Peak Attention: Focus & Concentration

Early interaction between perceptual load and involuntary attention: An event-related potential study

Whether selective attention affects C1, the first (earliest) visual cortical component of the event-related potential (ERP), remains controversial. We used a cued, involuntary attention task requiring discrimination of targets under low and high levels of perceptual load to examine early attentional modulation in visual cortex. Potential confounds due to physical stimulus differences between load conditions and cue-target sensory interaction were minimized. An interaction between perceptual load and involuntary attention was observed for the P1m component (peak latency between 100 and 140 ms). Furthermore, the parieto-central C1 component (peak latency 80 ms) was modulated by attention, but only under the high-load condition. Thus, whereas attention typically modulates the later P1 component, attentional modulation of C1 is possible under optimal conditions. Specifically, a high perceptual load is necessary for eliciting this earliest attentional effect on cortical processing.

Improvements in Spelling after QEEG-based Neurofeedback in Dyslexia: A Randomized Controlled Treatment Study

Phonological theories of dyslexia assume a specific deficit in representation, storage and recall of phonemes. Various brain imaging techniques, including qEEG, point to the importance of a range of areas, predominantly the left hemispheric temporal areas. This study attempted to reduce reading and spelling deficits in children who are dyslexic by means of neurofeedback training based on neurophysiological differences between the participants and gender and age matched controls. Nineteen children were randomized into an experimental group receiving qEEG based neurofeedback (n = 10) and a control group (n = 9). Both groups also received remedial teaching. The experimental group improved considerably in spelling (Cohen’s d = 3). No improvement was found in reading. An indepth study of the changes in the qEEG power and coherence protocols evidenced no fronto-central changes, which is in line with the absence of reading improvements. A significant increase of alpha coherence was found, which may be an indication that attentional processes account for the improvement in spelling. Consideration of subtypes of dyslexia may refine the results of future studies.

Altered spontaneous low frequency brain activity in Attention Deficit/Hyperactivity Disorder

Background: Resting brain activity appears altered in Attention Deficit/Hyperactivity Disorder (ADHD). The default mode interference hypothesis (Sonuga-Barke and Castellanos, 2007) postulates that patterns of spontaneous very low frequency brain activity, typical of the resting brain, cause attention lapses in ADHD when they remain unattenuated following the transition from rest to active task performance. Here we test this hypothesis using DC-EEG. Methods: DC-EEG recordings of very low frequency brain activity (< 1.5 Hz) were compared for 16 male children with ADHD and 16 healthy controls during both rest and active task performance (two choice reaction time task). Results: A previously identified very low frequency resting network of electrodes was replicated. At rest ADHD children showed less EEG power in very low frequency bands (i.e., .02–.2 Hz). They also showed less attenuation of power at these frequency bands during rest-to-task transition. Reduced attenuation was associated with a number of measures of performance. Discussion: We confirmed the existence of altered very low frequency brain activity in ADHD. ADHD children may have deficits both in maintaining a resting brain when needed and ‘protecting’ an active brain from the intrusion of resting state brain activity.

Efficacy of Neurofeedback Treatment in ADHD: The Effects on Inattention, Impulsivity and Hyperactivity: A Meta-Analysis

Since the first reports of neurofeedback treatment in Attention Deficit Hyperactivity Disorder (ADHD) in 1976, many studies have investigated the effects of neurofeedback on different symptoms of ADHD such as inattention, impulsivity and hyperactivity. This technique is also used by many practitioners, but the question as to the evidence-based level of this treatment is still unclear. In this study selected research on neurofeedback treatment for ADHD was collected and a meta-analysis was performed. Both prospective controlled studies and studies employing a pre-and post-design found large effect sizes (ES) for neurofeedback on impulsivity and inattention and a medium ES for hyperactivity. Randomized studies demonstrated a lower ES for hyperactivity suggesting that hyperactivity is probably most sensitive to nonspecific treatment factors. Due to the inclusion of some very recent and sound methodological studies in this meta-analysis, potential confounding factors such as small studies, lack of randomization in previous studies and a lack of adequate control groups have been addressed, and the clinical effects of neurofeedback in the treatment of ADHD can be regarded as clinically meaningful. Three randomized studies have employed a semi-active control group which can be regarded as a credible sham control providing an equal level of cognitive training and client-therapist interaction. Therefore, in line with the AAPB and ISNR guidelines for rating clinical efficacy, we conclude that neurofeedback treatment for ADHD can be considered “Efficacious and Specific” (Level 5) with a large ES for inattention and impulsivity and a medium ES for hyperactivity.

How Do Trait Dimensions Map onto ADHD Symptom Domains?

