball task before and 1.5 h after atomoxetine or placebo administration, in a randomized, double-blind, placebo-controlled, crossover design. Fifteen age-, gender-, and intelligence quotient-matched normal controls without atomoxetine administration were also monitored. In the control subjects, the oddball task recruited the right prefrontal and inferior parietal cortices. The right prefrontal and parietal activation was normalized after atomoxetine administration in ADHD children. This was in contrast to our previous study using a similar protocol showing methylphenidate-induced normalization of only the right prefrontal function. fNIRS allows the detection of differential neuropharmacological profiles of both substances in the attentional network: the neuropharmacological effects of atomoxetine to upregulate the noradrenergic system reflected in the right prefrontal and inferior parietal activations and those of methylphenidate to upregulate the dopamine system reflected in the prefrontal cortex activation.

Event related potentials study of aberrations in voice control mechanisms in adults with attention deficit hyperactivity disorder

OBJECTIVE

The present study was designed to test for neural signs of impulsivity related to voice motor control in young adults with ADHD using EEG recordings in a voice pitch perturbation paradigm.

METHODS

Two age-matched groups of young adults were presented with brief pitch shifts of auditory feedback during vocalization. Compensatory behavioral and corresponding bioelectrical brain responses were elicited by the pitch-shifted voice feedback.

RESULTS

The analysis of bioelectrical responses showed that the ADHD group had shorter peak latency and onset time of motor-related bioelectrical brain responses as compared to the controls.

CONCLUSIONS

These results were interpreted to suggest differences in executive functions between ADHD and control participants.

SIGNIFICANCE

We hypothesize that more rapid motor-related bioelectrical responses found in the present study may be a manifestation of impulsiveness in adults with ADHD at the involuntary level of voice control.

Comparison of auditory and visual oddball fMRI in schizophrenia

Individuals with schizophrenia often suffer from attentional deficits, both in focusing on task-relevant targets and in inhibiting responses to distractors. Schizophrenia also has a differential impact on attention depending on modality: auditory or visual. However, it remains unclear how abnormal activation of attentional circuitry differs between auditory and visual modalities, as these two modalities have not been directly compared in the same individuals with schizophrenia. We utilized event-related functional magnetic resonance imaging (fMRI) to compare patterns of brain activation during an auditory and visual oddball task in order to identify modality-specific attentional impairment. Healthy controls (n=22) and patients with schizophrenia (n=20) completed auditory and visual oddball tasks in separate sessions. For responses to targets, the auditory modality yielded greater activation than the visual modality (A-V) in auditory cortex, insula, and parietal operculum, but visual activation was greater than auditory (V-A) in visual cortex. For responses to novels, A-V differences were found in auditory cortex, insula, and supramarginal gyrus; and V-A differences in the visual cortex, inferior temporal gyrus, and superior parietal lobule. Group differences in modality-specific activation were found only for novel stimuli; controls showed larger A-V differences than patients in prefrontal cortex and the putamen. Furthermore, for patients, greater severity of negative symptoms was associated with greater divergence of A-V novel activation in the visual cortex. Our results demonstrate that patients have more pronounced activation abnormalities in auditory compared to visual attention, and link modality specific abnormalities to negative symptom severity.

Influence of stimulant and non-stimulant drug treatment on driving performance in patients with attention deficit hyperactivity disorder: a systematic review

Adults with Attention Deficit Hyperactivity Disorder (ADHD), especially teenagers and young adults, show important car driving impairments, including risky driving, accidents, fines and suspension of driver׳s license. We systematically reviewed the efficacy of stimulant and non-stimulant drugs on driving performance of ADHD patients. We searched several databases for randomized controlled trials (RCTs) published through March, 2013. Fifteen RCTs (the majority with crossover design) evaluated methylphenidate (MPH) immediate-release (MPH-IR), MPH osmotic-controlled oral system (MPH-OROS), MPH transdermal system (MTS), extended-release mixed amphetamine salts (MAS-XR); atomoxetine (ATX) and lisdexamfetamine (LDX). Methods varied widely; including simulators and/or cars and different courses and scenarios. Various outcomes of driving performance, including a 'composite' or 'overall' driving score were considered. In general, stimulants improved driving performance in ADHD patients (either in RCTs conducted in simulators and/or cars). MPH-OROS improved driving performance compared with MAS-XR, placebo, or no-drug conditions. Although MPH-OROS and MPH-IR produced similar improvements during the day, MPH-IR lost its efficacy in the evening. MAS-XR also improved driving performance, but worsened driving performance in the evening. MTS (one study) showed a positive effect, but drug compliance varied widely across patients. LDX had positive effect on driving (two studies with the same sample). Studies with ATX report conflicting results. Improvement was more consistent in teenagers and young adults. In general, treatment with psychostimulants or ATX in therapeutic dosages had no negative impact on driving performance of ADHD patients. To conclude, treatment with stimulants in therapeutic doses improves driving performance in ADHD patients, especially teenagers and young adults.

