fMRI imaging supports neurofeedback
Review of 2006 fMRI study on ADHD showing improved neural processing after brain wave biofeedback.
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David Rabner, Ph.D. reviews recent research on ADHD.
New New Evidence Supporting Neurofeedback for Treating ADHD **
is a popular albeit controversial intervention used in the treatment of
ADHD. Scientists have known for many years that the brain emits various
brainwaves that are indicative of the electrical activity of the brain
and that different types of brainwaves are emitted depending on whether
the person is in a focused and attentive state or a drowsy/day-dreaming
Neurofeedback allows a person to view these brainwaves on a
computer screen as they occur. By teaching a person to produce
brainwave patterns that are associated with a relaxed, alert, and
focused state, and having them practice this skill for many hours of
training, neurofeedback practitioners contend that individuals with ADHD
can learn to maintain this state and that many symptoms of ADHD will
diminish. Many scientists do not believe that such claims have been
sufficiently documented, however.
A typical clinical session of
neurofeedback training for a child with ADHD involves pasting electrodes
(sensors that pick up the electrical activity of the brain) to the head
with conductive gel. Wires from these electrodes are connected to a
device that amplifies the small signal obtained from the electrodes. The
child sits in a comfortable chair and watches a computer monitor. The
monitor displays a picture such as a moving graph that indicates the
degree to which the child is producing the desired pattern of brainwave
activity. The goal is for the child to learn to produce the type of
brainwave activity that is associated with a focused and attentive
Over the course of numerous training sessions it may
gradually become easier for the child to achieve this state and to
maintain it for longer periods of time. Proponents of neurofeedback
often describe this training as an exercise program for the brain, and
training continues until the client demonstrates the ability to
consistently achieve and maintain a pattern of EEG activity indicative
of a relaxed and attentive state. This typically requires 40-60
By the conclusion of treatment, neurofeedback advocates
believe that increases in attention and reductions in impulsivity that
are evident during training will transfer to important areas of the
child's life - e.g. home and school - and there are several published
studies (see below) that are consistent with this position. Critics of
neurofeedback, however, do not believe there is credible evidence to
indicate that such transfer occurs.
** Prior Neurofeedback Research Reviewed in Attention Research Update **
prior issues of Attention Research Update I have reviewed several
neurofeedback studies that highlight the promise of this approach for
helping individuals with ADHD. In the first study (Monastra et al.,
2001), 101 children and adolescents with AD/HD received multimodal
treatment that included stimulant medication, behavioral therapy, and
school consultation services. Fifty-one of these participants also
received neurofeedback because their parent(s) decided to include it in
their child's overall treatment plan. Participants in each group (i.e.
multimodal treatment vs. multimodal treatment + neurofeedback) did not
differ in the severity of symptoms before treatment began, and the
treatment provided differed only by whether it included neurofeedback.
months later, participants whose treatment included neurofeedback
showed greater improvement according to parent and teacher behavior
ratings, and no longer demonstrated the brainwave patterns that were
substantially different from children without ADHD. These gains remained
evident a week after medication was discontinued and suggest that
adding neurofeedback to a multimodal treatment program was associated
with important incremental benefits. You can find a comprehensive review
of this study at www.helpforadd.com/2003/january.htm.
a second study (Fuchs et al., 2003), parents of 34 children with AD/HD
between the ages of 8 and 12 chose either stimulant medication or
neurofeedback treatment for their child. The majority - the parents of
22 children -- opted for neurofeedback treatment. After 3 months,
children in both groups showed significant and comparable reductions in
ADHD symptoms according to parents and teachers. Laboratory tests of
attention also showed equivalent improvement. A comprehensive review of
this study is available at www.helpforadd.com/2003/april.htm.
children in both studies who received neurofeedback appeared to benefit
from this treatment. Critics of these studies would correctly point
out, however, that neither employed random assignment. The absence of
random assignment makes it impossible to rule out other factors the
groups may have differed on - besides whether they received
neurofeedback - as an explanation for the results obtained. This
limitation is found in virtually all studies of neurofeedback.
limitation is the failure to control for the substantial extra
therapist attention provided to children who received neurofeedback
treatment. It is possible that this extra attention - and not
neurofeedback training per se - is what accounts for children's
improvement. Although this strikes us unlikely given the intractability
of ADHD symptoms to adult attention and support alone, it cannot be
conclusively ruled out as an explanation.
