Gait in single- and dual-task conditions : investigations of children with and without developmental risks and disorders

Gait is a complex human motor activity with walking being considered the most important
mode of locomotion. Engaging in concurrent tasks while walking is routine in daily
life, and although walking is a highly practiced task, dual tasking has shown to alter gait performance,
revealing the involvement of cognitive processes in gait control. Yet for children,
research on single- and dual-task walking is scarce. This cumulative dissertation comprises
five articles that extend the research on gait in children with and without developmental risks
and disorders. The samples in the research were 138 typically developing children, 44 very
preterm children, 32 children with autism spectrum disorder (ASD), and 30 children with attention
deficit/hyperactivity disorder (ADHD). For gait analysis (i.e., measurements of spatiotemporal
and variability gait parameters) the GAITRite system was used. Single-task walking
was investigated in children with ASD whereas the gait of the other children was further assessed
while they concurrently performed motor and cognitive tasks. Findings for typically
developing children showed an increase in gait maturation with increasing age in single- and
dual-task conditions, indicating that in middle childhood gait is still developing. Further, results
revealed a developmental delay in gait variability in children with ASD and ADHD, indicating
that these children walk less regularly than controls. Dual tasking caused gait alterations
in all children, indicating that walking is not an automatic activity but rather requires
cognitive processes. Finally, in typically developing children and children with ADHD, a motor
concurrent task had a greater effect on gait than a cognitive concurrent task, possibly because
it competes more strongly with walking for processing resources. The present results
emphasize that gait forms an important part of children’s motor development with maturational
changes across childhood and support the idea that cognitive processes are involved in
the control of gait. Furthermore, they highlight the necessity to account for the type of concurrent
task in dual-task walking paradigms and the careful selection and interpretation of the
gait parameters under consideration.