A new brain imaging study suggests that children’s everyday movement hiccups can reflect how their brains are wired, even when those kids do not have an ADHD diagnosis. The research linked small differences in brain wiring to small but noticeable differences in coordination, speed and “extra” movements.
In the study, C. Hyde and colleagues reported in Human Brain Mapping that subtle motor signs were related to the structure of white matter, the brain’s “connection cables.” The twist was that these white matter patterns were not unique to children with ADHD, which matters for how we think about motor development in general.
Why Researchers Looked at Motor “Soft Signs” in ADHD
When people hear “ADHD,” they often think about attention, restlessness and impulse control. Yet many kids with ADHD also show small movement differences, like clumsiness, trouble with rhythm, or an awkward pencil grip. These are often called “soft signs” because they are subtle and can be easy to miss.
Why would movement be connected to ADHD at all? One reason is that attention and movement share brain systems. Planning, timing and holding back a response can apply to both behavior and motion. If a child struggles with self-control, they might also struggle to control small body movements in the same moment.
Another motivation was a gap in the evidence. Past studies hinted that ADHD could involve differences in white matter, but it was not always clear if those differences related to motor issues or to other parts of ADHD. The researchers wanted to test a more focused question, do motor “soft signs” match specific white matter features and do those features show up mainly in ADHD or across children more broadly?
Who Took Part and What Ages Were Studied
The study included 277 children between ages 8 and 12. Of those, 92 had ADHD and 185 were typically developing. This age range matters because many basic movement skills are still getting smoother during late childhood.
Notably, the researchers did not only compare “ADHD” versus “not ADHD.” They also looked at how motor scores lined up with brain measures across all children. That kind of design can reveal whether a brain feature is a general marker of motor development, instead of a marker tied to one diagnosis.
How Motor Skills Were Tested With PANESS
To measure movement in a structured way, the team used a standardized exam called the PANESS, which stands for Physical and Neurological Examination for Soft Signs. It includes tasks that check balance, coordination, speed and the presence of small extra movements.
For example, children might be timed while doing repeating hand or foot motions. Some tasks focus on how smoothly a child can switch from one movement pattern to another. Others look for overflow movements, like a hand tensing when the task is meant for the foot.
As expected, children with ADHD tended to show more motor difficulties on average. They had higher PANESS scores, which indicates more “soft signs.” Still, the main goal was not to label kids as good or bad movers. It was to see whether motor differences tracked with brain wiring in a consistent way.
How Diffusion MRI Mapped White Matter Pathways
To look inside the brain’s wiring, the researchers used diffusion MRI. This type of scan tracks how water moves through brain tissue. In white matter, water tends to move along the length of nerve fibers, which helps scientists estimate the direction and organization of those pathways.
Unlike a typical MRI that highlights broad anatomy, diffusion MRI is designed to capture connectivity. It gives clues about how strongly different brain regions may be linked through fiber pathways. For movement and timing, these pathways help the brain send signals quickly and in a coordinated way.
The team used an approach called fixel-based analysis. In plain language, it is a method that can separate fiber directions within the same tiny brain area. That matters because white matter can cross and branch like a busy highway system. This method helps researchers avoid mixing different “roads” into one number.
Instead of focusing only on one general index, the study examined a measure related to the size of the fiber bundle in a tract. The paper discussed “fiber cross-section,” which is a way of describing how thick or wide a bundle appears at a larger scale. In everyday terms, it is one possible clue about how much “capacity” a pathway might have for carrying signals.
Smaller Fiber Bundles Linked to More Motor Difficulties
The key pattern was simple. Children who showed more motor “soft signs” also tended to show smaller-looking white matter bundles in certain pathways. This link showed up across the whole sample, not only in the ADHD group.
One tract that stood out was the corticospinal tract, a major pathway involved in voluntary movement. Lower fiber cross-section in this tract was associated with worse overall motor performance. Other links appeared in the corpus callosum, which connects the left and right sides of the brain.
Think of it like this: the study suggests that subtle movement differences can track with how robust certain brain “connection routes” look on scans, even when kids are otherwise healthy and developing typically.
Timed tasks were also part of the story. Associations emerged for specific PANESS measures tied to timed hand and foot movements. When children had more difficulty with speed and coordination, the researchers saw related differences in motor-linked pathways, including tracts that connect frontal brain areas with deeper movement-planning regions.
Why the White Matter Links Were Not Specific to ADHD
Here is the part that may surprise many parents and educators. Even though children with ADHD showed more motor difficulties on average, the white matter features that tracked motor scores did not cleanly separate the ADHD group from the non-ADHD group.
In other words, the brain wiring patterns that matched motor “soft signs” seemed to be part of motor development more generally. A child could have ADHD and show these patterns, but so could a child without ADHD who also struggles with coordination or speed.
This does not mean ADHD has no brain basis. It does suggest that these specific white matter differences may not explain why motor problems are more common in ADHD. The results point toward a broader view, where some movement-related brain features cut across diagnoses and reflect shared development pathways.
What This Could Mean for Everyday Tasks Like Handwriting and Sports
In daily life, “soft signs” can look like small struggles that add up. A child may press too hard with a pencil, fatigue quickly during writing, or fall behind in games that require timing. These are not always dramatic problems, but they can affect confidence and participation.
One practical takeaway is that motor coordination is not just about practice or motivation. The study supports the idea that brain wiring differences can be part of why some kids find smooth movement harder. That can encourage more patience when a child seems “awkward” or slow during fast classroom routines.
If you are wondering where these motor “soft signs” might show up, here are a few common examples people notice at home or school:
Messy handwriting that stays effortful even after lots of practice
Trouble keeping a steady rhythm during clapping, jumping, or dribbling
It also suggests a more careful message about ADHD. Some kids with ADHD do have real motor challenges and those challenges can deserve attention on their own. At the same time, movement differences are not a “signature” of ADHD in the brain. A child can have motor issues without ADHD and a child can have ADHD without major motor issues.
Study Limits and What Future Research Needs to Test
Every brain study has limits and this one is no exception. First, it was cross-sectional, meaning the researchers measured children at one point in time. That makes it hard to tell what came first. White matter differences could contribute to motor issues, but motor practice and development could also shape white matter over time.
Another limitation is what the brain measure represents. The study focused on larger-scale features of pathways, like fiber cross-section. It did not directly measure things like myelin quality in a detailed way. Different imaging approaches, or higher-resolution scans, might reveal other aspects of white matter that matter for movement.
The findings are best read as a map of connections, not a medical test. Brain scans cannot diagnose ADHD or predict a child’s future motor skills on their own.
Future studies could follow children for several years to watch how motor skills and white matter change together. Researchers could also examine whether specific experiences, like learning an instrument or playing certain sports, relate to changes in the same pathways. Another open question is how these motor-linked tracts relate to school outcomes, such as writing speed, note-taking and classroom fatigue.