** New Study of Neurofeedback for Treating ADHD **
recently published study addresses one of these important concerns,
i.e., the absence of random assignment, and also provides direct
evidence of changes in brain activity for children receiving
neurofeedback (Levesque, J., Beauregard, M., & Mensour, B. 2006.
Effect of neurofeedback training on the neural substrates of selective
attention in children with AD/HD: A functional magnetic resonance
imaging study. Neuroscience Letters, 394, 216-221.)
were 20 8-12-year-old children (4 girls and 16 boys) meeting DSM-IV
criteria for ADHD; children who were also diagnosed with learning
disabilities or a psychiatric diagnosis in addition to ADHD were
excluded. Fifteen children were randomly assigned to receive 40
hour-long sessions of neurofeedback training conducted over a 13-week
period. More children were assigned to the treatment group so that a
greater number of treated subjects could participate in the fMRI
procedure described below.
Consistent with what is known about
EEG (i.e., brainwave) activity in individuals with ADHD, training
focused on reducing the production of lower frequency theta waves and
increasing the production of higher frequency waves that are associated
with a more focused and attentive state. Control children received no
active intervention, nor did they receive comparable amounts of adult
attention. Although children in both groups had received stimulant
medication treatment prior to the study, no child received medication
during the study.
** STUDY MEASURES **
before and after neurofeedback training, the following measures were
collected on participants in the treatment and control groups:
1) Parent ratings of ADHD symptoms;
2) Digit Span Test-
This test requires children to repeat in correct order strings of
digits that are read to them. The strings get increasingly longer until
the child fails 2 trials in succession. After failing 2 successive
trials, the test is repeated with children required to repeat the digits
back in reverse order. Performance on this test depends on both
attention and working memory skills.
3) Continuous Performance Test
- This is a computerized test of sustained attention and the ability to
inhibit impulsive responding. In this test, the child is presented with
a series of auditory and visual stimuli via computer and must either
respond or inhibit responding by pressing particular keys according to
the stimulus that is presented. To well on this task, children need to
sustain careful attention and refrain from pressing keys impulsively
when the wrong stimulus is presented. This measure is widely used in the
evaluation of attention difficulties.
4) Counting Stroop Task
- This is a complex experimental task that involves both selective
attention and the ability to inhibit a well-learned response. In this
task, children are told that they will see sets of 1-4 identical words
appear on the computer screen. Their job is to indicate how many words
were presented by pressing a button the appropriate number of times.
some trials, the words consisted of names of common animals, e.g., dog,
cat, bird, etc.). For example, the word "cat" would appear 3 times and
the child would need to press the button 3 times. If the word appeared
only once, the child would press the button once. During these "neutral"
trials, the task was thus relatively easy.
On other trials,
however, referred to as "interference" trials, number words, e.g.,
"one", "two", "three", appeared on the screen. For example, the word
"one" might be written 3 times, requiring the child to button press 3
times. This is a more difficult task, however, because the content of
the word - the number one - conflicts with the number of button presses
the child must make. Because what the child reads interferes with how
he/she must respond, the processing required to do well on these trials
is more complex than when neutral animal words are presented. Prior
research has demonstrated that different brain areas are activated
during these different types of trials. (Note - This is a variant of the
more familiar color Stroop task, in which it is harder to name the
color that words are printed in when the ink color is different from the
word itself, e.g., when color words are written in green ink, it takes
longer to say the ink is gren when the word written is "red" than when
the word written is "green". You can try this for youself at http://faculty.washington.edu/chudler/words.html
children completed the Counting Stroop Task both before and after those
in the experimental group received neurofeedback treatment. A total of
120 "neutral" and "interference" trials were conducted during each
testing session and children's score was the number of trials they
An especially important feature of this study
is that children received fMRI scans as while completing the Counting
Stroop Task. FMRI is a technique for determining which parts of the
brain are activated as individuals perform certain tasks by "imaging"
the increased blood flow to the activated areas of the brain.
inclusion of fMRI scans during the Counting Stroop Task enabled the
researchers to examine results on this task in 2 ways. First, they could
determine whether treated children performed better after treatment
compared to the control group. And, second, they could determine via
fMRI data whether patterns of brain activation during the task changed
in neurofeedback treated children. Because neurofeedback is intended to
change the underlying pattern of brain activity, demonstrating such a
change is an important step in documenting the efficacy of this
** RESULTS **
Results indicated clear
improvements for children receiving neurofeedback treatment.
Specifically, the authors reported the following:
treated children, parent ratings of inattentive ADHD symptoms declined
significantly - into the normal range - while those of control children
remained clinically elevated.