Neuropharmacological effect of methylphenidate on attention network in children with attention deficit hyperactivity disorder during oddball paradigms as assessed using functional near-infrared spectroscopy

The current study aimed to explore the neural substrate for methylphenidate effects on attentional control in school-aged children with attention deficit hyperactivity disorder (ADHD) using functional near-infrared spectroscopy (fNIRS), which can be applied to young children with ADHD more easily than conventional neuroimaging modalities. Using fNIRS, we monitored the oxy-hemoglobin signal changes of 22 ADHD children (6 to 14 years old) performing an oddball task before and 1.5 h after methylphenidate or placebo administration, in a randomized, double-blind, placebo-controlled, crossover design. Twenty-two age- and gender-matched normal controls without methylphenidate administration were also monitored. In the control subjects, the oddball task recruited the right prefrontal and inferior parietal cortices, and this activation was absent in premedicated ADHD children. The reduced right prefrontal activation was normalized after methylphenidate but not placebo administration in ADHD children. These results are consistent with the neuropharmacological effects of methylphenidate to upregulate the dopamine system in the prefrontal cortex innervating from the ventral tegmentum (mesocortical pathway), but not the noradrenergic system from the parietal cortex to the locus coeruleus. Thus, right prefrontal activation would serve as an objective neurofunctional biomarker to indicate the effectiveness of methylphenidate on ADHD children in attentional control. fNIRS monitoring enhances early clinical diagnosis and the treatment of ADHD children, especially those with an inattention phenotype.

Omega-3 fatty acids are related to abnormal emotion processing in adolescent boys with attention deficit hyperactivity disorder

BACKGROUND

In addition to the core symptoms, attention deficit hyperactivity disorder (ADHD) is associated with poor emotion regulation. There is some evidence that children and young adults with ADHD have lower omega-3 levels and that supplementation with omega-3 can improve both ADHD and affective symptoms. We therefore investigated differences between ADHD and non-ADHD children in omega-3/6 fatty acid plasma levels and the relationship between those indices and emotion-elicited event-related potentials (ERPs).

METHODS

Children/adolescents with (n=31) and without ADHD (n=32) were compared in their plasma omega-3/6 indices and corresponding ERPs during an emotion processing task.

RESULTS

Children with ADHD had lower mean omega-3/6 and ERP abnormalities in emotion processing, independent of emotional valence relative to control children. ERP abnormalities were significantly associated with lower omega-3 levels in the ADHD group.

CONCLUSIONS

The findings reveal for the first time that lower omega-3 fatty acids are associated with impaired emotion processing in ADHD children.

Exogenous orienting of visual-spatial attention in ADHD children

Visual spatial orienting of attention towards exogenous cues has been one of the attentional functions considered to be spared in ADHD. Here we present a design in which 60 (30 ADHD) children, age: 10.9±1.4, were asked to covertly orient their attention to one or two (out of four) cued locations, and search for a target stimulus in one of these locations, while recording behavioral responses and EEG/ERP. In all conditions, ADHD children showed delayed reaction times and poorer behavioral performance. They also exhibited larger cue-elicited P2 but reduced CNV in the preparation stage. Larger amplitude of CNV predicted better performance in the task. Target-elicited N1 and selection negativity were also reduced in the ADHD group compared to non-ADHD. Groups also differed in the early and late P3 time-windows. The present results suggest that exogenous orienting of attention could be dysfunctional in ADHD under certain conditions. This limitation is not necessarily caused by an impairment of the orienting process itself, but instead by a difficulty in maintaining the relevant information acquired during the early preparation stage through the target processing stage, when it is really needed.

