 |
| One teacher, one scientist, and one paper; but how many conclusions? |
Today's
post is a little bit different, but this type of post will hopefully
become a semi-regular thing as the 'she blinded me with science' series. I'm cross-posting with Dr. Kris.
Dr. Kris and I met when she moved into my townhouse as a tenant while she was pursuing her Ph.D. in Genetics. She is a fabulous person, and I thoroughly loved living with her. Unfortunately, she was kidnapped by an errant boy-creature whom she subsequently married. I blame Stockholm Syndrome. Anyway, in an effort to class up the joint, I am doing a semi-regular science Wednesday with the good doctor. Prepare yourself for her being science-y and me being my typical irreverent self. If you like what you see, step on over to
Housewife, Ph.D
Her content and
comments are in purple; mine are in black.
ADHD 101 -
Attention
Deficit Hyperactivity Disorder is a condition that affects impulsivity
(the ability to control reactions/impulses), perseveration/task
persistence, the ability to read social cues, and maturity. Teachers and
school staff are likely to be the first people to notice these
behaviors in young children. In the early 1900’s, the perception was
that these behaviors were due to poor child-rearing. More recent
research points to a combination or environmental agents, food
additives, sugar, brain chemistry, and genetics as possible causes. ADHD
is also tentatively considered to be a dopamine linked disorder,
similar to Parkinson's Disease. Lower levels of dopamine are common in
children with ADHD. Dopamine is the chemical that activates the reward
principle in our brains, helps with hormone release, and has ties to
motor control. More discussion on causes can be found at
psychcentral.com. Also, students with ADHD have slower – but normally developing brains (see here).
This is why many teachers show some frustration with students and their
impulsivity and social skills – it can be up to three years behind that
of their same age peers. There do seem to be a lot of genetic ties – so
you are more likely to be diagnosed if you have an ADHD family member.
ADHD is a very commonly diagnosed disorder (at least one student in
every classroom across the country), and boys are diagnosed with it more
frequently than girls. More data and stats on diagnosis and prevalence
can be found here.
What did the authors of this paper in Medicine & Science in Sports & Exercies find out about ADHD and exercise?
This study was based on previous findings that aerobic activity works synergistically with medical therapy (methylphenidate AKA Concerta or Ritalin) for ADHD.
Previous work had shown that while about 10%-30% of children with ADHD
are not helped enough by medication, adding as little as 20 minutes
daily of aerobic exercise in addition to the medication improved
attention, cognitive symptoms, and social skills within 6 weeks. This
study sought to further our understanding of these improvements by
looking for normalization of brain function (measured by functional MRI
brain scans) in children who were treated with exercise and medication
for their ADHD.
For this study, researchers recruited
35 teenagers (13-18) with diagnosed ADHD who were not currently taking
medication. They also recruited 15 normal teenagers. Teens were excluded
from the study if they had any history of non-ADHD processing or
emotional diagnoses including Axis I mental disorders (depression,
bipolar, ODD, many others), history of head trauma, or intellectual
disability; or if they had a history of substance abuse. The ADHD teens
were then split into two different treatment groups: one group was given
methylphenidate and exercise (exercise group), the other group was
given methylphenidate and classes on interpersonal skills (education
group). The normal teenagers formed the control group.
For
both treatment groups methylphenidate was started at 10mg/day. Then
based on each teen's response to the drug, the dose was increased over
the first 4 weeks to as much as 40mg/day, and then held at that dose for
the duration of the study (6 more weeks).
For the
exercise group, exercise was done 3 days per week with the researchers.
In these 90min sessions teens first warmed up, then did 60 min of
aerobic exercise, and finished with a cool down. The aerobic exercise
was running, jumping rope, or playing basketball with the goal of
keeping each teen's heart rate over 120bpm for the full hour.
For
the education group the teens attended 50min classes twice per week.
The classes were intended to help teach skills kids with ADHD often
struggle with, including how to make friends and how to pay attention.
In both groups the exercise or education sessions were continued for 6
weeks (starting after the 4 week period for adjusting to methylphenidat)
and overseen by a psychiatrist and a social worker.
