The effect of a concurrent task on the walking performance of preschool children

Abstract

Forty-eight children, aged 4–6 years, walked while performing or not performing an easy or difficult concurrent motor task (carrying a tray with or without marbles on it) or cognitive task (repeating a series of digits forwards or backwards). The temporal-distance gait parameters were measured using a GAITRite electronic walkway system. Dual-task costs were calculated as the difference between the children's walking performances with and without the concurrent task. Overall, walking alone was easier than walking while performing a concurrent task. A greater dual-task cost was observed when the concurrent task was difficult compared to when it was easy. However, this effect of difficulty was found for the motor task only. The results suggest that walking demands both the central processing capacity and the domain- and modality-specific processing resources in normal 4–6-year-old children.

Introduction

Walking has traditionally been considered to be an automatic activity without the involvement of cognitive processing. However, this concept has been challenged by the results of recent studies. Through a dual-task paradigm in which participants were asked to perform two tasks at the same time, these studies showed that walking was affected by a concurrent task, indicating that walking, in fact, required attention [1], [2], [3], [4], [5], [6]. These studies also suggested that the effect of a concurrent task on walking depended on the type of task and its level of difficulty [1], [7], [8]. The effect of a concurrent task on walking was also found to be greater in elderly participants or in participants with postural control problems [8], [9]. As yet, little is known about the dual-task effect in children.

Whitall [10] examined the effects of concurrent cognitive tasks on running and galloping in female children ranging in age from 2.5 to 10 years, as well as in young female adults. The cognitive tasks were vocal singing and non-vocal memorization. The researcher found that both tasks interfered with gait speed in all age groups. For the 4 and the 6 years old, decrease in gait speed was more pronounced when the concurrent task was non-vocal memorization. The decrease in running gait speed caused by non-vocal memorization manifested itself in step length, while that caused by vocal singing manifested itself in both step time and step length.

Huang et al. [11] found that the effect of a concurrent task on gait was task-related. Comparing the effects of different cognitive tasks (visual identification, auditory identification and memorization) on gait variables in typically developing 5–7-year-old children, the researchers found that the auditory identification task caused the greatest interference in gait speed, cadence and step length, while memorization caused the smallest interference and only in speed and cadence. Huang and her colleagues also acknowledged that these differential effects could be due to the different difficulty levels of the tasks, which they failed to control.

The locomotion tasks studied by Whitall [10] and Huang et al. [11] were running, galloping and fast walking. These are more advanced, more balance-challenging and less automatic locomotor tasks than free walking, the latter being considered by intuition as easy and automatic. We were interested in knowing whether a concurrent task might also affect free walking in children.

Most children, by 3.5 years of age, have achieved an adult-like walking pattern (e.g. reciprocal arm swing) [12]. However, gait and balance are not fully developed until 7 years of age or even older [12], [13]. It is also reported that 7-year-old children still demonstrate high stride-to-stride variability [14]. Thus, because walking is still developing in children under 7 years, it is conceivable that walking may be vulnerable to interference from a concurrently performed task. Here, we report a study that examined the effect of a concurrent task on walking in typically developing 4–6-year-old preschool children. Two types of concurrent tasks were employed, one motor and the other cognitive. Two levels of difficulty were defined within each type of task (easy and difficult). We hypothesized that preschool children's walking would be affected by the concurrent tasks and that the effect would depend on the type as well as the difficulty level of the task.