A detailed examination of the physiological and cognitive mechanisms of handwriting difficulties in children with Developmental Coordination Disorder: the role of attention, fatigue and joint hyper-mobility
Up to 90% of referrals to Children’s Occupational Therapy (OT) are for difficulties with handwriting. Handwriting is a vital childhood skill as it is an important gateway to academic success and deficits often result in academic underachievement. Children with Developmental Coordination Disorder (DCD) are one group in particular known for a high incidence of handwriting difficulties. The aim of this project is to examine writing pauses that frequently occur in the handwriting of children with DCD. The study is using methods in eye-tracking and electromyography to investigate the role of cognition and fatigue. The findings of this project will be used to inform a much-needed evidence base for intervention.
The project examined writing pauses that occur in the handwriting of children with DCD using eye tracking technology and EMG to examine cognitive and physical processes during writing.
Eye-tracking technology was used to capture cognitive and attentional data during handwriting tasks. Eye & Pen software integrates the handwriting process (outlined above) with eye movements during handwriting tasks. To capture the eye movements the children positioned their forehead against an eye tracker. It was hypothesised that eye movements during writing would reveal whether distractors or other strategies, such as reviewing could interfere with the free writing process.
Electromyography (EMG) was used to measure muscle activation during the copy fast task in children with DCD. Surface electrodes were placed on the skin over the First Dorsal Interosseous, Opponens Brevis and the Extensor Carpi Radialis Brevis. Muscle activity of the dominant arm and hand was measured to ascertain whether fatigue occurred during writing.
The ROM for active flexion and extension were assessed in the metacarpal phalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints of the hand in children with DCD (n=16) and typically developing controls (n=31). A standard hand goniometer was used to measure ROM to the nearest degree. In addition, hand grip strength was assessed using a dynamometer across three types of grips; power, pinch and tripod.
Implications of the findings for Practice
- The eye movements of children with DCD indicate the labour demands of handwriting production in this group. Explicit teaching of the skill to this group is essential for their handwriting development.
- Children with DCD may benefit from strategies for revising text during writing.
- Extension in the joints of the fingers did not relate to handwriting performance. Clinicians need to be cautious when considering ‘joint mobility as a factor in poor handwriting performance.
- There were no group differences in hand strength (pinch, tripod & palmar). Clinicians need to be cautious when considering poor muscle strength as a factor in the handwriting of children with DCD.
- Children with DCD exerted less pressure on the work surface but this did not correlate with handwriting performance. Clinicians need to be cautious when attributing poor handwriting performance to pressure on the pen.