Study Finds Adults with Developmental Coordination Disorder Show Deficits in Pre-Ordering Sequential Movements
A new study published on bioRxiv found that adults with Developmental Coordination Disorder (DCD) show reduced ability to pre-order upcoming movements during motor sequence planning, leading to higher error rates and slower initiation of sequences. The research used a delayed sequence production task with finger sequences to assess competitive queuing — the process by which elements of a movement sequence are ranked before execution. The findings suggest that motor difficulties in DCD stem specifically from disrupted sequence planning rather than general working memory impairments.
Researchers examined motor sequence planning in 28 adults with DCD and 54 control participants across three sessions using a delayed sequence production task involving four-element finger sequences. The study focused on competitive queuing (CQ), a mechanism by which the brain pre-orders upcoming movements before execution, previously documented in monkey neurophysiology and human behavioral research. Probe trials measured reaction time and error rate at each sequence position to assess planning quality. Adults with DCD showed significantly reduced pre-ordering of sequence elements, higher error rates, and slower initiation and execution of correct sequences compared to controls. Although the DCD group also performed worse on a working memory task, working memory performance was not correlated with the degree of motor pre-ordering, indicating these are separable deficits. The authors argue that the core motor planning problem in DCD is a failure to retrieve and rank movement sequences from memory, rather than a general cognitive impairment. These results extend prior motor imagery research by demonstrating that internal modelling deficits in DCD are also evident during actual motor plan execution.
What's missing
As a preprint, this study has not yet undergone peer review, and its findings should be interpreted with caution. The study's sample sizes are relatively modest, and it is unclear how findings generalize beyond the specific finger-sequencing task used. The authors do not address whether interventions targeting competitive queuing could improve outcomes in DCD, nor do they discuss the neurological substrates underlying the observed pre-ordering deficits in this population.
What different sources said
- bioRxivCenter
Developmental coordination disorder affects the pre-ordering of sequential movements
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