Theories of Attention-Deficit/Hyperactivity Disorder (ADHD) implicate dysfunctional regulation mechanisms that have been conceptually grouped into “top-down” control and “bottom-up” affective/reactive processes. This dual-process account can be invoked in relation to temperament or personality traits and may clarify how traits relate to ADHD. Two samples were examined to illuminate developmental effects. The younger sample was 179 youngsters aged 7 to 12 years (113 boys; 107 with ADHD). The older sample was 184 adolescents (109 boys; 87 with ADHD) aged 13 to 18 years. Structural equation models included parent-rated traits, teacher-rated ADHD symptoms, and laboratory-obtained executive functions. A control or “top-down” factor included cognitive control and conscientiousness/effortful control. A second factor labeled affective or “bottom-up” included neuroticism/negative emotionality, agreeableness, and reactive control. In the younger sample, these two factors were differentially and specifically related to inattention and hyperactivity, respectively. However, in the older sample, the first factor was related to inattention and hyperactivity, whereas the second factor was related to hyperactivity. Personality traits appear to map onto ADHD symptoms in a meaningful manner consistent with a dual-process model of temperament and ADHD.

EEG Asymmetry Analysis of the Left and Right Brain Activities During Simple versus Complex Arithmetic Learning

Repeated practice of simple arithmetic such as addition, subtraction, and multiplication has been widely used for effective math education. Brain activity patterns during simple and complex arithmetic calculation have been explored by several research groups using magnetic resonance images (MRI) and functional MRI (fMRI), and some have reported that the balanced whole brain (both left and right brain) activities during simple arithmetic in contrast to the predominant left brain activities during complex arithmetic. Methods. In this work, we have identified the characteristic brainwaves and asymmetric activation patterns of the left and right brain during the process of simple and complex arithmetic by measuring theta, alpha, Sensory Motor Response (SMR), and beta brainwaves of 24 participants from the location FP1 (left brain) and FP2 (right brain) using EEG. Results. Simple statistics analysis showed the significantly different beta activities from the left brain during complex arithmetic compared to simple arithmetic process, and through the asymmetry analysis of the left and right brain activities, less symmetrical brain activation during complex calculation, that is, specifically higher SMR, and beta brainwaves in the left hemisphere more than right hemisphere was identified, which is consistent with recent fMRI findings. Conclusion. The results imply that simple arithmetic process may improve the whole brain activities in a balanced way while complex arithmetic induce unbalanced activities of the left and right brain.

Connectivity Theory of Autism: Use of Connectivity Measures in Assessing and Treating Autistic Disorders

Background. Autism is a disorder characterized by deficits in communication, social interaction, a limited range of interests, and repetitive stereotypical behavior. Although it is believed that changes in the brain leading to Autism occur early on in prenatal and early postnatal development, there is no definitive test for a diagnosis of Autism. The diagnosis is made on the basis of behavioral signs and symptoms alone and is usually not made until age 2 or later. There have been numerous neuroanatomical abnormalities noted in Autism, some of which can be linked to neuropsychological dysfunction. Recently a new theory has become prominent which suggests the disorder may be due to aberrant neural connectivity patterns. Evidence in support of this theory has come from anatomical studies of white matter as well as functional neuroimaging studies. Methods. Most studies have employed functional magnetic resonance imaging to investigate connectivity, or electroencephalography (EEG) coherence studies. The high temporal resolution of EEG lends itself well to the investigation of cerebral connectivity. Research suggests there may be patterns of both hyper- and hypoconnectivity between various brain regions. Seven different patterns of abnormal connectivity which can be analyzed with EEG are proposed. Results. Patterns of hyperconnectivity may be found in frontotemporal and left hemispheric regions, whereas patterns of hypoconnectivity are often seen in frontal (orbitofrontal), right posterior (occipital/parietal-temporal), frontal-posterior, and left hemispheric regions. In addition to these patterns of hypo- and hyperconnectivity, a mu rhythm complex has been identified. Treatment goals may be based on coherence anomalies identified by quantitative EEG analysis. Increased coherence between brain regions may be downtrained, whereas decreased coherence between brain regions may be uptrained. Clinical examples of each pattern and a discussion of their neurofeedback treatment are provided. Conclusion. A theory of autistic disorders is presented that has at its' core neural connectivity disturbances. Multivariate EEG connectivity indices are utilized to formulate a typology of connectivity anomalies or patterns that have been observed over a series of autistic patients. These represent phenotypic expressions of the underlying pathology that leads to autistic symptoms. Examples demonstrate how these connectivity metrics can be used to understand autistic disturbances and formulate neurofeedback strategies for remedying these difficulties.

EEG PHENOTYPES PREDICT TREATMENT OUTCOME TO STIMULANTS IN CHILDREN WITH ADHD

This study demonstrates that the EEG Phenotypes as described by Johnstone, Gunkelman & Lunt [19] are clearly identifiable EEG patterns with good inter-rater reliability. Furthermore, it was also demonstrated that these EEG phenotypes occurred in both ADHD subjects as well as healthy control subjects. The Frontal Slow, the Slow Alpha Peak Frequency and the Low Voltage EEG Phenotype seemed to discriminate ADHD subjects best from the control group, however not significantly. The Frontal Slow group responded to a stimulant with a clinically relevant decreased number of false negative errors on the CPT. The Frontal Slow and Slowed Alpha Peak Frequency phenotypes, have very different etiologies as evidenced by the treatment response to stimulants. In previous research the slowed alpha peak frequency has most likely erroneously shown up as a Frontal Theta sub-group. This implies that future research employing EEG measures in ADHD should avoid using traditional frequency bands, but clearly dissociate slowed alpha peak frequency from frontal theta by taking the individual alpha peak frequency into account. Furthermore, the divergence from normal of the frequency bands pertaining to the various phenotypes is greater in the clinical group than in the controls. Investigating EEG Phenotypes seems to be a promising new way to approach EEG data, explaining much of the variance in EEG’s, and thereby potentially leading to more specific prospective treatment outcomes.

