Spatiotemporal gait variables and step-to-step variability in preschool-aged children born < 30 weeks' gestation and at term in preferred speed, dual-task paradigm, and tandem walking

BACKGROUND: Children born very preterm (< 32 weeks' gestation) are at greater risk of motor impairment and executive/attentional dysfunctions than term-born children; however, little is known about how functional tasks, including walking, may be affected by very preterm birth. RESEARCH QUESTION: How does the gait pattern of preschool-age children born < 30 weeks compare with term-born controls under a variety of walking conditions? METHODS: In this prospective cohort study, children born < 30 weeks and at term were assessed at 4.5-5 years' corrected age, blinded to birth group. Four walking conditions were assessed using the GAITRite® system: preferred speed, cognitive dual-task, motor dual-task, and tandem walking. Gait variables analysed included speed, cadence, step length, step time, base of support (BOS), and single and double support time. Spatiotemporal variables were compared between groups using linear regression, adjusting for lower-limb length, corrected age at assessment, and number of trials. RESULTS: 224 children (112 < 30 weeks and 112 term-born) were assessed. Gait variables of children born < 30 weeks did not differ from their term-born peers when walking at their preferred speed, except for higher BOS variability (mean difference [MD] = 0.19 cm, 95% confidence interval [CI] 0.10, 0.27, p < 0.001). Under the motor dual-task condition, children born < 30 weeks walked faster (MD= 3.06 cm/s, 95% CI 0.14, 5.97, p = 0.040), with a longer step length (MD= 1.10 cm, 95%CI 0.19, 2.01, p = 0.018), and a wider BOS (MD= 0.37 cm, 95%CI 0.06, 0.67, p = 0.019). In cognitive dual-task and tandem conditions, children born < 30 weeks walked with a wider BOS compared with term-born peers (MD= 0.43 cm, 95%CI 0.05, 0.81, p = 0.028; and MD= 0.30 cm, 95%CI 0.09, 0.51, p = 0.005, respectively). SIGNIFICANCE: This research highlights the need to consider the walking performance of preschool-age children born < 30 weeks under challenging conditions, such as dual-task or tand