Parents of ADHD Children
Biomarkers for adhd (from UC Davis)
More proof this illness we share has nothing to do with parenting.
*UC Davis researchers find potential biomarker for ADHD*
by Amy Swinderman
SACRAMENTO A study out of UC Davis <http://www.ucdavis.edu> has honed in
on a potential biomarker for certain types of
attention-deficit/hyperactivity disorder (ADHD), a finding that may help
distinguish between different ADHD subtypes and aid in the diagnosis and
treatment of a condition that affects more than 5 million children in the
According to the U.S. Centers for Disease Control and
an estimated 5.5 million children 4 to 17 years of age were diagnosed with
ADHD in 2007. The percentage of children with parent-reported ADHD
increased by 22 percent between 2003 and 2007. ADHD is approximately twice
as common among boys as girls, and is one of the most commonly diagnosed
psychiatric illnesses among children.
ADHD is a real brain disorder, not a pull-up-your-socks or a better
parenting issue, says Dr. Catherine Fassbender, a research scientist at
the UC Davis MIND Institute
<http://www.ucdmc.ucdavis.edu/mindinstitute>and a lead author on the
study. Kids struggle with this every day, and
ADHD is also a huge economic drain on the country involving more ER visits,
higher divorce rates, people not doing as well in their jobs as they could
be. One of our passions is to make people realize that ADHD is a real
disorder, and here is one more study showing that these children have
different challenges to deal with than regular kids do.
ADHD subtypes appear subjectively very different in the clinical setting,
but there are few objective physiological markers that have been able to
detect those differences. The goal of the study was to use oscillatory
changes in the electroencephalogram (EEG) related to informative cue
processing, motor preparation and top-down control to investigate
neurophysiological differences between typically developing (TD)
adolescents, and those diagnosed with predominantly inattentive (IA) or
combined (CB) (associated with symptoms of inattention as well as
impulsivity/hyperactivity) subtypes of ADHD.
In the old days, we didn t have technology like we do now, so we could
only look at observable behaviors, like how many items a child gets right
on certain tests, or how they perform certain tasks. But there may be very
different upstream reasons for what is happening. Electrophysiology gives
us a window into the brain and what is going on, and a better handle on the
different sorts of impairments that might be producing these behaviors,
The EEG was recorded from 57 rigorously screened adolescents (12 to 17
years old; 23 TD, 17 IA, and 17 CB), while they performed a cued flanker
task. The UC Davis researchers examined the oscillatory changes in theta
(3 5 Hz), alpha (8 12 Hz) and beta (22 25 Hz) EEG bands after cues that
informed participants with which hand they would subsequently be required
Some cues were more helpful than others, so the task required the
participants to sometimes override an initial impulse in order to respond
correctly situations that are particularly challenging for people with
ADHD. For example, brain waves were recorded during evaluations of the
subjects performance on a computer task during which they were asked to
look at a series of arrows pointing in different directions on a computer
screen, and then indicate the direction in which the center arrow pointed
by pressing a button for either left or right.
The researchers examined the teens alpha and beta brain waves after they
viewed the visual cues, and found differences between the teens with the
subtypes of ADHD and typically developing teens. The alpha wave patterns of
teens with the inattentive type did not process the important information
in the visual cues, limiting their ability to succeed.
The researchers also examined the subjects beta waves, which are
associated with the performance of motor tasks. These also differed among
those with and without ADHD and were most deficient in teens with the
combined type, suggesting that these teens had greatest difficulty
accomplishing the motor task pressing a button.
We found both distinct and common task-related neurophysiological
impairments in ADHD subtypes. Our results suggest that task-induced changes
in EEG oscillations provide an objective measure, which in conjunction with
other sources of information might help distinguish between ADHD subtypes
and therefore aid in diagnoses and evaluation of treatment, the
According to Fassbender, researchers in the field of ADHD have questioned
whether the ADHD combined subtype simply represents a more severe form of
Our study suggests differential impairment profiles in the ADHD subtypes,
and not simply an additive effect of impairments in the ADHD combined
subtype, Fassbender says. The inattentive group had problems processing
the cues, whereas the combined type had problems using the cues to prepare
a motor response.
The UC Davis finding could also inform the development of treatments to
address the underlying processing differences between ADHD subtypes,
Most treatments for ADHD do not take subtype differences into account,
she notes. Our findings suggest targets for treatment should differ for
the ADHD inattentive versus combined subtypes, and that advanced analysis
of brain waves may provide a biomarker for testing treatment responses.
There may be non-medical implications as well, she adds.
Studies like ours can pinpoint exactly what the different impairment is
for different children, so you can even develop teaching strategies for
specific impairments, she gives as an example.
However, Fassbender notes, It s still early in the game, and this would
require more extensive testing of our methods, but I feel that the more you
understand the underlying biology, the better chance we have of developing
an obvious commercial application down the road.
The study, Differential Oscillatory Electroencephalogram Between
Attention-Deficit/Hyperactivity Disorder Subtypes and Typically Developing
Adolescents, was published online on Oct. 11 in *Biological Psychiatry*, a
journal of the Society of Biological
Fassbender s co-authors included Ali Mazaheri, assistant professor at
of Amsterdam <http://www.uva.nl/en/home> s Academic Medical Center and a
guest researcher at the UC Davis Center for Mind and
as well as Sharon Coffey-Corina, Tadeus A. Hartanto, Julie B. Schweitzer
and George. R. Mangun. The study was funded by grants from the National
Institute of Mental Health <http://www.nimh.nih.gov/index.shtml> of the U.S.
National Institutes of Health <http://www.nih.gov>, the UC Davis MIND
Institute and the Netherlands Organisation for Scientific
as well as a Klingenstein Third Generation Foundation ADHD Fellowship.
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