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When
considering the use of stimulant medication treatment for their child,
parents often wonder whether it is possible to know in advance if it will
work and if there will be any adverse side effects. To date, the answer to
this question has been that it is not possible to determine such outcomes.
Thus, although most children with ADHD will show clear reductions in ADHD
symptoms when stimulant medication is administered appropriately, results
from prior research suggest that predicting the response for individual
children is not possible. The same holds true for predicting which children
may experience unpleasant side effects.
Making accurate predictions would be useful for several reasons. First, if
parents reluctant to consider medication could be assured that it would help
their child, they might be more willing to give it a try. Second, for those
children who were unlikely to benefit and were likely to experience adverse
reactions to the medication, an unpleasant and ineffective treatment
experience could be avoided
A study appearing in a recent issue of the journal Biofeedback provides
intriguing evidence that such predictions may be possible (Monastra, V., vol. 28, 2000). A bit of background
information is necessary before discussing these important findings.
In an issue of Neuropsychology, Dr. Monastra and his colleagues demonstrated that individuals
with ADHD showed a distinctive pattern of results on a quantitative
electroencephalography (QEEG) reading.
QEEG is a procedure in which the pattern of electrical activity in different
brain regions is recorded and measured. The research of Dr. Monastra and others indicates that most individuals
diagnosed with ADHD via traditional methods, such as diagnostic interviews
and standardized behavior rating scales, show a QEEG
pattern that indicates under-activity in prefrontal brain areas. It is
suggested, although not yet confirmed, that under-activity in this brain region
causes the behavioral symptoms that individuals with ADHD display. In
contrast, very few individuals not showing the behavioral symptoms
characteristic of ADHD showed this same pattern of cortical under-activity.
Of course, because ADHD is currently diagnosed based on the presence of
observable behaviors rather than any particular QEEG pattern, not all
individuals who meet diagnostic criteria for ADHD show this pattern of
cortical slowing in their QEEG results. This fact is the basis for the
current study.
Participants in this study included 144 individuals between the ages of 6 and
20 who were diagnosed with ADHD using DSM-IV diagnostic criteria. QEEG
recordings were then conducted with these individuals. As expected, the
majority (103) demonstrated the anticipated cortical slowing on their QEEG.
The other 41 individuals did not. Remember, all 144 had already shown a
sufficient number of inattentive and/or hyperactive-impulsive symptoms to
warrant a diagnosis of ADHD. The difference between the two groups was not in
the behavioral symptoms they displayed, but rather, whether a particular type
of QEEG result was received.
After the diagnostic and QEEG procedures, all patients received a careful
trial of stimulant medication. Participants were started on a low dose of
methylphenidate (the generic form of Ritalin) two times per day and were
given up to a maximum dose of 20 mg twice per day as needed. If
methylphenidate was not helpful, a switch was made to Adderall,
and the titration procedure began again. Careful measures were taken to
determine whether each individual obtained clinically significant benefits
from stimulant medication. Those who responded to medication (either
medication or any dose) received behavior ratings on an ADHD rating scale from
parents and teachers that placed them in a non-clinical range, and they
obtained a "normal" score on a computerized test of sustained
attention while on medication. Individuals who did not attain such benefits
on either medication were classified as non-responders.
Results
Of the 103 participants who showed the cortical slowing pattern on their
QEEG, 96 responded positively to stimulant medication. In contrast, of the 41
participants who showed no cortical slowing on their QEEG, none responded
positively to methylphenidate or Adderall.
(Remember, a positive medication response was defined as normalized behavior
ratings from parents and teachers as well as a “normal” performance on a
computerized test of sustained attention. The criterion for determining
positive responders was quite strict.) In addition, each of these 41
non-responders exhibited at least 3 of the following side effects: headaches,
increased irritability, sedation, rapid speech, increased impulsive
behaviors, or increased hyperactivity. These side effects were rarely
reported among those who responded positively to medication.
When efforts were made to predict medication response according to the number
and severity of ADHD symptoms or performance on the computerized attention
tests, no accurate predictions were achieved. Thus, it was only the
indication of cortical slowing on the QEEG that enabled accurate predictions
to be made.
Summary And Implications
The results of this study are impressive. Although almost every participant
with ADHD who showed cortical slowing obtained substantial benefits from
medication, those showing the behavioral symptoms of ADHD without this QEEG
pattern never obtained a similar benefit. While these results require careful
replication, they are exciting. Not only may QEEG prove to be a useful tool
to assist in the ADHD diagnostic process, but it may also help to identify
individuals showing the behavioral manifestations of ADHD who are (and are
not) likely to benefit from stimulant medication.
As noted earlier, this would be quite helpful for treatment planning
purposes. Although not examined in this study, it is also possible that
individuals not showing the cortical slowing pattern would have responded to
a different class of medication, such as an antidepressant. This would be an
interesting question to explore in subsequent research.
These results also highlight something that is important for clinicians and
parents to be aware of: the behavioral symptoms of ADHD can have different
origins. Typically, recently published research suggests that individuals
diagnosed with ADHD using the current behavioral criteria will show the
pattern of cortical slowing that researchers like Dr. Monastra
have identified. However, other individuals showing the ADHD behaviors will
not. This suggests that some individuals with ADHD have developed their
symptoms for other reasons. Accurately identifying those reasons may be key to providing appropriate treatment.
There is other published research which suggests that dietary factors,
elevated lead levels, deficiencies in trace minerals like iron and magnesium,
along with a variety of other factors may be important contributors to ADHD
symptoms in individuals without the pattern of cortical slowing. When
specific causes are identified for an individual, it is often directly linked
to a specific treatment. For example, providing magnesium supplementation to
children with ADHD found to be deficient in magnesium. This is an area where
additional research is needed, and it is important to note that such ideas
are not widely accepted within the medical and scientific community.
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