Electroencephalography (brain waves), neurofeedback, and childhood disorders of learning, behavior and development

Examination of the brain's electrical activity (electroencephalography, EEG, 'brain waves') in ADHD, autistic spectrum disorder and other problems of pediatric learning, behavior and development has advanced greatly in the past decade, establishing the physiological basis for effective non-pharmacological interventions. In a review article published in the journal NeuroMolecular Medicine several years back the authors state in regard to ADHD:

"Cognitive and functional studies using electrophysiology and brain imaging frequently indicate altered processing in ADHD during performance on cognitive tasks hypothesized to measure a “core” deficit, such as response inhibition. Yet, children with ADHD appear to suffer from a more general deficit, including impairment in attentional alerting, orienting, response preparation, and control. Reward processes are also altered and, further, a strong association emerges with intraindividual variability... Task performance correlates with underactivation of, especially, frontostriatal areas of the brain, but an extended network of brain regions is also implicated. Electroencephalography studies indicate abnormalities in ADHD in relation to slow-wave activity, linked to underarousal."

They proceed to discuss how these electrophysiological abnormalities are associated with neurotransmitter regulation in ADHD.A fascinating study published recently in the journal Neuropharmacology investigates the correlation between brain fatty acids and EEG activity:

"Abnormal fatty acid status has been implicated in the aetiology of attention deficit hyperactivity disorder (ADHD). Delayed maturation in ADHD may result in raised frontal low frequency (theta) electroencephalographic activity (EEG) and a reduction in posterior high frequency (beta, alpha) activity. The current study used sequential linear regression to investigate the association between age, resting-state EEG and levels of long-chain polyunsaturated omega-3 and omega-6 fatty acids in red blood cells in 46 adolescent boys with ADHD symptoms."

They observed significant correlations between docosahexaenoic acid (DHA) levels and fast frequency activity and eicosapentaenoic acid (EPA) levels and frontal theta activity. Alpha activity correlated positively with semantic memory and theta activity correlated inversely with performance on verbal memory. They conclude by summarizing:

"Results support differential associations for DHA and EPA with fast and slow EEG activity respectively. Results support EEG activity as an objective biomarker of neural function associated with long-chain omega-3 fatty acids in ADHD."

Impaired functional connectivity in the brain networks involved in paying attention is described in a paper published recently in the journal Biological Psychiatry:

"Current pathophysiologic models of attention-deficit/hyperactivity disorder (ADHD) suggest that impaired functional connectivity within brain attention networks may contribute to the disorder. In this electroencephalographic (EEG) study, we analyzed cross-frequency amplitude correlations to investigate differences in cue-induced functional connectivity in typically developing children and children with ADHD."

The authors measured EEG activity in 25 children (14 with ADHD) while they performed a cross-modal attention task. They observed distinct deficits in EEG correlates of attentional control in the children with ADHD. Their conclusion:

"Our findings provide neurophysiological evidence for a specific deficit in top-down attentional control in children with ADHD that is manifested as a functional disconnection between frontal and occipital cortex."

An interesting paper published earlier in Biological Psychiatry demonstrates that children of parents with childhood onset depression exhibit EEG deficits in selective attention:

"Individual differences in selective attention may play a role in moderating psychological vulnerabilities by shaping the ability to self-regulate emotion. Children of parents with childhood-onset depression (COD) are at increased risk for socioemotional difficulties. This study examined potential differences in selective attention as a function of parental COD."

The authors observed that children of parents with COD were slower in their EEG response rates compared with control children. The at-risk children also showed abnormally larger slow wave amplitudes in anterior scalp sites that correlate with attention. They conclude:

"These data suggest that there are subtle deficits in selective attention among the offspring of individuals with COD, requiring that they engage more processing resources to perform effectively. This may affect their ability to adequately regulate emotion under stress."

Another study in the same issue of Biological Psychiatry provides evidence that functional impairments in ADHD are not due to 'developmental lag' but to neural processing deficits that can be observed in the brain's electrical activity. The authors state:

"We examined the development of neurophysiological markers of attention (Cue P300; contingent negative variation [CNV]) and inhibition (NoGo P300) in ADHD and control groups from childhood to adolescence for support of the developmental lag hypothesis of ADHD."