Evaluation of a neurotherapy program for a child with ADHD with Benign Partial Epilepsy with Rolandic Spikes (BPERS) using event-related potentials

BACKGROUND

We hypothesized that there would be a good response to relative beta training, applied to regulate the dynamics of brain function in a patient with benign partial epilepsy with Rolandic Spikes (BPERS), associated with neuropsychiatric deficits resembling the symptoms of attention deficit-hyperactivity disorder (ADHD).

CASE REPORT

The patient, E.Z., age 9.3, was suffering from neuropsychiatric symptoms, cognitive dysfunction, especially attention deficits, and behavioral changes, rendering him unable to function independently in school and in many situations of everyday life. He was treated for epilepsy, but only slight progress was made. The patient took part in 20 sessions of relative beta training combined with behavioral training. We used standardized neuropsychological testing, as well as ERPs before the experiment and after the completion of the neurotherapy program. Neuropsychological testing at baseline showed multiple cognitive deficits. Over the course of neurotherapy, E.Z.'s verbal and non-verbal IQ increased significantly. His cognitive functions also improved, including immediate and delayed logical and visual recall on the WMS-III, maintaining attention on the WMS-III, and executive functions, but remained below norms. Physiologically, the patient showed substantial changes after neurotherapy, including fewer spikes and an increased P300 NOGO component.

CONCLUSIONS

The cognitive deficits characteristic for ADHD in a child with BPERS may be unresponsive to antiepileptic treatment, but are reversible after a carefully selected neurotherapy program, combined with antiepileptic treatment. Event Related Potentials (ERPs) in the GO/NOGO task can be used to assess functional brain changes induced by neurotherapeutical programs.

Neurophysiological correlates of delinquent behaviour in adult subjects with ADHD

The attention deficit/hyperactivity disorder (ADHD) shows an increased prevalence in arrested offenders compared to the normal population. The aim of the present study was to investigate whether ADHD symptoms are a major risk factor for criminal behaviour, or whether further deficits, mainly abnormalities in emotion-processing, have to be considered as important additional factors that promote delinquency in the presence of ADHD symptomatology. Event related potentials (ERPs) of 13 non-delinquent and 13 delinquent subjects with ADHD and 13 controls were compared using a modified visual Go/Nogo continuous performance task (VCPT) and a newly developed version of the visual CPT that additionally requires emotional evaluation (ECPT). ERPs were analyzed regarding their topographies and Global Field Power (GFP). Offenders with ADHD differed from non-delinquent subjects with ADHD in the ERPs representing higher-order visual processing of objects and faces (N170) and facial affect (P200), and in late monitoring and evaluative functions (LPC) of behavioural response inhibition. Concerning neural activity thought to reflect the allocation of neural resources and cognitive processing capability (P300 Go), response inhibition (P300 Nogo), and attention/expectancy (CNV), deviances were observable in both ADHD groups and may thus be attributed to ADHD rather than to delinquency. In conclusion, ADHD symptomatology may be a risk factor for delinquency, since some neural information processing deficits found in ADHD seemed to be even more pronounced in offenders with ADHD. However, our results suggest additional risk factors consisting of deviant higher-order visual processing, especially of facial affect, as well as abnormalities in monitoring and evaluative functions of response inhibition.

Cognitive training for impaired neural systems in neuropsychiatric illness

Neuropsychiatric illnesses are associated with dysfunction in distributed prefrontal neural systems that underlie perception, cognition, social interactions, emotion regulation, and motivation. The high degree of learning-dependent plasticity in these networks-combined with the availability of advanced computerized technology-suggests that we should be able to engineer very specific training programs that drive meaningful and enduring improvements in impaired neural systems relevant to neuropsychiatric illness. However, cognitive training approaches for mental and addictive disorders must take into account possible inherent limitations in the underlying brain 'learning machinery' due to pathophysiology, must grapple with the presence of complex overlearned maladaptive patterns of neural functioning, and must find a way to ally with developmental and psychosocial factors that influence response to illness and to treatment. In this review, we briefly examine the current state of knowledge from studies of cognitive remediation in psychiatry and we highlight open questions. We then present a systems neuroscience rationale for successful cognitive training for neuropsychiatric illnesses, one that emphasizes the distributed nature of neural assemblies that support cognitive and affective processing, as well as their plasticity. It is based on the notion that, during successful learning, the brain represents the relevant perceptual and cognitive/affective inputs and action outputs with disproportionately larger and more coordinated populations of neurons that are distributed (and that are interacting) across multiple levels of processing and throughout multiple brain regions. This approach allows us to address limitations found in earlier research and to introduce important principles for the design and evaluation of the next generation of cognitive training for impaired neural systems. We summarize work to date using such neuroscience-informed methods and indicate some of the exciting future directions of this field.

