Background: Motor difficulties are a hallmark feature of Williams Syndrome (WS), yet limited research exists on the quality of early walking in this population. Purpose: This study examined the motor characteristics of first unsupported walking in toddlers with WS compared to neurotypical (NT) peers. Research design: The study used an observational between-subjects design, analysing data from a single time point. Study Sample: Twenty children with WS (age in days at first walking onset: M = 791.75 days, SD = 147.51) were compared to 24 NT children (M = 395.67 days, SD = 72.17). Data analysis: Home videos from children with WS and NT children were analysed using two observational frameworks: the Walking Observation Scale (WOS; Esposito Esposito et al., 2011) to assess gait symmetry. Results: Age of independent walking onset differed significantly between groups. There were no significant differences in overall gait quality, but a significant interaction demonstrated different profiles of gait quality. Axis-specific analyses revealed a significant interaction with group for foot atypicality only. This was due to the WS children showing marginally more out-toeing than the NT group. Analysis of gait symmetry identified significantly greater symmetry during walking in the WS group compared to NT peers. However, this effect did not remain significant when age was partialled out. Conclusion: Walking in WS is delayed, but does not differ substantially in quality. Instead, it is marked by subtle atypical motor strategies. These results emphasise the importance of fine-grained analysis of early motor development. Motor atypicalities may be antecedents of later difficulties and thus can inform targeted interventions and shed light on developmental mechanisms.
Yoshkova et al. (Wed,) studied this question.