Slow cortical potential neurofeedback in attention deficit hyperactivity disorder: is there neurophysiological evidence for specific effects?

This study compared changes in quantitative EEG (QEEG) and CNV (contingent negative variation) of children suffering from ADHD treated by SCP (slow cortical potential) neurofeedback (NF) with the effects of group therapy (GT) to separate specific from non-specific neurophysiological effects of NF. Twenty-six children (age: 11.1 ± 1.15 years) diagnosed as having ADHD were assigned to NF (N = 14) or GT (N = 12) training groups. QEEG measures at rest, CNV and behavioral ratings were acquired before and after the trainings and statistically analyzed. For children with ADHD-combined type in the NF group, treatment effects indicated a tendency toward improvement of selected QEEG markers. We could not find the expected improvement of CNV, but CNV reduction was less pronounced in good NF performers. QEEG changes were associated with some behavioral scales. Analyses of subgroups suggested specific influences of SCP training on brain functions. To conclude, SCP neurofeedback improves only selected attentional brain functions as measurable with QEEG at rest or CNV mapping. Effects of neurofeedback including the advantage of NF over GT seem mediated by both specific and non-specific factors.

Controlled evaluation of a neurofeedback training of slow cortical potentials in children with Attention Deficit/Hyperactivity Disorder (ADHD)

Background: Although several promising studies on neurofeedback training in Attention Deficit/Hyperactivity Disorder (ADHD) have been performed in recent years, the specificity of positive treatment effects continues to be challenged. Methods: To evaluate the specificity of a neurofeedback training of slow cortical potentials, a twofold strategy was pursued: First, the efficacy of neurofeedback training was compared to a group training program for children with ADHD. Secondly, the extent of improvements observed in the neurofeedback group in relation to successful regulation of cortical activation was examined. Parents and teachers rated children's behaviour and executive functions before and after treatment. In addition, children underwent neuropsychological testing before and after training. Results: According to parents' and teachers' ratings, children of the neurofeedback training group improved more than children who had participated in a group therapy program, particularly in attention and cognition related domains. On neuropsychological measures children of both groups showed similar improvements. However, only about half of the neurofeedback group learned to regulate cortical activation during a transfer condition without direct feedback. Behavioural improvements of this subgroup were moderately related to neurofeedback training performance, whereas effective parental support accounted better for some advantages of neurofeedback training compared to group therapy according to parents' and teachers' ratings. Conclusion: There is a specific training effect of neurofeedback of slow cortical potentials due to enhanced cortical control. However, non-specific factors, such as parental support, may also contribute to the positive behavioural effects induced by the neurofeedback training.

Effect of neurofeedback training on the neural substrates of selective attention in children with attention-deficit/hyperactivity disorder: a functional magnetic resonance imaging study

Attention Deficit Hyperactivity Disorder (AD/HD) is a neurodevelopmental disorder mainly characterized by impairments in cognitive functions. Functional neuroimaging studies carried out in individuals with AD/HD have shown abnormal functioning of the anterior cingulate cortex (ACC) during tasks involving selective attention. In other respects, there is mounting evidence that neurofeedback training (NFT) can significantly improve cognitive functioning in AD/HD children. In this context, the present functional magnetic resonance imaging (fMRI) study was conducted to measure the effect of NFT on the neural substrates of selective attention in children with AD/HD. Twenty AD/HD children - not taking any psychostimulant and without co-morbidity-participated to the study. Fifteen children were randomly assigned to the Experimental (EXP) group (NFT), whereas the other five children were assigned to the Control (CON) group (no NFT). Subjects from both groups were scanned 1 week before the beginning of the NFT (Time 1) and 1 week after the end of this training (Time 2), while they performed a Counting Stroop task. At Time 1, for both groups, the Counting Stroop task was associated with significant loci of activation in the left superior parietal lobule. No activation was noted in the ACC. At Time 2, for both groups, the Counting Stroop task was still associated with significant activation of the left superior parietal lobule. This time, however, for the EXP group only there was a significant activation of the right ACC. These results suggest that in AD/HD children, NFT has the capacity to normalize the functioning of the ACC, the key neural substrate of selective attention

Functional Magnetic Resonance Imaging Investigation of the Effects of Neurofeedback Training on the Neural Bases of Selective Attention and Response Inhibition in Children with Attention-Deficit/Hyperactivity Disorder

