Tuesday September 16 2014
Modern scanners can study the brain at work
"Doctors could soon diagnose ADHD in children with a brain scan," is the over-exuberant headline from the Mail Online.
The underlying research, based on comparing the brain scans of 133 people with attention deficit hyperactivity disorder (ADHD) with people without the condition, highlighted areas of brain connectivity that were different in the two groups. These differences may be a result of the slower maturation of these connections in people with ADHD.
These regions of the brain have previously been associated with some of the symptoms characteristic of the condition, such as impulsivity. This suggests these areas may be involved in the development of ADHD.
The study authors' conclusions were considered and did not suggest that improvements in ADHD diagnosis were imminent based on these results alone. They called for further research to confirm and validate their findings and to develop further understanding of the neurological basis of ADHD.
If you think you or your child may have ADHD, you might want to consider speaking to your GP about the condition.
Where did the story come from?
The study was carried out by researchers from the Department of Psychiatry at the University of Michigan, and was funded by the US National Institutes of Health, a University of Michigan Center for Computational Medicine pilot grant, and the John Templeton Foundation.
It was published in the peer-reviewed journal, Proceedings of the National Academy of Sciences (PNAS).
The Mail Online coverage was generally accurate, but their headline suggesting that "Doctors could soon diagnose ADHD in children with a brain scan" read too much into these early-stage results.
Researchers neither tested nor validated the use of brain scans alone as a method of diagnosing ADHD, or when coupled with current diagnosis methods.
What kind of research was this?
This was a case-control study comparing the brain scans of children and young adults with ADHD with those of typically developing control participants without ADHD.
The researchers state individuals with ADHD have delays in brain maturation. This study aimed to investigate this in detail by establishing which parts of the brain, and which connections between different parts of the brain circuitry, were delayed in people with ADHD.
What did the research involve?
The research involved comparing the brain scans of 133 people diagnosed with ADHD, the cases (age range 7.2 to 21.8 years), with 443 typically developing controls (age range selected to match cases). The analysis compared the connectivity between a number of distinct areas of the brain to look for differences between the cases and controls.
The scans assessed functional connectivity to gauge which areas of the brain were functionally connected to other areas. They referred to this approach as a "connectomic" method.
This is slightly different from many previous studies, which mainly looked at whether certain areas are active or not, or at the relative sizes of different areas of the brain. The analysis took account of age differences in the two samples.
What were the basic results?
The scans showed differences between the brain connectivity maturation of people with ADHD and those without.
Those with ADHD had a lag in the maturation of connections in a specific brain network region called the default mode network, a poorly understood structure whose functions are uncertain.
They also had delays in connections between the default mode network and two other areas called task-positive networks, which deal with tasks requiring attention: the frontoparietal network and ventral attention network.
The research team indicated these areas of brain connectivity and interaction have previously been associated with the behavioural characteristics of ADHD, such as impulsivity, providing some degree of external validity for the importance of this region.
How did the researchers interpret the results?
The researchers stated their results suggest "maturational lag of regulatory control networks contributes to inattention and/or impulsivity across different clinical populations, and they invite new research aimed at direct comparative investigation".
This research, based on comparing the brain scans of people with ADHD with those without, highlighted areas of brain connectivity that were different in the two groups. These regions have previously been associated with some of the symptoms characteristic of ADHD.
The study's authors were considered in their conclusions and did not suggest that improvements in ADHD diagnosis could be made based on their results. They called for further research to confirm and validate their findings and to develop further understanding of the neurological basis of ADHD.
It is feasible this sort of technology might be used to aid ADHD or other mental health-related conditions in the future, but this is very speculative based on what is a relatively small early-stage study.
Larger studies comparing more diverse groups of people with and without ADHD could shed more light on whether this sort of scan could be used as a diagnostic tool.
This is just one avenue of research – a related aim of this type of scanning is to generally increase understanding of the neurological basis of ADHD, which could then lead to new treatments.
ADHD is currently diagnosed through a formal assessment performed by a health professional such as a psychiatrist, a doctor specialising in children's health, a learning disability specialist, a social worker, or an occupational therapist with expertise in ADHD.
If you think you or your child may have ADHD, you might want to consider speaking to your GP about the condition first.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.