Using HD-sEMG to Uncover Neuromuscular Biomarkers in Children with DCD

Developmental Coordination Disorder (DCD) affects about 1 in 20 children and is characterized by difficulties in performing activities of daily living due to deficits in motor control. Yet little is currently known about the neuromuscular patterns associated with DCD. Using high-density surface EMG (HD-sEMG), researchers have been able to record motor-unit data to better understand the differences in neuromuscular activity between typically developing (TD) children and children with DCD. Results indicate that children with DCD have more fixed motor-unit firing strategies, which may explain why they struggle to adopt new movement patterns.

What is Developmental Coordination Disorder?

In a typical classroom, at least one child will have DCD — a developmental disorder characterized by difficulties in performing activities of daily living due to deficits in movement control. Children with DCD may appear uncoordinated or overly clumsy and tend to struggle with age-appropriate motor tasks, which can cause frustration and affect their social lives. The disorder affects around 5% of children, yet it is often overlooked and considered a symptom of other disorders. Children with DCD struggle with:

• Everyday tasks: tying shoelaces, using a fork and knife, and opening bottles.
• Sports and social activities: catching and throwing in PE class, organized sports, and playing musical instruments.
• General balance: tripping and falling regularly.

A paradigm shift in understanding DCD

Until recently, DCD was widely misunderstood and often thought of as a subset of ADHD. Although children with DCD frequently also experience ADHD, these two conditions are fundamentally different and their underlying mechanisms must be understood independently. Traditional approaches for managing DCD have largely focused on addressing specific motor-control deficits through occupational and physical therapy. While these can help children make short-term, task-specific improvements, they often fail to address the persistent challenges of motor control and daily functioning — and it is not known how these therapies impact the deeper neuromuscular mechanisms that contribute to the condition.

Using HD-sEMG to identify neuromuscular markers

Research by Dr. Maaike Esselaar and her team at Manchester Metropolitan University takes a critical first step toward understanding the neuromuscular mechanisms behind DCD. Using Trigno Galileo HD-sEMG sensors, the team identified motor-unit patterns in children with DCD and compared them to those of TD children, revealing initial findings on how the brain and muscles communicate in DCD and how that differs from typical development.

A look at the neuromuscular level

HD-sEMG data was recorded from the first dorsal interosseus muscle during a hand-grip task, with force output recorded via a hand-held dynamometer. Hand grip was chosen because it underlies many actions DCD children struggle with, including tying shoes and buttoning shirts. Participants contracted six times at 10% of their maximum voluntary contraction, alternating bursts of contraction and relaxation, yielding 66 individual bursts of muscle activity per participant. Data was then decomposed in Neuromap software, where motor-unit information was extracted and compared between the DCD and TD groups.

Source: Delsys blog.