Two functional magnetic resonance imaging (fMRI) experiments were undertaken to measure the effect of neurofeedback training (NFT), in AD/HD children, on the neural substrates of selective attention and response inhibition. Twenty unmedicated AD/HD children participated to these experiments. Fifteen children were randomly assigned to the Experimental (EXP) group whereas the other five children were randomly assigned to the Control (CON) group. Only subjects in the EXP group underwent NFT. EXP subjects were trained to enhance the amplitude of the SMR (12–15 Hz) and beta 1 activity (15–18 Hz), and decrease the amplitude of theta activity (4–7 Hz). Subjects from both groups were scanned one week before the beginning of NFT (Time 1) and 1 week after the end of NFT (Time 2), while they performed a “Counting Stroop” task (Experiment 1) and a Go/No-Go task (Experiment 2). At Time 1, in both groups, the Counting Stroop task was associated with significant activation in the left superior parietal lobule. For the Go/No-Go task, no significant activity was detected in the EXP and CON groups. At Time 2, in both groups, the Counting Stroop task was associated with significant activation of the left superior parietal lobule. This time, however, there were significant loci of activation, in the EXP group, in the right ACC, left caudate nucleus, and left substantia nigra. No such activation loci were seen in CON subjects. For the Go/No-Go task, significant loci of activation were noted, in the EXP group, in the right ventrolateral prefrontal cortex, right ACcd, left thalamus, left caudate nucleus, and left substantia nigra. No significant activation of these brain regions was measured in CON subjects. These results suggest that NFT has the capacity to functionally normalize the brain systems mediating selective attention and response inhibition in AD/HD children.

Hemoencephalography–A New Therapy for Attention Deficit Hyperactivity Disorder (ADHD): Case Report

Background. Hemoencephalography (HEG) is cortical circulatory biofeedback using refracted light tuned to oxygenated hemoglobin, emitted into the skull and detected at the scalp using a photoelectric cell. Red light at 660 nm is used as the probe, with changes in the returning refracted light representing changes in cortical circulation. Method. A single-subject design case study was employed. TL, at age twelve, had a well-established diagnosis of ADHD given by pediatric neurologists, and required significant stimulant medication that was clinically effective. He was performing well in school on Concerta 36 mg at 7 a.m. and Ritalin 5 mg at 4 p.m. Off medication, he had significant abnormalities on IVA testing (Attention Quotient or AQ = 78) and in the quantitative electroencephalogram (QEEG). Using HEG, the patient engaged the system to exercise increases in signals corresponding to cortical circulation in the prefrontal cortex. QEEG, Continuous Performance Testing (CPT) and clinical status measurements were made before and after 10 sessions of HEG therapy. HEG exercise was typically given in weekly to bi-weekly sessions for 10 minutes in each of three standard prefrontal EEG locations: FP1, FP2 and FPz. Results. During the 10 therapy sessions TL's HEG data showed positive gain indicating success at raising the biofeedback signal. Following the 10 sessions, TL showed a normal QEEG with improved Z scores for relative power and normal IVA testing off medication (mean AQ 99.75 ± 7.85 on three dates), which persisted in the 18-month follow-up. His medication was lowered to Focalin 2.5 mg twice daily. Conclusion. This work documents a patient who showed clinically significant improvement after only 10 sessions using a new form of neurobiofeedback, hemoencephalography. If confirmed in controlled studies, this represents a breakthrough in treatment options for ADHD. Future studies should explore synergies between HEG and EEG neurofeedback therapies.

Long-term stability and consistency of EEG event-related (de-)synchronization across different cognitive tasks

Objective We examined whether task-related band power changes (event-related desynchronization/synchronization; ERD/ERS) that have been linked to individual differences in cognitive ability demonstrate satisfying temporal stability and cross-situational consistency. Methods Multi-channel EEG recordings from 29 adults, assessed at three different occasions over 2 years were examined. Between-session correlations and consistency coefficients (Cronbach's alpha) across the three experiments were evaluated for both, spectral power features of the resting EEG and ERD/ERS estimates while the participants performed some cognitive task (i.e. different elementary cognitive tasks that put comparable demands on the participants). Results ERD/ERS values, while subjects performed a cognitive task, demonstrated satisfactory stability and consistency (i.e. >0.7), whereby the degree of consistency varied as a function of frequency band and brain region. Highest consistency was found for the 8–10Hz ERD in parieto-occipital recording sites (i.e. >0.9). In resting EEG, mean alpha (gravity) frequency was the most stable EEG feature. Conclusions The present data suggest that ERD/ERS phenomena in different narrow frequency bands are rather stable over time and across different situations. The relatively high reproducibility of ERD/ERS promotes the usefulness of this measure in assessing individual differences of physiological activation patterns accompanying cognitive performance. Significance This study addresses the issue of reproducibility of EEG in general and ERD/ERS experiments in particular, which is a prerequisite for both basic research and clinical studies.