The data they compiled led to a dismissal of the developmental lag hypothesis in favor of dysfunctional neural processing:

"These results provide strong evidence for multiple and persistent neural processing deficits in ADHD. They do not support the developmental lag hypothesis for attentional dysfunction in ADHD despite partial evidence that developmental lag contributes to inhibitory brain dysfunction during early adolescence."

Is there good evidence for using neurofeedback (brain wave biofeedback) as an effective, physiological, non-pharmacologic intervention to promote normal function in disorders of learning, behavior and development? European scientists have made numerous contributions to this field. Consider this paper published six years ago in the German medical journal Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie (Journal of Child and Adolescent Psychiatry and Psychotherapy) in which the authors state:

"Neurofeedback is aiming at an improvement of ADHD core-symptoms via the voluntary modification of abnormal neurophysiologic parameters, e.g. EEG-frequency spectrum and event-related potentials...Our review presents an overview of the current research on neurofeedback for the treatment of ADHD."

They examined the outcomes of three studies that pitted neurofeedback against standard pharma stimulant treatment. What did the data show?

"Neurofeedback lead to significant improvement of attention, impulsivity and hyperactivity, without adversive side effects. Additionally, there was a  persistent amelioration of EEG parameters, while stimulants did not lead to a comparable normalization...Neurofeedback is a promising approach for the treatment of children with ADHD."

A more recent review published in Current Psychiatry Reports documents that quantitative electroencephalography (QEEG, computerized mathematical analysis of raw EEG data) offers both diagnostic and therapeutic advantages:

"Although behavioral symptoms of inattention, impulsivity, and hyperactivity serve as a foundation for the accurate diagnosis of attention-deficit/hyperactivity disorder (ADHD), the low interrater reliability and specificity of behavioral rating scales and the absence of comprehensive screening for medical conditions that mimic ADHD have created a barrier to the effective treatment of ADHD. Recently published studies using quantitative electroencephalographic techniques have identified abnormal patterns of cortical activation through power spectral analysis, in event-related cortical potentials, and in slow cortical potentials that may serve as a basis for overcoming these barriers."

The authors examine studies that provide evidence for the use of QEEG in differentiating ADHD from other psychiatric disorders, evaluating the response to medications, and its role in neurofeedback therapy.More confirmation of the efficacy of neurofeedback is offered in a study published earlier this year in the European Child & Adolescent Psychiatry. The authors state:

"In a randomised controlled trial, NF [neurofeedback] training was found to be superior to a computerised attention skills training (AST)... In the present paper, treatment effects at 6-month follow-up were studied."

They examined 94 children with ADHD, aged 8–12 years, who completed either 36 sessions of NF training or a computerised AST. Pre-training, post-training and follow-up assessment were assessed by several behaviour rating scales...with follow-up information analysed...on a per-protocol basis. What did the data show?

"Improvements in the NF group at follow-up were superior to those of the control group and comparable to the effects at the end of the training...In conclusion, behavioural improvements induced by NF training in children with ADHD were maintained at a 6-month follow-up. Though treatment effects appear to be limited, the results confirm the notion that NF is a clinically efficacious module in the treatment of children with ADHD."

The authors of a study published last year in the Journal of Child Psychology and Psychiatry also confirmed the efficacy of neurofeedback as a treatment for ADHD in a randomised controlled clinical trial:

"...we evaluated the clinical efficacy of neurofeedback in children with ADHD in a multisite randomised controlled study using a computerised attention skills training as a control condition."

They examined 102 children with ADHD who performed either 36 sessions of neurofeedback with one block of theta/beta training and one block of slow cortical potential (SCP) training or did a comparable amount computerised attention skills training as a control. Outcomes were evaluated by several behaviour rating scales, with 'placebo' scales applied to control for parental expectations. What did the data show?

"...improvements in the NF group were superior to those of the control group...Comparable effects were obtained for the two NF protocols (theta/beta training, SCP training). Parental attitude towards the treatment did not differ between NF and control group."

The authors conclude by stating:

"Superiority of the combined NF training indicates clinical efficacy of NF in children with ADHD."