2) For treated children, parent
ratings of hyperactive/impulsive ADHD symptoms declined significantly -
although not quite into the normal range - while those of control
children showed a modest increase.
3) On the Digit Span test,
scores for treated children increased significantly from time 1 to time
2; for control children, no significant increase was found.
the Continuous Performance Test, scores for treated children increased
significantly from time 1 to time 2; for control children, no
significant increase was found.
5) On the Counting Stroop Task,
treated children performed significantly better on both neutral and
interference trials at time 2 compared to time 1; for control children,
no increase in the accuracy of their performance was found.
FMRI results showed no difference in patterns of brain activation
between treated and control children at time 1. At time 2, however,
treated children showed a different pattern of brain activation during
the interference trials, i.e., those that required more complex
cognitive processing. The brain regions that were now activated were
those believed to play important roles in selective attention and the
suppression of inappropriate responses.
** SUMMARY and IMPLICATIONS **
study provides important new evidence to support the use of
neurofeedback as a treatment for ADHD. Advantages over several
previously published neurofeedback studies are that participants were
randomly assigned to the treatment vs. control conditions and the
inclusion of fMRI scans to document that neurofeedback treatment was
associated with actual changes in brain activity during a complex
As with previously published studies, treatment
was associated with a significant reduction in parent ratings of their
child's ADHD symptoms. Because parents were not blind to condition,
however, one can argue that this finding is confounded by parents'
knowledge of whether or not their child received treatment. In other
words, parents may have reported their child symptoms to improve simply
because they expected this would happen and not because objective
changes actually occurred.
Improvements for treated children in
Digit Span and the Continuous Performance test - both considered to be
objective assessments of attention and other cognitive skills - are not
subject to this same criticsm, and thus provide a stronger basis for
suggesting the neurofeedback treatment was helpful.
compelling of all, however, is the finding that neurofeedback treatment
was associated with changes in brain activation detected by fMRI scans
during the Counting Stoop Task. Proponents of neurofeedback treatment
have long suggested that it produces enduring changes in brain
functioning, and it is these changes that cause ADHD symptoms to
diminish. Results from this study provide important initial evidence
consistent with this hypothesis, although the absence of any long-term
follow up makes it impossible to know whether the changes detected were
transient or enduring.
While these results are encouraging, a
balanced review of any study requires a discussion of it's limitations,
and there are several to note. First, the sample size is relatively
small and replicating the findings with a larger sample would be
Another limitation of the sample is that children with
learning disabilities and diagnoses in addition to ADHD were excluded.
Because many children with ADHD have one or more co-occurring conditions
which can complicate treatment, it is not clear whether the results
obtained would generalize to a broader and more representative sample of
children with ADHD.
Third, the only behavior measure obtained
fwas rom parents who were not blind to treatment condition. Because
improving children's behavioral and academic functioning in school is an
especially important goal of ADHD treatment, the absence of such
information in this study is problematic; it should not be assumed that
such changesin the classroom would have occurred. Finally, as the
authors note, the control participants did not receive any attentional
training intervention whatsoever. Thus, although it is tempting to
conclude that specific training in changing brainwave activity was
responsible for the treatment effects, including changes in the fMRI
scans, this conclusion cannot be made with certainty.
example, training a different pattern of EEG activity using
neurofeedback, or an attention training intervention in which no direct
feedback on EEG activity was provided, may have yielded similar results.
One could even argue that the greater contact with researchers received
by children in the treatment group - 40 hours vs. 0 for those in the
control group - is what accounted for the treatment gains and that
neurofeedback itself had nothing to do with it.
Although I do not
find this to be a likely explanation, the study design does not enable
this possibility to conclusively ruled out. In an ideal design, control
children would go through a neurofeedback procedure that appeared
identical to what treated children received, only the training would
provide "sham" feedback that was not linked to their actual EEG
activity. If group differences were found with this procedure it would
be a clear indication that the specific EEG training received by
experimental subjects, rather than any type of "placebo" effect, is what
caused the improvements.
While these limitations are important
to be aware of, the pattern of findings reported add to the increasing
evidence base for using neurofeedback as a treatment for ADHD. While
many experts would argue that additional studies are required to clearly
demonstrate that this is an effective intervention - and I personally
agree with this statement - it is also important to recognize that a
number of studies provide converging evidence for the potential value of
I will continue to publish summaries of new
studies in this interesting area in Attention Research Update as they