Altered patterns of brain electrical activity found in adults with ADHD, but not in siblings and parents – by Hanni Kiiski.

Last week I presented a scientific poster at the European College of Neuropsychopharmacology (ECNP) Conference in Paris (http://2017.ecnp.eu/programme/AbstractList.aspx#). In this study, I found adults with ADHD to have altered patterns of brain electrical activity, whereas siblings and parents of people with ADHD had brain activity similar to healthy volunteers. I will tell a little bit more about these new findings and why this study can help us to better understand ADHD.

As ADHD affects roughly 5% of adults worldwide it is important to investigate how the symptoms emerge and in what way they are related to the brain functions. One way to study this is to measure the electrical activity while the brain “rests”. This means that a person’s brainwaves are measured using sensors that are placed on top of their head while they are just simply sitting in a quiet room for a couple of minutes. The researchers record these brainwaves that can tell basic things about a person’s behaviour, for example, whether the person is alert and focused, or getting drowsy and not paying attention.

I set out to find answers to two questions. First, I wanted to know if and how brainwaves, while the brain is resting, might differ between people with ADHD, versus siblings and parents of people with ADHD, as well as healthy volunteers? Second, if and how these brain activity patterns are related to the symptoms people with ADHD have?

My study revealed that people with ADHD have altered brainwave patterns in comparison to the unaffected siblings and parents of people with ADHD, and to the healthy volunteers. People with ADHD had higher slow brainwave patterns (=alpha, delta and theta) especially over the front and centre part of their scalp, and smaller fast brainwave patterns (=beta, gamma) over the head. These brainwave patterns were also linked to difficulties in memory and paying attention in people with ADHD.

These findings, together with current scientific theories on ADHD, can be thought to show that while the brain of a person with ADHD is resting and not engaged in an activity, it appears to go to a drowsy, suboptimal energetic state. This means that the brain is not getting enough new, exciting input from the environment, which is not sufficiently stimulating and rewarding feeling for the person with ADHD. This might then lead to difficulties to concentrate, to pay attention and to remember things. These findings show that the electrical brainwave patterns might potentially show some promise to be developed into a measure that can link ADHD symptoms to the underlying alterations in brain activity.

Next, I would like to tackle an important question: are the brainwave patterns different between the siblings and parents of people with ADHD? I did not have sufficient number of siblings of people with ADHD in my study to be able to reliably investigate this question. However, my results implicated the sibling group as showing elevated degree of ADHD symptoms compared to the parent and healthy volunteer groups. If the brainwaves of siblings are similar to the people with ADHD, this simple task could be used as a way to find out more about the genetic interactions that are known to underlie ADHD. To be able to answer this question, I would need more siblings of people with ADHD to take part in our research project here in Trinity College Institute of Neuroscience (TCIN).

If you are interested, or have questions or comments about my study, please email us at ADHDproject@tcd.ie.

You can find a copy of my poster here: Hanni Kiiski ADHD poster ECNP 2017.

This research is funded by a post-doctoral award to Dr. Kiiski from the Irish Research Council.

A paper from the lab has been published in Current Addiction Reports, you can read it by clicking here.

We describe the contribution of impulsivity and reward processing endophenotypes to understanding youth alcohol misuse. We discuss studies that included self-report, behavioral and neural measures of these endophenotypes.