The
majority of the results of this study focus on a comparison between the
two treatment groups after 0, 4,and 10 weeks (i.e. baseline, medication
only, and medication + 6weeks of exercise/education). These comparisons
were made two ways. First, by conducting a traditional symptom-based
ADHD assessment. Severity of symptoms is expressed with a numeric value.
A higher number represents more sever symptoms. Second, by having the
teens take a Wisconsin Card Sorting test while undergoing an fMRI brain
scan. This sorting test works by asking the participant match cards, but
with a catch: the participant isn't told in advanced what the matching
rules are, but they are told if a match is right or wrong after it's
been made. This test is used by researchers and psychiatrists to measure
frontal lobe function: strategic planning, organized searching, using
feedback, directing behavior toward achieving a goal, and modulating
impulsive responding. All things kids with ADHD struggle with. Therefor,
an improvement in performance on the sorting test suggests an
improvement in ADHD symptoms. Performance can be measured in total time
to complete the test or in the number of times the participant tries to
use the same incorrect sorting rule (called preservative errors: in
psychology "preservative" refers to failing to update behavior based on
feedback).
At baseline both ADHD groups had an average
symptom severity score of about 25, the control group had and average
score of 4 (difference is statistically significant, p-value <0.01).
Both ADHD groups had a non-statistically significantly longer time to
complete the sorting test compared to the control (46.0 vs 33.6, p-value
0.06), and a statistically significantly larger number of preservative
error (13.3 vs 8.1, p-value <0.01).
After 10 weeks
both groups of ADHD teens showed improvement in their symptoms and in
performance on the sorting test. For the exercise group their new
average ADHD assessment score was 9.4, and for the education group it
was 14.9. Both groups showed a statistically significant improvement
over baseline, and the exercise group showed statistically significantly
more improvement than the education group. The researchers do not say
if the 9.4 score is statistically significantly different from the 4 for
the control group; I suspect that it is (if it was statistically
non-significant I think they would point this out as it would mean the
exercise teens were "cured"). When looking at their sorting card tests
the change in preservative errors showed the same pattern: both groups
showed improvement, but the improvement was statistically significantly
greater in the exercise group (baseline 13.3 errors, 10wk exercise 7.8,
and 10wk education 11.1). In this case the exercise group appears to
have achieved "normal" compared to the control teens (8.1 errors). These
results were all consistent with previous findings that exercise
improves ADHD symptoms.
This research wanted to answer
an additional question: did the brain function normalize along with the
symptom relief? Many parts of the ADHD teens brain showed less activity
during the sorting test compared to the normal teens: right occipital
lobe (vision processing), middle temporal gyri (image
recognition/memory), right cerebellum posterior lobe (fine motor
coordination), right prefrontal cortex (planning/focus/impulse control),
right and left parietal lobes (sensory integration). The right limbic
lobe (memory) showed more activity in the ADHD teens. One might imagine,
based on this, that these teens are struggling to focus on the task at
hand (more memory in use, less actual looking at / dealing with the
cards).
After the 10 week intervention statistically
significant changes in brain activity were seen. For the education
group, changes were only seen in the right prefrontal cortex
(planning/impulse control) and left parietal lobe (sensory integration).
For the exercise group, changes were seen in those two areas and in the
right middle temporal gyrus (but not left; image recognition/memory).
The changes in activity withing the right prefrontal cortex
(planning/focus/impulse control) were statistically significantly
negatively correlated with change in the severity of ADHD symptoms and
the number of preservative errors. Because this area was less active in ADHD teens, this means that as activity rose (towards normal levels), ADHD symptoms improved.
Based on these findings and the work of other researcher, this paper's authors conclude that aerobic
exercise, when combined with medication, improved ADHD symptoms by
increasing activity in the prefrontal cortex (planning/focus/impulse
control) towards the levels seen in normal teens. Specifically,
while they have not found a conclusive mechanism for this increased
activity, they hypothesize that it may be related to increased dopamine
and oxygenation/cellular metabolism due to better blood flow. The
authors say that their study is limited because they did not include
exercise only and education only (no medication) groups, so they cannot
determine if the effects of exercise are synergistic or additive. They
suggest further research to make this determination and see if specific
types of exercise are more helpful.
What are our conclusions?
