I am now 1/3 of the way through the class and overall I’ve really enjoyed it. The course description estimated the workload at 2-4 hours per week and that has been correct. The TA’s have done a good job responding to questions about the weekly quizzes and making changes when there is a consensus that a question had confusing wording. This week they are adding another unique feature for a Massive Open Online Course (MOOC) — office hours! We can submit questions to the professor and Friday he will answer as many as he can.
This week we explored the neuro-imaging of ADHD. Although there are differences seen in PET and fMRI scans in adults with ADHD versus adults without ADHD, neuro-imaging cannot be used to diagnose ADHD. Looking at ADHD from a parenting or educator lens, here is the information I found most relevant.
First, while maximum brain volume is typically reached by age 16 for all children, those diagnosed with ADHD show about a 3-year lag in brain development. This is most likely one of the reasons they seem less mature than their classmates. Once their brains are fully developed at about age 16, people who have ADHD still show smaller and less active orbital-prefrontal cortexes, basal ganglias, and cerebellums. The size difference of these regions compared to a more typical brain is directly correlated with how sever the ADHD symptoms are in a given person. Individuals diagnosed with ADHD also show lower levels of dopamine transporters in the brain’s reward center. Although the lecture didn’t cover it, I suspect that an impaired reward system is one of the reasons some ADHD individuals are susceptible to drug abuse and addition.
One area of brain anatomy and function covered in-depth for the first time this week is the role of the anterior cingulate cortex. Individuals with ADHD have less activity in the anterior cingulate cortex than more neuro-typical people and this can significantly impair their performance. The anterior cingulate cortex is an essential part of the cognitive and emotional executive attention system and has a role in emotion, motivation, timing, focused attention, willed motor control, working memory, pain, error detection, reward, monitoring, and feedback-mediated decision-making. One of these, working memory, is explicitly tested for in IQ tests such as the Stanford-Binet and some researchers feel that working memory is more important than IQ when predicting overall achievement. A child may be highly gifted but not perform as expected if their working memory (and attention for that matter) is less than ideal. Although some high-energy gifted kids are incorrectly diagnosed with ADHD, there is most likely another group of gifted kids that are not recognized as being gifted or having ADHD because their performance is average and their behavior isn’t annoying enough for the adults to suspect ADHD.
So what effect do drugs, especially methylphenidate, have on brain function and anatomy as viewed with neuro-imaging? They definitely increase brain activity while they are in the system, however, they do not change brain structure. The medications can help a child improve their classroom behavior, performance, and teacher and peer interactions in the short-term. Yet psychostimulants do not seem to create long-term changes in outcomes for peer relationships, social skills, academic skills, or school achievement. This little tidbit, buried at the top of page 146 of the 1999 Surgeon General’s report on ADHD, assigned for our week 5 reading, sent me on a search for more studies and more information.
If ADHD medicine is only a short-term fix, why are we drugging our kids’s developing brains? Aren’t there other ways to change their behavior? And if their symptoms are so bad, why is it common to just prescribe drugs without also helping them with behavioral techniques? The combined treatment of drugs plus behavior modification has better results than just treatment with drugs alone. The drugs may make a child more attentive, less impulsive, and less disruptive but they have no effect on academic achievement. Just because a child is sitting still, better at completing homework, and easier to handle in class, does not mean that child is actually learning more. The lack of long-term improvement with the use of stimulant medication, combined with study results that indicate that they may increase depression in some children and have negative long-term cardiovascular implications, makes me question why they are prescribed so freely in the US. This in-depth, long-term view is beyond the scope of the Coursera class which is more focused on the basics of how ADHD is viewed, diagnosed, and treated by doctors today.
People with ADHD can have a more difficult time completing tasks and attending to directions, especially if they are not interested in or are bored by the subject matter. Our current view has classified ADHD as a disorder because of this impairment. What if evolutionarily speaking, this isn’t the case? What if ADHD tendencies are a different way for a perfectly normal brain to function and the ADHD brain is optimized in some other way that isn’t compatible with our current education system?
The most interesting part of the lecture this week, for me, was something I noticed on a brain scan that wasn’t directly addressed. The brain scan from a study on anterior cingulate cortex dysfunction in ADHD, left me with a strong desire for more research. In it we see differences in brain activity during a counting stroop task for individuals with “normal” brains vs individuals with diagnosed ADHD. The “normal” brain on the left shows the anterior cingulate (green rectangle) lit up with bright yellow and red activity while the ADHD brain on the right shows nothing going on in the anterior cingulated cortex but lots of activity in the frontal stratal, insular and thalamic network. The lecture highlighted the fact that ADHD individuals had to work harder and were slower at solving the task than were other individuals because they were solving the task with a less than ideal brain region. This begs the question, what are the ADHD individuals thinking about and what connections are they making? Clearly there is a lot of something going on in their brains, by colored area alone there is actually more activity than in the “normal” brain. Just because they can’t perform as well on the counting stroop task does not mean that this activity should be deemed suboptimal. See the images yourself on page 1547 of the study.
We know that studies of scans of men’s and women’s brains clearly show that men and women process information differently and use different areas of their brains to solve the same problems. We also know that men’s brains are, on average, larger than women’s brains. This does not mean that men are smarter or that one sex uses the more correct areas of their brains. Perhaps the same is true in people with ADHD. Individuals whose brains are more wired with ADHD tendencies may struggle with tasks that are easier for people with more typically wired brains but does this really mean that ADHD is a disorder?
Coming up the course will explore the neuroplasticity of the brain and interventions shown through neuro-imaging to improve brain functions in individuals with ADHD. Given the lack of proven long-term positive outcomes with drug therapy, I am looking forward to good data on behavioral interventions.