Published On March 29, 2021
EVEN THE MOST GRACEFUL BALLERINA may trip over a curb now and then, but research is beginning to show how lack of physical coordination is, for some people, hard-wired. Approximately one in 20 children is estimated to have developmental coordination disorder (DCD), formerly known as clumsy child syndrome , which causes them to struggle with activities and tasks. They may be slow to learn basic dexterity skills, such as how to tie their shoes or get through dinner without spilling the milk. At school, they may stumble and bump into others on the playground, and their illegible handwriting can lead to academic problems.
Being a born klutz can also mean more serious, longer-term consequences. Kids with DCD may shy away from sports and other group activities, which could be linked to their increased risk of obesity, social isolation, depression and anxiety. For these and other reasons, researchers have started to look not only at motor deficiencies but also at root differences in the nervous systems of people with DCD, with the hope of finding better treatments.
Mentions of children with unexplained motor difficulties appear in the medical literature as early as 1900, and a flurry of study from the 1960s through the 1980s, provided a better understanding of the condition. DCD is up to almost three times more common in males than females and at least six times more likely to affect children born before 32 weeks of gestation or with a low birth weight. The causes of DCD are still unknown, but one theory suggests that children with the condition have difficulty imagining the execution of a motor skill and using feedback to correct errors, says Priscila Tamplain, an associate professor of kinesiology at the University of Texas at Arlington, who studies and works with children who have the condition.
When typical children throw a ball for the first time, for instance, it may fly wide of the target. But in succeeding attempts, they are able to adjust muscle movements to make tosses more accurate. The improved motion eventually becomes automatic. That process appears to be impaired in children with DCD, says Tamplain. “It’s almost as if they are always performing a motor skill for the first time,” she says.
Nor does the condition tend to improve naturally with age, despite a long-held belief that children outgrow physical awkwardness. “The majority of children with DCD grow up to be adults with DCD,” says Elisabeth Hill, a professor of neurodevelopmental disorders at Goldsmith’s, University of London. Those adults may never learn to drive a car or could experience problems at work, outcomes that can profoundly affect quality of life.
Impaired motor skills are undoubtedly a key feature of DCD, but kids with DCD often meet their developmental milestones—such as crawling and walking— on time, even though they may fumble with tricky tasks such as tying a shoelace. It has become clear in recent years that DCD often also is accompanied by deficits in mental skills such as planning and attention, says Jill Zwicker, an associate professor of occupational science and occupational therapy at the University of British Columbia. Last year, Zwicker and her colleagues published the first study to use advanced magnetic resonance imaging techniques to compare the whole brains of kids with and without DCD, instead of focusing only on regions related to motor function, as past imaging studies had done.
The results, published in JAMA Network Open, revealed widespread evidence of alterations in the development of axons, or nerve fibers, in the children with DCD. “We saw differences in brain development in both motor and sensory regions, as well as the corpus callosum, which suggests that how the two sides of the brain communicate with one another is also impacted,” says Zwicker. “These children are neurobiologically different from typically developing children.”
There are now treatment programs for DCD, though some approaches are more effective than others, says Tamplain. “Programs that focus on general skills don’t necessarily transfer to a child’s specific motor skills needs,” she says. In other words, improving a kid’s balance alone may not help him or her navigate a stairway safely, she says.
But there is some hope that neuroplasticity in the brain may lead to better, nimbler outcomes with evidence-based rehabilitation. In other ongoing research, Zwicker and her colleagues have shown that children with DCD who followed a program called Cognitive Orientation to Occupational Performance (CO-OP) improved specific motor skills, such as handwriting or bike-riding, and showed increased volume in the cerebellum. Another region of the brain also showed changes from CO-OP intervention: the anterior thalamic radiation, which may be related to happiness. The researchers suggest that observed improvements in white matter structure in the region “could reflect the sense of satisfaction and happiness that children experience after achieving their motor goals.”
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