Effects of Hemoencephalographic (HEG) Training at Three Prefrontal Locations Upon EEG Ratios at Cz

Background. Light in the wavelength region of 650 to 1000 nanometers is able to penetrate living human tissue, including bone. Medical research has exploited this optical window into the body to develop non-invasive monitoring of brain functioning. In 1994 Herschel Toomim discovered that he could both measure and teach persons to control the amount of oxygenated blood flowing in the prefrontal regions with such an optical device. He has labeled the biofeedback of brain blood flow hemoencephalography (HEG). Methods. A fifteen-year-old male with a history of mild articulation problems and poor spelling was administered twenty sessions of combined HEG/EEG biofeedback, with a referential recording at Cz. Feedback in each session was conducted in three trials with the HEG optodes placed over the left eye, at midline, and over the right eye for ten minutes each. The order of placement was counterbalanced across trials. Changes in HEG levels within each trial were computed and plotted across sessions, as was the theta/beta ratio for each trial. Results. The subject clearly learned improved voluntary control over brain blood flow. The slope of increases of HEG within each trial improved across sessions at all three forehead locations. There were three indications from this case that HEG training to improve attention might be most efficacious at the midline location: (a) the theta/beta ratio at Cz decreased slightly over sessions only in response to HEG training at midline, (b) bursts of beta lasting ten seconds or more occurred more often, and (c) occasionally a marked increase in HEG within a trial was associated with a corresponding increase in power in beta. This occurred only with HEG at midline. Conclusion. HEG biofeedback is a promising treatment modality, especially for improving the functioning of executive control systems mediated by the prefrontal regions of the cerebral cortex.

A controlled study of the effectiveness of EEG biofeedback training on children with attention deficit hyperactivity disorder

Summary In order to study the treatment of the children with attention deficit hyperactivity disorder (ADHD), the integrated visual and auditory continuous performance test (IVA-CPT) was clinically applied to evaluate the effectiveness of electroencephalogram (EEG) biofeedback training. Of all the 60 children with ADHD aged more than 6 years, the effective rate of EEG biofeedback training was 91.6% after 40 sessions of EEG biofeedback training. Before and after treatment by EEG biofeedback training, the overall indexes of IVA were significantly improved among predominately inattentive, hyperactive, and combined subtype of children with ADHD (P<0.001). It was suggested that EEG biofeedback training was an effective and vital treatment on children with ADHD.

Neurofeedback in adolescents and adults with attention deficit hyperactivity disorder

Abstract Neurofeedback is being utilized more commonly today in treating individuals who have attention deficit hyperactivity disorder (ADHD). Neurofeedback, which is based on theories that recognize the organic basis of ADHD, utilizes biofeedback to guide individuals to regulate their brain activity. Neurofeedback relies on research that has demonstrated that most individuals who have ADHD, as compared to matched peers, have excess slow wave activity and reduced fast wave activity. It provides immediate feedback to the individual about his or her brain wave activity in the form of a video game, whose action is influenced by the individual's meeting predetermined thresholds of brain activity. Over several sessions of using the video and auditory feedback, individuals reduce their slow wave activity and/or increase their fast wave activity. Individuals who complete a course of training sessions often show reduced primary ADHD symptoms. Research has shown that neurofeedback outcomes compare favorably to those of stimulant medication. © 2005 Wiley Periodicals, Inc. J Clin Psychol/In Session 61: 621–625, 2005.

Neurofeedback in der Behandlung der Aufmerksamkeitsdefizit-Hyperaktivitätsstörung (ADHS) im Kindes- und Jugendalter

Zusammenfassung: Einleitung: In der Therapie der Aufmerksamkeitsdefizit-Hyperaktivitätsstörung (ADHS) sind viele nicht-medikamentöse Behandlungsmethoden den Nachweis ihrer Wirksamkeit schuldig geblieben. Für das Neurofeedback (auch EEG-Biofeedback) hat sich die Evidenzbasis in den vergangenen Jahren verbessert. Neurofeedback bewirkt abhängig vom Trainings-Protokoll Veränderungen des EEG-Frequenzspektrums oder der ereigniskorrelierten Potentiale bei ADHS und strebt über die gelernte Modifikation dieser Parameter eine Verbesserung der ADHS-Kernsymptome an. Methoden: In dieser Übersichtsarbeit werden die vorliegenden Forschungsbefunde detailliert dargelegt. Ergebnisse: Die durch das Neurofeedback erreichten kurzfristigen Verbesserungen entsprachen in drei kontrollierten Studien denen einer pharmakotherapeutischen Stimulanzien-Behandlung. Neurofeedback führte zu einer signifikanten Reduktion von Unaufmerksamkeit, Impulsivität und Hyperaktivität. Darüber hinaus fand sich eine anhaltende Normalisierung des Spontan-EEGs, während eine Stimulanzientherapie keine vergleichbare Normalisierung bewirkte; es traten keine unerwünschten Wirkungen auf. Untersuchungen zur Wirkdauer der Neurofeedback-Effekte sind ermutigend, stützen sich aber auf kleine Patientenzahlen. Schlussfolgerung: Neurofeedback ist ein viel versprechender Ansatz in der Behandlung aufmerksamkeitsgestörter, hyperaktiver Kinder. Gleichwohl besteht Bedarf an weiteren kontrollierten Studien mit einheitlichen diagnostischen Kriterien, ausreichend großen Stichproben, geeigneten Veränderungsmaßen und Katamnese-Untersuchungen.

