Developmental changes in lateralized inhibition of symmetric movements in children with and without Developmental Coordination Disorder.
A fast two-to-one finger tap shows that kids with DCD need extra help shutting down the unused hand.
01Research in Context
What this study did
The team asked kids to tap with both index fingers, then keep only the right finger going.
They timed how fast each child stopped the left finger.
Participants were children with developmental coordination disorder and typically developing peers.
What they found
Typical kids got better at stopping the left finger as they grew older.
Kids with DCD stayed slow at stopping the left finger even as trials went on.
Both groups improved a little with practice, but the gap never closed.
How this fits with other research
Ruddock et al. (2015) extend these results. They showed the same DCD group also makes slower mid-move corrections when they must inhibit a reach.
Together the papers paint one picture: DCD is not just clumsy arms and legs. It is a stubborn difficulty in shutting down the non-working side.
Jelsma et al. (2015) add that kids with DCD also learn balance tasks more slowly. The common thread is that more practice trials and clear stop cues help.
Why it matters
You can spot DCD quickly by watching how a child switches from two-hand to one-hand tapping.
Add a brief bilateral-to-unilateral task to your motor screen.
If the left hand lags, plan extra stop-and-start drills and give the child more trials to cement the skill.
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02At a glance
03Original abstract
The present study investigates developmental changes in selective inhibition of symmetric movements with a lateralized switching task from bimanual to unimanual tapping in typically developing (TD) children and with Developmental Coordination Disorder (DCD) from 7 to 10 years old. Twelve right-handed TD children and twelve gender-matched children with DCD and probable DCD produce a motor switching task in which they have (1) to synchronize with the beat of an auditory metronome to produce bimanual symmetrical tapping and (2) to selectively inhibit their left finger's tapping while continuing their right finger's tapping and conversely. We assess (1) the development of the capacity to inhibit the stopping finger (number of supplementary taps after the stopping instruction) and (2) the development of the capacity to maintain the continuing finger (changes in the mean tempo and its variability for the continuing finger's tapping) and (3) the evolution of performance through trials. Results indicate that (1) TD children present an age-related increase in the capacity to inhibit and to maintain the left finger's tapping, (2) DCD exhibits persistent difficulties to inhibit the left finger's tapping, and (3) both groups improve their capacity to inhibit the left finger's movements through trials. In conclusion, the lateralized switching task provides a simple and fine tool to reveal differences in selective inhibition of symmetric movements in TD children and children with DCD. More theoretically, the specific improvement in selective inhibition of the left finger suggests a progressive development of inter-hemispheric communication during typical development that is absent or delayed in children with DCD.
Research in developmental disabilities, 2013 · doi:10.1016/j.ridd.2013.05.020