Mar 11, 2009
Neurofeedback — also known as EEG Biofeedback — is an approach for treating ADHD in which individuals are provided real-time feedback on their brainwave patterns and taught to alter their typical EEG pattern to one that is consistent with a focused, attentive state. This is typically done by collecting EEG data from individuals as they focus on stimuli presented on a computer screen. Their ability to control the stimuli, for example, keeping the smile on a smiley face, is contingent on maintaining the particular EEG state being trained. According to neurofeedback proponents, learning how to do this during training generalizes to real world situations and this results in improved attention and reduced hyperactive/impulsive behavior.
Neurofeedback treatment for ADHD has been controversial in the field for many years and remains so today. Although a number of published studies have reported positive results many prominent ADHD researchers believe that problems with the design of these studies preclude concluding that neurofeedback is an effective treatment. These limitations have included the absence of random assignment, the lack of appropriate control groups, raters who are not ‘blind’ to children’s treatment status, and small samples. For additional background, you can find a recent review I wrote on existing research support for neurofeedback treatment of ADHD — along with links to extensive reviews of several recently published studies -: How Strong is the Research Support for Neurofeedback in Attention Deficits?
- Results from a New Study of Neurofeedback -
Recently, a study of neurofeedback treatment for ADHD was published that addresses several limitations that have undermined prior research [Gevensleben, et al., (2009). Is neurofeedback an efficacious treatment for ADHD? A randomized controlled clinical trial. Journal of Child Psychology and Psychiatry.]
The study was conducted in Germany and began with 102 children aged 8 to 12. All had been carefully diagnosed with ADHD and approximately over 90% had never received medication treatment. About 80% were boys. Children were randomly assigned to one of two treatment conditions: 36 sessions of neurofeedback training or 36 sessions of computerized attention training. The computerized attention training task was intended to serve as the control intervention. Training was conducted in two 50-minute blocks per sessions, with a short break in-between; children in both groups participated in two to three such training sessions per week.
- Description of Training -
Neurofeedback Training — As noted above, neurofeedback entails providing children with real-time feedback on their EEG state so that they become able to learn how to create and maintain a state that is consistent with focused attention. This is done by linking their ability to control what appears on the computer screen to their ability to produce and maintain the EEG state being trained. Technical details of the training protocols are not summarized here but were based on research findings suggesting the specific EEG differences between children with and without ADHD that training should address. For example, one part of training focused on teaching children to elevate their production of higher frequency beta waves and supress the production of lower frequency theta waves. This is based on prior findings that individuals with ADHD tend to have an elevated ratio of theta to beta activity relative (see Neurofeedback/ Quantitative EEG for ADHD diagnosis).
Computerized Attention Training — This treatment was based on a program called ‘Skillies’, described as award-winning German learning software that provides systematic exercises in visual and auditory perception, vigilance, sustained attention, and reactivity. It was considered the ‘control’ condition to which the results of neurofeedback training was compared.
Performing well on the program requires children to sustain their attention to a variety of game-like tasks that become increasingly challenging and that provide children with frequent feedback about their performance. Children thus receive extended practice in ‘paying attention’ for increasing periods to tasks that become increasingly demanding and need to learn to sustain their attention in order to do well. Unlike neurofeedback treatment,however, no direct feedback on EEG state is provided.
- Experimental Controls -
As noted above, children were randomly assigned to treatment condition, which is essential when comparing different interventions. Efforts were also made to make the intervention experience as similar as possible, except for the critical difference as to whether children received direct training in managing their EEG state. Thus, treatment for both groups entailed computer-game like tasks that demanded attention. In both conditions, children were encouraged to develop strategies to focus attention and to practice these strategies at home and school. They also received similar amounts of attention and praise for doing so.
By equalizing as many aspects of the training experience as possible, the researchers could attribute any outcome differences that emerged to critical differences in the programs themselves, i.e., whether feedback on EEG state was provided, as opposed to some extraneous factor such as attention from the experimenters, time spent on a demanding computer task, etc.
In addition to these important controls, efforts were made to keep parents and teachers ‘blind’ to the type of training children received. Thus, parents were only told that their child would receive either of two promising computer-based treatments for ADHD. They also did not accompany their child into the treatment room to observe. Children’s teachers were also not informed about the child’s treatment. Although a number of parents became aware of which treatment their child received, and perhaps some teachers did as well, it is not possible to keep everyone truly ‘blind’ in a study like this.
- Measuring Treatment Outcomes -
The main outcome measure used were parent and teacher ratings of children’s ADHD symptoms. In addition to ratings of core inattentive and hyperactive-impulsive symptoms, ratings were collected on a variety of other behaviors, e.g., oppositional behavior, conduct problems, emotional problems, and social problems. These rating scales were obtained before and after treatment.