A meta-analysis published last year in the journal Clinical EEG & Neuroscience is also reassuring:

"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...In this study selected research on neurofeedback treatment for ADHD was collected and a meta-analysis was performed."

The authors examined both prospective controlled studies and studies employing a pre- and post-design and found large effect sizes (ES) for neurofeedback on impulsivity and inattention and a medium ES for hyperactivity, leading to this conclusion:

"Due to the inclusion of some very recent and sound methodological studies in this meta-analysis...the clinical effects of neurofeedback in the treatment of ADHD can be regarded as clinically meaningful...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."

Neurofeedback training (operant conditioning) can be applied according to a wide range of protocols. Additional research is revealing the value and importance of specific protocol selection according to the case. A recent study published in the International Journal of Psychophysiology adds to this body of knowledge:

"In a randomized controlled trial, neurofeedback (NF) training was found to be superior to a computerised attention skills training concerning the reduction of ADHD symptomatology...The aims of this investigation were to assess the impact of different NF protocols (theta/beta training and training of slow cortical potentials, SCPs) on the resting EEG and the association between distinct EEG measures and behavioral improvements."

EEG changes before and after specific NF trainings (theta/beta and SCP) or a control training were examined in 72 children with ADHD aged 8–12. Activity in the different EEG frequency bands was analyzed. What did the data show?

"In contrast to the control condition, the combined NF training was accompanied by a reduction of theta activity. Protocol-specific EEG changes...were associated with improvements in the German ADHD rating scale. Related EEG-based predictors were obtained."

Their conclusion has significant practical importance for the neurofeedback practitioner:

"Thus, differential EEG patterns for theta/beta and SCP training provide further evidence that distinct neuronal mechanisms may contribute to similar behavioral improvements in children with ADHD."

Interesting work with neurofeedback is also being done in China. A study published in the Chinese Journal of Contemporary Pediatrics examines the effect of neurofeedback training on the ratio slow theta (θ) and fast beta (β) brain waves:

"When the [ADHD] children fulfill cognition tasks, brain θ wave activity increases and β wave activity weakens. This study aimed to explore the efficacy of electroencephalographic (EEG) biofeedback therapy for ADHD in children by assessing the changes of the ratio of brain θ to β waves and the integrated visual and auditory continuous performance test (IVA-CPT)."

They performed EEG biofeedback therapy with 30 children with ADHD and measured the ratio of brain θ to β waves before and after therapy. IVA-CPT was used to assess the effectiveness of biofeedback therapy. What did their data show?

"After two courses of treatment, the mean ratio of brain θ to β waves in the 30 children with ADHD was significantly reduced from 12.32±4.35 (before treatment) to 6.54±1.27. IVA-CPT demonstrated that the values of six indexes measured, including integrate reaction control quotient, integrate attention quotient, auditory and visual reaction control quotients, auditory and visual attention control quotients, were significantly increased after biofeedback therapy."

Their conclusion should be appreciated by parents and clinicians alike:

"EEG biofeedback can reduce the ratio of brain θ to β waves and lead to significant decreases in inattention and hyperactivity and it is effective for treatment of ADHD in children."

Neurofeedback is, of course, beneficial for many more conditions than ADHD. A paper published in Applied Psychophysiology and Biofeedback reviews the evidence for the effectiveness of neurofeedback for Asperger's syndrome (AS) and autistic spectrum disorder.

"This paper summarizes data from a review of neurofeedback (NFB) training with 150 clients with Asperger’s Syndrome (AS) and 9 clients with Autistic Spectrum Disorder (ASD) seen over a 15 year period (1993–2008) in a clinical setting. The main objective was to investigate whether electroncephalographic (EEG) biofeedback, also called neurofeedback (NFB), made a significant difference in clients diagnosed with AS."

Clients received 40–60 sessions of NFB, which was combined with training in metacognitive strategies and, for most older adolescent and adult clients, with other supportive biofeedback...Significant improvements were found on measures of attention, core symptoms, achievement, and intelligence along with a decrease in relevant EEG ratios was also observed. The authors conclude:

"The positive outcomes of decreased symptoms of Asperger’s and ADHD (including a decrease in difficulties with attention, anxiety, aprosodias, and social functioning) plus improved academic and intellectual functioning, provide preliminary support for the use of neurofeedback as a helpful component of effective intervention in people with AS."

