Support
for Attention Research Update is provided
by Cogmed
Cogmed has developed a computerized
training program to improve
working memory, which is a frequent problem for children and adults
with ADHD. Research has shown that Cogmed's program can enhance
working memory, and that improvements in working memory are associated
with reductions in attention and learning problems. You can learn
more at
Cogmed.com. Clinicians interested
in learning about the
benefits of
incorporating working memory training into their practice are invited
to
request an information package for
professionals.
Support for this issue has also been provide
Shire US Inc. Shire has developed an
excellent education site at
www.adhdsupport.com where you
will find a wide range of educational information and support resources
and where you can request a Free ADHD took kit.
DISCLOSURE
- It is the policy of Attention Research Update to disclose when
a study reviewed in the newsletter is closely related to a product or
service from a company that provides support for the newsletter.
In keeping with this policy, I want to disclose that Attention Research
Update receives financial support from a company that licenses
the working memory training program that is evaluated in the study
described below. My review of this study was written over a year
before the company became a supporter of Attention Research Update and
has not been altered in any way. I thus believe the summary below
provides an objective review of the published account but want you to
be aware of this potential conflict of interest. The
citation for the study is highlighted below in red should you wish to
review the original publication.
There is a pressing need to
develop treatments for ADHD in addition to medication and behavior
therapy that have strong research support and a number of different
reasons why this is important.
Regarding medication, not all
children benefit from taking it, some experience intolerable side
effects, and many continue to struggle even though medication may be
somewhat helpful. Behavior therapy can be difficult for parents to
consistently implement, and does not generally reduce behavior
difficulties to normative levels. Furthermore, even though both
treatments can be extremely helpful in managing ADHD symptoms and
reducing oppositional behavior, they do not induce lasting changes in
the child that persist after treatments is discontinued. Finally,
despite numerous studies documenting the short- and intermediate term
benefits of these treatments, their impact on children's long-term
success remains to be clearly documented.
Because of these limitations, there
have been numerous efforts to develop alternative treatments for ADHD
that may enhance the benefits offered by medication and behavior
therapy. In a future issue of Attention Research Update, I hope
to provide an overview of these efforts. Today, however, I am excited
to report results from a recently published study on the use of
computerized training of working memory in children with ADHD
(Klingberg, et al., 2005.
Computerized training of working memory in
children with ADHD - A randomized controlled trial,. Journal of the
American Academy of Child and Adolescent Psychiatry, 44,
177-186.) Unlike many studies of alternative or
complementary
ADHD treatments, this study includes a number of experimental controls
that allow for greater confidence in the findings.
As noted in a recent issue of
Attention Research Update - http://www.helpforadd.com/2005/february.htm
- executive functioning deficits are believed to play an important role
in ADHD. Executive functions refer to those mental operations
that help to organize and direct complex behavior, and include such
operations as goal setting, planning, reasoning, cognitive flexibility,
and the ability to delay responding. Working memory (WM) - the
ability to hold information in one's mind for subsequent use - is a
particularly important executive function because it may underlie other
executive functions such as reasoning. WM deficits in individuals
with ADHD have been demonstrated repeatedly and have been suggested to
contribute to the academic struggles that many children with ADHD
experience. Developing an intervention to enhance WM in children
with ADHD could thus be extremely helpful.
The study reviewed below
investigated whether systematic training of WM tasks during a 5-week
period could improve WM, other executive functions, and reduce ADHD
symptoms in 50 7-12 year old children - approximately 90% male -
diagnosed with ADHD. None of the children were on medication when
the study began, or at any time during the study. For reasons
that are unclear, children with oppositional defiant disorder or
depression in addition to ADHD were excluded, and only those with ADHD
diagnoses exclusively were recruited into the sample.
Participants were randomly assigned
to 1 of 2 conditions - a high intensity (HI) WM training condition and
a low intensity (LI) WM training condition. The HI treatment
consisted of performing WM tasks via a computer program developed for
the study. These included visuospatioal WM tasks - remembering
the position of objects on the screen - as well as verbal tasks -
remembering sequences of letters, sounds, and digits. In all
cases, children responded to the WM task by clicking on various choices
with the computer mouse. Each training session provided exposure
to 90 WM tasks and required about 45 minutes to complete. The
difficulty level of the WM tasks was automatically adjusted to match
the WM ability of the child by modifying the number of elements the
child was required to hold in memory on a trial-by-trial basis.
By this method, children were continually challenged to improve their
WM ability by presenting them with more difficult tasks after they
succeeded with easier ones. In addition to improving their
working memory, children had to attend consistently and remain
relatively inactive - remaining seated in front of the computer - to
perform well. Thus, in addition to training memory, benefits in
attention and reductions in activity level might be expected to occur
as well.
The LI condition was identical to
that described above except that the difficulty of the 90 WM trials
remained at a low level throughout, i.e., the number of items children
were required to recall never increased beyond 2 to 3. Thus,
these children had the same experience as children in the high
intensity treatment group, i.e., they spent the same amount of time
engaging in computerized WM tasks, but they were not challenged to
improve. As a result, children in this condition were not
expected to show the same improvement in WM, other executive functions,
or ADHD symptoms as children receiving the high intensity treatment.
During the 5-weeks of training,
children needed to complete a minimum of 20 training sessions that were
completed at home or wherever else children had access to a computer.
(Note: Parents had been given a CD with the training software and
simply had to install it on a computer their child had access
to.) Training session results were uploaded by the researchers
via the Internet so that they could maintain a database of each child's
performance. Parents were contacted by phone on a weekly basis to
inquire about any technical difficulties and provide feedback about how
many training sessions the child had completed that week. This
was intended to insure that all children completed the required number
of sessions.
