TS & ADHD study of young people

Posted on 19 January 2015

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Researchers wanted to investigate why TS and ADHD are sometimes found together and how having symptoms of both conditions affects young people

Tourettes Action supported a study which was investigating patterns of electrical brain activity (electrophysiology) in young people with Tourette Syndrome (TS) and/or ADHD while they learn new skills and control their thought and action (cognitive control). It is also known as the ELECTA study.

The researchers from Nottingham University hoped to find out more about what causes these disorders and why some young people have symptoms of both conditions. They also wished to compare brain activity measured during tic suppression and when ticcing freely. This will help us to find out how the brain activity changes during suppression and how ADHD may impact on this.

Background to the ELECTA study

Tourette Syndrome and ADHD are conditions that begin in childhood. Young people with Tourette Syndrome make movements and sounds (tics) that they don’t mean to. Young people with ADHD find it very difficult to sit still and concentrate for long periods. Sometimes, young people have symptoms of both Tourette Syndrome and ADHD, but it is unclear why. We aimed to find out more about why this happens and how having symptoms of both conditions affects young people. In the long term, the results of this study may be useful in improving treatments for young people with Tourette Syndrome and/or ADHD.

The study

Eighteen young people with Tourette Syndrome (TS), 11 young people with ADHD, 17 young people with Tourette Syndrome and ADHD (TS+ADHD) and 20 young people without either of these conditions took part in this study at the University of Nottingham. All participants were aged 9-17 years. We recorded electrical brain activity while the participants played two tasks on a computer. Brain activity was recorded using EEG, a technique which involves wearing a special cap on the head, while participants performed two computerised cognitive tasks.

In Task 1, participants learned to make left or right hand button-presses to cartoon characters to win points; then participants learned to reverse those button-presses. Positive and negative feedback (happy and sad face images) were presented after each button press to let the participants know whether they had made the correct or incorrect response for each character. This task measured the ability to learn and alter behaviours which is an important skill in human development. Brain regions that are thought to be atypical in TS and ADHD are involved in this ability. In Task 2, participants had to press a button quickly to one character to win points and try to stop themselves making button–presses to another character to avoid losing points. It is very difficult to stop oneself making button presses to the second character. This ability to withhold certain, almost automatic behaviours is thought to be involved in the ability to suppress ticsWhat did we find?

Task 1

We found that young people with TS were as good as young people without either of these conditions at learning and reversing the button presses. However, when these young people also had ADHD, they were slower and less accurate in learning the button presses and reversing those learned responses. This suggests that co-occurring symptoms of ADHD make it harder for young people with TS to learn new responses . This might explain why tics can be harder to control in TS+ADHD than TS alone.

Task 2

Young people with TS without ADHD symptoms performed as well as young people without these conditions in withholding responses and brain activity patterns were comparable in young people with TS without ADHD and young people without these conditions. In contrast, young people with ADHD and TS+ADHD were less able to withhold responses to the second character than young people without ADHD. Brain activity patterns associated with withholding the responses were also weaker in young people with ADHD and TS+ADHD than in young people with TS without ADHD and young people without either condition.  This suggests co-occurring symptoms of ADHD in young people with TS make it harder for them to control and inhibit automatic responses. Again, this might explain why their tics can be worse.

Summary

All young people in the study performed the tasks very well and showed expected brain activity patterns associated with learning and altering behaviours and withholding responses. However, young people with TS+ADHD were less able to learn and alter new behaviours and withhold unwanted behaviours than young people with TS without ADHD.  Brain activity underlying the ability to withhold unwanted behaviours was also weaker in TS+ADHD than in TS without ADHD. It will be important for future research to examine whether co-occurring ADHD symptoms affect how easily young people with TS+ADHD can suppress tics and whether they may need additional help in learning to control their tic symptoms.

If you have any further questions regarding research please contact Seonaid Anderson at Tourettes Action.

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