Advances in the science of brain electrophysiology and neurofeedback have yielded a richer repertoire of methods to individualize interventions for enhanced outcomes. Brain wave biofeedback addressing slow cortical potentials (SCP, the direct versus alternating currents in the brain generated partly by glial cells that outnumber neurons) has been vigorously investigated particularly by European researchers. A study published in the Journal of Neural Transmission...

"...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."

The authors assigned children with ADHD to either SCP neurofeedback or group therapy and correlated the effects with QEEG measurements and behavioral ratings. Children with ADHD-combined type in the NF group had improvement of selected QEEG markers that were associated with behavioral scales, with specific influences of SCP training on brain functions evident.

"To conclude, SCP neurofeedback improves only selected attentional brain functions as measurable with QEEG at rest or CNV mapping."

Another study just published by German scientists in the journal Clinical Neurophysiology presents further evidence for neurofeedback from a randomised controlled trial:

"Children with ADHD either completed a NF training or a computerized attention skills training...At three times (pre-training, between the two training blocks and at post-training), event-related potentials (ERP) were recorded during the Attention Network Test."

They observed an increase of the CNV specific for the slow cortical potential neurofeedback training which was associated with a larger reduction of ADHD symptomatology.

"These distinct ERP effects are closely related to a successful NF training in children with ADHD."

A valuable study published in the journal Pediatrics offers additional evidence for the neurofeedback training of slow cortical potentials for ADHD:

"We investigated the effects of self-regulation of slow cortical potentials for children with attention-deficit/hyperactivity disorder. Slow cortical potentials are slow event-related direct-current shifts of the electroencephalogram. Slow cortical potential shifts in the electrical negative direction reflect the depolarization of large cortical cell assemblies, reducing their excitation threshold. This training aims at regulation of cortical excitation thresholds considered to be impaired in children with attention-deficit/hyperactivity disorder. Electroencephalographic data from the training and the 6-month follow-up are reported, as are changes in behavior and cognition."

The authors gave 30 sessions of self-regulation training of slow cortical potentials to 23 children with ADHD by feeding back increasing and decreasing slow cortical potentials at central brain regions through visual and auditory stimuli. Their data painted a gratifying picture:

"Measurement before and after the trials showed that children with attention-deficit/hyperactivity disorder learn to regulate negative slow cortical potentials. After training, significant improvement in behavior, attention, and IQ score was observed...All changes proved to be stable at 6 months' follow-up after the end of training."

They added an intriguing hypothesis:

"It is suggested that regulation of frontocentral negative slow cortical potentials affects the cholinergic-dopaminergic balance and allows children to adapt to task requirements more flexibly."

Another study published in Applied Psychophysiology and Biofeedback confirms that different approaches to exercising healthier brain self-regulation with neurofeedback can be successful.

"Behavioral and cognitive improvements in children with ADHD have been consistently reported after neurofeedback-treatment...This study addresses previous methodological shortcomings while comparing a neurofeedback-training of Theta-Beta frequencies and training of slow cortical potentials (SCPs). The study aimed at answering (a) whether patients were able to demonstrate learning of cortical self-regulation, (b) if treatment leads to an improvement in cognition and behavior and (c) if the two experimental groups differ in cognitive and behavioral outcome variables."

Two groups of 19 children with ADHD ages 8-13 were assigned to either SCP or Theta/Beta training for three phases of 10 sessions each. Both groups were blind to their assignment and potentially confounding variables were assessed. What were the results?

"Both groups were able to intentionally regulate cortical activity and improved in attention and IQ. Parents and teachers reported significant behavioral and cognitive improvements. Clinical effects for both groups remained stable six months after treatment. Groups did not differ in behavioural or cognitive outcome."

Neurofeedback practitioners hail from a variety of professional backgrounds. Good outcomes are more likely if the practitioner has multiple neurofeedback modalities to choose from according to the needs of the individual, access to objective evaluation of brain function by QEEG assessment, and the brain is supported according to its metabolic, hormonal and other needs from a functional medicine perspective.