The effects of neurofeedback training on the spectral topography of the electroencephalogram

Objective: To investigate the impact of EEG frequency band biofeedback (neurofeedback) training on spectral EEG topography, which is presumed to mediate cognitive-behavioural training effects. In order to assess the effect of commonly applied neurofeedback protocols on spectral EEG composition, two studies involving healthy participants were carried out. Methods: In Experiment 1, subjects were trained on low beta (12–15 Hz), beta1 (15–18 Hz), and alpha/theta (8–11 Hz/5–8 Hz) protocols, with spectral resting EEG assessed before and after training. The specific associations between learning indices of each individual training protocol and changes in absolute and relative spectral EEG topography was assessed by means of partial correlation analyses. Results of Experiment 1 served to generate hypotheses for Experiment 2, where subjects were randomly allocated to independent groups of low beta, beta1, and alpha/theta training. Spectral resting EEG measures were contrasted prior and subsequent to training within each group. Results: Only few associations between particular protocols and spectral EEG changes were found to be consistent across the two studies, and these did not correspond to expectations based on the operant contingencies trained. Low-beta training was found to be somewhat associated with reduced post-training low-beta activity, while more reliably, alpha/theta training was associated with reduced relative frontal beta band activity. Conclusions: The results document that neurofeedback training of frequency components does affect spectral EEG topography in healthy subjects, but that these effects do not necessarily correspond to either the frequencies or the scalp locations addressed by the training contingencies. The association between alpha/theta training and replicable reductions in frontal beta activity constitutes novel empirical neurophysiological evidence supporting inter alia the training's purported role in reducing agitation and anxiety. Significance: These results underline the complexity of the neural dynamics involved EEG self-regulation and emphasize the need for empirical validation of predictable neurophysiological outcomes of training EEG biofeedback protocols.

EEG biofeedback of low beta band components: frequency-specific effects on variables of attention and event-related brain potentials

OBJECTIVE: To test a common assumption underlying the clinical use of electroencephalographic (EEG) biofeedback training (neurofeedback), that the modulation of discreet frequency bands is associated with frequency-specific effects. Specifically, the proposal was assessed that enhancement of the low beta components sensorimotor rhythm (SMR: 12-15 Hz) and beta1 (15-18 Hz) affect different aspects of attentional processing. METHODS: Subjects (n=25) were randomly allocated to training with either an SMR or beta1 protocol, or to a non-neurofeedback control group. Subjects were assessed prior and subsequent to the training process on two tests of sustained attention. The neurofeedback participants were also assessed on target P300 event-related potential (ERP) amplitudes in a traditional auditory oddball paradigm. RESULTS: Protocol-specific effects were obtained in that SMR training was associated with increased perceptual sensitivity 'd prime' (d'), and reduced omission errors and reaction time variability. Beta1 training was associated with faster reaction times and increased target P300 amplitudes, whereas no changes were evident in the control group. CONCLUSIONS: Neurofeedback training of SMR and beta1 band components led to significant and protocol-specific effects in healthy subjects. The data can be interpreted as indicating a general attention-enhancing effect of SMR training, and an arousal-enhancing effect of beta1 training.

Learned self-regulation of EEG frequency components affects attention and event-related brain potentials in humans

Learned enhancement of EEG frequency components in the lower beta range by means of biofeedback has been reported to alleviate attention deficit hyperactivity disorder (ADHD) symptoms. In order to elucidate frequency-specific behavioural effects and neurophysiological mediators, this study applied neurofeedback protocols to healthy volunteers, and assessed impact on behavioural and electrocortical attention measures. Operant enhancement of a 12-15Hz component was associated with reduction in commission errors and improved perceptual sensitivity on a continuous performance task (CPT), while the opposite relation was found for 15-18Hz enhancement. Both 12-15Hz and 15-18Hz enhancement were associated with significant increases in P300 event-related brain potential amplitudes in an auditory oddball task. These relations are interpreted as stemming from band-specific effects on perceptual and motor aspects of attention measures

EEG Signature and Phenomenology of Alpha/theta Neurofeedback Training Versus Mock Feedback

Alpha/theta (a/t) neurofeedback training has in the past successfully been used as a complementary therapeutic relaxation technique in the treatment of alcoholism. In spite of positive clinical outcomes, doubts have been cast on the protocol's specificity when compared to alternative relaxation regimes. This study investigated the basic tenet underlying the a/t training rationale, that accurate a/t feedback representation facilitates the generation of these frequency components. Two groups of healthy volunteers were randomly assigned to either (a) real contingent a/t feedback training or (b) a noncontingent mock feedback control condition. The groups were compared on measures of theta/alpha (t/a) ratios within and across training sessions, as well as activational self-report scales after each session. The contingent a/t feedback group displayed significant within-session t/a ratio increments not evident in the mock control group, as well as higher overall t/a ratios in some but not all of the training sessions. No differences were found between the groups in terms of subjective activational phenomenology, in that both groups reported significantly lower levels of activation after training sessions. The data demonstrate that irrespective of considerations of clinical relevance, accurate a/t neurofeedback effectively facilitates production of higher within-session t/a ratios than do noncontingent feedback relaxation.