Do resting brain dynamics predict oddball evoked-potential?

Background

The oddball paradigm is widely applied to the investigation of cognitive function in neuroscience and in neuropsychiatry. Whether cortical oscillation in the resting state can predict the elicited oddball event-related potential (ERP) is still not clear. This study explored the relationship between resting electroencephalography (EEG) and oddball ERPs. The regional powers of 18 electrodes across delta, theta, alpha and beta frequencies were correlated with the amplitude and latency of N1, P2, N2 and P3 components of oddball ERPs. A multivariate analysis based on partial least squares (PLS) was applied to further examine the spatial pattern revealed by multiple correlations.

Results

Higher synchronization in the resting state, especially at the alpha spectrum, is associated with higher neural responsiveness and faster neural propagation, as indicated by the higher amplitude change of N1/N2 and shorter latency of P2. None of the resting quantitative EEG indices predict P3 latency and amplitude. The PLS analysis confirms that the resting cortical dynamics which explains N1/N2 amplitude and P2 latency does not show regional specificity, indicating a global property of the brain.

Conclusions

This study differs from previous approaches by relating dynamics in the resting state to neural responsiveness in the activation state. Our analyses suggest that the neural characteristics carried by resting brain dynamics modulate the earlier/automatic stage of target detection.

Evaluation of differentiated neurotherapy programs for a patient after severe TBI and long term coma using event-related potentials

BACKGROUND

This article examines the effectiveness of differentiated rehabilitation programs for a patient with frontal syndrome after severe TBI and long-term coma. We hypothesized that there would be a small response to relative beta training, and a good response to rTMS, applied to regulate the dynamics of brain function.

CASE REPORT

M. L-S, age 26, suffered from anosognosia, executive dysfunction, and behavioral changes, after a skiing accident and prolonged coma, rendering him unable to function independently in many situations of everyday life. Only slight progress was made after traditional rehabilitation. The patient took part in 20 sessions of relative beta training (program A) and later in 20 sessions of rTMS (program B); both programs were combined with behavioral training. We used standardized neuropsychological testing, as well as ERPs before the experiment, after the completion of program A, and again after the completion of program B. As hypothesized, patient M.L-S showed small improvements in executive dysfunction and behavioral disorders after the conclusion of program A, and major improvement after program B. Similarly, in physiological changes the patient showed small improvement after relative beta training and a significant improvement of the P300 NOGO component after the rTMS program.

CONCLUSIONS

The rTMS program produced larger physiological and behavioral changes than did relative beta training. A combination of different neurotherapeutical approaches (such as neurofeedback, rTMS, tDCS) can be suggested for similar severe cases of TBI. ERPs can be used to assess functional brain changes induced by neurotherapeutical programs.

Event-related potentials in patients with adult attention-deficit/hyperactivity disorder versus schizophrenia

Event-related potentials (ERPs) such as Nd, N2b, and P300 in an attentional task and an auditory oddball task were compared among 54 adult AD/HD patients, 43 schizophrenic patients (SZ), and 40 healthy age-matched volunteers (HC). It is known that Nd, N2b, and P300 reflect selective attention, voluntary attention, and cognitive context updating respectively. The peak amplitude of P300 was significantly lower in the adult AD/HD and SZ groups than in the HC group. The peak latencies of late Nd, N2b, and P300 were significantly longer in the SZ group than in the HC and adult AD/HD groups. Thus, attenuated amplitude and prolonged latency of various ERP components in the SZ group suggest the possibility of impairment of basic mechanisms underlying cognitive processing. Unlike the SZ group, the adult AD/HD group exhibited reduced amplitude of P300 but not prolonged latency. These findings suggest the existence of a different type of cognitive dysfunction in the adult AD/HD group, which might be closely related to attentional function.