The effects of a motor and a cognitive concurrent task on walking in children with developmental coordination disorder

The effects of type (cognitive vs. motor) and difficulty level (easy vs. hard) of a concurrent task on walking were examined in 10 boys and 4 girls (age 4–6 years) with developmental coordination disorder (DCD) and 28 age- and gender-matched unaffected children. Each child performed free walking (single task), walking while carrying an empty tray (dual task, the concurrent task being motor and easy), walking while carrying a tray with 7 marbles (the concurrent task being motor and hard), walking while repeating a series of digits forward (the concurrent task being cognitive and easy), and walking while repeating the digits backward (the concurrent task being cognitive and hard). Walking was affected by the concurrent task (i.e., dual-task cost) in the children with DCD more so than in the comparison children. Greater task difficulty also increased the dual-task cost in the children with DCD more so than in the comparison children. These patterns were only noted for the motor concurrent task. The cognitive concurrent task also affected walking, but the dual-task costs did not differ between difficulty levels, nor between the groups.