Neuroscience of attention-deficit/hyperactivity disorder: the search for endophenotypes

Research on attention-deficit/hyperactivity disorder (ADHD), a highly prevalent and controversial condition, has, for the most part, been descriptive and atheoretical. The imperative to discover the genetic and environmental risk factors for ADHD is motivating the search for quantifiable intermediate constructs, termed endophenotypes. In this selective review, we conclude that such endophenotypes should be solidly grounded in the neurosciences. We propose that three such endophenotypes — a specific abnormality in reward-related circuitry that leads to shortened delay gradients, deficits in temporal processing that result in high intrasubject intertrial variability, and deficits in working memory — are most amenable to integrative collaborative approaches that aim to uncover the causes of ADHD.

EEG Biofeedback Training and Attention-Deficit/Hyperactivity Disorder in an Elementary School Setting

Introduction: EEG biofeedback was conducted on site in an elementary school. Method: An experimental group of eight children ages 8-10 completed 35-47 sessions of EEG biofeedback training over a six-month period. Four participants in the experimental group were diagnosed with Attention-Deficit/Hyperactivity Disorder (ADHD) and four were not diagnosed with ADHD. Eight children in the waitlist control group were matched to the experimental group on age, grade, teacher, and diagnosis. None of the 16 participants were medicated for ADHD. Results: Attention abilities as measured by the Test of Variables of Attention showed the experimental group of children with ADHD reduced errors of commission and anticipation, indicating a reduction in impulsivity. Teacher reports using the McCarney Scale indicated improvements in attention but no changes in impulsivity and hyperactiv-ity. Discussion: Several confounds require exploration before attribution of changes are assigned to neurofeedback. Whether the effects are due to the neurofeedback protocols, attendance at individual sessions away from the classroom, the attention of the technician, or the excitement of a special program cannot be determined with this study. It will be necessary to have a placebo group in order to separate systematically the variables in the training program.

Effect of Neurofeedback on Variables of Attention in a Large Multi-Center Trial

Background: Neurofeedback studies have been criticized for including small numbers of subjects. The effect of SMR-beta neuro-feedback training on the Test of Variables of Attention was evaluated in more than 1, 000 subjects from thirty-two clinics. Methods: 1089 subjects (726 children, 324 females, 186 with ADHD or ADD diagnoses) underwent twenty or more sessions of SMR-beta neurofeedback training for attentional and behavioral complaints at thirty-two clinical settings affiliated with EEG Spectrum, Inc. Subjects were evaluated prior to training and at training completion. One hundred and fifty-seven subjects who elected extensive training (forty sessions or more) were tested after both twenty and forty training sessions. Results: Neurofeedback training produced significant improvement in attentiveness, impulse control, and response variability. Significant clinical improvement in one or more measures was seen in eighty-five percent of those subjects with moderate pre-training deficits. Conclusions: Neurofeedback training is effective in remediating atten-tional dysfunction. Nevertheless, large-scale studies with greater control (e.g., wait-list designs) are sorely needed

EEG Biofeedback in the schools the use of EEG Biofeedback to treat ADHD in a school setting

The study reports on Patient-Directed neurofeedback for Attention Deficit/Hyperactivity Disorder (AD/H.). Therapist involvement was limited to 10 treatment sessions used to train the patient or parents of younger children to use the equipment, to monitor treatment, and to make changes in the treatment protocol as necessary. The remaining 50 sessions were conducted at home using inexpensive, easy to operate, 1 or 2 channel Lexicor PODS. Results from the initial Gpatients, ages 7 to 45, are reported. Thirteen of 24 Test of Variables of Attention (TOVA) measures (attention, impulsivity, reaction time and variability) were below average (SS c 90) at baseline. After 30 neurofeedback sessions, only 5 TOVA variables remained below average. It is concluded that Patient-Directed neurofeedback may be an effective alternative to merapist-Directed treatment for many AD/HD patients and can be delivered at substantially less cost.

Estimating alertness from the EEG power spectrum

In tasks requiring sustained attention, human alertness varies on a minute time scale. This can have serious consequences in occupations ranging from air traffic control to monitoring of nuclear power plants. Changes in the electroencephalographic (EEG) power spectrum accompany these fluctuations in the level of alertness, as assessed by measuring simultaneous changes in EEG and performance on an auditory monitoring task. By combining power spectrum estimation, principal component analysis and artificial neural networks, we show that continuous, accurate, noninvasive, and near real-time estimation of an operator's global level of alertness is feasible using EEG measures recorded from as few as two central scalp sites. This demonstration could lead to a practical system for noninvasive monitoring of the cognitive state of human operators in attention-critical settings.