If
you examine the criteria used to select/eliminate test subjects, the
researchers did an excellent job eliminating co-morbid issues as well as
blocking individuals on non-prescribed drugs. The study size ended up
being small. Additionally, the study shrank more as subjects had
negative reactions to medications and were unable to work out daily and
were disqualified (more on that later). The scanning of the brains of
the subjects showed what areas of the brain changed after the
application of the treatments (exercise showed the best results)--and it
was the prefrontal cortex! This is a GREAT outcome. Dopamine is likely a
key player in the change as exercise helps to raise dopamine levels! Don’t we all love some dopamine?
Here’s
where we get to my more specific questions/concerns. Accepting the
science at face value and assuming a larger study would have similar
results – I am still not sure how practical the findings of this study
are. In as school setting, we have no influence over (and should not
suggest) putting students on medication to begin with. We can comment if
we’ve seen changes from a child’s dosage changes, but medical decisions
are family business. This study started with the subjects all being
medicated. Medication does work for some, but I know it does not work in
all situations (from personal experience as well as observations).
Additionally, the amount of exercise in the test group totaled about 80
minutes a day 3 days a week. Not only was this a larger quantity of time
then the soft skills lessons, it is a large block of time for many busy
high school students. It would eliminate time for after school
tutoring, organized sports, and outside pursuits.
For
research-motivated special educators and parents, this study confirms
what years of anecdotal evidence have suggested. Kids need to move.
People need to move. Aerobic activity helps immensely with focus and
helps speed up the lagging prefrontal cortex development. Exercise
is something I heartily endorse at meetings and in forming plans for
students. It is also an opportunity for parents and students to take
ownership of the student’s educational progression. If running,
swimming, or basketball is going to help your child succeed, steps need
to be taken to make that a priority on the family level. Schools can
provide some outlets through team sports/ROTC/PE, but cannot bear the
full responsibility. A
team sport could provide some of the suggested aerobic activity, such
as soccer or cross-country. I will be reading more studies focusing on
shorter sessions of aerobic activity or less days of training a week
and seeing if the results are similar. Traditionally, team sports are
considered to be an excellent way to grow social skills – perhaps it is
because of the dopamine and those little blossoming prefrontal
cortexes!
It
is important here to remember that while schools are mandated to
provide learning opportunities to all students, we are also bound to
provide all students free and appropriate education and equal access.
Equal access does not necessarily mean providing every conceivable
resource. So while I think adding more movement at every level would be
beneficial for ADHD (and possibly all!) students, it would take a major
overhaul of schedules, student expectations, massive amounts of funding
and a huge amount of parental support and effort to have movement
classes tacked on or added to a school day. I think this is a situations
where individual parents and families have a lot of power in enabling
their students by encouraging a school sport, or even just buying their
child some running shoes. Policy changes won't happen overnight - if
this is a direction parents want to see our schools going, we need to
hear from them!
I
mostly agree with everything said here, but I think that there are
policy changes that schools can make that will be good for all kids, and
it sounds like particularly good for kids with ADHD. Sara-Liz
said, and I 100% agree, kids (people) need to move their bodies. At its
very simplest, let's get recess and PE (and art, music, and drama!) into
all schools. Especially elementary and middle schools. More time for
math and science sounds great (especially to me), but if the kids can't
focus because they need to wiggle then it doesn't benefit them and may
just make them hate the subjects or think they're bad at them. These
aren't changes that one (special ed) teacher can institute; these are
changes that need to be made at the district or state level. So while a
parent can (and should) make sure his/her child gets the chance to run
and move and play outside of school hours, maybe parents of kids in
schools with no recess should also start talking about this kind of
research with the people who can change school policies/schedules.
Adding more "stuff" to the schools' list of responsibilities isn't an easy
fix, it's complicated and expensive. And, of course, making time for
recess won't force kids to get their heart rates up--the schools can't
and shouldn't do that. But we have public school so that every kid has
the opportunity to learn, grow, and succeed. If more research
continues to find that movement and time outside is important to kids'
development, then the effort and expense to ensure all kids have access
to some supervised safe outdoor play time will be money well spent.
References (paywall)
Choi, JW. et al. "Aerobic Exercise and Attention Deficit Hyperactivity Disorder: Brain Research" Medicine & Science in Sports & Exercise. Published ahead of print April 2014. Accessed Nov 5, 2014.