To rule out placebo effects as an explanation for any treatment differences found, the researchers also asked parents about their attitudes towards treatment, how motivated they thought their children were, and how satisfied they were with their child’s treatment.
- Results -
Preliminary analysis revealed no group differences in parents’ attitudes towards, or satisfaction with, their child’s treatment or in how motivated they felt their child was. These factors thus should not have influenced parents’ ratings of core symptoms.
Results of the parent and teacher behavior ratings indicated the following:
1. Parents of children treated with neurofeedback reported significantly greater reductions in inattentive and hyperactive-impulsive symptoms than parents of control children, i.e,. those who received computerized attention training. The size of the group difference was in a range that would be considered moderate, i.e., about .5 standard deviations.
2. Teachers of children treated with neurofeedback reported significantly greater reductions in inattentive and hyperactive-impulsive symptoms than teachers of control children. The size of the group difference was similar in magnitude to that found for parents, about .5 standard deviations.
3. Apart from these differences in core ADHD symptoms, few group differences were found. However, neurofeedback was associated with greater reductions in parents’ ratings of oppositional and aggressive behavior. Teacher ratings for the two groups did not differ on any of the remaining behavioral measures.
The results summarized above reflect average differences between the groups. The authors also examined the percentage of children in each group that were judged to derive significant benefit where this was defined as at least a 25% reduction in core ADHD symptoms. Fifty-one percent of children in the neurofeedback group met this threshold compared to only 26% of children in the attention training control group. This difference was statistically significant as well.
- Summary and Implications -
This was a well-designed study of neurofeedback treatment for ADHD that used random assignment, blind raters, and included an appropriate control group. Results indicate that neurofeedback treatment yielded significantly greater reductions in parent and teacher ratings of core ADHD symptoms than the comparison treatment. Furthermore, the magnitude of the reductions appear large enough to be clinically meaningful. Although the impact of neurofeedback treatment on other aspects of children’s functioning was less pronounced, significant reductions in parents’ ratings of oppositional behavior were also found.
Overall, these findings add to the research support for neurofeedback as a treatment for ADHD. However, despite the many strengths of this study, there are concerns to note and reasons why some researchers will find a basis for criticizing it. The main concerns — and my own take on them — include the following:
1. Without getting too technical, some researchers will argue that the statistical tests used in this study were not ideal and may have overestimated the advantages of neurofeedback treatment. My sense from examining the data is that the primary findings would hold up even if more conservative statistical tests were employed. However, it would be really nice to see that done.
2. Neurofeedback is supposed to work by teaching children to transform their EEG state to one that is characteristic of children without ADHD. However, there were no EEG measures taken in this study. Thus, there is no way to know whether neurofeedback actually resulted in these hypothesized changes in EEG. While this is certainly true, this has more to do with documenting the mechanism by which neurofeedback led to reductions in ADHD symptoms and has nothing to do with whether those reductions actually occurred.
I believe that some neurofeedback practitioners would argue that this may have also diminished the benefits provided by neurofeedback treatment. The reason for this is that training was not matched to the specific EEG parameters that needed to be altered for each individual and that additional benefits would have accrued had this been done. Whether this is actually the case, however, would require additional research to determine.
3. No measures of children’s academic functioning were collected. Because improving academic performance is a critical treatment target for most children with ADHD, the absence of this data is an important study limitation. There is no arguing with this and it is unfortunate that measures of academic performance in the classroom were not collected.
4. No long-term follow up was conducted. There is thus no basis for knowing whether neurofeedback treatment resulted in any enduring benefits. While this is certainly a limitation, it should be noted that neither medication treatment nor behavioral treatment have been shown to have enduring benefits after treatment ends. However, one of the reputed advantages of neurofeedback is that it may result in enduring gains. Thus, adding a long-term follow up to this study would have been an important addition.
5. It is important to remember that when improvement was defined as at least a 25% reduction in core ADHD symptoms, about 50% of children treated with neurofeedback did not meet this threshold. Thus, many children did not derive significant benefit from this treatment even though the benefits averaged across all children were statistically significant.
This is not surprising as no treatment — including medication — will help everyone. However, the rate of non-responders is less than what is typically found in controlled studies of medication treatment and this is important to remain aware of.
Despite these limitations and concerns, my take on this study is that it represents an important addition to the research literature on neurofeedback treatment for ADHD. In the context of other positive findings that have been reported for neurofeedback, it provides additional basis for regarding this as an extremely promising treatment approach for some children with ADHD.
– Dr. David Rabiner is a child clinical psychologist and Director of Undergraduate Studies in the Department of Psychology and Neuroscience at Duke University. His research focuses on various issues related to ADHD, the impact of attention problems on academic achievement, and attention training. He also publishes Attention Research Update, a complimentary online newsletter that helps parents, professionals, and educators keep up with the latest research on ADHD.