Neocortical Dynamics: Implications for Understanding the Role of Neurofeedback and Related Techniques for the Enhancement of Attention

For nearly 25 years, EEG biofeedback (neurofeedback) has been utilized in research and clinical settings for the treatment and investigation of a number of disorders ranging from attention deficit hyperactivity disorder to seizure disorders as well as many other established and investigational applications. Until recently, mechanisms underlying the generation and origins of EEG have been poorly understood but now are beginning to become much more clarified. Now it is important to combine the information gathered on the genesis of EEG and neocortical dynamics with the findings from neurofeedback investigations. This will help us to develop models of how neurofeedback might operate in producing the changes in EEG and in clinical symptomatology. We know that the cortex operates in terms of resonant loops between neocortical columns of cells known as local, regional, and global resonances. These resonances determine the specific EEG frequencies and are often activated by groups of cells in the thalamus known as pacemakers. There are complex excitatory and inhibitory interactions within the cortex and between the cortex and the thalamus that allow these loops to operate and provide the basis for learning. Neurofeedback is a technique for modifying these resonant loops, and hence, modifying the neurophysiological and neurological basis for learning and for the management of a number of neurologically based disorders. This paper provides an introduction to understanding EEG and neocortical dynamics and how these concepts can be used to explain the results of neurofeedback training and other interventions particularly in the context of understanding attentive mechanisms and for the management of attention deficit/hyperactivity disorders.

Computer-Assisted Cognitive Training for ADHD A Case Study

A computer-assisted cognitive training program was used to treat a 13-year-old Caucasian male with attention deficit hyperactivity disorder. The subject was administered a cognitive training computer program, Captain's Log, for 35 sessions. Pre/post differences on the Conners Parent Rating Scale revealed a decrease on all subscales. The scores on the Conners Teacher Rating Scale were less conclusive. Electrophysiological testing on the A620 EEG/Neurofeedback revealed a reduction in EMG, theta, and beta wave amplitudes. However, the theta/beta ratio increased. A 7-month follow-up revealed that most of the acquired gains were maintained, but at a slightly lower level.

EEG biofeedback for the enhancement of attentional processing in normal college students

College students diagnosed as free of any neurological or attention deficit disorder received EEG biofeedback to enhance beta (16-22 hertz) activity while simultaneously inhibiting high theta and low alpha (6-10 hertz) activity in order to evaluate improvements in attentional measures. Following short-term treatment (mean number of sessions=20), subjects were evaluated as either learners or non-learners based upon standard pre- versus post-treatment neurofeedback measures. Attention quotients taken from pre and post-treatment measurements using the Intermediate Visual and Auditory (IVA) Continuous Performance Test identified significant improvements in attentional measures in learners, while non-learners showed no significant improvements. Results suggest that some "normal" young adults can learn to increase EEG activity associated with improved attention. Twenty sessions, however, even for this population may represent the lower limit for achieving significant improvement.

Area-specific self-regulation of slow cortical potentials on the sagittal midline and its effects on behavior

Exteroceptive feedback was given for negative and positive shifts in slow potentials (SPs) recorded from Fz, Cz, or Pz (between groups design). Slow potentials at the feedback site were referred to adjacent scalp and non-cephalic electrodes, so as to confine SP shifts to the feedback location. Area-specific regulation of SPs was obtained at each midsagittal site after 3 days of feedback training. Subjects reported sensorimotor and emotional arousal when negative SP shifts were trained frontally, but not when negative shifts were trained parietally (cognitive/attentional strategies reported after parietal feedback). Area-specific regulation of SPs was subsequently abolished when behavioral tasks were added to further probe frontal/parietal differences (dual-task procedure). These findings indicate that area-specific self-regulation of SPs is possible on the sagittal midline, and that self-regulated parietal SPs (in contrast to frontal ones) arise from non-motoric generators. The source of SP self-regulation was more readily probed by verbal reports of feedback strategy than by study of dual-task relations, because feedback control was disrupted by the dual-task requirement.

Discourse on the development of EEG diagnostics and biofeedback for attention-deficit/hyperactivity disorders

This article presents a review of work that my colleagues and I have been doing during the past 15 years developing a rationale for the diagnosis of attention-deficit/hyperactivity disorder (ADHD) and treatment of ADHD employing EEG biofeedback techniques. The article first briefly reviews the history of research and theory for understanding ADHD and then deals with the development of EEG and event-related potential (ERP) assessment paradigms and treatment protocols for this disorder, including our work and that of others who have replicated our results. Illustrative material from our current research and child case studies is included. Suggestions for future experimental and clinical work in this area are presented and theoretical issues involving the understanding of the neurophysiological and neurological basis of ADHD are discussed.

Slow potentials of the cerebral cortex and behavior.

Use of Biofeedback in the Treatment of Seizure Disorders and Hyperactivity

During the past 15 years, considerable basic research and applied effort has been directed toward developing methods for controlling internal physiological processes. These processes include autonomic functions, both unit and gross (summated) neuromuscular activity, and central neural electrophysiological responses, all of which may be modifiable through the application of behavioral methods. Psychophysiology is the discipline most concerned with this type of research. A relatively new applied branch of psychophysiology, now known as biofeedback, is undergoing rapid development to fulfill basic research and clinical needs related to the control of physiological processes.