A number of different measures were
collected so that the impact of the computerized training of WM could
be evaluated. These included several measures of WM, a measure of
response inhibition, i.e., the ability to delay responding, and a
measure of non-verbal reasoning ability. In addition, ratings of
ADHD symptoms were obtained from parents and teachers. These
measures were collected before treatment began, immediately following
treatment, and 3 months after treatment ended. This enabled the
researchers to determine whether children receiving high intensity
treatment showed greater improvement immediately following the
intervention, and whether these benefits remained evident 3 months
later, even though no further training had occurred.
Before summarizing the results, it
is important to highlight several important design features that make
this study exceptionally strong. First, children were assigned at
random to the HI or LI conditions. There is thus no reason to
expect that pre-existing differences between children in the 2 groups
could explain any treatment differences that emerged.
Second, parents, children, nor and
teachers were not aware of which condition children had been
assigned to. Parents and children were simply told that the child
would be taking part in 1 of 2 different treatments, and that 1 of
these treatments was expected to be more helpful than the other. It
would not have been evident to parents or children, however, whether
the child was in the condition that was expected to be more or less
helpful. In addition, psychologists who performed the
neuropsychological assessments were "blind" to the child's condition.
Thus, the outcome measures collected can be considered "unbiased"
because no one responsible for providing or obtaining the data really
knew whether the child would be expected to show improvement.
Finally, the experience of children
in the HI and LI conditions was highly similar. They spent the
same amount of time in training and completed training exercises that
were similar in form. The only difference was in the difficulty
level of the training tasks that were presented to them.
Collectively, these design elements
help rule out the possibility that any treatment differences could be
attributed to pre-existing differences between the groups, biased
reports from raters, or non-specific differences in children's
experience during the study. Instead, any such differences that
emerged are likely to reflect the actual WM training that children in
the high intensity condition received.
RESULTS
To examine intervention
effects, researchers compared results for the HI and LI groups
immediately following the intervention and 3 months after treatment
ended. In all analyses, baseline assessments were included as
controls, which further assures that treatment differences could not be
explained by pre-existing group differences. Results from this study
were as follows: (Note - Participants included children with the
combined and inattentive subtypes of ADHD. The results reported below
apply to each subtype and no subtype differences in treatment response
were observed.)
1) Immediately following the
treatment, children in the HI group showed significantly better WM than
children in the LI group. The gains made by children in the HI group
were comparable to gains associated with medication treatment that had
been demonstrated in prior studies. These benefits remained
evident at the 3-month follow up and showed no decline in magnitude.
2) The HI group performed better on
all other executive functioning assessments - non-verbal reasoning and
response inhibition - at post treatment than the LI group, although the
magnitude of the difference was not as great as for WM. The
better performance was still evident at the 3-month follow up.
3) Parent ratings of inattentive and
hyperactive-impulsive symptoms were lower at post-intervention and at
the 3-month follow up for children in the HI group. The
reductions in parent ratings of attention difficulties were substantial
while reductions in ratings of hyperactive-impulsive symptoms were more
moderate. Parent ratings of oppositional behavior were also
significantly lower in the HI group at both time points.
4) Group differences in ADHD
symptoms ratings completed by children's teachers were not significant.
SUMMARY AND IMPLICATIONS
Results from this study
provide strong evidence that approximately 20 hours of computerized WM
training over a 5-week period produced gains in this important
executive function and in other executive functions that were not the
specific focus of training. These benefits were evident
immediately following training and remained evident 3 months later,
even though no further training had occurred. In addition, there were
significant reductions in children's ADHD symptoms according to
parents, although no comparable benefits were evident in teachers'
ratings. The gains in WM and the reductions in attention difficulties
reported by parents were large, and comparable in magnitude to effects
obtained by medication.
The strong design of this study,
which included random assignment and "blind" raters, provides a basis
for attributing these gains to the WM training itself rather than to
other confounding factors. As such, this would appear to be a
very promising intervention for children with ADHD. It is
especially noteworthy that benefits persisted for 3 months after
treatment ended. This suggests that, unlike medication and
behavior therapy, gains associated with computerized WM training may be
more enduring. How long these gains might last is unclear,
however, as is the need for continued training in order to sustain
these gains over a longer period.
Despite the exciting nature of these
findings, the authors themselves highlight several limitations to their
study that will be important to address in future research.
First, despite the exciting nature
of the findings, replication with a larger sample that includes more
females will be important.
Second, because children with
co-occurring oppositional defiant disorder and/or depression were
excluded, the extent to which the results would generalize to children
with ADHD and these other conditions is not known. Because many
children with ADHD also have these other conditions, it will be
especially important to learn whether this intervention is helpful to
these children as well.
Third, the absence of teacher
reported gains is concerning. Although the authors suggest that
ratings from parents are more reliable because they were consistent
with the executive functioning results, the basis for this suggestion
is unclear. Because a goal of ADHD treatment is improving children's
functioning at school, demonstrating that this treatment produces this
effect remains critically important. This would include
assessment of "real-world" academic functioning, which was not part of
the current study.
In summary, this study provides
preliminary evidence that computerized training of WM may be an
effective intervention for children with ADHD. It is important to
recognize, however, that additional research will be required in order
to conclusively document the benefits of this intervention as well as
to understand its limitations. Lets hope that such research is
currently underway and will become available shortly.